Blood pressure changes during and after anaesthesia in treated and untreated hypertensive patients.

The blood pressure responses of 34 unselected hypertensive patients with and without preoperative antihypertensive therapy during thiopentone-N2O-O2-relaxant-analgesic anesthesia and the immediate postoperative period were studied. The blood pressure fluctuations, expressed as differences between the highest and lowest levels of both systolic and diastolic pressure during anaesthesia were significantly (p less than 0.01) greater in untreated hypertensive patients than in treated ones. A significant decline (p less than 0.01) of the mean blood pressure values from the initial level was seen in both treated and untreated patients during the first 24 postoperative hours. Urinary output was greater (p less than 0.05) in treated than in untreated hypertensive patients during a postoperative follow-up of 4 hours. The results show that hypertensive patients treated with antihypertensive drugs until the day of operation endure the anesthesia and the operation better than untreated patients.