Twenty-three patients who developed intraoperative
hypertension (mean arterial pressure greater than 110 mmHg) during abdominal surgery under balanced general anaesthesia were randomly assigned to two groups. The
isradipine group (n = 12) received 0.5 mg of
isradipine, and the placebo group (n = 11) received 10 ml of
isradipine solvent over a 5-min period in a blind manner. Arterial pressure was recorded 12 min after the injection was started. If the mean arterial pressure had not decreased by at least 10% at 12 min, patients received in an open manner 0.5 mg of
isradipine. None of the patients in the
isradipine group received
isradipine in an open manner, in contrast with nine of the 11 patients in the placebo group (P less than 0.0001, Fisher's exact test). During both the blind period and the open trial,
isradipine induced a 40% decrease in systolic, diastolic, and mean arterial pressures within the first two min of infusion. Arterial pressure remained below the pre-
isradipine injection values for at least 45 min. Transient
hypotension (mean arterial pressure less than 70 mmHg) was noted in 6/21 patients (29%). Mean heart rate remained statistically unchanged during the decrease in arterial pressure in both groups, but a
tachycardia (increase in heart rate greater than 20 beats min-1) was noted in 4/21 patients (19%). This study indicates that intravenous
isradipine is an effective
therapy with sustained efficacy for intraoperative
hypertension during abdominal surgery. The safety of its use needs a close monitoring of arterial pressure.