β‐Receptor Blockade and Neurolept Anaesthesia. Withdrawal vs Continuation of Long‐Term Therapy in Gall‐Bladder and Carotid Artery Surgery

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Abstract
Forty‐eight chronically (>3 months) β‐receptor‐blocked patients with ischaemic heart disease and/or hypertension were studied on 49 occasions after random distribution to a 4‐day, gradual preoperative withdrawal (n = 26) or a continuation (n = 23) of β‐receptor blockers. The patients were scheduled for either a cholecystectomy (n = 28) or a carotid thrombendarterectomy (n = 21) under neurolept anaesthesia. Three patients were excluded from the randomized part of the study due to complications (tachycardia, hypertension, severe angina) after therapy withdrawal. In subgroups, central haemodynamics (β‐receptor blockers withdrawn n = 6, continued n = 8) and creatinine‐kinase B (β‐receptor blockers withdrawn n = 9, continued n= 11) were studied. Withdrawal of β‐receptor blockers was associated with high heart rates, supraventricular tachyarrhythmias and a hyperkinetic circulation during pain stimuli. Significantly more postoperative ECG changes (p<0.02) indicative of myocardial ischaemia were found than in β‐receptor blocked patients. These patients had low heart rates but also pronounced increases in pulmonary capillary wedge pressures, which in single patients could be associated with myocardial damage. These results imply that β‐receptor blockers should be continued before surgery and that a concomitant vasodilatatory therapy is likely to avoid the drawbacks of an increased cardiac afterload.