Prophylactic intramuscular ephedrine prior to caesarean section.

Thirty healthy parturients, having given informed consent, were randomly allocated in a double-blind study to receive an intramuscular injection of either 0.9% sodium chloride (control), ephedrine 25 mg, or ephedrine 50 mg, 30 minutes prior to general anaesthesia for caesarean section. Nine patients (90%) in the 50 mg group and five patients (50%) in the 25 mg group demonstrated reactive hypertension of 20% or greater from control. The mean maximum increase in the 50 mg group was 28.2% (range 4.4-38.3%). Maternal pH was significantly lower (P = 0.03) in the ephedrine 50 mg group. Neonatal acid base status was significantly impaired in the ephedrine 50 mg group with umbilical venous pH (P = 0.0001) and umbilical arterial pH (P = 0.001) being significantly lower than the control group. The associated increase in umbilical arterial base deficit suggests a metabolic component due to fetal asphyxia related to decreased uterine blood flow. We conclude that the prophylactic administration of intramuscular ephedrine prior to spinal anaesthesia is associated with an unacceptably high incidence of maternal hypertension, and should the spinal fail and general anaesthesia be required, also results in adverse neonatal biochemical changes. The technique is therefore not to be recommended.

Prevention of hypotension following spinal anaesthesia for elective caesarean section by wrapping of the legs.

Twenty-four parturients undergoing elective Caesarean section were allocated randomly to have the legs wrapped with elasticated Esmarch bandages immediately following spinal anaesthesia or to serve as controls. Significant hypotension (systolic arterial pressure less than 100 mm Hg and less than 80% of baseline value) was treated with i.v. ephedrine in 5-mg boluses. Leg wrapped patients had a significantly (P = 0.0033) lower incidence (16.7%) of hypotension than controls (83.3%). Only two patients in the leg wrapped group required ephedrine compared with 10 in the control group. Systolic arterial pressure was significantly (P less than 0.05) less in control subjects at 4, 5 and 6 min following spinal injection. No patient in the leg wrapped group became hypotensive following removal of the elasticated bandages.