Impact of the opening of a specialized cardiac surgery recovery unit on postoperative outcomes in an academic health sciences centre

Abstract

Purpose: It is controversial as to whether cardiac surgery patients are optimally managed in a mixed medical-surgical intensive care unit (ICU) or in a specialized postoperative unit. We conducted a prospective cohort study in an academic health sciences centre to compare outcomes before and following the opening of a specialized cardiac surgery recovery unit (CSRU) in April 2005. Methods: The study cohort included 2,599 consecutive patients undergoing coronary artery bypass grafting (CABG), valve and combined CABG-valve procedures from April 2004 to March 2006. From April 2004 to March 2005 (year 1) all patients received postoperative care in mixed medical-surgical ICUs at two different sites staffed by critical care consultants, fellows and residents. From April 2005 until March 2006 (year 2) patients were cared for in a newly-established CSRU on one site staffed by cardiac anesthesiology fellows, a nurse practitioner and consultants in critical care, cardiac anesthesiology and cardiac surgery. The effect of this change on in-hospital mortality, the incidence of ten major postoperative complications, postoperative ventilation hours, readmission rates and case cancellations due to a lack of capacity was assessed using Chi-square or Wilcoxon tests, where appropriate. Results: Coronary artery bypass grafting, valve and combined CABG-valve mortality rates were similar in years 1 and 2. There was a significant reduction in the composite major complication rate (16.3% to 13.0%, P = 0.02) and in median postoperative ventilation hours (8.8 vs 8.0 hr, P = 0.005) from year 1 to 2. On multivariable logistic regression analysis, the pre-merger interval (year 1) was a significant independent predictor of the occurrence of death or major complications. Conclusion: A specialized CSRU with a multi-disciplinary consultant model was associated with stable or improved outcomes postoperatively, when compared to a mixed medical-surgical ICU model of cardiac surgical care.