The effects of different timing fluid regimen on maternal myocardial repolarization in elective cesarean section patients undergoing spinal anesthesia.

Introduction and Purpose: Caesarean section is one of the most common operations performed under elective or emergency conditions as an alternative to normal birth. Spinal anesthesia is a frequently used method in cesarean section operations. However, maternal hypotension occurs in 85% of cases as a side effect. Continuation of maternal hypotension causes decreased oxygen delivery to maternal tissues and organs, as well as uteroplacental hypoperfusion and fetal distress. Hypotension must be treated to prevent these effects from occurring. With this study, we aimed to investigate the effects of fluid regimen applied at different times on maternal myocardial repolarization in elective cesarean section patients who underwent spinal anesthesia, and to see the changes of myocardial repolarization on f(QRS-T) angle, one of the last-stage ECG (Electrocardiography) parameters, and QT and QTc measurements.. Methods: For this study, ethics committee approval was received from Harran University Faculty of Medicine Ethics Committee dated 20.09.2023 and numbered 261950. 80 patients between the ages of 18 and 45, who were ASA I-II and would undergo elective cesarean section, were included in the study. Liver and/or kidney failure patients, obese patients (BMI>30), trauma patients, cancer patients, ASA III-IV patients and patients who did not want to participate in the study were excluded from the study. Venous access was opened with an 18 G (Gauge) peripheral vein cannula for the patients who would be taken to the operating room, and standard monitoring (Electrocardiography (ECG), oxygen saturation (SpO2), non-invasive blood pressure (NIBP)) was applied. Mean arterial pressure (MAP) and heart rate (HR) were recorded. The patients were divided into two groups of 40 each using the sealed envelope method. To the patients in the Preload Ringer Lactate Group, before spinal anesthesia, 15 milliliters/kilogram (ml/kg) Ringer Lactate was administered intravenously (iv) so that the liquid would disappear within 20 minutes (min). Patients in the Co-load Ringer Lactate Group were given 15 ml/kg Ringer Lactate after spinal anesthesia. The patients were placed in a sitting position, and 2.5 ml hyperbaric bupivacaine was administered by reaching the subarachnoid space with a 25 G Quincke spinal needle from the L3-L4 or L4-L5 space. Following the application, the patients were laid down on their back. Sensory block levels of the cases were evaluated at the 10th minute. After spinal anesthesia, MAP and HR of the patients were measured intraoperatively and postoperatively for 5 minutes each. recorded with an interval. A 12-lead ECG recording was taken from all subjects while they were resting in the supine position after resting for at least 10 minutes, with a paper speed of 25 millimeters (mm) per second, height of 10 mm/mV, and filter range of 0.16-100 Hz. ECG evaluation was performed by two cardiologists. QT and Tp-e interval measurements were calculated with the help of magnifying glasses. f(QRS/T) was calculated. ECGs were taken before spinal anesthesia, at 0 minutes and 30 minutes after spinal anesthesia. Findings: Age, gestational week, gravida, and C/S distributions of the cases did not show a statistically significant difference according to the groups (p>0.05). HR and MAP measurements of the cases do not show statistically significant differences according to the groups (p>0.05). According to the groups, the changes in QRS, f(QRS/T), QTc and QT measurements of the cases before spinal anesthesia, at the 0th minute after spinal anesthesia and at the 30th minute after spinal anesthesia do not show a statistically significant difference (p>0.05). A statistically significant difference was found between the QT measurements of the preload group cases before spinal anesthesia, at 0 minute and at 30 minute after spinal anesthesia (p <0.05). It has been determined that the QT interval gradually lengthens. It was determined that there was a tendency for an increase between the QT measurements at the 0th minute and 30th minute after spinal anesthesia in the co-load group cases, but this difference was not statistically significant (p = 0.054). A statistically significant difference was found between the QTc measurements of the preload group cases before spinal anesthesia, at the 0th minute and at the 30th minute after spinal anesthesia (p<0.001). It was observed that there was an increase in the QTc value after spinal anesthesia compared to before spinal anesthesia. No statistically significant difference was detected between the QTc measurements of the co-load group cases before spinal anesthesia, at 0 minutes and at 30 minutes after spinal anesthesia (p = 0.496). Conclusion: As a result of this study; When the changes in QRS, f(QRS/T), QT and QTc values of the Preload and Co-load groups were examined, no change was observed in the QRS and f(QRS/T) measurements, while it was observed that the QT interval and QTc measurements were prolonged in the Preload group. No significant prolongation was detected in the co-load group. Based on this, we can say that fluids administered as Co-load have a more positive effect on myocardial functions.