The hemodynamics of beta-blockade in patients undergoing abdominal aortic aneurysm repair.

To assess the intraoperative and postoperative hemodynamic effects of beta-blockade and its benefits in limiting myocardial ischemia and infarction, a group of 32 patients scheduled for abdominal aortic aneurysm (AAA) surgery (group 1) was treated with oral metoprolol immediately before surgery and with intravenous metoprolol during the postoperative period. Mean age was 71 years, and mean ejection fraction was 56% (range 36% to 83%). Eight patients had a preoperative history of angina, 13 had a history of myocardial infarction, and five had electrocardiographic evidence of prior myocardial infarction. A group of 51 closely matched patients with AAA who did not receive metoprolol served as controls (group 2). In group 1, overall hemodynamic tolerance of metoprolol intraoperatively and postoperatively was good, and there was no incidence of congestive heart failure, hypotension, or asthma. Furthermore, in group 1 significant reduction of systolic blood pressure and heart rate was consistently noted at frequent intraoperative intervals and for 48 hr after surgery, with only a transient reduction of cardiac index. In group 1, only one patient (3%) suffered an acute myocardial infarction. In contrast, nine group 2 patients (18%; p less than .05) suffered perioperative myocardial infarction. Furthermore, only four (12.5%) group 1 patients developed significant cardiac arrhythmias as opposed to 29 group 2 patients (56.9%; p less than .001). These data demonstrate that beta-blockade with metoprolol is effective in controlling systolic blood pressure and heart rate both intraoperatively and postoperatively in patients undergoing repair of AAA and can significantly reduce the incidence of perioperative myocardial infarction and arrhythmias.

Blood transfusion requirements in coronary artery surgery with and without the activated clotting time (ACT) technique.

Control of anticoagulation during cardiopulmonary bypass (CPB) with the automated activated whole blood clotting time (ACT) and reversal of heparin after CPB using a computerized ACT dose-response curve method resulted in significant reductions of blood transfusion requirements, surgical time, and protamine doses in 150 patients undergoing coronary artery bypass grafting procedures (ACT group) as compared to 200 patients for whom a standard fixed dose protocol for heparin and protamine was used (control patients). Mean transfusion requirements were 1,938 +/- 60 SEM ml whole blood and 853 +/- 48.3 SEM ml red blood cells for control patients and 1,397 +/- 59 SEM ml whole blood (P less than 0.001) and 695 +/- 34 SEM ml red blood cells (P less than 0.01) in the ACT group. ACT group patients also required less protamine with 26.2 +/- 0.60 SEM ml Protamine 1,000 (Roche) as compared to 33.9 +/- 0.49 SEM ml for control patients (P less than 0.001) but more heparin with 31,440 +/- 783 SEM I.U. versus 26,760 +/- 263 SEM I.U. (P less than 0.001). Surgical time decreased from 321 +/- 5.5 SEM min for control patients to 289 +/- 5.4 SEM min for ACT group patients (P less than 0.001).

Dose-response studies on glycopyrrolate and atropine in conscious cardiac patients.

The dose-heart rate response relationship for the two anticholinergics, atropine and glycopyrrolate, were studied in non-anaesthetised patients about to undergo coronary artery surgery. Two methods were used, the administration of increasing doses to different groups of patients, and an incremental dose technique in the same patient. Both drugs increased heart rate in a dose-related manner with glycopyrrolate being approximately twice as potent as atropine. Glycopyrrolate is as effective as atropine in correcting bradycardia prior to open heart surgery.