Effect of tourniquet use on Index of Cardiac-Electrophysiological Balance (ICEB) in upper extremity surgeries, prospective cross-sectional study

Effect of tourniquet use on Index of Cardiac-Electrophysiological Balance (ICEB) in upper extremity surgeries, prospective cross-sectional study | 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 Effect of tourniquet use on Index of Cardiac-Electrophysiological Balance (ICEB) in upper extremity surgeries, prospective cross-sectional study Fatma Nur Arslan, Recai Dagli, Güzin Ceran, Levent Horoz This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7033414/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background This study aimed to investigate the effects of tourniquet application during upper extremity surgeries on the Index of Cardiac Electrophysiological Balance (ICEB) and its corrected form (ICEBc), which are novel, non-invasive electrocardiographic markers used to assess arrhythmia risk. Methods This prospective cross-sectional study included 20 patients aged 18–65 years with ASA physical status I–III, scheduled for elective upper extremity fixation surgery. ICEB and ICEBc values were calculated at six different time points perioperatively using electrocardiographic measurements. Additional parameters such as heart rate (HR), QT interval, QRS duration, systolic/diastolic/mean arterial pressure (SAP/DAP/MAP) were also recorded. Data were analyzed using repeated-measures ANOVA and Friedman tests, as appropriate. Results ICEB and ICEBc values showed significant increases after tourniquet deflation compared to baseline (ICEB p < 0.001). QT intervals were also significantly prolonged after deflation (p = 0.021). While tourniquet inflation caused slight decreases in ICEB and ICEBc, these changes were not statistically significant. Heart rate and blood pressure showed expected perioperative fluctuations but did not significantly influence ICEB trends. Conclusions Tourniquet deflation in upper extremity surgeries may cause transient increases in ICEB and ICEBc, suggesting a possible, though limited, impact on cardiac electrophysiological balance. However, given the short duration and smaller ischemic area of upper extremity tourniquet use, the arrhythmogenic risk appears to be minimal. ICEB and ICEBc may serve as useful markers for perioperative cardiac risk stratification and warrant further investigation. Clinical Trial : PRS Number:NCT06936150 / Registration Date : 12.04.2025 /Retrospectively Registered Arrhythmias Cardiac Tourniquets Electrocardiography Figures Figure 1 Figure 2 Figure 3 Background The use of a tourniquet during surgical repair of traumatic upper extremity fractures is a very common practice. Surgical Tourniquets are used in orthopaedic for creation of a bloodless field, greater safety, better precision, and more convenience for the surgeon. Despite the ease it provides in terms of surgery, the use of a tourniquet can lead to some complications. Most surgical tourniquets are of the pneumatic design.(1) When using a pneumatic tourniquet in upper extremity surgeries, a pressure of 150–250 mmHg is usually applied. The blood flow to the extremity is cut off by this pressure effect. However, stopping the circulation causes temporary ischemia. Limb occlusion causes metabolic changes in the ischemic limb that include: Increased lactic acid, PaCO 2 and potassium levels, and decreased levels of PaO 2 , and pH. Toxic metabolites produce pathophysiological changes when released into the general circulation.(2, 3). The degree of these changes correlates with the duration of ischemia. All of these changes are fully reversed within 30 min of tourniquet deflation. (4) These metabolic changes may have negative effects on cardiac electrical activity. Theoretically, there is a risk that these ischemic metabolites and pH changes may trigger cardiac malignant arrhythmias. Indeed, pre-clinical studies demonstrated that λ,( λ = effective refractory period × conduction velocity) was the best predictor of arrhythmic tendency, increasing with pro-arrhythmic conditions and decreasing by anti-arrhythmic therapy.(5) The fact that λ must be assessed invasively using electrophysiological investigations in a clinical context is a significant drawback, though. The index of Cardiac-Electrophysiological Balance” (iCEB), which is the ratio of QT/QRS of the ECG, was proposed as the noninvasively measured equivalent of λ by Lu et al. Therefore, iCEB could be used as a new biomarker to detect drug-induced broad cardiac arrhythmias including TdP and non-TdP-like VT/VF.(6) In addition, ICEBc, a version calculated with Qtc instead of Qt, has been used in various studies to predict arrhythmia risk, similar to ICEB (7, 8). In our study, we aimed to investigate whether ischemic metabolites and other systemic effects occurring after tourniquet application in upper extremity surgeries create any changes on the ICEB and ICEBc values ​​of patients. Methods The study was designed as a prospective, observational study. Patients were included in the study after their informed consent to participate was obtained by the anesthesiologists during the preoperative evaluation in the anesthesia outpatient clinic of a training and research hospital. The research was conducted in 2024. All data related to the study were recorded by the same anesthesia team. During the preoperative evaluation, American Society of Anesthesiology (ASA) risk group I-III, patients between the ages of 18–65, who were scheduled for elective upper extremity fixation surgery were included in the study. Patients with bundle branch block in preoperative ECG, patients with arrhythmia, those taking antiarrhythmic drugs, those with pacemakers, patients with known drug-specific allergies, and patients with electrolyte disorders were not included in the study. Practices for anesthesia application Patients were taken to surgery under general anesthesia or axillary block. Induction was performed with 2 mg/kg propofol, 2 mcg/kg fentanyl, 0.6 mg/kg rocuronium for patients who received general anesthesia and maintenance was performed with 2% sevoflurane and 1 mcg/kg/min remifentanil. In patients who underwent axillary block, axillary plexus block was performed with 0.25% bupivacaine 20 ml. Practices for tourniquet After anesthesia application, a VBM (VBM Medizintechnik GmbH, Germany) tourniquet was placed on the humerus of the upper extremity where surgery was performed. The tourniquet pressure was set to 200-250mmHg. The tourniquet start time and pressure were recorded. Standart study practice ECG measurements were taken from the patients at 6 different time points.After calculating QT, QTc and QRS durations from D II and V5 derivations, iCEB and ICEBc calculations was made. iCEB is calculated by dividing the QT interval by the QRS duration (QT/ QRS). iCEBc is calculated by dividing the QTc interval by the QRS duration (QTc/ QRS). Primarly, ICEB and ICEBc values were evaluated at across six time points: Time 1: 5 minutes before anesthesia (ICEB1&ICEBc1), Time 2: 5 minutes after anestehesia (ICEB2&ICEBc2), Time 3: before 5 minutes tourniquet inflation(ICEB3&ICEBc3), Time 4: after 5 minutes tourniquet inflation (ICEB4&ICEBc4), Time 5: before 5 minutes tourniquet deflation (ICEB5&ICEBc5), Time 6: after 5 minutes tourniquet deflation (ICEB6&ICEBc6). ICEB and ICEBc changes in the perioperative period was evaluated in three different stages. Effects of general anesthesia or Peripheral Nerve Blocks on ICEB (ICEB 1 vs ICEB 2) and ICEBc (ICEBc 1 vs ICEBc 2), Effects of tourniquet inflation on ICEB (ICEB 3 vs ICEB 4) and ICEBc (ICEBc 3 vs ICEBc 4), Effects of tourniquet deflation on ICEB (ICEB 5 vs ICEB 6) and ICEBc (ICEBc 5 vs ICEBc 6). Simultaneously, systolic arterial pressures ( SAP), diastolic arterial pressures (DAP), mean arterial pressure (MAP), heart rate (HR), were recorded non-invasively. The primary outcome of our study was whether there was a significant increase in ICEB and ICEBc values ​​in those three stages. The secondary outcomes of the study was whether there was a significant changes in HR, QT, QRS, SAP, DAP, and MAP values at those three time points. Sample size Forty patients accepted to participate in the study, 11 of whom were excluded because they met the exclusion criteria as a result of preoperative evaluation. Of the remaining 29 patients, the pilot study was conducted with 20 patients to determine the study's sample size because 9 patients had incomplete data or refused surgery. As a result of statistical tests, Partial Eta Squared was found to be 0.149. G * Power 3.1.9.7 (Franz Faul, Universitat Kiel, Germany) was used for A priori power analysis. Effect size was determined as f = 0.418 by F tests - ANOVA (Repeated measures, within factors). Test input parameters were, respectively, α err probe = 0.05, Power (1-β err probe) = 0.95, Corr among rep measures = 0.5, Nonsphericity correction ε = 1. The total sample size was 12. Statistical analysis was performed on 20 patients evaluated in the pilot study. See strobe diagram in Fig. 1. Statistics IBM SPSS Statistics, version 29.0.0 (IBM Corp, Armonk, NY, USA), was used to analyse the study's data. The research results were presented with frequency (n), percentage (%), mean, standard deviation, 95% CI (Confidence Interval), median, 25%-75% percentile (Q1-Q3) values. The Shapiro Wilk Test were used for the normality assumption of data. It was evaluated whether the difference between repeated measurements occurred over time. When the data were normally distributed, a one-way repeated measures ANOVA was used, and when they were not, the Friedman Test was used. To Pairwise comparisons of significant results after ANOVA, was used with Bonferroni. Statistically significant is p < .05. Results Patients’ basic characteristics and perioperative data are presented in Table 1 . Total of 20, 10 female and 10 male, patients were evaluated. The mean age was 50.55 (15.88). Table 1 Patient’s basic characteristics ASA ASA I (n) 3 ASA II (n) 14 ASAIII (n) 3 Gender Female (n) 10 Male (n) 10 Anesthesia General (n) 13 Peripheral Nerve Blocks (n) 7 Age (Year) 50.55 (15.88) Height (m) 1.67 (7.91) Weight (kg) 81.05 (6.75) BMI (kg/m 2 ) 28.84 (5.79) Operation duration (min) 105.50 (20.12) Intravenous fluid volume (ml) 1200.00 [1000.00–1500.00] Turniquet duration (min) 52.00 [46.00–67.00] Turniquet pressure 243.00 (27.93) ASA: American Society of Anesthesiologists physical status score . BMI: Body Mass Index Data were presented as n, mean (SD), and median [Q1-Q3]. When the comorbidities of the patients were examined, ten patients had hypertension, and they were regularly using medical drugs for the treatment of hypertension. ICEB The primary variable evaluated in our study is changing the ICEB values before and after the deflated tourniquet. ICEB values were evaluated at across six time points (Fig. 1) (ICEB1), Time 2 (ICEB2), Time 3 (ICEB3), Time4 (ICEB4), Time 5 (ICEB5), Time 6 (ICEB6)). A One-Way repeated measures ANOVA test indicated there was a significant effect for ICEB across the times, F (5,95) = 11.560, p < .001, ηp2 = .378. (Table 2 ) Table 2 ICEBc measurements. Mean [SD] 95% Confidence Interval Mean Difference 95% Confidence Interval for Difference p ICEBc ICEBc1 4.697 (.480) [4.472–4.922] − .059 [-,366 − .247] p = 1.000 df: 5 F = 3.315 * p = .061 ICEBc2 4.757 (.580) [4.485–5.028] ICEBc3 4.931 (.745) [4.583–5.280] .102 [-.220 − .425] p = 1.000 ICEBc4 4.829 (.572) [4.561–5.097] ICEBc5 4.978 (.579) [4.707–5.249] − .006 [-.241 − .228] p = 1.000 ICEBc6 4.985 (.598) [4.704–5.265] * One-Way repeated measures ANOVA test, Descriptive statistics are presented with mean (standard deviation), 95% CI (Confidence Interval). On average, Time 1 ICEB values (ICEB1 4.273 (.588)) were lower than Time 2 (ICEB2 4.405 (.586)). Time 3 (ICEB3 4.652 (.773)) were higher than Time 4 (ICEB4 4.581 (.684)). Time 5 (ICEB5 4.797 (.650)) were lower than Time 6 (ICEB6 4.927 (.711)). (Table 2 ) ICEB change in the perioperative period was evaluated in three different stages. Effects of general or Peripheral Nerve Blocks on ICEB (Time 1 vs Time 2), Effects of tourniquet inflation on ICEB (Time 3 vs Time 4), Effects of tourniquet deflation on ICEB (Time 5 vs Time 6). Anesthesia and tourniquet deflation has increased the ICEB, Tourniquet inflation has decreased the ICEB but had no statistical significance. Pairwise Comparisons were conducted using the Bonferroni correction. The values ​​measured after the tourniquet deflation were higher than all measurements in the perioperative period. The difference between Time 6 and Time 1, .655 95% CI [.234–1.075] (p < .001), Time 6 and Time 2, .523 95% CI [.103 − .942] (p < 001), Time 6 and Time 4, .347 95% CI [.023 − .670], was statistically significant (p = .029). See also Fig. 2. ICEBc The other primary variable evaluated in our study is changing the ICEBc values before and after the deflated tourniquet. ICEBc values were evaluated at across six time points (Fig. 1). Time 1 (ICEBc1), Time 2 (ICEBc2), Time 3 (ICEBc3), Time4 (ICEBc4), Time 5 (ICEBc5), Time 6 (ICEBc6)). A One-Way repeated measures ANOVA test indicated there was a significant effect for ICEBc across the times, F (5,95) = 3.315, p = .061, ηp2 = .149 (Table 2 ). On average, Time 1 ICEBc values (ICEBc1 4.697 (.480)) were lower than Time 2 (ICEBc2 4.757 (.580)). Time 3 (ICEBc3 4.931 (.745)) were higher than Time 4 (ICEBc4 4.829 (.572)). Time 5 (ICEBc5 4.978 (.579)) were lower than Time 6 (ICEBc6 4.985 (.598)) (Table 2 ). Anesthesia and tourniquet deflation has increased the ICEBc, Tourniquet inflation has decreased the ICEBc but had no statistical significance. The ICEBc values ​​measured after the tourniquet deflation were higher than all measurements in the perioperative period. The difference across Times was not statistically significant. See also Fig. 3. HR The secondary variable evaluated in our study is changing the HR values at across six time points. On average, Time 1 HR values (79.850 (14.173)) were higher than Time 2 (HR2 78. 79.300 (16.219)). Time 3 (HR3 74.100 (14.772)) were hihger than Time 4 (HR4 73.300 (16.461)). Time 5 (HR5 69.250 (14.015)) were higher than Time 6 (HR6 63.400 (11.509)) (Table 3 ) Table 3 Heart rate, QT, QRS measurements. Mean [SD] 95% Confidence Interval Mean Difference 95% Confidence Interval for Difference p HR HR 1 79.850 (14.173) ABCD [73.217–86.483] .550 [-7.985–9.085] p = 1.000 df: 5 F = 11.089 * p < .001 HR 2 79.300 (16.219) ABCD [71.709–86.891] HR 3 74.100 (14.772) ABCDE [67.187–81.013] .800 [-7.593–9.193] p = 1.000 HR 4 73.300 (16.461) ABCDE [65.596–81.004] HR 5 69.250 (14.015) BCDEF [62.691–75.809] 5.850 [-.694–12.394] p = .111 HR 6 63.400 (11.509) EF [58.013–68.787] QT QT 1 374.000 (30.116) AB [359.905-388.095] -15.100 [-37.934–7.734] p = .584 df = 5 F = 19.009 * p < .001 QT 2 389.100 (36.502) ABCD [372.016-406.184] QT 3 409.700 (39.859) BCDE [391.045-428.355] 9.800 [-16.371–35.971] p = 1.000 QT 4 399.900 (39.632) BCD [381.351-418.449] QT 5 418.200 (34.713) EC [401.954-434.446] -16.700 [-31.686 - -1.714] p = .021 QT 6 434.900 (47.090) F [412.861-456.939] QRS QRS 1 88.400 (9.236) [84.077–92.723] − .800 [-4.705–3.105] p = 1.000 df = 5 F = .308 * p = .837 QRS 2 89.200 (8.883) [85.043–93.357] QRS 3 89.500 (11.404) [84.163–94.837] 1.300 [ -5.288–7.888] p = 1.000 QRS 4 88.200 (8.965) [84.004–92.396] QRS 5 87.900 (8.322) [84.005–91.795] -1.100 [-4.158–1.958] p = 1.000 QRS 6 89.000 (9.481) [84.563–93.437] HR: Heart rate, QT: QT interval QRS: QRS interval. * One-Way repeated measures ANOVA test. Descriptive statistics are presented with mean (standard deviation), 95% CI (Confidence Interval). Different letters on the same rows indicate statistical differences between measurements at other times. Anesthesia, Tourniquet inflation and tourniquet deflation has decreased the HR, but had no statistical significance (Table 3 ). The HR values measured after the tourniquet deflation (HR6) were lower than all measurements in the perioperative period. The difference across Time 1, 2,3 and,4 were statistically significant. QT The secondary variable evaluated in our study is changing the QT values at across six time points. On average, Time 1 QT values (374.000 (30.116)) were higher than Time 2 (QT2 389.100 (36.502)). Time 3 (QT3 409.700 (39.859)) were hihger than Time 4 (QT4 399.900 (39.632)). Time 5 (QT5 418.200 (34.713)) were higher than Time 6 (QT6 434.900 (47.090)) (Table 3 ). Anesthesia has increased and tourniquet inflation has decreased the QT, but had no statistical significance. Tourniquet deflation has increased the QT as statistical significance (p = 0.021) (Table 3 ). The QT values ​​measured after the tourniquet deflation (QT6) were higher than all measurements in the perioperative period and all the difference across all Times were statistically significant. QRS The secondary variable evaluated in our study is changing the QRS values at across six time points. Anesthesia, and tourniquet deflation has increased the QRS, tourniquet inflation has decreased the QRS, but had no statistical significance (Table 3 ). The changes in QRS values were not statistically significant at any time in the perioperative period. SAP, DAP, and MAP The secondary variables, such as SAP, DAP, and MAP has been evelueted at across six time points. Anesthesia and tourniquet deflation has decreased the SAP, DAP, and MAP. Tourniquet inflation has increased the SAP, DAP, and MAP, but had no statistical significance (Table 4 ). Table 4 Arterial blood pressure measurements. Mean [SD] 95% Confidence Interval Mean Difference 95% Confidence Interval for Difference p SAP SAP 1 150.250 (29.042) ABD [136.658-163.842] 24.650 [-.343–49.643] p = .055 df: 5 F = 9.898 * p < .001 SAP 2 125.600 (25.910) ABCDEF [113.474-137.726] SAP 3 116.550 (20.221) BCDEF [107.086-126.014] -7.600 [-18.897–3.697] p = .540 SAP 4 124.150 (19.626) ABCDEF [114.965-133.335] SAP 5 119.300 (19.863) BCDEF [110.004-128.596] 4.400 [-2.108–10.908] p = .528 SAP 6 114.900 (23.387) BCDEF [103.955-125.845] DAP DAP 1 84.950 (14.196) ABD [78.306–91.594] 6.950 [-6.553–20.453] P = 1.000 df = 5 F = 6.443 * p < .001 DAP 2 78.000 (14.411) ABCDEF [71.255–84.745] DAP 3 68.900 (13.102) BCDEF [62.768–75.032] -6.150 [-14,577–2.277] p = .364 DAP 4 75.050 (13.153) ABCDEF [68.894–81.206] DAP 5 69.800 (11.808) BCDEF [64.274–75.326] 1.400 [-7.667–10.467] p = 1.000 DAP 6 68.400 (14.901) BCDEF [61.426–75.374] MAP MAP 1 110.400 (17.307) ABD [102.300-118.500] 15.850 [-.384–32.084] p = .060 df = 5 F = 10.304 * p < .001 MAP 2 94.550 (18.875) ABCDE [85.716-103.384] MAP 3 82.350 (16.461) BCDEF [74.646–90.054] -10.250 [-23.091–2.591] p = .224 MAP 4 92.600 (17.313) ABCDEF [84.497-100.703] MAP 5 87.400 (14.009) BCDEF [80.844–93.956] 3.850 [-1.370–9.070] p = .345 MAP 6 83.550 (17.620) BCDEF [75.303–91.797] SAP: systolic arterial blood pressure, DAP: diastolic arterial blood pressure MAP: mean arterial blood pressure. * One-Way repeated measures ANOVA test. Descriptive statistics are presented with mean (standard deviation), 95% CI (Confidence Interval). Different letters on the same rows indicate statistical differences between measurements at other times. The SAP, DAP, and MAP values ​​ after the tourniquet deflation (SAP6) were lower than all measurements in the perioperative period. The difference across Time 1 was statistically significant. Discussion The frequency of intraoperative arrhythmia is quite high, in fact, this frequency rises to 89% with continuous monitoring, similar to the figures for cardiac surgery (9). The vast majority of these arrhythmias are transient benign arrhythmias. Fluid shifts, inflammatory responses, and the resulting cardiovascular stress appear to be important triggers of perioperative arrhythmias (10). However, malignant arrhythmias, especially broad cardiac arrhythmias including TdP and non-TdP-like VT/VF, are among the most dangerous arrhythmias that require urgent intervention and can be life-threatening. As a potential triggering factor of those malignant arrythmias, possible contributing factors of a tourniquet use include increased serum levels of lactate, carbon dioxide, free radicals and prostaglandins as a result of local tissue hypoxia(4) Tourniquets may also increase blood pressure, probably because of autonomous nervous system changes (11) which may all contribute triggering malignant arrhythmias. Many parameters have been studied to predict malignant arrhythmias by using ECG measurements. There is no comprehensive easy-to-measure risk marker for drug-induced ventricular arrhythmias (VAs) to assess sudden cardiac death (SCD) The prolonged corrected (QTc) interval alone is insufficient for identifying malignant ventricular arrhythmias.(12) According to the Lu et. Al, the very first team to introduce ICEB, the iCEB (the ratio of QT/QRS) derived from the ECG, should be the equivalent of the classic λ (ERPxCV), and significant changes in iCEB may reflect an imbalance in cardiac electrophysiology, and therefore predict cardiac arrhythmias. Therefore, iCEB could be used as a new biomarker to detect drug-induced broad cardiac arrhythmias including TdP and non-TdP-like VT/VF (6). The iCEB is a measure of the balance between the sympathetic and parasympathetic nervous systems in the heart. Studies have shown that an imbalance in the autonomic nervous system can increase the risk of developing ventricular arrhytmias (VA). (12) ICEB has some degree of heart-rate dependency, meaning that ICEB, like the QT interval itself, should optimally be corrected for underlying heart rate (13).ICEBc, a new, noninvasive marker, may predict Premature Ventricular Contractions(PVC) in structurally normal hearts. The iCEBc indicates electrophysiological balance and arrhythmia risk beyond other ECG measures A high iCEB, indicating a sympathetic predominance, has been associated with an increased risk of VA’s in patients with various cardiac conditions, including heart failure and myocardial infarction. (7). Although clear value ranges for ICEB and ICEBc are not given in the studies in the literature, study-based data show that normal ICEB values ​​are around 4 (14, 15) One study claims that the normal value for ICEB is 4.24, with a reference range of 3.14 to 5.35.(16). Some conditions like cigarette smoking(15), type 1 diabetes mellitus(17) and sevoflurane inhalation(18) increases ICEB values. Experimental studies have shown that 10% increases or decreases in ICEB could be a promising marker for risk of drug-induced cardiac arrhythmias(8, 19). Most of the studies in the literature focus on the increase in baseline ICEB and ICEBc values ​​and the risk of cardiac arrhythmia that occurs as a result, rather than providing specific value ranges as we did in our study. In our study, there was no significant difference between the ICEB and ICEBc values ​​calculated before and after tourniquet deflation. One reason for this may be that the ischemic area is smaller in upper extremity surgeries compared to the lower extremities, and that our tourniquet times are within the safe range specified in the literature (less than 2 hours), thus shortening the ischemia times. Two hours has a logical basis, since after this time of ischemia, progressive venous acidosis will occur in the region the tourniquet effects (20). Based on this, it can be suggested that tourniquet use alone does not increase the risk of arrhythmia in upper extremity surgeries. Our study showed that there was a significant increase in the QT interval between tourniquet inflation and deflation. Despite the increased QT, the lack of a significant increase in ICEB and ICEBc values ​​indicates that QT and ICEB values ​​do not follow a parallel course. In fact, in a previous study by Sivri et al., similarly, QT values ​​and ICEB values ​​followed an independent course from each other, and the study showed that iCEB and iCEBc were elevated after hemodialysis but there was no significant change in the QT interval or QTc, indicating that the new ECG marker was more sensitive to cardiac electrophysiological balance. ICEBc lengthening or shortening increased the risk of malignant arrhythmia (8). Also in a retrospective cohort study involved 5010 adults aged 40–65 years who participated in the Third National Health and Nutrition Examination Survey (NHANES-III) and whose electrocardiograms were in sinus rhythm, it was found that Prolonged iCEBc was associated with an increased risk of all-cause or cardiac mortality and the association was independent of conventional risk factors, even QRS duration and prolonged QTc. In the normal QTc subgroup of interest, prolonged iCEBc remained significantly associated with all-cause mortality. This suggests that the indicator can identify high-risk populations that QTc cannot identify. Elevated iCEBc (male ≥ 4.57, female ≥ 4.98) is an independent risk factor for cardiac or all-cause death among middle-age adults (21). In our study, ICEB and ICEBc values ​​were found to be higher than all other measurements after tourniquet deflation. In patient groups with already high ICEB and ICEBc values, this effect may increase the risk of cardiac arrhythmia compared to patients with normal initial values. Further studies are required to evaluate such patient groups. Limitations In order for the study to yield more reliable and generalizable results, it would have yielded better results if it was conducted on patients with a similar health profile in a similar age group using a single type of anesthesia method. We did not have any cases where the tourniquet duration was longer than 2 hours. It may be interesting to examine these values ​​in dangerous tourniquet durations. In addition, we could not see the effects of rhythm regulators such as beta-blockers in this study. This study can be repeated with patients at high cardiac risk who use these types of drugs. Analyzing these data with larger sample sizes and multicenter studies may yield better results. Conclusion This prospective cross-sectional study demonstrated that tourniquet deflation during upper extremity surgeries causes a significant transient increase in the Index of Cardiac Electrophysiological Balance (ICEB) and its corrected form (ICEBc), as well as a prolongation of the QT interval. However, these changes appear to be limited and clinically insignificant in the context of short-duration ischemia and smaller ischemic areas characteristic of upper extremity procedures. The observed increase in ICEB and ICEBc after tourniquet release may suggest a subtle alteration in cardiac electrophysiological balance, though the arrhythmogenic risk remains minimal in otherwise healthy patients. These findings highlight ICEB and ICEBc as promising non-invasive markers for perioperative cardiac risk assessment. Further research involving patients with preexisting cardiac conditions or longer tourniquet times is warranted to better elucidate the clinical implications of these changes. Abbreviations ICEB Index of Cardiac Electrophysiological Balance ICEBc Corrected Index of Cardiac Electrophysiological Balance QT QT Interval (a measure of the heart's electrical cycle) QTc Corrected QT Interval (QT interval adjusted for heart rate) QRS QRS Complex (represents ventricular depolarization on ECG) ECG Electrocardiogram HR Heart Rate SAP Systolic Arterial Pressure DAP Diastolic Arterial Pressure MAP Mean Arterial Pressure ASA American Society of Anesthesiologists (Physical Status Classification System) TdP Torsades de Pointes (a specific type of abnormal heart rhythm) VT/VF Ventricular Tachycardia / Ventricular Fibrillation PVC Premature Ventricular Contractions VA Ventricular Arrhythmias SCD Sudden Cardiac Death Declarations Ethics approval and consent to participate : The study was initiated after obtaining ethical approval from the Ethics Committee of Scientific Research in Health Sciences at Kırşehir Ahi Evran University (Approval No: 2024-13/108). All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all patients prior to their inclusion in the study. Consent for publication: Not Applicable Funding and Conflict of Interest Statement : The authors declare that no financial support was received for this study. The authors have no conflicts of interest to disclose. Author Contribution Authors' contributions: FNA contributed to the study design and was the major contributor to the writing of the manuscript. She was responsible for data interpretation and the literature review. RD contributed to the study design, organized the study in terms of ethical and technical aspects, and performed the statistical analyses. GC contributed to data collection and interpretation, and assisted with statistical analysis and interpretation. LH contributed to data collection and supported the final editing of the manuscript and data interpretation. All authors read and approved the final manuscript. Acknowledgement Acknowledgments: The authors would like to express their sincere gratitude to Prof. Recai Dağli for their invaluable guidance and support throughout the design and execution of this study. We also thank our research assistants and colleagues in the department for their contributions to data collection and their constructive input during the study process. Data Availability The data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request. References Saied A, Mousavi AA, Arabnejad F, Heshmati AA. Tourniquet in surgery of the limbs: a review of history, types and complications. Iranian Red Crescent Medical Journal. 2015;17(2):e9588. Oragui E, Parsons A, White T, Longo UG, Khan WS. Tourniquet use in upper limb surgery. Hand. 2011;6(2):165-73. Estebe J-P, Davies JM, Richebe P. The pneumatic tourniquet: mechanical, ischaemia–reperfusion and systemic effects. European Journal of Anaesthesiology| EJA. 2011;28(6):404-11. Kumar K, Railton C, Tawfic Q. Tourniquet application during anesthesia:“What we need to know?”. Journal of Anaesthesiology Clinical Pharmacology. 2016;32(4):424-30. Tse G, Sun B, Wong ST, Tse V, Yeo JM. Anti-arrhythmic effects of hypercalcemia in hyperkalemic, Langendorff-perfused mouse hearts. Biomed Rep. 2016;5(3):301-10. Lu HR, Yan GX, Gallacher DJ. A new biomarker--index of cardiac electrophysiological balance (iCEB)--plays an important role in drug-induced cardiac arrhythmias: beyond QT-prolongation and Torsades de Pointes (TdPs). J Pharmacol Toxicol Methods. 2013;68(2):250-9. Adali MK, Davutoglu Y, Yilmaz S. The relationship between premature ventricular complexes and index of cardiac-electrophysiological balance. Revista da Associação Médica Brasileira. 2023;69:142-6. Sivri S, Çelik M. Evaluation of index of cardiac-electrophysiological balance before and after hemodialysis in patients with end-stage renal disease. Journal of electrocardiology. 2019;54:72-5. Bertrand CA, Steiner NV, Jameson AG, Lopez M. Disturbances of cardiac rhythm during anesthesia and surgery. JAMA. 1971;216(10):1615-7. Pecha S, Kirchhof P, Reissmann B. Perioperative Arrhythmias. Dtsch Arztebl Int. 2023;120(33-34):564-74. Tetzlaff JE, O'Hara Jr J, Yoon HJ, Schubert A. Tourniquet-induced hypertension correlates with autonomic nervous system changes detected by power spectral heart rate analysis. Journal of clinical anesthesia. 1997;9(2):138-42. Aşkın L, Tanrıverdi O. The Cardio-Electrophysiological Balance Index in Cardiovascular Diseases. 2023. Dabrowski W, Siwicka-Gieroba D, Robba C, Badenes R, Kotfis K, Schlegel TT, et al. Decompressive Craniectomy Improves QTc Interval in Traumatic Brain Injury Patients. Int J Environ Res Public Health. 2020;17(22). Yücetas SC, Kaya H, Kafadar S, Kafadar H, Tibilli H, Akcay A. Evaluation of index of cardiac-electrophysiological balance in patients with subarachnoid hemorrhage. BMC Cardiovascular Disorders. 2022;22(1):477. Özdemir L, Sökmen E. Effect of habitual cigarette smoking on the index of cardiac electrophysiological balance in apparently healthy individuals. Journal of Electrocardiology. 2020;59:41-4. Lin Y, Zhou F, Wang X, Guo Y, Chen W. Effect of the index of cardiac electrophysiological balance on major adverse cardiovascular events in patients with diabetes complicated with coronary heart disease. PeerJ. 2023;11:e15969. Zorlu Ç, Ömür SE. Evaluation of index of cardiac electrophysiological balance in type 1 diabetes mellitus. Harran Üniversitesi Tıp Fakültesi Dergisi. 2021;18(3):441-5. Fu X, Yan X, Liu Y. Index of cardiac electrophysiological balance can better predict the risk of arrhythmia than QT and Tp-e interval in patients inhalating sevoflurane. 2023. Tse G, Yan BP. Traditional and novel electrocardiographic conduction and repolarization markers of sudden cardiac death. EP Europace. 2016;19(5):712-21. Wilgis ES. Observations on the effects of tourniquet ischemia. JBJS. 1971;53(7):1343-6. Chen X, Wang Z, Liu L, Zhang W, Tang Z, Liu B, et al. Prognostic value of index of cardiac electrophysiological balance among US middle-aged adults. Frontiers in Cardiovascular Medicine. 2023;10:1139967. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. 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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-7033414","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":513129951,"identity":"80d812f3-c3b6-4c2e-8eff-2aca5c172241","order_by":0,"name":"Fatma Nur Arslan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABA0lEQVRIiWNgGAWjYDCCA0CcwCABJBkfMDBUHIAIPiBOC7MBA8OZAww8IMEEQlogAKiFsQ2ihQGfFr7bB5g/PNxjkTi/gZntwc95d+TsxQ4/BNpiJ6fbgF2L5LkENomEZxKJGw4wsxv2bntmzCOdZgDUkmxsdgC7FoMzDGwMCQeAWhj4j0nwbjuc2COdANJyIHEbbi3MH0BaQA6T/DsHpCX9AyEtDBIgLQ0HmNmkeRtAWnLw2yJ5hrENpMV4w2GgFpljh415bucUHEgwwO0XvjPMhz/+OFAnO7+9mU3yTc1hOfbZ6Zs/fKiwk8OlBRjpDRCaGdXBuJSPglEwCkbBKCAGAACHsWDstT6/dgAAAABJRU5ErkJggg==","orcid":"","institution":"Kırşehir Ahi Evran University","correspondingAuthor":true,"prefix":"","firstName":"Fatma","middleName":"Nur","lastName":"Arslan","suffix":""},{"id":513129952,"identity":"646c1c39-d872-408f-bddb-cb34dfdfee2d","order_by":1,"name":"Recai Dagli","email":"","orcid":"","institution":"Kırşehir Ahi Evran University","correspondingAuthor":false,"prefix":"","firstName":"Recai","middleName":"","lastName":"Dagli","suffix":""},{"id":513129954,"identity":"7896628b-97de-4438-a4ea-8225d40e44b3","order_by":2,"name":"Güzin Ceran","email":"","orcid":"","institution":"Kırşehir Ahi Evran University","correspondingAuthor":false,"prefix":"","firstName":"Güzin","middleName":"","lastName":"Ceran","suffix":""},{"id":513129956,"identity":"4e62ab7e-15a3-4635-b9aa-92be96c47da5","order_by":3,"name":"Levent Horoz","email":"","orcid":"","institution":"Kırşehir Ahi Evran University","correspondingAuthor":false,"prefix":"","firstName":"Levent","middleName":"","lastName":"Horoz","suffix":""}],"badges":[],"createdAt":"2025-07-03 02:23:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7033414/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7033414/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":91191960,"identity":"7a319424-ed0b-4104-a163-be14b5b4d201","added_by":"auto","created_at":"2025-09-12 14:40:56","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":87054,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend.\u003c/p\u003e","description":"","filename":"Figure1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7033414/v1/a9764bf4c2b2605327788786.jpeg"},{"id":91193993,"identity":"316b323e-815a-49bf-83db-a183381a2620","added_by":"auto","created_at":"2025-09-12 14:48:56","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":30807,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7033414/v1/b199298de682f1f85576367f.png"},{"id":91188900,"identity":"eb966950-5c11-427f-b1bc-4349c138822b","added_by":"auto","created_at":"2025-09-12 14:24:57","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":103154,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7033414/v1/44a5e7f9861c26d921b6dfe4.jpg"},{"id":92416583,"identity":"ffa0fe21-7ce4-4722-96c1-0e000438fd9d","added_by":"auto","created_at":"2025-09-29 13:32:10","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1073127,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7033414/v1/c390b9d0-c4c2-470d-967b-69c351a2558f.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effect of tourniquet use on Index of Cardiac-Electrophysiological Balance (ICEB) in upper extremity surgeries, prospective cross-sectional study","fulltext":[{"header":"Background","content":"\u003cp\u003eThe use of a tourniquet during surgical repair of traumatic upper extremity fractures is a very common practice. Surgical Tourniquets are used in orthopaedic for creation of a bloodless field, greater safety, better precision, and more convenience for the surgeon. Despite the ease it provides in terms of surgery, the use of a tourniquet can lead to some complications.\u003c/p\u003e\u003cp\u003eMost surgical tourniquets are of the pneumatic design.(1) When using a pneumatic tourniquet in upper extremity surgeries, a pressure of 150\u0026ndash;250 mmHg is usually applied. The blood flow to the extremity is cut off by this pressure effect. However, stopping the circulation causes temporary ischemia. Limb occlusion causes metabolic changes in the ischemic limb that include: Increased lactic acid, PaCO\u003csub\u003e2\u003c/sub\u003e and potassium levels, and decreased levels of PaO\u003csub\u003e2\u003c/sub\u003e, and pH. Toxic metabolites produce pathophysiological changes when released into the general circulation.(2, 3). The degree of these changes correlates with the duration of ischemia. All of these changes are fully reversed within 30 min of tourniquet deflation. (4) These metabolic changes may have negative effects on cardiac electrical activity. Theoretically, there is a risk that these ischemic metabolites and pH changes may trigger cardiac malignant arrhythmias.\u003c/p\u003e\u003cp\u003eIndeed, pre-clinical studies demonstrated that \u003cem\u003eλ,(\u003c/em\u003e λ\u0026thinsp;=\u0026thinsp;effective refractory period \u0026times; conduction velocity) was the best predictor of arrhythmic tendency, increasing with pro-arrhythmic conditions and decreasing by anti-arrhythmic therapy.(5) The fact that λ must be assessed invasively using electrophysiological investigations in a clinical context is a significant drawback, though. The index of Cardiac-Electrophysiological Balance\u0026rdquo; (iCEB), which is the ratio of QT/QRS of the ECG, was proposed as the noninvasively measured equivalent of λ by Lu et al. Therefore, iCEB could be used as a new biomarker to detect drug-induced broad cardiac arrhythmias including TdP and non-TdP-like VT/VF.(6) In addition, ICEBc, a version calculated with Qtc instead of Qt, has been used in various studies to predict arrhythmia risk, similar to ICEB (7, 8).\u003c/p\u003e\u003cp\u003eIn our study, we aimed to investigate whether ischemic metabolites and other systemic effects occurring after tourniquet application in upper extremity surgeries create any changes on the ICEB and ICEBc values ​​of patients.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eThe study was designed as a prospective, observational study.\u003c/p\u003e\u003cp\u003ePatients were included in the study after their informed consent to participate was obtained by the anesthesiologists during the preoperative evaluation in the anesthesia outpatient clinic of a training and research hospital. The research was conducted in 2024. All data related to the study were recorded by the same anesthesia team.\u003c/p\u003e\u003cp\u003eDuring the preoperative evaluation, American Society of Anesthesiology (ASA) risk group I-III, patients between the ages of 18\u0026ndash;65, who were scheduled for elective upper extremity fixation surgery were included in the study.\u003c/p\u003e\u003cp\u003ePatients with bundle branch block in preoperative ECG, patients with arrhythmia, those taking antiarrhythmic drugs, those with pacemakers, patients with known drug-specific allergies, and patients with electrolyte disorders were not included in the study.\u003c/p\u003e\u003cp\u003e\u003cb\u003ePractices for anesthesia application\u003c/b\u003e\u003c/p\u003e\u003cp\u003ePatients were taken to surgery under general anesthesia or axillary block. Induction was performed with 2 mg/kg propofol, 2 mcg/kg fentanyl, 0.6 mg/kg rocuronium for patients who received general anesthesia and maintenance was performed with 2% sevoflurane and 1 mcg/kg/min remifentanil. In patients who underwent axillary block, axillary plexus block was performed with 0.25% bupivacaine 20 ml.\u003c/p\u003e\u003cp\u003e\u003cb\u003ePractices for tourniquet\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAfter anesthesia application, a VBM (VBM Medizintechnik GmbH, Germany) tourniquet was placed on the humerus of the upper extremity where surgery was performed. The tourniquet pressure was set to 200-250mmHg. The tourniquet start time and pressure were recorded.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStandart study practice\u003c/b\u003e\u003c/p\u003e\u003cp\u003eECG measurements were taken from the patients at 6 different time points.After calculating QT, QTc and QRS durations from D II and V5 derivations, iCEB and ICEBc calculations was made. iCEB is calculated by dividing the QT interval by the QRS duration (QT/ QRS). iCEBc is calculated by dividing the QTc interval by the QRS duration (QTc/ QRS).\u003c/p\u003e\u003cp\u003ePrimarly, ICEB and ICEBc values were evaluated at across six time points: Time 1: 5 minutes before anesthesia (ICEB1\u0026amp;ICEBc1), Time 2: 5 minutes after anestehesia (ICEB2\u0026amp;ICEBc2), Time 3: before 5 minutes tourniquet inflation(ICEB3\u0026amp;ICEBc3), Time 4: after 5 minutes tourniquet inflation (ICEB4\u0026amp;ICEBc4), Time 5: before 5 minutes tourniquet deflation (ICEB5\u0026amp;ICEBc5), Time 6: after 5 minutes tourniquet deflation (ICEB6\u0026amp;ICEBc6).\u003c/p\u003e\u003cp\u003eICEB and ICEBc changes in the perioperative period was evaluated in three different stages. Effects of general anesthesia or Peripheral Nerve Blocks on ICEB (ICEB 1 vs ICEB 2) and ICEBc (ICEBc 1 vs ICEBc 2), Effects of tourniquet inflation on ICEB (ICEB 3 vs ICEB 4) and ICEBc (ICEBc 3 vs ICEBc 4), Effects of tourniquet deflation on ICEB (ICEB 5 vs ICEB 6) and ICEBc (ICEBc 5 vs ICEBc 6). Simultaneously, systolic arterial pressures ( SAP), diastolic arterial pressures (DAP), mean arterial pressure (MAP), heart rate (HR), were recorded non-invasively.\u003c/p\u003e\u003cp\u003eThe primary outcome of our study was whether there was a significant increase in ICEB and ICEBc values ​​in those three stages. The secondary outcomes of the study was whether there was a significant changes in HR, QT, QRS, SAP, DAP, and MAP values at those three time points.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSample size\u003c/b\u003e\u003c/p\u003e\u003cp\u003eForty patients accepted to participate in the study, 11 of whom were excluded because they met the exclusion criteria as a result of preoperative evaluation. Of the remaining 29 patients, the pilot study was conducted with 20 patients to determine the study's sample size because 9 patients had incomplete data or refused surgery. As a result of statistical tests, Partial Eta Squared was found to be 0.149. G\u003csup\u003e*\u003c/sup\u003e Power 3.1.9.7 (Franz Faul, Universitat Kiel, Germany) was used for A priori power analysis. Effect size was determined as f\u0026thinsp;=\u0026thinsp;0.418 by F tests - ANOVA (Repeated measures, within factors). Test input parameters were, respectively, α err probe\u0026thinsp;=\u0026thinsp;0.05, Power (1-β err probe)\u0026thinsp;=\u0026thinsp;0.95, Corr among rep measures\u0026thinsp;=\u0026thinsp;0.5, Nonsphericity correction ε\u0026thinsp;=\u0026thinsp;1. The total sample size was 12. Statistical analysis was performed on 20 patients evaluated in the pilot study. See strobe diagram in Fig.\u0026nbsp;1.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStatistics\u003c/b\u003e\u003c/p\u003e\u003cp\u003eIBM SPSS Statistics, version 29.0.0 (IBM Corp, Armonk, NY, USA), was used to analyse the study's data.\u003c/p\u003e\u003cp\u003eThe research results were presented with frequency (n), percentage (%), mean, standard deviation, 95% CI (Confidence Interval), median, 25%-75% percentile (Q1-Q3) values.\u003c/p\u003e\u003cp\u003eThe Shapiro Wilk Test were used for the normality assumption of data.\u003c/p\u003e\u003cp\u003eIt was evaluated whether the difference between repeated measurements occurred over time.\u003c/p\u003e\u003cp\u003eWhen the data were normally distributed, a one-way repeated measures ANOVA was used, and when they were not, the Friedman Test was used.\u003c/p\u003e\u003cp\u003eTo Pairwise comparisons of significant results after ANOVA, was used with Bonferroni.\u003c/p\u003e\u003cp\u003eStatistically significant is p\u0026thinsp;\u0026lt;\u0026thinsp;.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003ePatients\u0026rsquo; basic characteristics and perioperative data are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Total of 20, 10 female and 10 male, patients were evaluated. The mean age was 50.55 (15.88).\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\u003ePatient\u0026rsquo;s basic characteristics\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eASA\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eASA I (n)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eASA II (n)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eASAIII (n)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGender\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFemale (n)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMale (n)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAnesthesia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eGeneral (n)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePeripheral Nerve Blocks (n)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eAge (Year)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50.55 (15.88)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eHeight (m)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.67 (7.91)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eWeight (kg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e81.05 (6.75)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28.84 (5.79)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eOperation duration (min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e105.50 (20.12)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eIntravenous fluid volume (ml)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1200.00 [1000.00\u0026ndash;1500.00]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eTurniquet duration (min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e52.00 [46.00\u0026ndash;67.00]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eTurniquet pressure\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e243.00 (27.93)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"3\"\u003eASA: American Society of Anesthesiologists physical status score .\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"3\"\u003eBMI: Body Mass Index\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"3\"\u003eData were presented as n, mean (SD), and median [Q1-Q3].\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eWhen the comorbidities of the patients were examined, ten patients had hypertension, and they were regularly using medical drugs for the treatment of hypertension.\u003c/p\u003e\u003cp\u003e\u003cb\u003eICEB\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe primary variable evaluated in our study is changing the ICEB values before and after the deflated tourniquet. ICEB values were evaluated at across six time points (Fig.\u0026nbsp;1) (ICEB1), Time 2 (ICEB2), Time 3 (ICEB3), Time4 (ICEB4), Time 5 (ICEB5), Time 6 (ICEB6)). A One-Way repeated measures ANOVA test indicated there was a significant effect for ICEB across the times, F (5,95)\u0026thinsp;=\u0026thinsp;11.560, p\u0026thinsp;\u0026lt;\u0026thinsp;.001, ηp2\u0026thinsp;=\u0026thinsp;.378. (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\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\u003eICEBc measurements.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMean [SD]\u003c/p\u003e\u003cp\u003e95% Confidence Interval\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMean Difference\u003c/p\u003e\u003cp\u003e95% Confidence Interval for Difference\u003c/p\u003e\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003eICEBc\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eICEBc1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.697 (.480)\u003c/p\u003e\u003cp\u003e[4.472\u0026ndash;4.922]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u0026minus;\u0026thinsp;.059 [-,366 \u0026minus;\u0026thinsp;.247]\u003c/p\u003e\u003cp\u003ep = 1.000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003edf: 5\u003c/p\u003e\u003cp\u003eF\u0026thinsp;=\u0026thinsp;3.315\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.061\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eICEBc2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.757 (.580) [4.485\u0026ndash;5.028]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eICEBc3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.931 (.745)\u003c/p\u003e\u003cp\u003e[4.583\u0026ndash;5.280]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e.102 [-.220 \u0026minus;\u0026thinsp;.425]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;1.000\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eICEBc4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.829 (.572)\u003c/p\u003e\u003cp\u003e[4.561\u0026ndash;5.097]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eICEBc5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.978 (.579)\u003c/p\u003e\u003cp\u003e[4.707\u0026ndash;5.249]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u0026minus;\u0026thinsp;.006 [-.241 \u0026minus;\u0026thinsp;.228]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;1.000\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eICEBc6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.985 (.598)\u003c/p\u003e\u003cp\u003e[4.704\u0026ndash;5.265]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e* One-Way repeated measures ANOVA test,\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eDescriptive statistics are presented with mean (standard deviation), 95% CI (Confidence Interval).\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eOn average, Time 1 ICEB values (ICEB1 4.273 (.588)) were lower than Time 2 (ICEB2 4.405 (.586)). Time 3 (ICEB3 4.652 (.773)) were higher than Time 4 (ICEB4 4.581 (.684)). Time 5 (ICEB5 4.797 (.650)) were lower than Time 6 (ICEB6 4.927 (.711)). (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eICEB change in the perioperative period was evaluated in three different stages. Effects of general or Peripheral Nerve Blocks on ICEB (Time 1 vs Time 2), Effects of tourniquet inflation on ICEB (Time 3 vs Time 4), Effects of tourniquet deflation on ICEB (Time 5 vs Time 6).\u003c/p\u003e\u003cp\u003eAnesthesia and tourniquet deflation has increased the ICEB, Tourniquet inflation has decreased the ICEB but had no statistical significance. Pairwise Comparisons were conducted using the Bonferroni correction.\u003c/p\u003e\u003cp\u003eThe values ​​measured after the tourniquet deflation were higher than all measurements in the perioperative period. The difference between Time 6 and Time 1, .655 95% CI [.234\u0026ndash;1.075] (p\u0026thinsp;\u0026lt;\u0026thinsp;.001), Time 6 and Time 2, .523 95% CI [.103 \u0026minus;\u0026thinsp;.942] (p\u0026thinsp;\u0026lt;\u0026thinsp;001), Time 6 and Time 4, .347 95% CI [.023 \u0026minus;\u0026thinsp;.670], was statistically significant (p\u0026thinsp;=\u0026thinsp;.029). See also Fig.\u0026nbsp;2.\u003c/p\u003e\u003cp\u003e\u003cb\u003eICEBc\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe other primary variable evaluated in our study is changing the ICEBc values before and after the deflated tourniquet. ICEBc values were evaluated at across six time points (Fig.\u0026nbsp;1). Time 1 (ICEBc1), Time 2 (ICEBc2), Time 3 (ICEBc3), Time4 (ICEBc4), Time 5 (ICEBc5), Time 6 (ICEBc6)). A One-Way repeated measures ANOVA test indicated there was a significant effect for ICEBc across the times, F (5,95)\u0026thinsp;=\u0026thinsp;3.315, p\u0026thinsp;=\u0026thinsp;.061, ηp2\u0026thinsp;=\u0026thinsp;.149 (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eOn average, Time 1 ICEBc values (ICEBc1 4.697 (.480)) were lower than Time 2 (ICEBc2 4.757 (.580)). Time 3 (ICEBc3 4.931 (.745)) were higher than Time 4 (ICEBc4 4.829 (.572)). Time 5 (ICEBc5 4.978 (.579)) were lower than Time 6 (ICEBc6 4.985 (.598)) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAnesthesia and tourniquet deflation has increased the ICEBc, Tourniquet inflation has decreased the ICEBc but had no statistical significance.\u003c/p\u003e\u003cp\u003eThe ICEBc values ​​measured after the tourniquet deflation were higher than all measurements in the perioperative period. The difference across Times was not statistically significant. See also Fig.\u0026nbsp;3.\u003c/p\u003e\u003cp\u003e\u003cb\u003eHR\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe secondary variable evaluated in our study is changing the HR values at across six time points. On average, Time 1 HR values (79.850 (14.173)) were higher than Time 2 (HR2 78. 79.300 (16.219)). Time 3 (HR3 74.100 (14.772)) were hihger than Time 4 (HR4 73.300 (16.461)). Time 5 (HR5 69.250 (14.015)) were higher than Time 6 (HR6 63.400 (11.509)) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eHeart rate, QT, QRS measurements.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMean [SD]\u003c/p\u003e\u003cp\u003e95% Confidence Interval\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMean Difference\u003c/p\u003e\u003cp\u003e95% Confidence Interval for Difference\u003c/p\u003e\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003eHR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHR 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e79.850 (14.173)\u003csup\u003eABCD\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[73.217\u0026ndash;86.483]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e.550 [-7.985\u0026ndash;9.085]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;1.000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003edf: 5\u003c/p\u003e\u003cp\u003eF\u0026thinsp;=\u0026thinsp;11.089\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHR 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e79.300 (16.219)\u003csup\u003eABCD\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[71.709\u0026ndash;86.891]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHR 3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e74.100 (14.772)\u003csup\u003eABCDE\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[67.187\u0026ndash;81.013]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e.800 [-7.593\u0026ndash;9.193]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;1.000\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHR 4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e73.300 (16.461)\u003csup\u003eABCDE\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[65.596\u0026ndash;81.004]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHR 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e69.250 (14.015)\u003csup\u003eBCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[62.691\u0026ndash;75.809]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e5.850 [-.694\u0026ndash;12.394]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.111\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHR 6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e63.400 (11.509)\u003csup\u003eEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[58.013\u0026ndash;68.787]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003eQT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQT 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e374.000 (30.116)\u003csup\u003eAB\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[359.905-388.095]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e-15.100 [-37.934\u0026ndash;7.734]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.584\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003edf\u0026thinsp;=\u0026thinsp;5\u003c/p\u003e\u003cp\u003eF\u0026thinsp;=\u0026thinsp;19.009\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQT 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e389.100 (36.502)\u003csup\u003eABCD\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[372.016-406.184]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQT 3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e409.700 (39.859)\u003csup\u003eBCDE\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[391.045-428.355]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e9.800 [-16.371\u0026ndash;35.971]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;1.000\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQT 4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e399.900 (39.632)\u003csup\u003eBCD\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[381.351-418.449]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQT 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e418.200 (34.713)\u003csup\u003eEC\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[401.954-434.446]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e-16.700 [-31.686 - -1.714]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.021\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQT 6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e434.900 (47.090)\u003csup\u003eF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[412.861-456.939]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003eQRS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQRS 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e88.400 (9.236)\u003c/p\u003e\u003cp\u003e[84.077\u0026ndash;92.723]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u0026minus;\u0026thinsp;.800 [-4.705\u0026ndash;3.105]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;1.000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003edf\u0026thinsp;=\u0026thinsp;5\u003c/p\u003e\u003cp\u003eF\u0026thinsp;=\u0026thinsp;.308\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.837\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQRS 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e89.200 (8.883)\u003c/p\u003e\u003cp\u003e[85.043\u0026ndash;93.357]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQRS 3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e89.500 (11.404)\u003c/p\u003e\u003cp\u003e[84.163\u0026ndash;94.837]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e1.300 [ -5.288\u0026ndash;7.888]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;1.000\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQRS 4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e88.200 (8.965)\u003c/p\u003e\u003cp\u003e[84.004\u0026ndash;92.396]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQRS 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e87.900 (8.322)\u003c/p\u003e\u003cp\u003e[84.005\u0026ndash;91.795]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e-1.100 [-4.158\u0026ndash;1.958]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;1.000\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQRS 6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e89.000 (9.481)\u003c/p\u003e\u003cp\u003e[84.563\u0026ndash;93.437]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eHR: Heart rate, QT: QT interval QRS: QRS interval. * One-Way repeated measures ANOVA test.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eDescriptive statistics are presented with mean (standard deviation), 95% CI (Confidence Interval).\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eDifferent letters on the same rows indicate statistical differences between measurements at other times.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAnesthesia, Tourniquet inflation and tourniquet deflation has decreased the HR, but had no statistical significance (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe HR values measured after the tourniquet deflation (HR6) were lower than all measurements in the perioperative period. The difference across Time 1, 2,3 and,4 were statistically significant.\u003c/p\u003e\u003cp\u003e\u003cb\u003eQT\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe secondary variable evaluated in our study is changing the QT values at across six time points. On average, Time 1 QT values (374.000 (30.116)) were higher than Time 2 (QT2 389.100 (36.502)). Time 3 (QT3 409.700 (39.859)) were hihger than Time 4 (QT4 399.900 (39.632)). Time 5 (QT5 418.200 (34.713)) were higher than Time 6 (QT6 434.900 (47.090)) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAnesthesia has increased and tourniquet inflation has decreased the QT, but had no statistical significance. Tourniquet deflation has increased the QT as statistical significance (p\u0026thinsp;=\u0026thinsp;0.021) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe QT values ​​measured after the tourniquet deflation (QT6) were higher than all measurements in the perioperative period and all the difference across all Times were statistically significant.\u003c/p\u003e\u003cp\u003e\u003cb\u003eQRS\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe secondary variable evaluated in our study is changing the QRS values at across six time points. Anesthesia, and tourniquet deflation has increased the QRS, tourniquet inflation has decreased the QRS, but had no statistical significance (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe changes in QRS values were not statistically significant at any time in the perioperative period.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSAP, DAP, and MAP\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe secondary variables, such as SAP, DAP, and MAP has been evelueted at across six time points.\u003c/p\u003e\u003cp\u003eAnesthesia and tourniquet deflation has decreased the SAP, DAP, and MAP. Tourniquet inflation has increased the SAP, DAP, and MAP, but had no statistical significance (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eArterial blood pressure measurements.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMean [SD]\u003c/p\u003e\u003cp\u003e95% Confidence Interval\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMean Difference\u003c/p\u003e\u003cp\u003e95% Confidence Interval for Difference\u003c/p\u003e\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003eSAP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSAP 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e150.250 (29.042)\u003csup\u003eABD\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[136.658-163.842]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e24.650 [-.343\u0026ndash;49.643]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.055\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003edf: 5\u003c/p\u003e\u003cp\u003eF\u0026thinsp;=\u0026thinsp;9.898\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSAP 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e125.600 (25.910)\u003csup\u003eABCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[113.474-137.726]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSAP 3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e116.550 (20.221)\u003csup\u003eBCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[107.086-126.014]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e-7.600 [-18.897\u0026ndash;3.697]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.540\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSAP 4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e124.150 (19.626)\u003csup\u003eABCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[114.965-133.335]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSAP 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e119.300 (19.863)\u003csup\u003eBCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[110.004-128.596]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e4.400 [-2.108\u0026ndash;10.908]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.528\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSAP 6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e114.900 (23.387)\u003csup\u003eBCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[103.955-125.845]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003eDAP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDAP 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e84.950 (14.196)\u003csup\u003eABD\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[78.306\u0026ndash;91.594]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e6.950 [-6.553\u0026ndash;20.453]\u003c/p\u003e\u003cp\u003eP\u0026thinsp;=\u0026thinsp;1.000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003edf\u0026thinsp;=\u0026thinsp;5\u003c/p\u003e\u003cp\u003eF\u0026thinsp;=\u0026thinsp;6.443\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDAP 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e78.000 (14.411)\u003csup\u003eABCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[71.255\u0026ndash;84.745]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDAP 3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e68.900 (13.102)\u003csup\u003eBCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[62.768\u0026ndash;75.032]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e-6.150 [-14,577\u0026ndash;2.277]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.364\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDAP 4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e75.050 (13.153)\u003csup\u003eABCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[68.894\u0026ndash;81.206]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDAP 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e69.800 (11.808)\u003csup\u003eBCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[64.274\u0026ndash;75.326]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e1.400 [-7.667\u0026ndash;10.467]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;1.000\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDAP 6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e68.400 (14.901)\u003csup\u003eBCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[61.426\u0026ndash;75.374]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003eMAP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMAP 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e110.400 (17.307)\u003csup\u003eABD\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[102.300-118.500]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e15.850 [-.384\u0026ndash;32.084]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.060\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003edf\u0026thinsp;=\u0026thinsp;5\u003c/p\u003e\u003cp\u003eF\u0026thinsp;=\u0026thinsp;10.304\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMAP 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e94.550 (18.875)\u003csup\u003eABCDE\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[85.716-103.384]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMAP 3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e82.350 (16.461)\u003csup\u003eBCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[74.646\u0026ndash;90.054]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e-10.250 [-23.091\u0026ndash;2.591]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.224\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMAP 4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e92.600 (17.313)\u003csup\u003eABCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[84.497-100.703]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMAP 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e87.400 (14.009)\u003csup\u003eBCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[80.844\u0026ndash;93.956]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e3.850 [-1.370\u0026ndash;9.070]\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;.345\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMAP 6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e83.550 (17.620)\u003csup\u003eBCDEF\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e[75.303\u0026ndash;91.797]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eSAP: systolic arterial blood pressure, DAP: diastolic arterial blood pressure MAP: mean arterial blood pressure. * One-Way repeated measures ANOVA test.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eDescriptive statistics are presented with mean (standard deviation), 95% CI (Confidence Interval). Different letters on the same rows indicate statistical differences between measurements at other times.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe SAP, DAP, and MAP values ​​ after the tourniquet deflation (SAP6) were lower than all measurements in the perioperative period. The difference across Time 1 was statistically significant.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe frequency of intraoperative arrhythmia is quite high, in fact, this frequency rises to 89% with continuous monitoring, similar to the figures for cardiac surgery (9). The vast majority of these arrhythmias are transient benign arrhythmias. Fluid shifts, inflammatory responses, and the resulting cardiovascular stress appear to be important triggers of perioperative arrhythmias (10). However, malignant arrhythmias, especially broad cardiac arrhythmias including TdP and non-TdP-like VT/VF, are among the most dangerous arrhythmias that require urgent intervention and can be life-threatening. As a potential triggering factor of those malignant arrythmias, possible contributing factors of a tourniquet use include increased serum levels of lactate, carbon dioxide, free radicals and prostaglandins as a result of local tissue hypoxia(4) Tourniquets may also increase blood pressure, probably because of autonomous nervous system changes (11) which may all contribute triggering malignant arrhythmias.\u003c/p\u003e\u003cp\u003eMany parameters have been studied to predict malignant arrhythmias by using ECG measurements. There is no comprehensive easy-to-measure risk marker for drug-induced ventricular arrhythmias (VAs) to assess sudden cardiac death (SCD) The prolonged corrected (QTc) interval alone is insufficient for identifying malignant ventricular arrhythmias.(12) According to the Lu et. Al, the very first team to introduce ICEB, the iCEB (the ratio of QT/QRS) derived from the ECG, should be the equivalent of the classic λ (ERPxCV), and significant changes in iCEB may reflect an imbalance in cardiac electrophysiology, and therefore predict cardiac arrhythmias. Therefore, iCEB could be used as a new biomarker to detect drug-induced broad cardiac arrhythmias including TdP and non-TdP-like VT/VF (6). The iCEB is a measure of the balance between the sympathetic and parasympathetic nervous systems in the heart. Studies have shown that an imbalance in the autonomic nervous system can increase the risk of developing ventricular arrhytmias (VA). (12)\u003c/p\u003e\u003cp\u003eICEB has some degree of heart-rate dependency, meaning that ICEB, like the QT interval itself, should optimally be corrected for underlying heart rate (13).ICEBc, a new, noninvasive marker, may predict Premature Ventricular Contractions(PVC) in structurally normal hearts. The iCEBc indicates electrophysiological balance and arrhythmia risk beyond other ECG measures A high iCEB, indicating a sympathetic predominance, has been associated with an increased risk of VA\u0026rsquo;s in patients with various cardiac conditions, including heart failure and myocardial infarction. (7).\u003c/p\u003e\u003cp\u003eAlthough clear value ranges for ICEB and ICEBc are not given in the studies in the literature, study-based data show that normal ICEB values ​​are around 4 (14, 15) One study claims that the normal value for ICEB is 4.24, with a reference range of 3.14 to 5.35.(16). Some conditions like cigarette smoking(15), type 1 diabetes mellitus(17) and sevoflurane inhalation(18) increases ICEB values. Experimental studies have shown that 10% increases or decreases in ICEB could be a promising marker for risk of drug-induced cardiac arrhythmias(8, 19). Most of the studies in the literature focus on the increase in baseline ICEB and ICEBc values ​​and the risk of cardiac arrhythmia that occurs as a result, rather than providing specific value ranges as we did in our study.\u003c/p\u003e\u003cp\u003eIn our study, there was no significant difference between the ICEB and ICEBc values ​​calculated before and after tourniquet deflation. One reason for this may be that the ischemic area is smaller in upper extremity surgeries compared to the lower extremities, and that our tourniquet times are within the safe range specified in the literature (less than 2 hours), thus shortening the ischemia times. Two hours has a logical basis, since after this time of ischemia, progressive venous acidosis will occur in the region the tourniquet effects (20). Based on this, it can be suggested that tourniquet use alone does not increase the risk of arrhythmia in upper extremity surgeries. Our study showed that there was a significant increase in the QT interval between tourniquet inflation and deflation. Despite the increased QT, the lack of a significant increase in ICEB and ICEBc values ​​indicates that QT and ICEB values ​​do not follow a parallel course. In fact, in a previous study by Sivri et al., similarly, QT values ​​and ICEB values ​​followed an independent course from each other, and the study showed that iCEB and iCEBc were elevated after hemodialysis but there was no significant change in the QT interval or QTc, indicating that the new ECG marker was more sensitive to cardiac electrophysiological balance. ICEBc lengthening or shortening increased the risk of malignant arrhythmia (8). Also in a retrospective cohort study involved 5010 adults aged 40\u0026ndash;65 years who participated in the Third National Health and Nutrition Examination Survey (NHANES-III) and whose electrocardiograms were in sinus rhythm, it was found that Prolonged iCEBc was associated with an increased risk of all-cause or cardiac mortality and the association was independent of conventional risk factors, even QRS duration and prolonged QTc. In the normal QTc subgroup of interest, prolonged iCEBc remained significantly associated with all-cause mortality. This suggests that the indicator can identify high-risk populations that QTc cannot identify. Elevated iCEBc (male\u0026thinsp;\u0026ge;\u0026thinsp;4.57, female\u0026thinsp;\u0026ge;\u0026thinsp;4.98) is an independent risk factor for cardiac or all-cause death among middle-age adults (21).\u003c/p\u003e\u003cp\u003eIn our study, ICEB and ICEBc values ​​were found to be higher than all other measurements after tourniquet deflation. In patient groups with already high ICEB and ICEBc values, this effect may increase the risk of cardiac arrhythmia compared to patients with normal initial values. Further studies are required to evaluate such patient groups.\u003c/p\u003e\u003cp\u003e\u003cb\u003eLimitations\u003c/b\u003e\u003c/p\u003e\u003cp\u003eIn order for the study to yield more reliable and generalizable results, it would have yielded better results if it was conducted on patients with a similar health profile in a similar age group using a single type of anesthesia method. We did not have any cases where the tourniquet duration was longer than 2 hours. It may be interesting to examine these values ​​in dangerous tourniquet durations. In addition, we could not see the effects of rhythm regulators such as beta-blockers in this study. This study can be repeated with patients at high cardiac risk who use these types of drugs. Analyzing these data with larger sample sizes and multicenter studies may yield better results.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis prospective cross-sectional study demonstrated that tourniquet deflation during upper extremity surgeries causes a significant transient increase in the Index of Cardiac Electrophysiological Balance (ICEB) and its corrected form (ICEBc), as well as a prolongation of the QT interval. However, these changes appear to be limited and clinically insignificant in the context of short-duration ischemia and smaller ischemic areas characteristic of upper extremity procedures. The observed increase in ICEB and ICEBc after tourniquet release may suggest a subtle alteration in cardiac electrophysiological balance, though the arrhythmogenic risk remains minimal in otherwise healthy patients. These findings highlight ICEB and ICEBc as promising non-invasive markers for perioperative cardiac risk assessment. Further research involving patients with preexisting cardiac conditions or longer tourniquet times is warranted to better elucidate the clinical implications of these changes.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eICEB\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eIndex of Cardiac Electrophysiological Balance\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eICEBc\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eCorrected Index of Cardiac Electrophysiological Balance\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eQT\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eQT Interval (a measure of the heart's electrical cycle)\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eQTc\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eCorrected QT Interval (QT interval adjusted for heart rate)\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eQRS\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eQRS Complex (represents ventricular depolarization on ECG)\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eECG\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eElectrocardiogram\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eHR\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHeart Rate\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eSAP\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eSystolic Arterial Pressure\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eDAP\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eDiastolic Arterial Pressure\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eMAP\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMean Arterial Pressure\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eASA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eAmerican Society of Anesthesiologists (Physical Status Classification System)\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eTdP\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eTorsades de Pointes (a specific type of abnormal heart rhythm)\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eVT/VF\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eVentricular Tachycardia / Ventricular Fibrillation\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003ePVC\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePremature Ventricular Contractions\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eVA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eVentricular Arrhythmias\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eSCD\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eSudden Cardiac Death\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003e\u003cem\u003eEthics approval and consent to participate\u003c/em\u003e:\u003c/h2\u003e\u003cp\u003e The study was initiated after obtaining ethical approval from the Ethics Committee of Scientific Research in Health Sciences at Kırşehir Ahi Evran University (Approval No: 2024-13/108). All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all patients prior to their inclusion in the study.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConsent for publication:\u003c/strong\u003e\u003cp\u003eNot Applicable\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003e\u003cem\u003eand Conflict of Interest Statement\u003c/em\u003e: The authors declare that no financial support was received for this study. The authors have no conflicts of interest to disclose.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAuthors' contributions: FNA contributed to the study design and was the major contributor to the writing of the manuscript. She was responsible for data interpretation and the literature review. RD contributed to the study design, organized the study in terms of ethical and technical aspects, and performed the statistical analyses. GC contributed to data collection and interpretation, and assisted with statistical analysis and interpretation. LH contributed to data collection and supported the final editing of the manuscript and data interpretation. All authors read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eAcknowledgments: The authors would like to express their sincere gratitude to Prof. Recai Dağli for their invaluable guidance and support throughout the design and execution of this study. We also thank our research assistants and colleagues in the department for their contributions to data collection and their constructive input during the study process.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSaied A, Mousavi AA, Arabnejad F, Heshmati AA. Tourniquet in surgery of the limbs: a review of history, types and complications. Iranian Red Crescent Medical Journal. 2015;17(2):e9588.\u003c/li\u003e\n\u003cli\u003eOragui E, Parsons A, White T, Longo UG, Khan WS. Tourniquet use in upper limb surgery. Hand. 2011;6(2):165-73.\u003c/li\u003e\n\u003cli\u003eEstebe J-P, Davies JM, Richebe P. The pneumatic tourniquet: mechanical, ischaemia\u0026ndash;reperfusion and systemic effects. European Journal of Anaesthesiology| EJA. 2011;28(6):404-11.\u003c/li\u003e\n\u003cli\u003eKumar K, Railton C, Tawfic Q. Tourniquet application during anesthesia:\u0026ldquo;What we need to know?\u0026rdquo;. Journal of Anaesthesiology Clinical Pharmacology. 2016;32(4):424-30.\u003c/li\u003e\n\u003cli\u003eTse G, Sun B, Wong ST, Tse V, Yeo JM. Anti-arrhythmic effects of hypercalcemia in hyperkalemic, Langendorff-perfused mouse hearts. Biomed Rep. 2016;5(3):301-10.\u003c/li\u003e\n\u003cli\u003eLu HR, Yan GX, Gallacher DJ. A new biomarker--index of cardiac electrophysiological balance (iCEB)--plays an important role in drug-induced cardiac arrhythmias: beyond QT-prolongation and Torsades de Pointes (TdPs). J Pharmacol Toxicol Methods. 2013;68(2):250-9.\u003c/li\u003e\n\u003cli\u003eAdali MK, Davutoglu Y, Yilmaz S. The relationship between premature ventricular complexes and index of cardiac-electrophysiological balance. Revista da Associa\u0026ccedil;\u0026atilde;o M\u0026eacute;dica Brasileira. 2023;69:142-6.\u003c/li\u003e\n\u003cli\u003eSivri S, \u0026Ccedil;elik M. Evaluation of index of cardiac-electrophysiological balance before and after hemodialysis in patients with end-stage renal disease. Journal of electrocardiology. 2019;54:72-5.\u003c/li\u003e\n\u003cli\u003eBertrand CA, Steiner NV, Jameson AG, Lopez M. Disturbances of cardiac rhythm during anesthesia and surgery. JAMA. 1971;216(10):1615-7.\u003c/li\u003e\n\u003cli\u003ePecha S, Kirchhof P, Reissmann B. Perioperative Arrhythmias. Dtsch Arztebl Int. 2023;120(33-34):564-74.\u003c/li\u003e\n\u003cli\u003eTetzlaff JE, O'Hara Jr J, Yoon HJ, Schubert A. Tourniquet-induced hypertension correlates with autonomic nervous system changes detected by power spectral heart rate analysis. Journal of clinical anesthesia. 1997;9(2):138-42.\u003c/li\u003e\n\u003cli\u003eAşkın L, Tanrıverdi O. The Cardio-Electrophysiological Balance Index in Cardiovascular Diseases. 2023.\u003c/li\u003e\n\u003cli\u003eDabrowski W, Siwicka-Gieroba D, Robba C, Badenes R, Kotfis K, Schlegel TT, et al. Decompressive Craniectomy Improves QTc Interval in Traumatic Brain Injury Patients. Int J Environ Res Public Health. 2020;17(22).\u003c/li\u003e\n\u003cli\u003eY\u0026uuml;cetas SC, Kaya H, Kafadar S, Kafadar H, Tibilli H, Akcay A. Evaluation of index of cardiac-electrophysiological balance in patients with subarachnoid hemorrhage. BMC Cardiovascular Disorders. 2022;22(1):477.\u003c/li\u003e\n\u003cli\u003e\u0026Ouml;zdemir L, S\u0026ouml;kmen E. Effect of habitual cigarette smoking on the index of cardiac electrophysiological balance in apparently healthy individuals. Journal of Electrocardiology. 2020;59:41-4.\u003c/li\u003e\n\u003cli\u003eLin Y, Zhou F, Wang X, Guo Y, Chen W. Effect of the index of cardiac electrophysiological balance on major adverse cardiovascular events in patients with diabetes complicated with coronary heart disease. PeerJ. 2023;11:e15969.\u003c/li\u003e\n\u003cli\u003eZorlu \u0026Ccedil;, \u0026Ouml;m\u0026uuml;r SE. Evaluation of index of cardiac electrophysiological balance in type 1 diabetes mellitus. Harran \u0026Uuml;niversitesi Tıp Fak\u0026uuml;ltesi Dergisi. 2021;18(3):441-5.\u003c/li\u003e\n\u003cli\u003eFu X, Yan X, Liu Y. Index of cardiac electrophysiological balance can better predict the risk of arrhythmia than QT and Tp-e interval in patients inhalating sevoflurane. 2023.\u003c/li\u003e\n\u003cli\u003eTse G, Yan BP. Traditional and novel electrocardiographic conduction and repolarization markers of sudden cardiac death. EP Europace. 2016;19(5):712-21.\u003c/li\u003e\n\u003cli\u003eWilgis ES. Observations on the effects of tourniquet ischemia. JBJS. 1971;53(7):1343-6.\u003c/li\u003e\n\u003cli\u003eChen X, Wang Z, Liu L, Zhang W, Tang Z, Liu B, et al. Prognostic value of index of cardiac electrophysiological balance among US middle-aged adults. Frontiers in Cardiovascular Medicine. 2023;10:1139967.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Arrhythmias, Cardiac, Tourniquets, Electrocardiography","lastPublishedDoi":"10.21203/rs.3.rs-7033414/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7033414/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eThis study aimed to investigate the effects of tourniquet application during upper extremity surgeries on the Index of Cardiac Electrophysiological Balance (ICEB) and its corrected form (ICEBc), which are novel, non-invasive electrocardiographic markers used to assess arrhythmia risk.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eThis prospective cross-sectional study included 20 patients aged 18\u0026ndash;65 years with ASA physical status I\u0026ndash;III, scheduled for elective upper extremity fixation surgery. ICEB and ICEBc values were calculated at six different time points perioperatively using electrocardiographic measurements. Additional parameters such as heart rate (HR), QT interval, QRS duration, systolic/diastolic/mean arterial pressure (SAP/DAP/MAP) were also recorded. Data were analyzed using repeated-measures ANOVA and Friedman tests, as appropriate.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eICEB and ICEBc values showed significant increases after tourniquet deflation compared to baseline (ICEB p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). QT intervals were also significantly prolonged after deflation (p\u0026thinsp;=\u0026thinsp;0.021). While tourniquet inflation caused slight decreases in ICEB and ICEBc, these changes were not statistically significant. Heart rate and blood pressure showed expected perioperative fluctuations but did not significantly influence ICEB trends.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eTourniquet deflation in upper extremity surgeries may cause transient increases in ICEB and ICEBc, suggesting a possible, though limited, impact on cardiac electrophysiological balance. However, given the short duration and smaller ischemic area of upper extremity tourniquet use, the arrhythmogenic risk appears to be minimal. ICEB and ICEBc may serve as useful markers for perioperative cardiac risk stratification and warrant further investigation.\u003c/p\u003e\u003ch2\u003eClinical Trial\u003c/h2\u003e\u003cp\u003e: PRS Number:NCT06936150 / \u003cb\u003eRegistration Date\u003c/b\u003e: 12.04.2025 /Retrospectively Registered\u003c/p\u003e","manuscriptTitle":"Effect of tourniquet use on Index of Cardiac-Electrophysiological Balance (ICEB) in upper extremity surgeries, prospective cross-sectional study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-12 14:24:52","doi":"10.21203/rs.3.rs-7033414/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"d47aa647-2800-4f17-a715-d4b96bec6458","owner":[],"postedDate":"September 12th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-29T13:24:02+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-12 14:24:52","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7033414","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7033414","identity":"rs-7033414","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}