Studies of anaesthesia in relation to hypertension. VII: Adrenergic responses to laryngoscopy.

Arterial pressure and plasma catecholamine concentrations were measured in 16 normotensive and 10 hypertensive patients undergoing elective vascular surgery. Following induction of anaesthesia, both arterial pressure and plasma noradrenaline concentrations decreased in both groups. Following laryngoscopy, there was a moderate increase in arterial pressure in both normotensive and hypertensive patients. In normotensive patients, laryngoscopy was associated with a moderate increase in plasma noradrenaline concentration. There was no change in adrenaline concentration. By contrast, there was a marked increase in noradrenaline concentration, a moderate increase in adrenaline concentration and an arterial pressure response in the group of hypertensive patients. These data are consistent with transient sympathetic overactivity in hypertensive patients following noxious stimuli such as laryngoscopy.