Systemic and Pulmonary Blood Pressure During Caesarean Section in Parturients with Gestational Hypertension

Abstract

Twenty severely pre-eclamptic patients requiring caesarean section for delivery were allocated to two groups. One group received epidural anaesthesia consisting of either 20 ml of bupivacaine 0.75 per cent at L3-4 or 12ml at Ll-2. The other group received general anaesthesia consisting of thiopentone, 40 per cent nitrous oxide and halothane 0.5 per cent. Mean arterial pressure (MAP), pulmonary artery pressure (PAP), pulmonary wedge pressure (PWP), and central venous pressure (CVP) were recorded at five-minute intervals for at least 60 minutes before operation and at least every two minutes during anaesthesia. Patients receiving general anaesthesia had pressures recorded every minute during tracheal intubation and extubation. There was a mean increase of MAP of 45 mm Hg, of PAP 20 mm Hg, and PWP 20mm Hg during intubation and extubation. Apart from a slight mean fall in MAP the parturients receiving epidural anaesthesia showed little change in these cardiovascular parameters. It is concluded that tracheal intubation of patients with gestational hypertension produces an increase in MAP, PAP, and PWP which can lead to a significant risk of cerebral haemorrhage and pulmonary oedema. The value and dangers of using short-acting hypotensive agents to prevent these episodes of hypertension has still to be assessed. With epidural anaesthesia there is a danger of hypotension which can be treated with intravenous fluid replacement and ephedrine.