Acute lung injury and the acute respiratory distress syndrome in Ireland : a prospective audit of epidemiology and management The Irish Critical Care Trials

Introduction The aim of this study was to describe the epidemiology and management of acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) in Ireland. Methods As part of a 10-week prospective national audit of patient demographics and organ failure incidence in intensive care in Ireland, all patients with ALI/ARDS in 14 participating centres were prospectively identified using American European Consensus Conference definitions. Results There were 1,029 admissions during the study period; of these, 728 patients were invasively ventilated. A total of 196 (19%) patients had ALI/ARDS, and 141 of these (72%) had ALI/ARDS on admission and a further 55 (28%) developed ALI/ ARDS after admission. For the patients with ALI/ARDS, the mean (± standard deviation) age was 58 ± 17 years and 62% were male. The most common predisposing risk factors were pneumonia (50%) and nonpulmonary sepsis (26%). Mean (± standard deviation) tidal volume/kg was 7.0 ± 1.7 ml/kg. Median (interquartile range) duration of ventilation was 6.8 (2.0 to 12.8) days. Median (interquartile range) length of stay in the intensive care unit was 10.0 (5.0 to 18.5) days. The overall intensive care unit mortality for ALI/ARDS was 32.3%. Lower baseline arterial oxygen tension/fraction of inspired oxygen ratio and higher Sequential Organ Failure Assessment scores were associated with increased mortality. Although not significant, patients receiving treatment with a statin during admission had a 73% lower odds of death (odds ratio 0.27, 95% confidence interval 0.06 to 1.21; P = 0.09). Conclusion The incidence of ALI/ARDS is high and is associated with significant mortality. Protective lung ventilation is used commonly throughout participating centres. With low tidal volume ventilation, the degree of hypoxaemia is associated with outcome. These data will inform future multicentre clinical trials in ALI/ARDS in Ireland. Introduction Acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) occur in response to a variety of insults and are characterized by the development of noncardiogenic pulmonary oedema, impaired gas exchange and need for mechanical ventilation. ALI/ARDS is a major cause of acute respiratory failure associated with significant morbidity and mortality. Delivery of critical care to patients with ALI/ARDS accounts for a significant proportion of intensive care unit (ICU) capacity. The mean cost per ICU bed-day is €2,000 [1] and demand for ICU beds exceeds supply. Many pharmacological treatments for lung injury have been evaluated, but none have clearly decreased mortality [2]. There is therefore an urgent need to develop novel treatment strategies for patients with ALI/ARDS. Notably, statins – a promising potential new therapeutic option – modulate mechanisms that are important in the development of lung injury [3]. Statins attenuate lung injury in vivo in animal models, including ischemia-reperfusion [4], peritonitis [5] and endotoxaemic sepsis [6]. The Irish Critical Care Trials Group (ICCTG) was formed in 2006 with the aim of improving the capacity to conduct high quality clinical research in the critically ill in Ireland. In order to