Comparative study of analgesic efficacy of ultrasound-guided femoral nerve block and intravenous fentanyl for positioning during spinal anaesthesia for fracture femur

Comparative study of analgesic efficacy of ultrasound-guided femoral nerve block and intravenous fentanyl for positioning during spinal anaesthesia for fracture femur | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 4 October 2025 V1 Latest version Share on Comparative study of analgesic efficacy of ultrasound-guided femoral nerve block and intravenous fentanyl for positioning during spinal anaesthesia for fracture femur Authors : Jeyakumar G R , Padmanabha K , Sangeetha B , Ashna Shetty 0000-0001-8879-4543 [email protected] , and Shubha R M Authors Info & Affiliations https://doi.org/10.22541/au.175958118.82026988/v1 118 views 72 downloads Contents Abstract Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Background and aims: Patient positioning for spinal anaesthesia in femoral fractures is challenging. Peripheral nerve blocks and intravenous fentanyl are commonly practiced modalities to manage pain. However, results available in literature are conflicting, and there is need to decide best modality to manage pain. Methods: A comparative observational study was conducted among 104 American Society of Anaesthesiologists – physical status I to III patients in age group,18 - 70 years, scheduled to undergo fractured femur fixation under sub arachnoid block. The participants were conveniently divided into 2 groups (n = 52 per group); ultrasound-guided Femoral Nerve Block (FNB) group and intravenous (IV) Fentanyl group. Fifteen minutes before spinal anaesthesia, participants in FNB received 15 mL of 1.5% lignocaine with adrenaline solution and fentanyl group received fentanyl 1 µg/kg intravenously. Hemodynamic parameters and pain scores were assessed at baseline, 10 minutes after analgesia, and during positioning. Results: There was significant reduction in pain scores in FNB group compared to IV fentanyl group (P = 0.001). Median performance time was shorter in FNB group (P = 0.001). The ease of positioning (P = 0.37) and patient satisfaction (P = 0.69) were comparable between groups. There were no adverse effects, and no participant in either group required additional rescue dose of fentanyl. Conclusion: It can be concluded that ultrasound-guided FNB was effective in reducing pain scores at baseline, 10 minutes after analgesia, and during positioning of patient for spinal anaesthesia. However, both modalities were equally effective in enabling ease of position and Comparative study of analgesic efficacy of ultrasound-guided femoral nerve block and intravenous fentanyl for positioning during spinal anaesthesia for fracture femur Dr. Jeyakumar G R, MBBS Junior resident, Department of Anesthesiology, Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Manipal, India. [email protected] orcid: 0009-0008-7200-316X Dr. Padmanabha K, MD Associate Professor, Department of Anesthesiology, Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Manipal, India. [email protected] orcid: 0000-0002-0360-1181 Dr. Sangeetha B, DA Senior Resident, Department of Anesthesiology, Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Manipal, India. [email protected] orcid : 0000-0002-6482-4741 Corresponding author Dr. Ashna Shetty, MD Senior Resident, Department of Anesthesiology, Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Manipal, India. [email protected] orcid: 0000-0001-8879-4543 Dr Shubha M R, MD,DNB Senior Resident, Department of Anesthesiology, Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Manipal, India. [email protected] orcid: 0000-0001-5888-9998 Acknowledgement - We are extremely grateful to Kasturba Medical College, Mangalore and Manipal Academy of Higher Education, Manipal, India for their general support in conducting this study. Clinical Trial Registration Number – CTRI/2024/03/064605 Conflicts of Interest: No potential conflict of interest relevant to this article . Criteria for inclusion as authors- Concept, design, definition of intellectual content- Dr. Padmanabha KLiterature search, clinical studies, experimental studies- Dr. Sangeetha BData acquisition, data analysis, statistical analysis- Dr. Jeyakumar G RManuscript preparation, manuscript editing and manuscript review- Dr. Jeyakumar G R, Dr Ashna Shetty, Dr Shubha M RGuarantor- Dr. Padmanabha KThe manuscript has been read and approved by all the authors and requirements for authorship as stated earlier in this document have been met, and each author believes that the manuscript represents honest work Title and running title Comparative study of analgesic efficacy of ultrasound-guided femoral nerve block and intravenous fentanyl for positioning during spinal anaesthesia for fracture femur Comparison of ultrasound-guided femoral nerve block and intravenous fentanyl in managing pain for positioning during spinal anaesthesia for fracture femur Blinded Manuscript Abstract Background and aims: Patient positioning for spinal anaesthesia in femoral fractures is challenging. Peripheral nerve blocks and intravenous fentanyl are commonly practiced modalities to manage pain. However, results available in literature are conflicting, and there is need to decide best modality to manage pain. Methods: A comparative observational study was conducted among 104 American Society of Anaesthesiologists – physical status I to III patients in age group,18 - 70 years, scheduled to undergo fractured femur fixation under sub arachnoid block. The participants were conveniently divided into 2 groups (n = 52 per group); ultrasound-guided Femoral Nerve Block (FNB) group and intravenous (IV) Fentanyl group. Fifteen minutes before spinal anaesthesia, participants in FNB received 15 mL of 1.5% lignocaine with adrenaline solution and fentanyl group received fentanyl 1 µg/kg intravenously. Hemodynamic parameters and pain scores were assessed at baseline, 10 minutes after analgesia, and during positioning. Results: There was significant reduction in pain scores in FNB group compared to IV fentanyl group (P = 0.001). Median performance time was shorter in FNB group (P = 0.001). The ease of positioning (P = 0.37) and patient satisfaction (P = 0.69) were comparable between groups. There were no adverse effects, and no participant in either group required additional rescue dose of fentanyl. Conclusion: It can be concluded that ultrasound-guided FNB was effective in reducing pain scores at baseline, 10 minutes after analgesia, and during positioning of patient for spinal anaesthesia. However, both modalities were equally effective in enabling ease of position and for patient satisfaction. Keywords: Ultrasound-guided; femoral nerve block; IV fentanyl; femoral fractures; spinal anaesthesia; ease of positioning . INTRODUCTION A fracture of the femur is a common, painful bony injury with high disability, mortality, and poor outcomes, thereby emerging as a public health problem[1-3]. In addition, the pain is intolerable on movement, such as positioning during regional anaesthesia, or evaluation[4]. Spinal anaesthesia (SA) is routinely used during orthopaedic surgeries of the lower limb due to its proven advantages such as reduced pain, reduced opioid consumption, and better recovery[5]. However, correct positioning during spinal anaesthesia is important, which may be difficult to achieve due to pain. In addition, extreme pain and immobility of the limb are major deterrents for correct positioning during the procedure[6]. Various drugs such as opioids, non-steroidal anti-inflammatory drugs (NSAIDs) and nerve blocks such as femoral nerve blocks (FNB) or fascia iliac block with local anaesthetics have been tried to reduce the pain. The nerve blocks are newer additions to avoid high complications associated with opioids and drugs. The administration of FNB using the ultrasound method is gaining popularity, since the use of ultrasound ensures accuracy, requires a lower dose of anaesthetic, and reduces the use of systemic analgesics. Intravenous (IV) fentanyl is often used in conjunction with spinal anaesthesia for femur fracture surgery to manage pain during patient positioning effectively. The present study was conducted to compare the effectiveness of the two modalities in managing pain during patient positioning. jabbrv-ltwa-all.ldf jabbrv-ltwa-en.ldf Primary objective: Compare the analgesic efficacy of ultrasound-guided femoral nerve block and intravenous fentanyl. Secondary objective : 1. To record patient heart rate, non-invasive blood pressure, oxygen saturation., and 2. To note the quality of positioning of the patient. METHODS Study design and setting: A comparative observational study was conducted after obtaining approval from the Institutional Ethics Committee (IEC KMC MLR – 05/2023/192) , Institutional Review Board (IRB), and the Clinical Trial Registry of India (CTRI/2024/03/064605) . Written informed consent was obtained from all subjects, a legal surrogate, the parents or legal guardians for minor subjects The study was conducted between May 2023 and December 2024 at a tertiary care teaching hospital in South India. The procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional or regional) and with the Helsinki Declaration of 1975, as revised in 2000. Sample size and study participants: A sample size of 52 participants per group (total 104) was calculated considering an alpha error of 5%, a 95% confidence interval, 80% power, a clinically expected difference of 0.447 in pain score, and a standard deviation of 0.72. Both male and female patients in the age range of 18-70 years, belonging to the American Society of Anaesthesiologists – physical status I to III, who provided consent and were unable to sit and were scheduled to undergo fixation of fractured femur under the sub arachnoid block, were included as study participants. Patients with multiple fractures, unconscious, those who could sit comfortably, and those who did not provide consent were excluded from the study. Method: The participants were informed about the procedure and the visual analog scale (VAS) during pre-anaesthetic evaluation. On the day of the surgery, participants were monitored with electrocardiography, pulse oximeter, and non-invasive blood pressure measurement. The participants to receive an ultrasound-guided FNB or IV fentanyl were conveniently divided into 2 groups. For the ultrasound-guided FNB, participants were positioned in the supine position with the correct lower limb straightened, slightly abducted, and externally rotated. A linear, low-frequency (4 – 12 MHz) ultrasound transducer was placed transversely at the inguinal crease to locate the femoral nerve that appeared as a hyperechoic wedge or ovoid structure lateral to the femoral artery. The entry point was first cleaned using surgical spirit and infiltrated with 1 mL of 1% lignocaine, following which an echogenic 50 mm 22-gauge needle was introduced and 15 mL of 1.5% lignocaine with adrenaline solution was injected incrementally after a negative aspiration, 10 minutes before positioning for SA. Participants in the IV fentanyl group received an injection of fentanyl 1 µg/kg intravenously, 10 minutes before positioning for SA. In the event of VAS score ≥ 4, a supplemental dose of 0.5 µg/kg was administered every 5 minutes until the VAS scores reduced to < 4 or until a maximum dose of 3 µg/kg was achieved. Participants who were unable to achieve a VAS score of < 4 were excluded from the study. Hemodynamic parameters and VAS scores were assessed at baseline, 10 minutes after analgesia, and during the positioning of the participants. The median performance time between the two techniques was recorded. The grade of positioning, patient satisfaction (yes or no) with their position, and additional requirement of IV fentanyl were noted. In addition, the incidence of adverse effects was also noted. Thereafter, a spinal block was performed in the sitting position in either the midline or paramedian approach in L3 – L4 or L4–L5 level via a 27G Quincke Babcock spinal needle using 3cc of 0.5% heavy bupivacaine by an experienced anaesthesiologist. OBJECTIVES: Primary objective: Compare the analgesic efficacy of ultrasound-guided femoral nerve block and intravenous fentanyl. Secondary objective : 1. To record patient heart rate, non-invasive blood pressure, oxygen saturation., and 2. To note the quality of positioning of the patient. Parameters assessed were blood pressure, heart rate, saturation, VAS score, p ostoperative Nausea and Vomiting (PONV) , quality of positioning , performance time and patient satisfaction. The data was analysed using Statistical Package for Social Sciences [version 26.0, IBM Corp, Armonk, NY]. All continuous variables were assessed for normal distribution. A Mann-Whitney U test was conducted to compare continuous variables between the groups, and categorical data was compared using the Chi-square test. A P value ≤ 0.05 was chosen as the criterion for significance for the study. RESULTS The distribution of age and gender was comparable between the groups. (Table l) Hemodynamic parameters were comparable at baseline, while pain scores were higher in the intravenous fentanyl group (P = 0.03). (Table ll) Blood pressure and pain scores were significantly reduced in the FNB group 10 minutes after analgesia and during positioning, while heart rate was significantly higher in the FNB group (P < 0.05). (Table 2) Median performance time was shorter in the FNB. The ease of positioning and patient satisfaction were comparable between the groups. There were no adverse effects, and none of the participants in either group required additional fentanyl. (Table lll) DISCUSSION Though SA is the preferred technique for surgeries of the lower limb, the positioning of patients for the administration of spinal anaesthesia can be challenging due to pain. Various methods and techniques have been proposed to alleviate the pain, and the use of ultrasound-guided nerve blocks has gained popularity. The present comparative observational study showed that ultrasound-guided FNB was effective in reducing pain scores and improved the quality of positioning when compared to intravenous fentanyl. We observed a significant reduction in pain score 10 minutes after the administration of FNB and during patient positioning for spinal anaesthesia. Our results were consistent with studies conducted by Jadon et al[6], Sia et al[7], Reddy & Rao[8], Purohit & Badami[9], and Bantie et al[10]. In addition, a systematic review and meta-analysis by Hsu et al[11] in 2019 concluded that FNB is effective in reducing pain score before positioning when compared to intravenous anaesthetics. When comparing FNB with other agents, Moussa et al[12] in 2022 compared FNB with intravenous ketamine and found that FNB was more effective in reducing pain scores and the time duration for spinal block. The efficacy of FNB was evident from an decrease in the percentage of patients requiring rescue fentanyl before SA which was not observed in our study. In another study, Pradhan et al in 2022, compared FNB with IV nalbuphine and found FNB to be superior in terms of lowering pain scores[13]. The practice of ultrasound-guided nerve blocks has an enhanced success rate due to the precise location of the nerve, lower doses required, faster onset of action, and improved outcomes. The above data from literature, coupled with our findings, reinforce that FNB is perhaps the best modality in managing pain during positioning before administering SA. jabbrv-ltwa-all.ldf jabbrv-ltwa-en.ldf In our study, we found that HR was significantly elevated among participants in the FNB group compared to participants in the IV fentanyl group after analgesia and even during positioning. Our findings did not corroborate with results from Jadon et al[6], Reddy and Rao[8], and Pradhan et al[13] who found comparable results between FNB and IV anaesthetics. We can perhaps attribute tachycardia to the anticipation and experience of the FNB procedure. We also found that participants receiving IV fentanyl had slightly elevated SBP and DBP compared to participants in the FNB group. Similar results were observed in a study conducted by Pakhare and Pendyala[15] in 2016, thereby concluding that hemodynamic parameters are more stable in FNB compared to intravenous fentanyl. The saturation levels were found to be comparable at baseline and during positioning with a slight reduction in the FNB group of SPO2 levels 10 minutes after analgesia. We also observed that the time from the beginning of patient positioning to the end of spinal anaesthesia was shorter for participants receiving FNB, indicating faster and more effective relief from pain compared to those who received intravenous fentanyl. Similar results were reported by Sia et al[7] in 2004, Reddy and Rao[8] in 2016, and Moussa et al[12] in 2022. In the present study, we found that the quality of positioning was comparable among participants in both groups. Though a higher percentage of participants had grade 3 positioning (optimal) in the FNB group, we did not find any significant difference in distribution. This finding was in contrast to a report from Jadon et al[6] in 2014 and Bantie et al[10] in 2020, who reported better quality of positioning among participants with FNB. Since pain is directly proportional to the quality of positioning, Moussa et al[12] reported lower pain scores from participants with FNB, indirectly implying better quality of positioning[18]. Patient satisfaction was reported to be high among participants from both groups. Our results were in contrast to results from Sia et al[7], Purohit and Badami[9], Singh AP et al[16], and Reddy and Rao[8] , who reported better patient satisfaction after receiving FNB. Our findings were also similar to the results from Pradhan et al[13]. This difference in results may be attributed to different local anaesthetics and concentrations used for FNB. Lignocaine used in the present study has a shorter onset of action, while bupivacaine has a longer onset of action. We may not be able to substantiate in our study since we did not assess the time taken for the onset of analgesia. Irrespective of the outcomes, in our study, none of the participants required an additional dose of fentanyl, and none of the participants in either group had any adverse effects. In contrast to our results, Moussa et al[12] reported desaturation among participants receiving the intravenous ketamine group and hypotension among those receiving FNB. Our study did have certain limitations. First, the time taken for the onset of analgesia was not assessed. Second, the concept of blinding was not observed since there was a possibility of selection bias by the anaesthesiologist in allocating participants to different groups. Third, the site of fracture in the femur was not specified nor grouped, since literature reports varying levels of analgesia that are proportional to the fracture site. Fourth, the absence of randomization in allocating participants would have eliminated selection bias and improved the scientific weightage of the study. CONCLUSION From the parameters of the present study, it can be concluded that femoral nerve block is more effective in managing pain compared to intravenous fentanyl in femur fracture patients during positioning for spinal anaesthesia . Though HR was found to be elevated, hemodynamic parameters were found to be stable in the femoral nerve block. Though a reduction in pain was more with femoral nerve block, the quality of positioning was found to be comparable in both femoral nerve block and intravenous fentanyl. Patient satisfaction was found to be similar for both modalities and there were no incidences of PONV in either group. REFERENCES 1. Duc TA. Postoperative pain control In: Conroy JM, Dorman BH, editors. Anesthesia for orthopedic surgery. New York, NY: Raven Press; 1994: 355–65. 2. Wu J, Che Y, Zhang Y, Wang J, Chen M, Jiang J, et al. Global, regional, national trends of femur fracture and machine learning prediction: Comprehensive findings and questions from global burden of disease 1990–2019. Journal of Orthopaedic Translation 2024;46:46-52. 3. Trincado RM, Mari MAK, Fernandes LS, Perlaky TA, Hungaria JOS. Epidemiology of proximal femur fracture in older Adults in a Philanthropical hospital in SÃo Paulo. Acta Ortopedica Bras 2022;30 (6) 4. Somvanshi M, Tripathi A, Meena N. Femoral nerve block for acute pain relief in fracture shaft femur in an emergency ward. Saudi J Anaesth 2015;9(4):439–41. https://doi.org/10.4103/1658-354X.159471 5. Johnson MZ J. Perioperative regional anaesthesia and postoperative longer-term outcomes. F1000Research. 2016;5. 6. Jadon A, Kedia SK, Dixit S, Chakraborty S. Comparative evaluation of femoral nerve block and intravenous fentanyl for positioning during spinal anaesthesia in surgery of femur fracture. Indian J Anaesth. 2014;58(6):705–8. 7. Sia S, Pelusio F, Barbagli R, Rivituso C. Analgesia before performing a spinal block in the sitting position in patients with femoral shaft fracture: a comparison between femoral nerve block and intravenous fentanyl. Anesth Analg. 2004;99(4):1221–4 8. Reddy ED, Rao BD. Comparative study of efficacy of femoral nerve block and IV fentanyl for positioning during femur fracture surgery. Int Surg J 2016; 3:321-4. 9. Purohit S, Badami RN. Femoral nerve block versus intravenous fentanyl for positioning during central neuraxial block: A comparative study. Indian Journal of Anesthesia and Analgesia 2018;5 (3)430–5. 10. Bantie M, Mola S, Girma T, Aweke Z, Neme D, Zemedkun A. Comparing analgesic effect of intravenous fentanyl, femoral nerve block and fascia iliaca block during spinal anaesthesia positioning in elective adult patients undergoing femoral fracture surgery: a Randomised Controlled Trial. J Pain Res. 2020; 13:3139–46. 11. Hsu YP, Hsu CW, Chu KCW, Huang WC, Bai CH, Huang CJ, et al. Efficacy and safety of femoral nerve block for the positioning of femur fracture patients before a spinal block - A systematic review and meta-analysis. PLoS One. 2019;14(5): e0216337 12. Mohamed Moussa ME, Salama Awad HG, Abdel Hamid HS, Abdellatif AE, Sayed Sharaf AG. A comparative study between femoral nerve block and intravenous ketamine for pain management during positioning for spinal anesthesia in elderly patients with femur fracture. Anaesth. pain intensive care 2022;26(3):297-303. 13. Pradhan A, Panda A, Doppalapudi P. Effectiveness of Femoral Nerve Block versus Intravenous Nalbuphine in Positioning of Patients with Intertrochanteric Fractures for Spinal Anaesthesia: A Randomised Clinical Study. Journal of Clinical and Diagnostic Research. 2022 May, Vol-16(5): UC01-UC04. 14. Marhofer P, Schrögendorfer K, Wallner T, Koinig H, Mayer N, Kapral S. Ultrasonographic guidance reduces the amount of local anesthetic for 3-in-1 blocks. Reg Anesth Pain Med. 1998;23(6):584-8. 15. Pakhare PV, Pendayala P. A randomized prospective study of comparison of IV Fentanyl vs. femoral nerve block to facilitate administration of subarachnoid block in sitting position for femur fracture surgeries. Indian Journal of Clinical Anaesthesia, 2016;3(4): 507-11. 16. Singh AP, Kohli V, Bajwa SJ. Intravenous analgesia with opioids versus femoral nerve block with 0.2% ropivacaine as preemptive analgesic for fracture femur: A randomized comparative study. Anesth Essays Res. 2016; 10:338-42. TABLES Table l Age mean ± sd 57.96 ± 13.1 54.63 ± 10.9 P = 0.016 (NS) Gender Males; n (%) 28 (53.8) 28 (53.8) P = 0.99 Females; n (%) 24 (46.2) 24 (46.2) NS n-number; %-percentage; sd-standard deviation NS-not significant using unpaired t-test and Chi-square test Table ll jabbrv-ltwa-all.ldf jabbrv-ltwa-en.ldf Median IQR Median IQR Before HR 84 76.2 - 92.0 81 76.2 - 88.0 1129.5 P = 0.14 (NS) Analgesia SBP 140 138.0 - 150.0 140 136.5 - 147.7 1216 P = 0.46 (NS) DBP 90 82.0 - 94.0 88 86.0 - 90.0 1079.5 P = 0.07 (NS) VAS 6 5.0 – 6.0 6 6.0 – 7.0 1045 P = 0.03* SPO2 100 99.2 - 100.0 100 100.0 - 100.0 1192 P = 0.11 (NS) 10 minutes after HR 84.5 76.0 - 90.0 78 72.0 - 82.0 889.5 P = 0.003** analgesia SBP 130 122.0 - 140.0 138 130.0 - 144.0 798 P = 0.001** DBP 84 76.0 - 88.0 86 84.0 - 89.5 994.5 P = 0.019* VAS 2 2.0 – 3.0 3 2.2 – 4.0 714 P = 0.001** SPO2 100 99.2 - 100.0 100 100.0 - 100.0 1177 P = 0.023* During HR 87.5 80.0 - 90.7 83 76.2 - 87.0 10002.5 P = 0.023* positioning SBP 130 127.0 - 140.0 140 130.0 - 142.0 885.5 P = 0.002** DBP 80 80.0 - 90.0 88.5 80.5 - 90.0 981.5 P = 0.013* VAS 3 3.0 - 3.0 3 3.0 - 4.0 737.5 P = 0.001** SPO2 100 99.0 - 100.0 100 99.0 - 100.0 1287 P = 0.6 (NS) HR-Heart rate; SBP-Systolic Blood Pressure; DBP-Diastolic Blood Pressure; SPO2-Oxygen saturation IQR-inter quartile range; NS-not significant and statistically significant at *P < 0.05 and **P < 0.01 using Mann-Whitney U test Table lll Performance time median (IQR) 2.9 (2.1 – 3.07) 3.7 (3.0 – 4.1) P = 0.001** Positioning; n (%) Grade 1 0 0 P = 0.37 Grade 2 11 (21.2) 16 (30.8) NS Grade 3 38 (78.8) 36 (69.2) Patient satisfaction; n (%) Yes 49 (94.2) 48 (92.3) P = 0.69 No 3 (5.8) 4 (7.7) NS Additional fentanyl; n (%) Yes 0 0 NA No 52 (100) 52 (100) PONV; n (%) Yes 0 0 NA No 52 (100) 52 (100) IQR-interquartile range; NS-not significant and statistically significant at **P < 0.01 using the Mann-Whitney U test; NA-not applicable Footnotes Table l: Age and distribution of gender between the groups- The distribution of age and gender was comparable between the groups. Table ll: Comparison of median hemodynamic parameters and pain scores between the groups- Blood pressure and pain scores were significantly reduced in the FNB group 10 minutes after analgesia and during positioning, while heart rate was significantly higher in the FNB group (P < 0.05). Table lll: Comparison of different variables between the groups-Median performance time was shorter in the FNB. The ease of positioning and patient satisfaction were comparable between the groups. There were no adverse effects, and none of the participants in either group required additional fentanyl Information & Authors Information Version history V1 Version 1 04 October 2025 Copyright This work is licensed under a Non Exclusive No Reuse License. Authors Affiliations Jeyakumar G R Manipal Academy of Higher Education View all articles by this author Padmanabha K Manipal Academy of Higher Education View all articles by this author Sangeetha B Manipal Academy of Higher Education View all articles by this author Ashna Shetty 0000-0001-8879-4543 [email protected] Manipal Academy of Higher Education View all articles by this author Shubha R M Manipal Academy of Higher Education View all articles by this author Metrics & Citations Metrics Article Usage 118 views 72 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Jeyakumar G R, Padmanabha K, Sangeetha B, et al. Comparative study of analgesic efficacy of ultrasound-guided femoral nerve block and intravenous fentanyl for positioning during spinal anaesthesia for fracture femur. Authorea . 04 October 2025. 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