In these patients an increase in systemic vascular resistance should be prevented. The key to the anaesthetic management of these parturients is the maintenance of both preload and afterload. Analgesia for labour is best provided by parenteral narcotics as well as by inhalation of nitrous oxide and oxygen. For the second stage of labour, pudendal nerve blockade can be used. Good analgesia has also been provided by intrathecal narcotics.
General anaesthesia is the technique of choice for caesarean section.
These patients tolerate the circulatory overload produced by pregnancy very well and most techniques of analgesia and anaesthesia have been used successfully. This condition is the most common cyanotic heart condition observed in pregnant patients. One of the principal anaesthetic aims in managing these patients is to prevent an increase in this shunt. Tachycardia or infundibular spasm can be prevented by the administration of propranolol. A decrease in the ratio of systemic to pulmonary vascular resistance results in increasing cyanosis.