The sitting versus lateral position during induction of spinal anesthesia for elective cesarean delivery on block characteristics and severity of hypotension: a prospective randomized clinical trial, 2023

Background: Spinal anesthesia (SA) is the most preferred technique for cesarean delivery but is challenged by many adverse effects, mostly by maternal hypotension and bradycardia. Due to the high adversity effects of hypotension to mother and baby, prevention at any cost is much more advice. SA inductional positioning could be one of the preventive methods. Objective: To assess the effect of sitting and lateral SA induction positions on hemodynamic changes, severity of hypotension, and block characteristics in elective cesarean section. Methodology: A prospective double-blinded randomized control trial was conducted by recruiting 132 patients using a systematic random sampling technique. Patients were randomized into lateral position (n=66) and control group (sitting position) (n=66). Isobaric bupivacaine (0.5%) was injected into the spinal space at L3-L4 level in the lateral position for group 1 and in the sitting position for group 2. Afterward, the patient's blood pressure was measured at first and third minute, then every 5 min until the 20th minute, and then every 10 min until the end of cesarean section. Data analysis was performed using SPSS (version 21) software, and continuous variables were analyzed by independent sample t test while categorical by Fisher exact and chi(2) test. An intention-to-treat analysis was applied for those who lost follow-up and P value <0.05 was considered statically significant. Result: There was a statistically significant difference in the incidence of hypotension between lateral and supine positions [50 (75.8%) in sitting and 31 (47.0% lateral), dep=0.002)]. The frequency of hypotension was more in the sitting position, and there were no significant differences in heart rate. Vasopressor consumption was 14.98 +/- 20.50 in the lateral group and 30.89 +/- 22.259 in the sitting group, P value <0.001. The onset of sensory block was faster in the lateral group (1.92 +/- 0.56 vs. 3.8 +/- 0.01, P<0.001), but it requires more time for identification of subarachnoid space (2.95 +/- 2.0 vs. 1.5 +/- 1.0, P=0.002). Conclusion: Lateral positioning was superior in view of better hemodynamic stability, early onset, low vasopressor consumption, and low incidence of hypotension for parturients undergoing elective cesarean section.