PREOPERATIVE METOPROLOL IMPROVES CARDIOVASCULAR STABILITY AND REDUCESOXYGEN-CONSUMPTION AFTER THORACOTOMY

Background: increased sympathetic activity perioperatively and associa ted cardiovascular effects play a central role in cardiovascular compl ications. High thoracic epidural blockade attenuates the sympathetic r esponse, but even with complete pain relief, haemodynamic and endocrin e responses are still present. Beta-adrenoceptor blockade is effective in situations with increased sympathetic activity, This study was des igned to evaluate the perioperative haemodynamic effect of preoperativ e beta-blockade and its influence on the haemodynamic aspects of the s urgical stress response. Methods: Thirty-six otherwise healthy patient s undergoing elective thoracotomy for lung resection were randomised d ouble-blinded to receive either 100 mg metoprolol or placebo preoperat ively. Anaesthesia was combined high thoracic epidural block and gener al anaesthesia, The epidural analgesia was continued during recovery. Patients were monitored with EGG, pulse oximetry; invasive haemodynami c monitoring, arterial blood gases and electrolytes. Results: After in duction of anaesthesia the mean arterial pressure (MAP) decreased in b oth groups, and decreased further in the placebo group after initiatio n of the epidural block. The heart rate (HR) was slightly less through out the observation period after metoprolol. Peroperatively, the only difference in measured haemodynamics was a marginally higher MAP after metoprolol. Postoperative cardiac index (CI) was lower with a lower v ariability and cardiac filling pressures were slightly higher in the m etoprolol group. The oxygen consumption index was higher after placebo throughout the observation period, with no difference in the oxygen d elivery. Conclusion We found that preoperative beta-blockade during co mbined general anaesthesia and high thoracic epidural blockade stabili sed perioperative HR and CI and decreased total oxygen consumption.