Clinical characteristics of the intensive care patients at the Hospital Universitario de San Ignacio with acute renal failure and factors associated with mortality

Abstract

Introduction: acute renal failure (ARF) is one of the most frequent complications found in the Intensive Care Unit (ICU). In order to optimize resources, to improve the quality of patient care, and to reduce complications and morbidity-mortality, it is therefore important to identify risk factors and to implement early and timely management measures.

Objective: to identify the clinical characteristics of patients admitted to the ICU of Hospital Universitario de San Ignacio (HUSI) with ARF, as well as the risk factors possibly associated with mortality.

Materials and methods: a prospective study of a convenience sample of all patients aged 15 years or older admitted to the ICU of HUSI who developed ARF. ARF was defined as serum creatinin levels greater than 1.4 mg/dL (male) or greater than 1.2 mg/dL (female), or when the patient developed oliguria (urine output less than 400 ml in 24 hours), or a 50% increase in creatinin levels with respect to admission. The variables included at the moment of admission were: age, sex, APACHE, TISS, SOFA, indication for admission to ICU, comorbidities, infection, site of infection, azotemia values, electrolytes (sodium and potassium), arterial blood gases (pH and bicarbonate), relationship between PaO2 and FiO2, use of vasopressors (dopamine > 5 µg/kg/min, noradrenalin > 0.1 µg/kg/min), and urine output.

Results: during the period from June 1 to December 1 2006, 253 patients admitted to the ICU who afterwards developed ARF were studied. 56% were males and 60.3% required vasopressors. The most frequent diagnoses on admission were septic shock and acute coronary syndrome, with 35 patients each (13.83%). Mortality was 13.4% in this group. Exploratory analysis of the variables on admission to the ICU showed increased mortality associated with mechanical ventilation, pulmonary infection, use of vasopressors (specifically noradrenalin), altered sodium and potassium levels, APACHE scores greater than 20 and SOFA greater than 6, as well as comorbidities.

Conclusions: after adjusting a logistic regression model controlled by other independent variables, the only variables found to be associated with mortality were: need for mechanical ventilation, APACHE score greater than 20, SOFA score greater than 6, and abnormal sodium levels