A method to assess the passage of diethyl ether and halothane across the placenta during anaesthesia for caesarean...

A method was elaborated to assess the transplacental passage of inhalatory anaesthetic agents--diethyl ether and halothane during Caesarean section. The method is based on measurements of blood concentrations of these agents in material venous blood and in arterial and venous blood taken from the umbilical cord during the operation. Halothane and diethyl ether concentrations were determined by means of gas chromatography. The studies were carried out on 2 groups of 25 cases each. The obtained results indicate that diethyl ether passes in a higher degree across the placenta than halothane. The mean ratio of halothane concentrations in foetal venous blood to maternal venous blood determined in 25 cases was 0.664 and diethyl ether ratio was 0.988.