Determinants of Outcome in Patients Admitted to a Surgical Intensive Care Unit

Outcome in intensive care have primarily been focused on hospital survival and resource utilisation adjusted for severity of illness. Many outcome prediction systems for Intensive care unit (ICU) patients have been developed (1-4) and are routinely used in many ICU all over the world measuring severity of illness as mortality prediction models. They have been widely used and their performance well studied in large international data set (5). Predicted outcomes may also be used both for clinical decision making in individual patients and for assessing quality of care. Severity of illness in the ICU setting is typically quantified using models relating risk of death to physiologic variables within 24 hours of admission to the ICU. Such models include the Acute Physiology and Chronic Health Evaluation (APACHE) II (6), APACHE III (7), the Introduction: Outcome in intensive care may be categorized as mortality or morbidity related. Mortality is an insufficient measure of Intensive Care Unit (ICU) outcome when measured alone and length of stay may be seen as an indirect measure of morbidity related outcome. Length of stay may be seen as a surrogate marker for adverse outcome and increased resource use following surgery. The aim of the present study was to evaluate case fatality rates and the determinants of death and length of stay in patients admitted to a surgical ICU. Methods: The study was observational and prospective in a surgical ICU and all consecutive adult patients admitted between October 2004 and April 2005, who underwent noncardiac surgery, were enrolled. Patients were categorized according age, gender, body mass index, ASA physical status, type and magnitude of surgical procedure, type and duration of anesthesia, core temperature at admission, Length of stay (LOS) in the ICU and in the hospital, and mortality in the ICU and in the hospital. The Simplified Acute Physiology Score II (SAPS II) was calculated. Postoperative prolonged ICU stay was defined as intensive care lasting for seven days and longer. Results: The mean ICU LOS was 4.22 ± 8.76 days. Significant risk factors for staying longer in ICU were SAPS II (OR 1.08; 95% CI: 1.06-1.11, p < 0.001), ASA physical status (OR 3.00; 95% CI: 1.49-6.07, p = 0.002 for ASA III/IV patients) and emergency surgery (OR 6.56; 95% CI: 1.89-12.44, p < 0.001 for emergency surgery). Forty two (11.2%) patients died during hospitalization. Mortality was significantly associated with ASA physical status (OR 3.04; 95% CI: 1.41-6.56, p = 0.005 for ASA III/IV patients), emergency surgery (OR 5.40; 95% CI: 2.74-10.64, p < 0.001), SAPS II scores (OR 1.09; 95% CI: 1.07-1.20, p < 0.001) and longer stay in ICU (OR 8.05; 95% CI: 3.95-37.18, p < 0.001). Conclusions: Severity of disease and emergency surgery resulted in prolonged ICU stay and higher mortality. Staying longer in ICU is also a determinant of hospital mortality. Key-words: intensive care; outcome; postoperative period; hospital mortality; length of stay.