Influence of case scheduling on outcome in cardiac surgery

Whether scheduling of patients for cardiac surgery as dictated by the availability of cardiopulmonary machines (CPBM) may influence postsurgical outcome, thought not to be an issue in the past, is unknown. EXPERIMENTAL DESIGN AND SETTING: Cardiac surgical outcomes were compared between two consecutive 12 months intervals surrounding the acquisition of a second CPBM by our department in a general hospital.

Patients in Group A (n=416) underwent surgery when only 1 CPBM was available (February 1990-January 1991) and in Group B (n=603) when 2 CPBM were used (February 1991 to January 1992). A cohort, Group C, consisted of patients (n=73), found only in Group A, scheduled as a 3rd and 4th operative case in the same day.

There were no significant differences in demographic and clinical characteristics, the duration of ICU stay or hospital discharge between groups A and B. The surgical or technical staff did not change, and the nurse to patient ratio remained constant. Median total bypass time was significantly greater in Group B (80 vs 73 min in Group A, p<0.05), but the frequency of mortality within the first 14 postoperative days was nevertheless lower in Group B than in Group A (3.3% vs 4.6%, respectively, p<0.05). Recurrent myocardial infarction, postoperative bleeding, arrhythmia, pulmonary embolism, acute renal failure, and duodenal ulcer were also significantly higher in Group A compared to Group B (p<0.05). The excess in postoperative complications could be attributed mainly to Group C. Overall, the relative risk for morbidity and mortality decreased when a second CPBM was implemented (p<0.001). CONCLUSIONS. Postoperative complications in our unit were significantly reduced by acquisition of a second CPBM permitting two cases to be started concomitantly early in the day. This data may be valuable to guide decision analysis in departments which need to expand resources in order to cope with the demand of expanding clinical case load.