The effects of perioperative coninuous administration of mivazerol on early postoperative haemodynamics and plasma catecholamines after major surgery.

Objective: During and after surgical procedures a strong activation of the sympatho-adrenergic system is common with correlation to adverse cardiac outcome. Several drugs (alpha(2)-adrenoceptor-agonists, beta blockers) are discussed to prevent this reaction. The new alpha(2)-adrenoceptor-agonist mivazerol with marked specifity for alpha(2)-adrenergic receptors may be suitable for this indication. The aim of the present study was to investigate the effects of perioperative continuous administration of mivazerol on plasma catecholamines, body temperature and calculated haemodynamic parameters in the early postoperative period in cardiac risk patients undergoing non-cardiac surgery. Methods: 36 patients with known coronary heart disease or risk factors for coronary heart disease scheduled for elective abdominal or vascular surgery were included in the study. Patients received either mivazerol (n=18) or placebo (n=18) [initial dose 4 mu g kg(-1) for 10 minutes before induction of anaesthesia, followed by a continuous infusion of 1,5 mu g kg(-1) h(-1) intraoperatively and for as long as 72 h after surgery] in a double-blinded, randomized manner. Blood pressure, heart rate and body temperature were measured every 10 minutes until 240 minutes after arrival at the ICU. During 240 minutes after arrival at the ICU measured parameters (CVP, PAP, PCWP, SaO(2), SvO(2), CO), calculated parameters (CI, SVR, PVR, VO2) and plasma catecholamines were measured at defined time intervalls. Results: The plasma concentrations of epinephrine and norepinephrine and the heart rate were significantly lower in the mivazerol group in the study period. Regarding blood pressure and body temperature there were no differences between the groups. At some measuring points preload was higher in the mivazerol group, but there were no differences between the groups for measured (SaO(2), SvO(2), CO) and calculated (CI, SVR, PVR, VO2) cardiorespiratory parameters. The incidence of shivering, nausea and vomiting were similar in both groups. Conclusion: Continuous, perioperative administration of mivazerol decreased the heart rate and the plasma catecholamines in the early postoperative period, but did not affect blood pressure, body temperature and the incidence of shivering. There were also no effects of mivazerol on calculated haemodynamic parameters (CO, SVR, PVR, VO2). These findings show a selective decrease in heart rate by Mivazerol without markedly cardiorespiratory side effects.