The effect of different noradrenaline administration methods on hypotension after spinal anesthesia in cesarean sections

The Effect of Different Noradrenaline Administration Methods on Hypotension After Spinal Anesthesia in Cesarean Sections Objective: In our study, in cases planned for cesarean delivery under spinal anesthesia; We aimed to investigate the effectiveness of different administration methods of noradrenaline (NA) on preventing maternal hypotension. Materials and Methods: 208 term pregnant women over 18 years of age, ASA II, who had a single pregnancy planned under spinal anesthesia under elective conditions, were included in the study. The pregnant women were randomly divided into 4 groups (n:52) by the closed envelope method. Following standard aspiration prophylaxis and monitoring, 1 ml/kg/hour Ringer Lactate solution was started. Spinal anesthesia was provided with a 25-gauge Quinke spinal needle through the L3-4 or L4-5 space with 2-2.2 ml of hyperbaric bupivacaine and 15 µg of fentanyl. Immediately after spinal anesthesia, rapid co-hydration was performed with 10 ml/kg Ringer's Lactate at a maximum of 1 L. For the study, NA was prepared as 4 µg/ml. In Group PB (Prophylactic Bolus), iv bolus 4 µg working solution was administered immediately after spinal anesthesia, and then saline (SF) infusion was started at 1 ml/min. In Group PI (Prophylactic Infusion), 1 ml of saline was administered immediately after spinal anesthesia and then infusion was started at 1 ml/min (4µg/min) of study drug. In Group TB (Treatment Bolus), 1 ml of saline followed by 1 ml/min infusion of saline was started immediately after spinal anesthesia, and then 1 ml of working solution and then 1 ml/min of saline infusion was started when the blood pressure decreased by 20%. In Group TBI (Treatment Bolus Infusion), 1 ml of study drug and 1 ml/min of study drug infusion were started when blood pressure of 1 ml/min SF infusion decreased by 20% immediately after spinal anesthesia, followed by 1 ml/min SF infusion. Heart rate, blood pressure, and peripheral oxygen saturation were recorded every 2 min from intrathecal drug administration until delivery. An additional 4 µg (1 ml) of NA was administered in all groups for hypotension attacks. According to the entry, 40% or more severe hypotension was considered and treated with 15 mg ephedrine. The number of episodes of hypotension and hypertension, bradycardia, nausea-vomiting, tremor, sensory block level, Apgar score, umbilical vein (UV) values, time from intrathecal injection to delivery, incision-delivery, uterine incision delivery times were recorded. Results: Systolic and mean blood pressures were statistically significantly higher in the PI Group than the other groups at the 4th, 6th, and 8th minutes (p˂0.05). Systolic blood pressure (SAB) at 10 and 12 min was similar in TBI and PI Groups. Hypotension; While it was observed in all cases in the TB and TBI Group, it was significantly lower in the PI Group compared to the other groups (p˂0.001). Number of cases with severe hypotension; It was statistically significantly higher in the TB, TBI and PB groups than in the PI Group (p˂0.001). Number of episodes of hypotension, ephedrine requirement and NA extra bolus number; It was statistically significantly lower in the PI Group compared to the other groups (p˂0.001). The probability of hypertension was significantly higher in the TBI group (p<0.05). Heart rate (HR) was statistically significant in the PI Group at the 2nd and 4th minutes according to the TB Group, at the 18th minute according to the TBI Group, and at the 20th and 22nd minutes compared to all other groups. was significantly lower (p˂0.05). However, bradycardia and atropine requirements were similar between groups. UV pH values; It was statistically significantly lower in the TBI Group compared to the other groups (p˂0.005). Nausea was significantly lower in the PI group compared to the other groups (p<0.05). Vomiting was significantly higher in the PD group (p<0.05). Conclusion: We believe that NA prophylactic 4 µg/min infusion application in the prevention of hypotension after spinal anesthesia in cesarean sections reduces the probability of maternal hypotension better, preserves fetal well-being and reduces the incidence of nausea compared to prophylactic bolus, treatment bolus or post-treatment bolus infusion applications at the same doses. Keywords: Cesarean section, Postspinal Hypotension, Noradrenaline