Frequency of acute lung injury and acute respiratory distress syndrome in the intensive care unit of a teaching hospital: a prospective study

Background

Ashbaugh et al. first described acute respiratory distress syndrome (ARDS) in 1967 in 12 patients with acute respiratory failure. In 1994, the American–European Consensus Conference on ARDS established the diagnosis criteria for acute lung injury (ALI) and ARDS, and also defined the associated risk factors.

Objective

To establish the frequency and the main risk factors for ALI and ARDS using American–European Consensus Conference diagnosis criteria, to describe the intensive care unit (ICU) and hospital mortality of these patients, and also to compare the outcome of ALI/ARDS patients (group I) with similar patients without ALI/ARDS (group II).

Design

A prospective observational study.

Setting

The Emergency Department (16 beds) ICU of a university hospital (Ribeirão Preto Medical School Hospital, University of São Paulo, Brazil).

Methods

All patients admitted from 1 May 2001 to 30 April 2002 with one or more of 14 predefined risk factors for ALI/ARDS were followed. Clinical data, Acute Physiology and Chronic Health Evaluation (APACHE) II score, complications, and ICU and hospital length of stay were recorded.

Results

From 524 admissions during the study period, 175 patients (33.4%) had one or more risk factors for ALI/ARDS and 37 patients (7.0%) developed this condition (group I). The main risk factors were pneumonia (37.7%), shock (32.0%), multiple trauma (21.7%) and sepsis (21.1%). The frequency of sepsis was higher in group I than in group II (46% vs 14.5%, P < 0.001). The comparison between groups showed that group I had a higher APACHE II score (20 vs 17, P < 0.001), more hospital complications (68% vs 40%, P < 0.05) and higher ICU mortality (73% vs 37%, P < 0.001) and hospital mortality (76% vs 50%, P < 0.05). The main causes of death were multiple organ dysfunction syndrome (38.5%) and shock (33.3%).

Conclusions

The prevalence of ALI/ARDS was 7% in this ICU population. The main risk factors were pneumonia, shock, multiple trauma and sepsis. Patients with ALI/ARDS had high ICU mortality and hospital mortality.