Effects of different bupivacaine injection speeds on hemodynamic and some other parameters during spinal anesthesia for cesarean section

Bupivacaine-induced spinal anesthesia is the most commonly used method for cesarean section. However, maternal hypotension may develop as a significant side effect. In this study, we aimed to investigate the effects of different injection speeds on maternal hypotension and other side effects. Patients undergoing spinal anesthesia for cesarean section were administered isotonic bupivacaine at three different injection speeds: 10 seconds, 15 seconds, and 20 seconds. Non-invasive systolic and diastolic blood pressure, mean arterial pressure, heart rate, oxygen saturation, and the incidence of nausea, vomiting, and the need for ephedrine were recorded. Parameters for the quality of anesthesia were assessed by monitoring the time to reach sensory block at T4 and T10 levels, sensory and motor block onset time, regression time to T10, and regression time from Bromage score 3 to 1. A longer time for the sensory block to reach T4, longer T10 regression time, and a longer time for regression from Bromage 3 to 1 were observed with the 15-second injection speed compared to the 10-second injection speed (p<0.05), but not with the 20-second injection speed (p>0.05). A higher incidence of nausea and vomiting, as well as a higher need for ephedrine, was also noted with the 15-second injection speed compared to the 10-second injection speed (p<0.05), but not with the 20-second injection speed (p>0.05). The results suggest that different speeds of isotonic bupivacaine injection cause minimal changes in hemodynamic parameters and side effects.