Hypotension following spinal anaesthesia for caesarean section may result in maternal nausea and vomiting and decreased uteroplacental blood flow with possible fetal acidaemia. Numerous methods have been tried to minimise hypotension. In developing countries where resources are limited, this study aimed to compare a standard infusion of ephedrine with traditional prehydration to prevent spinal hypotension.
Sixty patients for elective caesarean section were randomly allocated to group 1: 1 L 0.9% saline before spinal block, and group 2: infusion of ephedrine 30 mg in 1 L of 0.9% saline after spinal block, titrated to maternal systolic pressure. Spinal anaesthesia was achieved with 2.5 mL of 0.5% heavy bupivacaine in the L3/L4 interspace.
Systolic pressure decreased 5 min after spinal block. Group 2 had higher mean values of systolic pressure throughout most of the study period than group 1 (P < 0.05). Hypotension occurred in 70% of patients in group 1 and 40% of patients in group 2 (P = 0.037). Severe hypotension occurred in 40% of group 1 and 13.3% of group 2 (P = 0.039). Nausea was the most common side effect of hypotension, occurring in 39.4% of all hypotensive patients. Other complications, including hypertension, tachycardia and bradycardia were similar in the two groups. Neonatal outcome was similar in the two groups and median Apgar scores at one and five minutes were 8.
Prophylactic ephedrine given by standard infusion set was more effective than crystalloid prehydration in the prevention of hypotension during spinal anaesthesia for elective caesarean section.