Anaesthesia for Mitral Valvotomy Complicated by Hypotension Due to Pericardial Effusion. Report of Two Cases.

This lady, with mitral stenosis following rheumatic fever in childhood, had been seen for 3 years in the Outpatient Department following the onset of mild symptoms about 10 years ago. She was admitted for review and cardiac catheterization. Right heart catheterization was performed on August 2, 1963, but, as the effects of sedation were profound and the patient became hypotensive, the procedure was abandoned and simultaneous left heart catheterization was not undertaken. Soon afterwards atrial fibrillation developed and a course of anticoagulant drugs was started. Sinus rhythm returned after a course of quinidine. The anticoagulants were stopped thirteen days prior to mitral valvotomy which was performed on September 9. After premedication with pethidine 75 mg and hyoscine 0.3 mg the patient was awake and co-operative though drowsy. Anaesthesia was induced with thiopentone 100 mg, and endotracheal intubation with a No. 9.0 oral cuffed tube followed the injection of suxamethonium 50 mg and topical spray of 4 per cent lignocaine. On the return of spontaneous respiration, anaesthesia was maintained with nitrous oxide, oxygen and halothane (0.5—1 per cent). The systolic blood pressure remained around 80 mm Hg and the general condition was satisfactory. However, there was a dramatic fall in the blood pressure following the administration of tubocurarine 30 mg and the onset of intermittent positive pressure ventilation just prior to opening the pleura. A systolic pressure of 40 mm Hg did not respond to