Predictive value of blood clotting tests in cardiac surgical patients.

This study prospectively evaluated numerous tests of clotting function in 897 consecutive adult cardiac surgical patients over 18 months. This included coronary operation, valve replacement, and reoperative patients. The tests included activated clotting time, activated partial thromboplastin time, prothrombin time, thrombin time, fibrinogen, fibrin/fibrinogen degradation products, platelet count, and Duke's earlobe bleeding time. Other variables such as age, sex, and cardiopulmonary bypass duration were included in the multivariate analysis. Statistically significant correlations were found between 16-hour mediastinal drainage and activated partial thromboplastin time, fibrinogen, activated clotting time, fibrin/fibrinogen degradation products, platelet count, and prothrombin time. Scatter plots indicate that these relationships, although statistically significant, had little predictive value and were largely significant as a result of the large number of patients in each group, which permitted weak correlations to reach statistical significance. The best multivariate model constructed could explain only 12% of the observed variation in postoperative blood loss. Because the predictive values of the tests are so low, it does not appear sensible to screen patients routinely using these clotting tests shortly after cardiopulmonary bypass.

Conservation of blood in cardiac surgery.

The rising costs of surgical care and decreasing third-party reimbursement mandate conservation of surgical resources and supplies whenever possible. One such resource is autologous blood. Its conservation has the added benefit of protecting the patient from the potential dangers of homologous blood and its products. This article presents conservation techniques found to be feasible in open-heart surgery.

Mitral valve operation via an extended transseptal approach.

The extended transseptal approach to the mitral valve has been used for 71 consecutive procedures. Four patients died; none had complications directly attributable to the exposure. Twenty underwent a primary reparative procedure; 30, a primary replacement procedure; and 21, a repeat procedure. Despite division of the sinus node artery, 26 of 32 patients with sinus rhythm preoperatively had sinus rhythm postoperatively; 4 had atrial fibrillation postoperatively. Twenty-seven of 37 patients with atrial fibrillation preoperatively had atrial fibrillation postoperatively; 8 had sinus rhythm postoperatively. Because the exposure provided by this extended transseptal approach is superior to that of standard approaches, we now use it routinely for mitral valve operations.

Digoxin and propranolol in the prophylaxis of dysrhythmias after coronary artery bypass grafting.

Serious tachydysrhythmias occur in 10% to 30% of patients early after coronary artery bypass grafting (CABG). We studied the effects of digoxin and propranolol in preventing these dysrhythmias over the first week after CABG (average number of grafts, 2.7/patient). Consecutive patients (n = 179) undergoing CABG were randomized to a drug (group 1) or a control (group 2) group. Excluded were patients given digoxin before CABG and those with ejection fractions of less than 40%, those with dysrhythmias within 18 hr after CABG, those being pacer dependent, and those with low-output syndrome after CABG. Risk factors were comparable in both groups. Electrocardiographic examination showed perioperative myocardial infarction in five patients (2.8%). Digoxin (1 mg iv given over 24 hr, then 0.25 mg/day) and propranolol (10 mg given every 6 hr) were started 6 hr after CABG. Supraventricular dysrhythmias requiring treatment occurred in 3.4% of 89 group 1 patients and in 30% of 90 group 2 patients (p less than .001); ventricular dysrhythmias occurred in 1.1% of group 1 and 8.9% of group 2 patients (p less than .01). In this study, a regimen of post-CABG digoxin and propranolol significantly reduced the incidence of supraventricular and ventricular dysrhythmias without causing adverse reactions.

An appraisal of blood salvage techniques in vascular and cardiac operations.

This study compares blood salvage and reinfusion with the use of homologous blood in three groups of patients undergoing coronary artery bypass graft replacement or other cardiac operation. In Group 1 (100 patients), homologous blood was used and no effort was made to salvage blood. In Group 2 (68 patients), blood was salvaged before and after bypass and mediastinal blood was salvaged for 24 hours postoperatively. In Group 3 (46 patients), blood was salvaged before and after bypass and postoperatively. The average patient in Groups 2 and 3 required approximately one-third the amount of whole blood and approximately one-fourth the amount of packed red blood cells (RBC) required by a Group 1 patient. The hospital stays, blood chemistry levels, and costs per patient were comparable for the three groups. RBC survival studies in Group 3 patients showed a mild decrease from normal values. This study shows that currently available equipment and techniques allow safe and practical blood salvage during cardiac and vascular operations.