DIFFICULTIES IN PREDICTING OUTCOME IN CARDIAC-SURGERY PATIENTS

Objective: To evaluate a novel combination of preoperative, intraopera tive, and postoperative variables (including the Parsonnet, and the Ac ute Physiology and Chronic Health Evaluation II and III [APACHE II and III] scores) in cardiac surgery patients in order to predict hospital outcome, complications, and length of stay. Design: Prospective surve y. Setting: Adult intensive care unit (ICU) at a tertiary care cardiot horacic surgery center. Patients: All cardiac surgery patients admitte d to the ICU over a 1-yr period.Interventions: Medical history, Parson net score, intraoperative data (including bypass and ischemic times), APACHE II and III scores, complications, and outcome were collected fo r each patient. Measurements and Main Results: One thousand eight pati ents were entered into the study. The mean Parsonnet score was 7.8 (ra nge 0 to 33), mean APACHE II score 11.8 (range 2 to 33), and mean APAC HE III score 42.5 (range 9 to 132). ICU mortality rate was 2.7% and ho spital mortality rate was 3.8%. The mean APACHE II predicted risk of d ying was 5.31%, which gave a standardized mortality ratio of 0.71. The above scores were all statistically well correlated with hospital mor tality. Further, a logistic regression model was developed for the pro bability of hospital death. This model (which included bypass time, ne ed for inotropes, mean arterial pressure, urea, and Glasgow Coma Scale ) had an area under the receiver operating characteristic curve of 0.8 7, while the Parsonnet score had an area of 0.82 and the APACHE II ris k of dying had an area of 0.84. Conclusions: Cardiac surgery remains a difficult area for outcome prediction. A combination of intraoperativ e and postoperative variables can improve predictive ability.