Number of dermatomes blocked by conventional dose single shot spinal anesthesia for cesarean section is not positively related to hyperbaric bupivacaine dose – a retrospective analysis of 362 cases

Number of dermatomes blocked by conventional dose single shot spinal anesthesia for cesarean section is not positively related to hyperbaric bupivacaine dose – a retrospective analysis of 362 cases | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Number of dermatomes blocked by conventional dose single shot spinal anesthesia for cesarean section is not positively related to hyperbaric bupivacaine dose – a retrospective analysis of 362 cases Bartosz Horosz, Wojciech Morisson, Katarzyna Białowolska-Horosz, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6523285/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 17 Jan, 2026 Read the published version in BMC Anesthesiology → Version 1 posted 11 You are reading this latest preprint version Abstract Background Increasing the dose of local anesthetic administered into intrathecal space is associated with higher level of sensory blockade. Despite this common wisdom, the literature data on this relation in population of term parturients is scarce. The aim of this retrospective study was to assess the relation between intrathecal dose of 0,5% hyperbaric bupivacaine and the height of the sensory block level. Methods Medical notes of cesarean section cases were reviewed. All procedures under single – shot spinal anesthesia performed with the dose of more than 9 mg of hyperbaric bupivacaine were identified and scrutinized for availability and quality of the data required for analysis. Demographic and pregnancy – related data were noted. The dose of 0,5% hyperbaric bupivacaine, sensory block after 5 minutes, maximum sensory block level and spinal – related complications were recorded and analyzed. Study group was divided into three groups depending on their height. Results The maximum block level was > T6 in 96% of cases included. Weak negative correlation between the dose of local anesthetic and maximum sensory block level was found (Spearman correlation coefficient − 0.17, p = 0.002). This was confirmed in the two groups of taller women, while in parturients of less than 164 cm of height this relation was not present. With the increase in the dose of bupivacaine, the risk of nausea increased (OR 1.45), no relation was found between vomiting and lowest blood pressure parameters within 30 min of spinal injection. Conclusions No positive relation between the dose and maximum sensory block level was found in this study. Weak but negative relation was present between these variables in the whole study group, as well as in women of more than 165 cm of height. Spinal anesthesia cesarean section spinal block level Figures Figure 1 Background Single – shot spinal block for cesarean delivery is a gold standard in obstetric anesthesia [ 1 ]. Both level and density of the block may have direct impact on the quality of surgery, patient’s comfort and the course of postoperative recovery. Ideal dose of local anesthetic for a single – shot spinal anesthesia is still to be decided, with ongoing debate on using either “low” or “conventional” doses as routine approach. Use of conventional doses of local anesthetic (doses nearing ED95) have proven to be superior to low dose regimens in terms of effectiveness and therefore this strategy is widely used, despite the higher risk of spinal block – related complications [ 2 , 3 ]. Amount of local anaesthetic used is regarded to be a factor of significant influence on its intrathecal spread and the final level of block following single – shot spinal anesthesia [ 4 ]. It was investigated in both general and obstetric populations, although most of the studies with results in favor of this relation were designed to assess the other factors, and the extend of sensory block was not set as their primary outcome [ 5 – 9 ]. We have previously reported that adjusting the conventional dose of hyperbaric bupivacaine to parturient’s height does not change the risk of block failure and rate of complications when compared to fixed – dose regimen [ 10 ]. Whether the change in bupivacaine dose within the range of conventional doses results in significant change in sensory block level is not clear. Therefore we designed an retrospective analysis to assess the above relation. Methods Study Population After approval from the Ethical Committee of the Centre of Postgraduate Medical Education (97/2024) on November 13, 2024 and trial registration at ClinicalTrials.gov (NCT06729567) on December 8, 2024, all cases of cesarean sections performed under spinal anesthesia in years 2017–2022 in Orlowski Hospital CMKP, Warsaw, Poland were retrospectively identified. Initial screening process of the hospital electronic database aimed to identify cases that would meet the following inclusion criteria: operative delivery at term (> 37 weeks of gestation) under spinal anesthesia, age ≥ 18 years, BMI < 40 and American Society of Anesthesiology (ASA) physical status < 3. Following initial identification, manual search of the medical charts followed. Inadequately completed anesthetic record that failed to provide detailed information on technique and dynamic of sensory block, spinal block performed with local anesthetic other than hyperbaric bupivacaine, bupivacaine dose of less than 9 milligrams and “failed spinal” requiring repeated block or conversion to general anesthesia were exclusion criteria. All patient data were anonymized and requirement of consent was waived by Ethic’s Committee due to retrospective character of the study. Attention has been paid to assure that identification of the patient would not be possible with data used in this study. All identifiable data used in data retrieval process and analysis were accessible only for investigators. Spinal block technique and management. Perioperative care of cesarean section patient is standardized in our centre. Parturients fast for at least 6 hours and 1000ml of balanced crystalloid is infused within one hour prior to procedure. Intravenous ranitidine and metoclopramide are routinely used as precaution to decrease the volume and acidity of gastric content, as well as cefazoline for perioperative antimicrobial prophylaxis. With parturient in seated position, after routine ASA vital signs monitoring is established and under fully aseptic conditions, 27 G pencil-point spinal needle with introducer is inserted in L3/4 or L4/5 interspace judged by Tuffier’s line, until identification of subarachnoid space is confirmed with the presence of cerebrospinal fluid flow. Local anesthetic is then injected and parturient is placed in supine position within no more than 15 seconds of injection. Ten to 15 degrees left lateral tilt of the operating table is used to improve venous return and decrease the risk of hypotension. Hypotension is treated with boluses of ephedrine and atropine is used in the event of significant bradycardia. Block level is routinely assessed as sensory loss to cold in mid-clavicular line, checked with ethyl chloride spray or gauze soaked in alcohol-based aseptic solution. It is recorded in anesthetic chart at 1, 3, 5 and then every few minutes after spinal injection until the end of surgery. Bladder catheter is placed when the sensory block level is sufficient enough for it to be comfortable. Surgery is allowed to start when sensory block of at least T6 and complete motor block (Bromage scale level 4) is achieved. Data acquisition and statistical analysis Age, weight, height, parity, gravidity, weight gain during pregnancy, week of gestation and neonatal data were demographic data acquired from medical notes. Data related to spinal block technique and dynamic, including the dose of hyperbaric bupivacaine, were collected from anesthetic records. For the analysis of the sensory block level two values were used: block level at 5 minutes following spinal injection and the highest level of dermatomal block recorded during the whole procedure. In cases where level of the block at the end of surgery was lower than the highest block noted, the highest value was used for analysis. The same rule was applied in cases where differences in block levels between left and right side occurred at any point of assessment. The higher value of the two was used in analysis. Data related to spinal anesthesia complications that were analyzed were lowest values of systolic and mean blood pressure, total dose of ephedrine used and nausea and vomiting. For blood pressure values, as well as for episodes of nausea and vomiting, only data from the first 30 minutes of anesthesia were used in this study. For the purpose of statistical analysis a level of sensory blockade was converted into ordinal scores (T6 = 1 and C8 = 7) and number of blocked dermatomes, with 5 sacral, 5 lumbar, 12 thoracic and 8 cervical dermatomes (e.g. sensory blockade to first thoracic dermatome – T1 corresponds to 22 blocked dermatomes). All analyses were performed in the whole study group, as well as in the group of different body height. For that purpose study population was arbitrarily divided into three groups: ≤164 cm, 165–169 cm and ≥ 170 cm of height. Numerical data are presented as either mean and standard deviation or median and interquartile range, depending on the normality of distribution. Categorical variables are described using absolute and relative frequencies. Normality was assessed using Shapiro-Wilk test, skewness and kurtosis. Comparisons of numerical variables were conducted using ANOVA or Kruskal-Wallis test, as appropriate. Associations between bupivacaine dose and assessed variables were examined using Spearman’s correlation due to non-normal distribution and categorical nature of some variables. Univariate logistic regression was used to assess associations between bupivacaine dose and nausea and vomiting. A significance threshold of p < 0.05 was applied to all tests. The analysis was performed using R software (version 4.4.2). Results Three hundred and sixty two cases were included in final analysis. Demographic characteristic and baseline data are given in Table 1 . Median height and weight of the study population was 166 cm and 79kg, respectively, indicating that the group consisted of rather tall and lean women, with median gestational weight gain of 13kg. Median dose of the hyperbaric bupivacaine was 12.5 mg. Highest level of sensory block level was C8, which was noted in 2,5% of cases, while for the vast majority (81,2%) the maximum block level was between T2 and T4, T4 being the most common (Table 2 ). Although weak but significant negative correlation was found between the dose of hyperbaric bupivacaine and maximum sensory block level (Spearman correlation coefficient ρ = − 0,17, p = 0,002) and number of dermatomes blocked after 5 minutes of spinal injection (ρ = -0,11, p = 0,04). Hyperbaric bupivacaine dose was positively associated with episodes of nausea, but not with vomiting, lowest blood pressure within first 30 min following spinal injection and ephedrine dose. Each additional milligram of local anesthetic increased odds of nausea by 55% (OR = 1.45, 95% CI 1.08–2.01, p = 0.019). For the purpose of additional analysis the study group was divided into three subgroups: ≤164 cm, 165–169 cm and ≥ 170cm. No significant differences were found between the groups in their demographic characteristics except for height and weight. Weak but significant negative correlation between the dose and maximum block level was confirmed for two taller group of patients, but not for parturients of less than 164 cm of height, where no relation was noted (Fig. 1 ). No correlation between hyperbaric bupivacaine dose and other assessed variables in subgroups analysis was present. Table 1 Demographics and baseline characteristics of the study population. Study group Height group p ≤ 164 cm 165–169 cm ≥ 170cm N 362 141 108 113 Age, years 33.33 ± 4.83 33.33 ± 5.14 33.47 ± 4.71 33.20 ± 4.57 0.918 Weight, kg 79.00 (71.00;86.00) 73.00 (65.00;80.00) 79.00 (71.00;85.25) 85.00 (79.00;93.00) < 0.001 Height, cm 166.00 (162.00;170.00) 161.00 (159.00;163.00) 167.00 (165.00;168.00) 173.00 (170.00;176.00) < 0.001 Weight gain, kg 13.00 (10.00;16.00) 13.00 (9.00;16.00) 14.00 (10.00;16.00) 13.70 (11.00;17.00) 0.573 Hemoglobin, g/dL 12.40 (11.80;13.00) 12.40 (12.00;13.10) 12.30 (11.70;13.00) 12.40 (11.70;13.00) 0.728 Week of gestation 39.00 (38.00;39.00) 39.00 (38.00;39.00) 39.00 (38.00;39.00) 39.00 (38.00;39.00) 0.235 Newborn weight (g) 3409.24 ± 498.11 3311.81 ± 540.95 3379.17 ± 471.71 3559.56 ± 430.97 Gravidity 2.00 (1.00;3.00) 2.00 (1.00;3.00) 2.00 (1.00;3.00) 2.00 (2.00;3.00) 0.550 Parity 2.00 (1.00;2.00) 2.00 (1.00;2.00) 2.00 (1.00;2.00) 2.00 (1.00;2.00) 0.818 Bupivacaine dose (mg) 12.5 (11.0; 12.5) 11.60 (10.40;12.50) * 12.45 (11.00;12.50) # 12.50 (12.00;12.50) * # < 0.001 Data presented as mean ± standard deviation or median (interquartile range). * - p < 0.001; # - p < 0.001. Table 2 Associations between bupivacaine dose and studied parameters. Variable Study group Height group Height ≤ 164 cm Height 165–169 cm Height ≥ 170 cm ρ/OR p ρ/OR p ρ/OR p ρ/OR p Highest block level -0.17 0.002 -0.04 0.616 -0.21 0.027 -0.28 0.002 C8 9 (2.5) 3 (2.1) 3 (2.8) 3 (2.7) T1 33 (9.1) 14 (9.9) 12 (11.1) 7 (6.2) T2 63 (17.4) 25 (17.7) 15 (13.9) 23 (20.4) T3 106 (29.3) 39 (27.7) 36 (33.3) 31 (27.4) T4 125 (34.5) 55 (39.0) 31 (28.7) 39 (34.5) T5 13 (3.6) 2 (1.4) 5 (4.6) 6 (5.3) T6 13 (3.6) 3 (2.1) 6 (5.6) 4 (3.5) Max. number of dermatomes blocked 19.91 ± 1.26 -0.16 0.002 19.96 ± 1.20 -0.04 0.666 19.90 ± 1.35 -0.21 0.027 19.85 ± 1.25 -0.28 0.002 Number of dermatomes blocked after 5 min 17.48 ± 2.11 -0.11 0.040 17.62 ± 2.01 -0.05 0.543 17.53 ± 2.25 -0.07 0.496 17.25 ± 2.09 -0.15 0.103 Min. MAP in 30 min, mmHg 68.36 ± 13.55 0.04 0.440 67.94 ± 14.00 -0.01 0.880 68.05 ± 13.04 0.07 0.499 69.18 ± 13.53 0.09 0.324 Min. SBP in 30 min, mmHg 95.04 ± 19.30 0.06 0.235 94.78 ± 19.62 0.02 0.847 94.38 ± 18.16 0.10 0.313 96.00 ± 20.07 0.09 0.347 Ephedrine, mg -0.04 0.477 0.06 0.543 -0.15 0.137 -0.16 0.108 0 138 (43.3) 59 (48.4) 39 (40.6) 40 (39.6) 5 60 (18.8) 22 (18.0) 20 (20.8) 18 (17.8) 10 47 (14.7) 17 (13.9) 14 (14.6) 16 (15.8) 15 19 (6.0) 5 (4.1) 7 (7.3) 7 (6.9) 20 23 (7.2) 9 (7.4) 7 (7.3) 7 (6.9) 25 13 (4.1) 2 (1.6) 5 (5.2) 6 (5.9) 30 5 (1.6) 2 (1.6) 0 (0.0) 3 (3.0) 35 3 (0.9) 0 (0.0) 1 (1.0) 2 (2.0) 40 6 (1.9) 3 (2.5) 2 (2.1) 1 (1.0) 45 2 (0.6) 1 (0.8) 0 (0.0) 1 (1.0) 50 3 (0.9) 2 (1.6) 1 (1.0) 0 (0.0) Nausea 67 (18.5) 1.45 0.019 21 (14.9) 1.39 0.163 25 (23.1) 1.48 0.184 21 (18.6) 1.64 0.205 Vomiting 7 (1.9) 1.10 0.813 2 (1.4) 1.81 0.497 2 (1.8) 15.56 0.353 3 (2.6) 0.32 0.070 ρ – Spearman correlation coefficient; OR – odds ratio (nausea and vomiting); min MAP in 30 min – lowest recorded mean arterial pressure within 30 minutes of intrathecal injection; min SBP in 30 min – lowest recorded systolic blood pressure within 30 minutes of intrathecal injection. Data presented as number of cases and percentage in parentheses or mean ± standard deviation. Discussion This study demonstrated that there is no significant positive relation between sensory block level and increasing dose of intrathecal hyperbaric bupivacaine when used within the range of conventional doses for cesarean delivery. Quite the contrary – to our surprise, when the whole study group was considered, a negative relation between these variables was found, which was confirmed in subgroup analysis of women 165–169cm and ≥ 170cm of height, while no significant relation appeared in women of lower height. Differences in the spread of local anesthetic used for spinal anesthesia between general population and pregnant women at term result mainly from the compression of inferior vena cava, which is most pronounced in supine position. This results in engorgement of venous vasculature of the lumbar region of vertebral canal and – consequently – cephalad transition of cerebrospinal fluid [ 11 ]. Other contributing factors are possibly increased lumbar lordosis and hypersensitivity to local anesthetics. The latter may be caused by progesterone and endogenous opiates, increase of which is seen in late pregnancy, with some potential contribution of the fact that there is also a tendency towards respiratory alkalosis at that time [ 12 ]. Common knowledge is that the extent of sensory block is related to the dose of local anesthetic used for spinal injection [ 5 , 8 ]. Studies performed in non-obstetric population have demonstrated that the nerve block height is much less dependent on the dose when more than 10mg of hyperbaric bupivacaine is used. Above certain amount of local anesthetic, even significant increase in the dose may not produce the expected increase in the block leveI [ 13 ]. It indicates that relationship is not linear, and results in relatively large safety margin when it comes to calculating an effective dose. Trials focusing on spinal anesthesia in term parturients are much more challenging. Level of the block that is required for safe and comfortable cesarean delivery is so high that increase in more than 2 dermatomes may be considered dangerous. It is just one of the reasons for which research in obstetric anesthesia is more likely to focus on efficacy and safety than on block level as a solitary measure. The debate on local anesthetic dosing has been ongoing for decades, with two main options to choose from: standard (conventional) and low dose strategies. Lowering the dose of local anesthetic, usually below 10mg of hyperbaric bupivacaine, in order to minimize the rate of spinal block – related complications is the idea behind low dose strategy [ 3 ]. As lower rate of complications comes with the lower effectiveness of the low dose spinal anesthesia, it is usually mandatory to provide an option of rescue analgesia with the use of combined spinal – epidural anesthesia. A cornerstone research by Norris in late 1980’s demonstrated that the spread of hyperbaric local anesthetic is not related to parturient’s weight, height, body mass index and the length of vertebral column when performed with 15mg of hyperbaric bupivacaine [ 14 ]. In more recent trials lower doses of local anesthetic are usually used to identify factors that may influence the cephalad spread of spinal block and their outcomes are not consistent [ 7 , 15 – 18 ]. As a result, it is still common to adjust the dose of anesthetic to parturient’s size, like weight, height, vertebral column length or abdominal circumference. The main goal is to optimize the rate of spinal block – related complications and effectiveness of anesthesia, which is usually measured by the extent of sensory blockade and the need for intraoperative systemic analgesia. Results of the present study did not show any positive association between the dose of hyperbaric bupivacaine in the range used in this study and the extent of sensory blockade. Wei et al. have retrospectively assessed the relation between intrathecal dose and patient’s variables like height, weight, vertebral column length and abdominal circumference in parturients with the block level of T5. They found significant relationship between the dose (mean value 9,5mg) and the assessed variables in this group. Using the developed algorithm for the dose adjustment, authors managed to achieve final block level of T5 in more than 80% of parturients, with better outcomes in terms of complications rate and the need for rescue analgesia [ 19 ]. Although this could suggest close relation between the dose and block level in the study population, this separate analysis was not reported. Local anesthetic dose served as one of the variables used in the algorithm. In our study group we found no relation between the dose and final block level in parturients of lower height, while in the whole group the dose and final block level were found to be inversely related. Some similarities may be found between our results and trials performed in non-pregnant patients. Visavakul et al. have analyzed data of over a thousand spinal anesthesia cases performed with isobaric bupivacaine. They found that bupivacaine dose is associated with the level of sensory block in patients younger than 60 years, while the association was not relevant for older age. Based on statistical findings, the suggested dose of isobaric intrathecal bupivacaine for achieving favorable block of T5-T10 in younger and older patients was reported to be 15-17mg and 10,5–16mg, respectively. Age was indicated as the main determinant of intrathecal bupivacaine spread in this study [ 8 ]. Although the study groups can not be regarded as similar, their findings may challenge the common knowledge of dose – block level relationship for standard doses of local anesthetic. Our findings suggest that the relationship between the dose of hyperbaric bupivacaine and the sensory block level is less significant or even non-existent within the range typically used for cesarean sections, which is considered close to ED95. What is more – in the population of tall women the increase in dose within the range 9–12,5mg, being minimal, may not be enough to compensate for the difference in patient’s size. As a result, it can’t produce the adequate gain in block level and results in negative correlation. There are some significant limitations of this study. Firstly, this study bears all the disadvantages of the retrospective design, the greatest of which is enrollment bias. Although all available cesarean section cases in the specified period of time were reviewed, study cases were not prospectively screened and enrolled. Therefore, as anesthesia was provided by the team of anesthetists (specialists and trainees), a factor of anesthetist’s experience and professional habits could have played a role in the outcome of the study. To minimize the possible differences, only cases where all required data were available and recorded with due care were included. Secondly, our study population consisted primarily of relatively tall and lean women, which may not represent the general population or all ethnic groups. Nearly one-third of the study participants were taller than 170 cm, a characteristic seldom seen in literature on obstetric anesthesia. Although the significance of the parturient's height remains a topic of debate, it is conceivable that our results may have differed for shorter women, as suggested by our subgroup analysis. Thirdly, the analyzed cases were not selected based on the required block level. This excluded the option to conduct an analysis that included other variables related to the parturient’s size, such as abdominal girth and vertebral column length, in the dose correlation analysis. Therefore, it cannot be ruled out that other factors may have influenced the results. Conclusions To conclude, present study have shown that maximal sensory block level is not related to intrathecal hyperbaric bupivacaine dose within conventional dose range when used for cesarean section anesthesia in women ≤ 164 cm of height. Further studies are mandated to investigate this relation in taller women. Abbreviations ED95: Dose efeective in 95%; BMI: Body mass index; ASA: American Society of Anesthesiology; MAP: Mean arterial pressure; SBP: Systolic blood pressure; Declarations Ethical Committee and trial registration: Ethical Committee approval for retrospective analysis was granted by Ethic’s Committee of the Centre of Postgraduate Medical Education on November 13, 2024 ( 97/2024). It was registered at ClinicalTrials.gov on December 8, 2024. (NCT06729567). Acknowledgements Not applicable Authors’ contribution All authors have read and accepted the manuscript. BH: Study design, data collection, data analysis, manuscript preparation. WM: data collection, data analysis. KB-H: study design, data collection, manuscript preparation. MM-M: study design, data analysis, manuscript preparation. Funding Not applicable Availability of data and materials. The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. Ethics approval and consent to participate Ethical Committee approval for retrospective analysis was granted by Ethical Committee of the Centre of Postgraduate Medical Education on November 13, 2024 (97/2024). It was registered at ClinicalTrials.gov on December 8, 2024. (NCT06729567). Informed consent was waived due to retrospective design of the study. Consent for publication Not applicable Competing interests Authors declare that they have no competing interests References Bamber JH, Lucas DN, Plaat F, Russell R. Obstetric anaesthetic practice in the UK: a descriptive analysis of the National Obstetric Anaesthetic Database 2009-14. Br J Anaesth. 2020;125(4):580-587. Arzola C, Wieczorek PM. Efficacy of low-dose bupivacaine in spinal anaesthesia for Caesarean delivery: systematic review and meta-analysis. Br J Anaesth. 2011;107(3):308-18. 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Abdominal girth, vertebral column length and spread of intrathecal hyperbaric bupivacaine in the term parturient. Int J Obstet Anesth. 2017;31:63-67. Wei CN, Zhou QH, Wang LZ. Abdominal girth and vertebral column length aid in predicting intrathecal hyperbaric bupivacaine dose for elective cesarean section. Medicine (Baltimore). 2017;96(34):e7905. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 17 Jan, 2026 Read the published version in BMC Anesthesiology → Version 1 posted Editorial decision: Revision requested 18 Dec, 2025 Reviews received at journal 17 Dec, 2025 Reviewers agreed at journal 17 Dec, 2025 Reviewers agreed at journal 21 Nov, 2025 Reviews received at journal 13 Aug, 2025 Reviewers agreed at journal 30 Jul, 2025 Reviewers invited by journal 11 Jun, 2025 Editor invited by journal 21 May, 2025 Editor assigned by journal 09 May, 2025 Submission checks completed at journal 09 May, 2025 First submitted to journal 24 Apr, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6523285","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":469991499,"identity":"0b962287-ac5f-4bfd-b212-aa8445ee1576","order_by":0,"name":"Bartosz Horosz","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzklEQVRIiWNgGAWjYBACAwkILcfAwAaimUG4gSgtxkhaGInTkthAtBZz6eZjHz78qUvvn3Ys7QFDhXVig3Qjfi2Wc44lz5zZxpY743bacQOGM+mJDTIHCTjsRo4xM28DT+4G6fQ2Cca2w4kNEolEaOH5I5FuANbyj2gtbAYJBtJpxyQYG4jQYjkjLZlxZluCIdAv6QYJx9KN2wj5xVwi+TADMMTk+WenmT34UGMt2y/dfACvFmTAxpAAIiWI1gCNfgYGUrSMglEwCkbBiAAASrdD4Y+jDvUAAAAASUVORK5CYII=","orcid":"","institution":"Department of Anesthesiology and Intensive Care, Centre of Postgraduate Medical Education, Orlowski Hospital, Warsaw, Poland","correspondingAuthor":true,"prefix":"","firstName":"Bartosz","middleName":"","lastName":"Horosz","suffix":""},{"id":469991500,"identity":"48a9a5d4-b8c9-458e-ae3f-ddc6a00990bf","order_by":1,"name":"Wojciech Morisson","email":"","orcid":"","institution":"Department of Anesthesiology and Intensive Care, Centre of Postgraduate Medical Education, Orlowski Hospital, Warsaw, Poland","correspondingAuthor":false,"prefix":"","firstName":"Wojciech","middleName":"","lastName":"Morisson","suffix":""},{"id":469991501,"identity":"769a76a6-dd9a-43bb-bb79-09ee3cb9c32e","order_by":2,"name":"Katarzyna Białowolska-Horosz","email":"","orcid":"","institution":"Department of Anesthesiology and Intensive Care, Centre of Postgraduate Medical Education, Orlowski Hospital, Warsaw, Poland","correspondingAuthor":false,"prefix":"","firstName":"Katarzyna","middleName":"","lastName":"Białowolska-Horosz","suffix":""},{"id":469991502,"identity":"bcd17ec0-1c2b-4e06-ab39-78eabc9787b9","order_by":3,"name":"Małgorzata Malec-Milewska","email":"","orcid":"","institution":"Department of Anesthesiology and Intensive Care, Centre of Postgraduate Medical Education, Orlowski Hospital, Warsaw, Poland","correspondingAuthor":false,"prefix":"","firstName":"Małgorzata","middleName":"","lastName":"Malec-Milewska","suffix":""}],"badges":[],"createdAt":"2025-04-24 19:08:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6523285/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6523285/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12871-026-03626-0","type":"published","date":"2026-01-17T16:28:43+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":84685952,"identity":"d53d9fdf-6ea4-457a-a01e-f0a039592ce8","added_by":"auto","created_at":"2025-06-16 08:54:08","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":214920,"visible":true,"origin":"","legend":"\u003cp\u003eScatter plot of hyperbaric bupivacaine dose in milligrams and maximal sensory block level in study groups.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6523285/v1/8ffbb9c8f6470c1d839d2efd.png"},{"id":100614640,"identity":"6bbdd59d-6cd5-4bf7-8085-3fa94f298c4c","added_by":"auto","created_at":"2026-01-19 17:22:26","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1070417,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6523285/v1/cb674123-151f-4e51-b021-697bab7c9953.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Number of dermatomes blocked by conventional dose single shot spinal anesthesia for cesarean section is not positively related to hyperbaric bupivacaine dose – a retrospective analysis of 362 cases","fulltext":[{"header":"Background","content":"\u003cp\u003eSingle \u0026ndash; shot spinal block for cesarean delivery is a gold standard in obstetric anesthesia [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Both level and density of the block may have direct impact on the quality of surgery, patient\u0026rsquo;s comfort and the course of postoperative recovery. Ideal dose of local anesthetic for a single \u0026ndash; shot spinal anesthesia is still to be decided, with ongoing debate on using either \u0026ldquo;low\u0026rdquo; or \u0026ldquo;conventional\u0026rdquo; doses as routine approach. Use of conventional doses of local anesthetic (doses nearing ED95) have proven to be superior to low dose regimens in terms of effectiveness and therefore this strategy is widely used, despite the higher risk of spinal block \u0026ndash; related complications [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAmount of local anaesthetic used is regarded to be a factor of significant influence on its intrathecal spread and the final level of block following single \u0026ndash; shot spinal anesthesia [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. It was investigated in both general and obstetric populations, although most of the studies with results in favor of this relation were designed to assess the other factors, and the extend of sensory block was not set as their primary outcome [\u003cspan additionalcitationids=\"CR6 CR7 CR8\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWe have previously reported that adjusting the conventional dose of hyperbaric bupivacaine to parturient\u0026rsquo;s height does not change the risk of block failure and rate of complications when compared to fixed \u0026ndash; dose regimen [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Whether the change in bupivacaine dose within the range of conventional doses results in significant change in sensory block level is not clear.\u003c/p\u003e \u003cp\u003eTherefore we designed an retrospective analysis to assess the above relation.\u003c/p\u003e "},{"header":"Methods","content":"\n\u003ch3\u003eStudy Population\u003c/h3\u003e\n\u003cp\u003e After approval from the Ethical Committee of the Centre of Postgraduate Medical Education (97/2024) on November 13, 2024 and trial registration at ClinicalTrials.gov (NCT06729567) on December 8, 2024, all cases of cesarean sections performed under spinal anesthesia in years 2017\u0026ndash;2022 in Orlowski Hospital CMKP, Warsaw, Poland were retrospectively identified.\u003c/p\u003e \u003cp\u003eInitial screening process of the hospital electronic database aimed to identify cases that would meet the following inclusion criteria: operative delivery at term (\u0026gt;\u0026thinsp;37 weeks of gestation) under spinal anesthesia, age\u0026thinsp;\u0026ge;\u0026thinsp;18 years, BMI\u0026thinsp;\u0026lt;\u0026thinsp;40 and American Society of Anesthesiology (ASA) physical status\u0026thinsp;\u0026lt;\u0026thinsp;3. Following initial identification, manual search of the medical charts followed. Inadequately completed anesthetic record that failed to provide detailed information on technique and dynamic of sensory block, spinal block performed with local anesthetic other than hyperbaric bupivacaine, bupivacaine dose of less than 9 milligrams and \u0026ldquo;failed spinal\u0026rdquo; requiring repeated block or conversion to general anesthesia were exclusion criteria.\u003c/p\u003e \u003cp\u003e All patient data were anonymized and requirement of consent was waived by Ethic\u0026rsquo;s Committee due to retrospective character of the study. Attention has been paid to assure that identification of the patient would not be possible with data used in this study. All identifiable data used in data retrieval process and analysis were accessible only for investigators.\u003c/p\u003e \u003cp\u003e \u003cem\u003eSpinal block technique and management.\u003c/em\u003e \u003c/p\u003e \u003cp\u003ePerioperative care of cesarean section patient is standardized in our centre. Parturients fast for at least 6 hours and 1000ml of balanced crystalloid is infused within one hour prior to procedure. Intravenous ranitidine and metoclopramide are routinely used as precaution to decrease the volume and acidity of gastric content, as well as cefazoline for perioperative antimicrobial prophylaxis. With parturient in seated position, after routine ASA vital signs monitoring is established and under fully aseptic conditions, 27 G pencil-point spinal needle with introducer is inserted in L3/4 or L4/5 interspace judged by Tuffier\u0026rsquo;s line, until identification of subarachnoid space is confirmed with the presence of cerebrospinal fluid flow. Local anesthetic is then injected and parturient is placed in supine position within no more than 15 seconds of injection. Ten to 15 degrees left lateral tilt of the operating table is used to improve venous return and decrease the risk of hypotension.\u003c/p\u003e \u003cp\u003eHypotension is treated with boluses of ephedrine and atropine is used in the event of significant bradycardia.\u003c/p\u003e \u003cp\u003eBlock level is routinely assessed as sensory loss to cold in mid-clavicular line, checked with ethyl chloride spray or gauze soaked in alcohol-based aseptic solution. It is recorded in anesthetic chart at 1, 3, 5 and then every few minutes after spinal injection until the end of surgery. Bladder catheter is placed when the sensory block level is sufficient enough for it to be comfortable. Surgery is allowed to start when sensory block of at least T6 and complete motor block (Bromage scale level 4) is achieved.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eData acquisition and statistical analysis\u003c/h2\u003e \u003cp\u003eAge, weight, height, parity, gravidity, weight gain during pregnancy, week of gestation and neonatal data were demographic data acquired from medical notes. Data related to spinal block technique and dynamic, including the dose of hyperbaric bupivacaine, were collected from anesthetic records. For the analysis of the sensory block level two values were used: block level at 5 minutes following spinal injection and the highest level of dermatomal block recorded during the whole procedure. In cases where level of the block at the end of surgery was lower than the highest block noted, the highest value was used for analysis. The same rule was applied in cases where differences in block levels between left and right side occurred at any point of assessment. The higher value of the two was used in analysis. Data related to spinal anesthesia complications that were analyzed were lowest values of systolic and mean blood pressure, total dose of ephedrine used and nausea and vomiting. For blood pressure values, as well as for episodes of nausea and vomiting, only data from the first 30 minutes of anesthesia were used in this study.\u003c/p\u003e \u003cp\u003eFor the purpose of statistical analysis a level of sensory blockade was converted into ordinal scores (T6\u0026thinsp;=\u0026thinsp;1 and C8\u0026thinsp;=\u0026thinsp;7) and number of blocked dermatomes, with 5 sacral, 5 lumbar, 12 thoracic and 8 cervical dermatomes (e.g. sensory blockade to first thoracic dermatome \u0026ndash; T1 corresponds to 22 blocked dermatomes). All analyses were performed in the whole study group, as well as in the group of different body height. For that purpose study population was arbitrarily divided into three groups: \u0026le;164 cm, 165\u0026ndash;169 cm and \u0026ge;\u0026thinsp;170 cm of height.\u003c/p\u003e \u003cp\u003eNumerical data are presented as either mean and standard deviation or median and interquartile range, depending on the normality of distribution. Categorical variables are described using absolute and relative frequencies. Normality was assessed using Shapiro-Wilk test, skewness and kurtosis. Comparisons of numerical variables were conducted using ANOVA or Kruskal-Wallis test, as appropriate. Associations between bupivacaine dose and assessed variables were examined using Spearman\u0026rsquo;s correlation due to non-normal distribution and categorical nature of some variables. Univariate logistic regression was used to assess associations between bupivacaine dose and nausea and vomiting. A significance threshold of p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was applied to all tests. The analysis was performed using R software (version 4.4.2).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThree hundred and sixty two cases were included in final analysis. Demographic characteristic and baseline data are given in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Median height and weight of the study population was 166 cm and 79kg, respectively, indicating that the group consisted of rather tall and lean women, with median gestational weight gain of 13kg. Median dose of the hyperbaric bupivacaine was 12.5 mg. Highest level of sensory block level was C8, which was noted in 2,5% of cases, while for the vast majority (81,2%) the maximum block level was between T2 and T4, T4 being the most common (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Although weak but significant negative correlation was found between the dose of hyperbaric bupivacaine and maximum sensory block level (Spearman correlation coefficient ρ\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0,17, p\u0026thinsp;=\u0026thinsp;0,002) and number of dermatomes blocked after 5 minutes of spinal injection (ρ = -0,11, p\u0026thinsp;=\u0026thinsp;0,04). Hyperbaric bupivacaine dose was positively associated with episodes of nausea, but not with vomiting, lowest blood pressure within first 30 min following spinal injection and ephedrine dose. Each additional milligram of local anesthetic increased odds of nausea by 55% (OR\u0026thinsp;=\u0026thinsp;1.45, 95% CI 1.08\u0026ndash;2.01, p\u0026thinsp;=\u0026thinsp;0.019).\u003c/p\u003e \u003cp\u003eFor the purpose of additional analysis the study group was divided into three subgroups: \u0026le;164 cm, 165\u0026ndash;169 cm and \u0026ge;\u0026thinsp;170cm. No significant differences were found between the groups in their demographic characteristics except for height and weight. Weak but significant negative correlation between the dose and maximum block level was confirmed for two taller group of patients, but not for parturients of less than 164 cm of height, where no relation was noted (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). No correlation between hyperbaric bupivacaine dose and other assessed variables in subgroups analysis was present.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographics and baseline characteristics of the study population.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eStudy group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e \u003cp\u003eHeight group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;164 cm\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e165\u0026ndash;169 cm\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;170cm\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e362\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e141\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e108\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e113\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge, years\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33.33\u0026thinsp;\u0026plusmn;\u0026thinsp;4.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33.33\u0026thinsp;\u0026plusmn;\u0026thinsp;5.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33.47\u0026thinsp;\u0026plusmn;\u0026thinsp;4.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e33.20\u0026thinsp;\u0026plusmn;\u0026thinsp;4.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.918\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWeight, kg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e79.00 (71.00;86.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e73.00 (65.00;80.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e79.00 (71.00;85.25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e85.00 (79.00;93.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeight, cm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e166.00 (162.00;170.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e161.00 (159.00;163.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e167.00 (165.00;168.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e173.00 (170.00;176.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWeight gain, kg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.00 (10.00;16.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.00 (9.00;16.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14.00 (10.00;16.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e13.70 (11.00;17.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.573\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemoglobin, g/dL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.40 (11.80;13.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12.40 (12.00;13.10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12.30 (11.70;13.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e12.40 (11.70;13.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.728\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWeek of gestation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e39.00 (38.00;39.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e39.00 (38.00;39.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e39.00 (38.00;39.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e39.00 (38.00;39.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.235\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNewborn weight (g)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3409.24\u0026thinsp;\u0026plusmn;\u0026thinsp;498.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3311.81\u0026thinsp;\u0026plusmn;\u0026thinsp;540.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3379.17\u0026thinsp;\u0026plusmn;\u0026thinsp;471.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3559.56\u0026thinsp;\u0026plusmn;\u0026thinsp;430.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGravidity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.00 (1.00;3.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.00 (1.00;3.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.00 (1.00;3.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.00 (2.00;3.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.550\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.00 (1.00;2.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.00 (1.00;2.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.00 (1.00;2.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.00 (1.00;2.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.818\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBupivacaine dose (mg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.5 (11.0; 12.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.60 (10.40;12.50)\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12.45 (11.00;12.50)\u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e12.50 (12.00;12.50)\u003csup\u003e* #\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eData presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation or median (interquartile range). \u003csup\u003e*\u003c/sup\u003e - p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; \u003csup\u003e#\u003c/sup\u003e - p\u0026thinsp;\u0026lt;\u0026thinsp;0.001.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAssociations between bupivacaine dose and studied parameters.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"13\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" morerows=\"1\" nameend=\"c4\" namest=\"c2\" rowspan=\"2\"\u003e \u003cp\u003eStudy group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"9\" nameend=\"c13\" namest=\"c5\"\u003e \u003cp\u003eHeight group\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c7\" namest=\"c5\"\u003e \u003cp\u003eHeight\u0026thinsp;\u0026le;\u0026thinsp;164 cm\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c10\" namest=\"c8\"\u003e \u003cp\u003eHeight 165\u0026ndash;169 cm\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e \u003cp\u003eHeight\u0026thinsp;\u0026ge;\u0026thinsp;170 cm\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eρ/OR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eρ/OR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eρ/OR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c12\"\u003e \u003cp\u003eρ/OR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c13\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHighest block level\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.616\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e-0.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e\u003cb\u003e0.027\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e-0.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e\u003cb\u003e0.002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e9 (2.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3 (2.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e3 (2.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e3 (2.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e33 (9.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14 (9.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e12 (11.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e7 (6.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e63 (17.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e25 (17.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e15 (13.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e23 (20.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e106 (29.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e39 (27.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e36 (33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e31 (27.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e125 (34.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e55 (39.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e31 (28.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e39 (34.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13 (3.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2 (1.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5 (4.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e6 (5.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13 (3.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3 (2.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e6 (5.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e4 (3.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMax. number of dermatomes blocked\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e19.91\u0026thinsp;\u0026plusmn;\u0026thinsp;1.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e19.96\u0026thinsp;\u0026plusmn;\u0026thinsp;1.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.666\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e19.90\u0026thinsp;\u0026plusmn;\u0026thinsp;1.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e-0.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e\u003cb\u003e0.027\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e19.85\u0026thinsp;\u0026plusmn;\u0026thinsp;1.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e-0.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e\u003cb\u003e0.002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of dermatomes blocked after 5 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17.48\u0026thinsp;\u0026plusmn;\u0026thinsp;2.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.040\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e17.62\u0026thinsp;\u0026plusmn;\u0026thinsp;2.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.543\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e17.53\u0026thinsp;\u0026plusmn;\u0026thinsp;2.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e-0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0.496\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e17.25\u0026thinsp;\u0026plusmn;\u0026thinsp;2.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e-0.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e0.103\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMin. MAP in 30 min, mmHg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e68.36\u0026thinsp;\u0026plusmn;\u0026thinsp;13.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.440\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e67.94\u0026thinsp;\u0026plusmn;\u0026thinsp;14.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.880\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e68.05\u0026thinsp;\u0026plusmn;\u0026thinsp;13.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0.499\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e69.18\u0026thinsp;\u0026plusmn;\u0026thinsp;13.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e0.324\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMin. SBP in 30 min, mmHg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e95.04\u0026thinsp;\u0026plusmn;\u0026thinsp;19.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.235\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e94.78\u0026thinsp;\u0026plusmn;\u0026thinsp;19.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.847\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e94.38\u0026thinsp;\u0026plusmn;\u0026thinsp;18.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0.313\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e96.00\u0026thinsp;\u0026plusmn;\u0026thinsp;20.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e0.347\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEphedrine, mg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.477\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.543\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e-0.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0.137\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e-0.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e0.108\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e138 (43.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e59 (48.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e39 (40.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e40 (39.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e60 (18.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e22 (18.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e20 (20.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e18 (17.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47 (14.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e17 (13.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e14 (14.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e16 (15.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e19 (6.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5 (4.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e7 (7.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e7 (6.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e23 (7.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e9 (7.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e7 (7.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e7 (6.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13 (4.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2 (1.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5 (5.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e6 (5.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5 (1.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2 (1.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e3 (3.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3 (0.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e1 (1.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e2 (2.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6 (1.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3 (2.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e2 (2.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e1 (1.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2 (0.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1 (0.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e1 (1.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3 (0.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2 (1.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e1 (1.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNausea\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e67 (18.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.019\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e21 (14.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.163\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e25 (23.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0.184\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e21 (18.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e1.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e0.205\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVomiting\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7 (1.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.813\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2 (1.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.497\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e2 (1.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e15.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0.353\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e3 (2.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e0.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e0.070\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eρ \u0026ndash; Spearman correlation coefficient; OR \u0026ndash; odds ratio (nausea and vomiting); min MAP in 30 min \u0026ndash; lowest recorded mean arterial pressure within 30 minutes of intrathecal injection; min SBP in 30 min \u0026ndash; lowest recorded systolic blood pressure within 30 minutes of intrathecal injection. Data presented as number of cases and percentage in parentheses or mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study demonstrated that there is no significant positive relation between sensory block level and increasing dose of intrathecal hyperbaric bupivacaine when used within the range of conventional doses for cesarean delivery. Quite the contrary \u0026ndash; to our surprise, when the whole study group was considered, a negative relation between these variables was found, which was confirmed in subgroup analysis of women 165\u0026ndash;169cm and \u0026ge;\u0026thinsp;170cm of height, while no significant relation appeared in women of lower height.\u003c/p\u003e \u003cp\u003eDifferences in the spread of local anesthetic used for spinal anesthesia between general population and pregnant women at term result mainly from the compression of inferior vena cava, which is most pronounced in supine position. This results in engorgement of venous vasculature of the lumbar region of vertebral canal and \u0026ndash; consequently \u0026ndash; cephalad transition of cerebrospinal fluid [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Other contributing factors are possibly increased lumbar lordosis and hypersensitivity to local anesthetics. The latter may be caused by progesterone and endogenous opiates, increase of which is seen in late pregnancy, with some potential contribution of the fact that there is also a tendency towards respiratory alkalosis at that time [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCommon knowledge is that the extent of sensory block is related to the dose of local anesthetic used for spinal injection [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Studies performed in non-obstetric population have demonstrated that the nerve block height is much less dependent on the dose when more than 10mg of hyperbaric bupivacaine is used. Above certain amount of local anesthetic, even significant increase in the dose may not produce the expected increase in the block leveI [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. It indicates that relationship is not linear, and results in relatively large safety margin when it comes to calculating an effective dose. Trials focusing on spinal anesthesia in term parturients are much more challenging. Level of the block that is required for safe and comfortable cesarean delivery is so high that increase in more than 2 dermatomes may be considered dangerous. It is just one of the reasons for which research in obstetric anesthesia is more likely to focus on efficacy and safety than on block level as a solitary measure.\u003c/p\u003e \u003cp\u003eThe debate on local anesthetic dosing has been ongoing for decades, with two main options to choose from: standard (conventional) and low dose strategies. Lowering the dose of local anesthetic, usually below 10mg of hyperbaric bupivacaine, in order to minimize the rate of spinal block \u0026ndash; related complications is the idea behind low dose strategy [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. As lower rate of complications comes with the lower effectiveness of the low dose spinal anesthesia, it is usually mandatory to provide an option of rescue analgesia with the use of combined spinal \u0026ndash; epidural anesthesia.\u003c/p\u003e \u003cp\u003eA cornerstone research by Norris in late 1980\u0026rsquo;s demonstrated that the spread of hyperbaric local anesthetic is not related to parturient\u0026rsquo;s weight, height, body mass index and the length of vertebral column when performed with 15mg of hyperbaric bupivacaine [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn more recent trials lower doses of local anesthetic are usually used to identify factors that may influence the cephalad spread of spinal block and their outcomes are not consistent [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan additionalcitationids=\"CR16 CR17\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. As a result, it is still common to adjust the dose of anesthetic to parturient\u0026rsquo;s size, like weight, height, vertebral column length or abdominal circumference. The main goal is to optimize the rate of spinal block \u0026ndash; related complications and effectiveness of anesthesia, which is usually measured by the extent of sensory blockade and the need for intraoperative systemic analgesia.\u003c/p\u003e \u003cp\u003eResults of the present study did not show any positive association between the dose of hyperbaric bupivacaine in the range used in this study and the extent of sensory blockade.\u003c/p\u003e \u003cp\u003eWei et al. have retrospectively assessed the relation between intrathecal dose and patient\u0026rsquo;s variables like height, weight, vertebral column length and abdominal circumference in parturients with the block level of T5. They found significant relationship between the dose (mean value 9,5mg) and the assessed variables in this group. Using the developed algorithm for the dose adjustment, authors managed to achieve final block level of T5 in more than 80% of parturients, with better outcomes in terms of complications rate and the need for rescue analgesia [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Although this could suggest close relation between the dose and block level in the study population, this separate analysis was not reported. Local anesthetic dose served as one of the variables used in the algorithm. In our study group we found no relation between the dose and final block level in parturients of lower height, while in the whole group the dose and final block level were found to be inversely related.\u003c/p\u003e \u003cp\u003eSome similarities may be found between our results and trials performed in non-pregnant patients. Visavakul et al. have analyzed data of over a thousand spinal anesthesia cases performed with isobaric bupivacaine. They found that bupivacaine dose is associated with the level of sensory block in patients younger than 60 years, while the association was not relevant for older age. Based on statistical findings, the suggested dose of isobaric intrathecal bupivacaine for achieving favorable block of T5-T10 in younger and older patients was reported to be 15-17mg and 10,5\u0026ndash;16mg, respectively. Age was indicated as the main determinant of intrathecal bupivacaine spread in this study [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Although the study groups can not be regarded as similar, their findings may challenge the common knowledge of dose \u0026ndash; block level relationship for standard doses of local anesthetic.\u003c/p\u003e \u003cp\u003eOur findings suggest that the relationship between the dose of hyperbaric bupivacaine and the sensory block level is less significant or even non-existent within the range typically used for cesarean sections, which is considered close to ED95.\u003c/p\u003e \u003cp\u003eWhat is more \u0026ndash; in the population of tall women the increase in dose within the range 9\u0026ndash;12,5mg, being minimal, may not be enough to compensate for the difference in patient\u0026rsquo;s size. As a result, it can\u0026rsquo;t produce the adequate gain in block level and results in negative correlation.\u003c/p\u003e \u003cp\u003eThere are some significant limitations of this study.\u003c/p\u003e \u003cp\u003eFirstly, this study bears all the disadvantages of the retrospective design, the greatest of which is enrollment bias. Although all available cesarean section cases in the specified period of time were reviewed, study cases were not prospectively screened and enrolled. Therefore, as anesthesia was provided by the team of anesthetists (specialists and trainees), a factor of anesthetist\u0026rsquo;s experience and professional habits could have played a role in the outcome of the study. To minimize the possible differences, only cases where all required data were available and recorded with due care were included.\u003c/p\u003e \u003cp\u003eSecondly, our study population consisted primarily of relatively tall and lean women, which may not represent the general population or all ethnic groups. Nearly one-third of the study participants were taller than 170 cm, a characteristic seldom seen in literature on obstetric anesthesia. Although the significance of the parturient's height remains a topic of debate, it is conceivable that our results may have differed for shorter women, as suggested by our subgroup analysis.\u003c/p\u003e \u003cp\u003eThirdly, the analyzed cases were not selected based on the required block level. This excluded the option to conduct an analysis that included other variables related to the parturient\u0026rsquo;s size, such as abdominal girth and vertebral column length, in the dose correlation analysis. Therefore, it cannot be ruled out that other factors may have influenced the results.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eTo conclude, present study have shown that maximal sensory block level is not related to intrathecal hyperbaric bupivacaine dose within conventional dose range when used for cesarean section anesthesia in women\u0026thinsp;\u0026le;\u0026thinsp;164 cm of height. Further studies are mandated to investigate this relation in taller women.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eED95: Dose efeective in 95%; BMI: Body mass index; ASA: American Society of Anesthesiology; MAP: Mean arterial pressure; SBP: Systolic blood pressure;\u0026nbsp;\u003c/p\u003e\n"},{"header":"Declarations","content":"\u003cp\u003eEthical Committee and trial registration:\u003c/p\u003e\n\u003cp\u003eEthical Committee approval for retrospective analysis was granted by Ethic\u0026rsquo;s Committee of the Centre of Postgraduate Medical Education on November 13, 2024 ( 97/2024). It was registered at ClinicalTrials.gov on December \u0026nbsp;8, 2024. (NCT06729567).\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors have read and accepted the manuscript. BH: Study design, data collection, data analysis, manuscript preparation. WM: data collection, data analysis. KB-H: study design, data collection, manuscript preparation. MM-M: study design, data analysis, manuscript preparation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthical Committee approval for retrospective analysis was granted by Ethical Committee of the Centre of Postgraduate Medical Education \u0026nbsp;on November 13, 2024 (97/2024). It was registered at ClinicalTrials.gov on December \u0026nbsp;8, 2024. (NCT06729567). Informed consent was waived due to retrospective design of the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAuthors declare that they have no competing interests\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBamber JH, Lucas DN, Plaat F, Russell R. Obstetric anaesthetic practice in the UK: a descriptive analysis of the National Obstetric Anaesthetic Database 2009-14. Br J Anaesth. 2020;125(4):580-587. \u003c/li\u003e\n\u003cli\u003eArzola C, Wieczorek PM. Efficacy of low-dose bupivacaine in spinal anaesthesia for Caesarean delivery: systematic review and meta-analysis. Br J Anaesth. 2011;107(3):308-18. \u003c/li\u003e\n\u003cli\u003eRucklidge MW, Paech MJ. Limiting the dose of local anaesthetic for caesarean section under spinal anaesthesia--has the limbo bar been set too low? Anaesthesia. 2012;67(4):347-51. \u003c/li\u003e\n\u003cli\u003eHuang YY, Chang KY. Sensory block level prediction of spinal anaesthesia with 0.5% hyperbaric bupivacaine: a retrospective study. Sci Rep. 2021;11(1):9105. \u003c/li\u003e\n\u003cli\u003eHocking G, Wildsmith JA. Intrathecal drug spread. Br J Anaesth. 2004;93(4):568-78. \u003c/li\u003e\n\u003cli\u003eKhaw KS, Ngan Kee WD, Wong EL, Liu JY, Chung R. Spinal ropivacaine for cesarean section: a dose-finding study. Anesthesiology. 2001;95(6):1346-50. \u003c/li\u003e\n\u003cli\u003eHuang Q, Wen G, Hai C, Zheng Z, Li Y, Huang Z et al. A Height-Based Dosing Algorithm of Bupivacaine in Spinal Anesthesia for Decreasing Maternal Hypotension in Cesarean Section Without Prophylactic Fluid Preloading and Vasopressors: A Randomized-Controlled Non-Inferiority Trial. Front Med (Lausanne). 202210;9:858115. \u003c/li\u003e\n\u003cli\u003eVisavakul O, Leurcharusmee P, Pipanmekaporn T, Khorana J, Patumanond J, Phinyo P. Effective Dose Range of Intrathecal Isobaric Bupivacaine to Achieve T5-T10 Sensory Block Heights for Elderly and Overweight Patients: An Observational Study. Medicina (Kaunas). 2023;59(3):484. \u003c/li\u003e\n\u003cli\u003eKiran S, Singal NK. A comparative study of three different doses of 0.5% hyperbaric bupivacaine for spinal anaesthesia in elective caesarean section. Int J Obstet Anesth. 2002;11(3):185-9. \u003c/li\u003e\n\u003cli\u003eBiałowolska K, Horosz B, Sękowska A, Malec-Milewska M. Fixed Dose versus Height-Adjusted Conventional Dose of Intrathecal Hyperbaric Bupivacaine for Caesarean Delivery: A Prospective, Double-Blinded Randomised Trial. J Clin Med. 2020;9(11):3600. \u003c/li\u003e\n\u003cli\u003eBarclay DL, Renegar OJ, Nelson EW Jr. The influence of inferior vena cava compression on the level of spinal anesthesia. Am J Obstet Gynecol. 1968;101(6):792-800. \u003c/li\u003e\n\u003cli\u003eDatta S, Lambert DH, Gregus J, Gissen AJ, Covino BG. Differential sensitivities of mammalian nerve fibers during pregnancy. Anesth Analg. 1983;62(12):1070-2. \u003c/li\u003e\n\u003cli\u003eBrown DT, Wildsmith JA, Covino BG, Scott DB. Effect of baricity on spinal anaesthesia with amethocaine. Br J Anaesth. 1980;52(6):589-96. \u003c/li\u003e\n\u003cli\u003eNorris MC. Patient variables and the subarachnoid spread of hyperbaric bupivacaine in the term parturient. Anesthesiology. 1990;72(3):478-82. \u003c/li\u003e\n\u003cli\u003eHarten JM, Boyne I, Hannah P, Varveris D, Brown A. Effects of a height and weight adjusted dose of local anaesthetic for spinal anaesthesia for elective Caesarean section. Anaesthesia. 2005;60(4):348-53.\u003c/li\u003e\n\u003cli\u003eOzkan Seyhan T, Orhan-Sungur M, Basaran B, Savran Karadeniz M, Demircan F, Xu Z et al. The effect of intra-abdominal pressure on sensory block level of single-shot spinal anesthesia for cesarean section: an observational study. Int J Obstet Anesth. 2015;24(1):35-40. \u003c/li\u003e\n\u003cli\u003eShe YJ, Liu WX, Wang LY, Ou XX, Liang HH, Lei DX. The impact of height on the spread of spinal anesthesia and stress response in parturients undergoing caesarean section: a prospective observational study. BMC Anesthesiol. 2021;30;21(1):298. \u003c/li\u003e\n\u003cli\u003eWei CN, Zhang YF, Xia F, Wang LZ, Zhou QH. Abdominal girth, vertebral column length and spread of intrathecal hyperbaric bupivacaine in the term parturient. Int J Obstet Anesth. 2017;31:63-67. \u003c/li\u003e\n\u003cli\u003eWei CN, Zhou QH, Wang LZ. Abdominal girth and vertebral column length aid in predicting intrathecal hyperbaric bupivacaine dose for elective cesarean section. Medicine (Baltimore). 2017;96(34):e7905. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-anesthesiology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bane","sideBox":"Learn more about [BMC Anesthesiology](http://bmcanesthesiol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bane","title":"BMC Anesthesiology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Spinal anesthesia, cesarean section, spinal block level","lastPublishedDoi":"10.21203/rs.3.rs-6523285/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6523285/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eIncreasing the dose of local anesthetic administered into intrathecal space is associated with higher level of sensory blockade. Despite this common wisdom, the literature data on this relation in population of term parturients is scarce. The aim of this retrospective study was to assess the relation between intrathecal dose of 0,5% hyperbaric bupivacaine and the height of the sensory block level.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eMedical notes of cesarean section cases were reviewed. All procedures under single \u0026ndash; shot spinal anesthesia performed with the dose of more than 9 mg of hyperbaric bupivacaine were identified and scrutinized for availability and quality of the data required for analysis. Demographic and pregnancy \u0026ndash; related data were noted. The dose of 0,5% hyperbaric bupivacaine, sensory block after 5 minutes, maximum sensory block level and spinal \u0026ndash; related complications were recorded and analyzed. Study group was divided into three groups depending on their height.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe maximum block level was \u0026gt;\u0026thinsp;T6 in 96% of cases included. Weak negative correlation between the dose of local anesthetic and maximum sensory block level was found (Spearman correlation coefficient \u0026minus;\u0026thinsp;0.17, p\u0026thinsp;=\u0026thinsp;0.002). This was confirmed in the two groups of taller women, while in parturients of less than 164 cm of height this relation was not present. With the increase in the dose of bupivacaine, the risk of nausea increased (OR 1.45), no relation was found between vomiting and lowest blood pressure parameters within 30 min of spinal injection.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eNo positive relation between the dose and maximum sensory block level was found in this study. Weak but negative relation was present between these variables in the whole study group, as well as in women of more than 165 cm of height.\u003c/p\u003e","manuscriptTitle":"Number of dermatomes blocked by conventional dose single shot spinal anesthesia for cesarean section is not positively related to hyperbaric bupivacaine dose – a retrospective analysis of 362 cases","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-16 08:53:37","doi":"10.21203/rs.3.rs-6523285/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-18T08:09:54+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-17T13:52:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"236673344651243148600196988404849923447","date":"2025-12-17T10:20:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"159942630096681911613971375401983860187","date":"2025-11-21T09:02:50+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-14T02:56:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"271415833645652131659407104360469516046","date":"2025-07-30T12:56:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-11T06:29:00+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-05-21T09:16:14+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-09T06:17:45+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-09T06:12:47+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Anesthesiology","date":"2025-04-24T19:04:39+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-anesthesiology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bane","sideBox":"Learn more about [BMC Anesthesiology](http://bmcanesthesiol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bane","title":"BMC Anesthesiology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6657056f-bce6-4388-9bed-61373b81a4d1","owner":[],"postedDate":"June 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-01-19T16:45:31+00:00","versionOfRecord":{"articleIdentity":"rs-6523285","link":"https://doi.org/10.1186/s12871-026-03626-0","journal":{"identity":"bmc-anesthesiology","isVorOnly":false,"title":"BMC Anesthesiology"},"publishedOn":"2026-01-17 16:28:43","publishedOnDateReadable":"January 17th, 2026"},"versionCreatedAt":"2025-06-16 08:53:37","video":"","vorDoi":"10.1186/s12871-026-03626-0","vorDoiUrl":"https://doi.org/10.1186/s12871-026-03626-0","workflowStages":[]},"version":"v1","identity":"rs-6523285","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6523285","identity":"rs-6523285","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}