Acute physiology and chronic health evaluation (APACHE II) scoring in a cardiothoracic intensive care unit

Abstract

Objective: To evaluate the predictive value of the Acute Physiology and Chronic Health Evaluation (APACHE II) scoring system in cardiothoracic surgical patients.

Design: Prospective survey with follow-up to hospital discharge.

Setting: A cardiothoracic surgical ICU in a tertiary referral center.

Patients: Eight hundred sixty-nine consecutive patients admitted to the ICU were entered into this study. Data on 12 patients were incomplete. Forty-three patients had nonsurgical diagnoses. Three patients had noncardiothoracic operations. These exclusions left 811 patients for analysis, and all results pertain to these 811 cardiothoracic surgical patients.

Interventions: Demographic and physiologic data relevant to the APACHE II score were collected on all patients and entered into a microcomputer database for analysis.

Measurements and main results: The following procedures were performed: 65% of patients had coronary artery bypass grafts; 23% had heart valve surgery; 5% had thoracic surgical procedures; and the remainder had a variety of cardiothoracic operations. The mean duration of ICU care was 2.3 days and the mean age was 57 yrs. The mean APACHE II score was 9.5 and the overall predicted risk of dying was 4.59%, with an actual ICU mortality rate of 4.56%. The relationship between the APACHE II score and mortality rate was linear and significant (p less than .001). Patients with an APACHE II score of less than 10 had a mortality rate of 0.93%. Only a score of greater than 30 was uniformly associated with death, and then only in one patient. A chronic disease history, emergency surgery, and a longer ICU stay were significant markers for mortality.

Conclusions: There was a good relationship between the APACHE II score and mortality rate. Low APACHE II scores accurately predicted survival but only very high scores accurately predicted death.