Effectiveness of Intravenous Prophylactic Phenylephrine for the Prevention of Spinal Anaesthesia Induced Hypotension during Caesarean Section. A Prospective Observational Study

Background: Hypotension is one of the common complications of spinal anaesthesia. It has many detrimental effects to the mother and fetus if left untreated. Recently, phenylephrine is introduced for the treatment of hypotension in our hospital. However, its efficacy on the prevention of spinal anaesthesia induced hypotension is still under controversy. We aimed to assess the effectiveness of phenylephrine prophylaxis on spinal hypotension after caesarean section. Methods: A prospective observational study was conducted at the University of Gondar Hospital. Patients were allocated based on treatment received; 50/100 μgm phenylephrine prophylaxis vs. no prophylaxis. PR, SBP, DBP, SPO2 and APGAR score were measured before, immediately after spinal anaesthesia, every 2 min intra operatively till the delivery of the baby and every 5 min after delivery for 20 min, and every 10 min for 1 h in postoperative period. Results: The incidence of hypotension was significantly lower for those participants with prophylactic phenylephrine (26% vs. 81.6%, p<0.001) compared to the non-treatment group. Systolic and diastolic blood pressures immediately after spinal anaesthesia till delivery and after delivery of the baby were significantly lower in the none treatment group at all times (p<0.05). Moreover, the number of rescue treatments and total amount of fluid given during the intraoperative period for the treatment of hypotension were more in the non-treatment group P=0.001). The APGAR scores at 1 and 5 min and postoperative vital signs were comparable between groups. Conclusion and recommendation: The incidence of spinal anaesthesia induced hypotension was high. Prophylactic intravenous phenylephrine bolus remarkably reduced the incidence of spinal induced hypotension compared to the non-treatment group. We recommend prophylactic phenylephrine for parturients undergoing caesarean section under spinal anaesthesia. Moreover, other pharmacological and non-pharmacological methods need to be considered as the incidence of hypotension is still high in the treatment group.