Effect of nonpharmacological methods on incidence of postspinal hypotension during cesarean delivery

Abstract

Introduction Hypotension is caused by upward spread of anesthetic into the subarachnoid space; this results in venous pooling in the capacitance vessels of the lower limbs as a result of block of sympathetic tone and unopposed activity of parasympathetic tone. It also may be caused by aorto-caval syndrome and is accompanied by bradycardia, nausea, and vomiting. Hypotension may have deleterious effects on mother and fetus and may result in uteroplacental hypoperfusion, as placental perfusion is pressure dependent, and lack of autoregulation of placental blood vessels, if persisted, may threaten the life of the fetus. Aim The primary aim of the work is to compare incidence of intraoperative hypotension between the three groups. The secondary outcome is to assess Appearance, Pulse, Grimace, Activity, Respiration (Apgar) score, vasopressor consumption, and occurrence of complications (nausea, vomiting, and bradycardia). Patients and methods A total of 150 patients undergoing cesarean delivery under spinal anesthesia were included. Patients were divided into three equal groups, using simple randomization method, with 50 patients each: group S, in which the patient will sit for 1 min after induction of spinal anesthesia and then will lie down; group E, in which patient's legs will be elevated to 30° from the horizontal plane; and group C in which the patient will lie down immediately after induction of spinal anesthesia as a control group. Then, heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure were measured every 2 min until delivery of fetus and then every 5 min until the end of surgery. Sensory level was assessed before start of surgery, subsequently after lying down, and every 1 min using hot and cold test until it reaches T6 sensory level. Fetal well-being was assessed by Appearance, Pulse, Grimace, Activity, Respiration (Apgar) score measured by a pediatrician blinded to the study protocol at 1 and 5 min after delivery. Incidence of hypotension is defined as ‘at least one episode of decrease in systolic blood pressure to less than 90 mmHg or decrease in systolic pressure more than 20% from the baseline till the end of surgery’. It was treated immediately by 200 ml intravenous bolus fluids and injection of 5 mg ephedrine intravenous bolus every 2 min until elevation of blood pressure, and the total of ephedrine consumption was calculated. Duration of surgery and intraoperative complications was recorded as bradycardia, defined by heart rate below 60 beats/min, which was treated by 0.5 mg atropine sulfate, and nausea and vomiting, which were treated by ondansetron intravenous 4 mg after correction of hypotension. Results A total of 150 cesarean delivery patients between 22 and 34 years of age were included in the study. Regarding basic clinical and demographic data, it was found that the median age of all cesarean delivery patients was 30 years. The median BMI of all cesarean delivery patients was 32.5. Regarding the surgery duration, the median surgery duration of all cesarean delivery patients was 40 min. Regarding level of sensory block, most patients had sensory block at T6 (70%), and 30% at T4 in groups C, E, and S, correspondingly. Regarding primary outcome (incidence of hypotension mean arterial blood pressuer (MAP)<70 mmHg), there was a highly significant increase in incidence of hypotension in group C compared with other groups of patients, with highly significant statistical difference (P=0.0092). The incidence of hypotension in group C was 70%, in group E was 50%, whereas in group S was 40% (P=0.0092). Regarding secondary outcomes (ephedrine consumption, Apgar scores, and complications), there was a highly significant increase in ephedrine consumption in group C compared with other groups (P=0.000002). The median value of ephedrine consumption in group C was 7.5 mg, in group E was 2.5 mg, whereas no ephedrine was consumed in group S (P=0.000002). Moreover, there was a nonsignificant difference regarding Apgar score at 1 min (P>0.05). There was a highly significant increase in Apgar score at 5 min in group S compared with other groups (P=0.0047). There was a highly significant increase in bradycardia in group C compared with the other groups (P=0.0015). There was a highly significant increase in nausea in group C compared with the other groups (P=0.0008). There was a highly significant increase in vomiting in group C compared with the other groups (P=0.0008). Conclusion Incidence of hypotension in patients undergoing cesarean delivery under spinal anesthesia markedly decreased in patients who sat for 1 min after induction of spinal anesthesia and then lied down (group S) compared with patients who lied down immediately after induction of spinal anesthesia.