Study of different anaesthetic techniques on pulmonary haemodynamics during mitral commissurotomy

A comparative study of the effects of three different techniques of anaesthesia on pulmonary haemodynamics in 20 patients with pulmonary hypertension secondary to mitral stenosis was undertaken. The anaesthetic techniques employed were: (1) N2O + O2 (60:40), relaxant and IPPV. (2) N2O + O2 (50:50), 0.5% halothane, relaxant and IPPV. (3) 99% O2, 1% halothane, relaxant and IPPV. Identical premedication and induction were carried out in all the patients and maintained with N2O + O2 (70:30), relaxant and IPPV with cuffed endotracheal tube using closed circuit with CO2 absorber, at the beginning. Thereafter, anaesthesia was maintained using the above mentioned 3 different techniques in 4 study stages. The different parameters studied were pulmonary arterial pressure, left arterial pressure, PaO2, PaCO2 and pH in all the 4 stages. The pressure changes and blood gas analysis data were presented in Tables and analysed statistically. It was observed that O2 and halothane anaesthesia caused a fall in pulmonary vascular resistance which was beneficial for patients having pulmonary hypertension.