Perioperative determinants of morbidity and mortality in elderly patients undergoing cardiac surgery (Reprinted from Critical Care Medicine, vol 26, pg 225-235, 1998)

Objective: To determine perioperative predictors of morbidity and mortality in patients greater than or equal to 75 yrs of age after cardiac surgery. Design: Inception cohort study. Setting: A tertiary care, 54-bed cardiothoracic intensive care unit (ICU). Patients: All patients aged greater than or equal to 75 yrs admitted over a 30-month period for cardiac surgery. Intervention: Collection of data on preoperative factors, operative factors , postoperative hemodynamics, and laboratory data obtained on admission and during the ICU stay. Measurements and Main Results: Postoperative death, frequency rate of organ dysfunction, nosocomial infections, length of mechanical ventilation, and ICU stay were recorded. During the study period, 1,157 (14%) of 8,501 patie nts greater than or equal to 75 yrs of age had a morbidity rate of 54% (625 of 1,157 patients) and a mortality rate of 8% (90 of 1,157 patients) after cardiac surgery. Predictors of postoperative morbidity included preoperati ve intraaortic balloon counterpulsation, preoperative serum bilirubin of >1 .0 mg/dL, blood transfusion requirement of >10 units of red blood cells, ca rdiopulmonary bypass time of >120 mins (aortic cross-clamp time of >80 mins ), return to operating room for surgical exploration, heart rate of >120 be ats/min, requirement for inotropes and vasopressors after surgery and on ad mission to the ICU, and anemia beyond the second postoperative day. Predict ors of postoperative mortality included preoperative cardiac shock, serum a lbumin of <4.0 g/dL, systemic oxygen delivery of <320 mL/ min/m(2) before s urgery, blood transfusion requirement of >10 units of red blood cells, card iopulmonary bypass time of >140 mins (aortic cross-clamp time of >120 mins) , subsequent return to the operating room for surgical exploration, mean ar terial pressure of <60 mm Hg, heart rate of >120 beats/min, central venous pressure of >15 mm Hg, stroke volume index of <30 mL/min/m(2), requirement for inotropes, arterial bicarbonate of <20 mmol/L, plasma glucose of >300 m g/dL after surgery, and anemia beyond the second postoperative day. During the study period, the study cohort used 6,859 (21.5%) ICU patient-days out of a total 31,867 ICU patient-days. Nonsurvivors used 2,023 (30%) ICU patie nt-days and patients with morbidity used 5,903 (86%) ICU patient-days. Conclusions: Severe underlying cardiac disease (including shock, requiremen t for mechanical circulatory support, hypoalbuminemia, and hepatic dysfunct ion), intraoperative blood loss, surgical reexploration, long ischemic time s, immediate postoperative cardiovascular dysfunction, global ischemia and metabolic dysfunction, and anemia beyond the second postoperative day predi cted poor outcome in the elderly after cardiac surgery. Postoperative morbi dity and mortality disproportionately increased the utilization of intensiv e care resources in elderly patients. Future efforts should focus on preope rative selection criteria, improvement in surgical techniques, perioperativ e therapy to ameliorate splanchnic and global ischemia, and avoidance of an emia to improve the outcome in the elderly after cardiac surgery.