The cardiovascular complications of intravenous regional anaesthesia

In view of the uncertainty over the safety of intravenous regional anaesthesia the heart-rate, blood-pressure, and electrocardiogram were recorded seriany in 100 Bantu gold-miners in whom this form of anaesthesia was used for minor surgical procedures on the extremities. Changes in blood-pressure were infrequent and mild. In 31 patients the heart slowed by more than 10 beats per minute after release of the tourniquet, falling to less than 60 beats per minute in 27. One patient with sinus bradycardia developed sino-atrial block with cardiac standstill of short duration, a second developed an intermittent idioatrial tachycardia and premature atrial beats, and in 3 others sinus bradycardia was complicated by atrial escape beats, nodal rhythm, and premature ventricular beats respectively. These toxic effects were thought to be due either to direct myocardial depression or to increased vagal or decreased sympathetic tone, or to both of these mechanis. It is suggested that the cardiovascular depression caused by large doses of lignocaine may be aggravated by coexisting ischaemic heart disease. The importance of monitoring the patients carefully after release of the tourniquet and having facilities available for resuscitation is stressed.