Prognostic factors of patients admitted in a medical intermediate care unit: a prospective observational study

Background Medical Intermediate Care Units (IntCU’s) are high-dependency units intended for treatment of patients who do not meet criteria for admission to intensive care units (ICU’s) but require a higher level of care than can be provided in general ward. IntCU’s operate as a transitional unit, improving patients outcome. In addition, IntCU’s permit better resource utilization, reducing the length of stay in ICU and therefore increasing availability of critical care. Regardless of admission of unstable patients in IntCU’s, studies on prognostic factors are scarce. Our purpose was to identify prognostic factors of patients admitted in IntCU. Methods A prospective observational study was performed during 32 months in a IntCU of a central hospital. Main objective was evaluation of mortality and analysis of acute illness severity, nurse workload, comorbidity and previous functional status as prognostic factors. Assessment of these variables was performed using several standardized scores: Acute Physiology and Chronic Health Evaluation II (APACHE II), Simplified Acute Physiology Score II (SAPS II), Sequential Organ Failure Assessment (SOFA), Therapeutic Intervention Scoring System-28 (TISS-28), Nursing Activities Score (NAS), Charlson comorbidity index and Barthel index of basic activities of daily living. Bivariate and multiple logistic regression with forwards stepwise selection were used to identify prognostic factors of IntCU and in-hospital mortality. Results Two hundred and eighty-eight patients were included, mean age 65,67 ± 20,38 years-old. IntCU and in-hospital mortality was 9,38 and 17,71%, respectively. All the scores applied, concerning comorbidity, functional status, acute illness severity and nurse workload were good predictors of mortality. SAPS II was the better predictor of mortality followed by NAS. Conclusions Acute illness severity and nursing workload scores validated in ICU are useful and reliable in IntCU setting, being SAPS II and NAS the strongest predictors of mortality. Comorbidity, functional status and age were also prognostic factors. Consequently, a comprehensive assessment of patients admitted in IntCU is mandatory to reliably predict outcome. Several scores might be used to help clinical judgment, concerning admission criteria and clinical decisions.