Anaesthetic induction for Caesarean section with propanidid.

Propanidid was used for the induction of anaesthesia at Caesarean section in 50 healthy mothers. All parturients were considered to have normal placental function. Anaesthesia was maintained with nitrous oxide, oxygen, muscle relaxant and controlled ventilation. The patients were tilted laterally with a 15 degrees rubber wedge during the procedure in order to obviate the effects of aorta-caval occlusion. At the time of delivery, arterial blood was drawn from the mother and from the vessels of a double clamped section of umbilical cord, for blood-gas analysis. The results obtained are compared with those previously reported in a similar series anaesthetised with thiopentone, gas, oxygen and relaxant. Maternal blood-gas and acid-base levels were similar in the two groups at delivery. The clinical status of the infants in the present series, as judged by the modified Apgar score at 2 minutes after birth, was satisfactory. Umbilical venous and arterial pH values after propanidid were both 0-054 units (P less than 0-001) less than those following thiopentone; and average base deficits were 3-1 (Uv) and 3-9 (Ua) mEq/litre greater after propanidid (P less than 0-001). Mean oxygen levels in the umbilical cord bloods were 8-0 (Uv) and 3-5 (Ua) mmHg lower (P less than 0-001 & P less than 0-025 respectively) in the propanidid group. Derived oxygen contents was also significantly less than in the previous thiopentone series. (Ma-Uv) and (Ma-Ua) gradients were 0-053 and 0-051 pH units higher after propanidid than that following thiopentone (P less than 0-001). Mean (Ma-Uv) and (Ma-Ua) base deficits were 3-5 and 3-9 mEq/litre greater (P less than 0-001). Five patients offered definite evidence of factual recall, of whom three experienced pain. Propanidid, therefore, appeared to be associated with a greater degree of foetal acidaemia than did thiopentone. In addition, painful factual recall during surgery was encountered in 6 percent of cases. It is concluded that propanidid, although theoretically offering advantages over thiopentone to the obstetric anaesthetist, in practice, did not fulfil this promise.