Early identification of patients at risk of acute lung injury: evaluation of lung injury prediction score in a multicenter cohort study

Abstract

Rationale: Accurate, early identification of patients at risk for developing acute lung injury (ALI) provides the opportunity to test and implement secondary prevention strategies.

Objectives: To determine the frequency and outcome of ALI development in patients at risk and validate a lung injury prediction score (LIPS).

Methods: In this prospective multicenter observational cohort study, predisposing conditions and risk modifiers predictive of ALI development were identified from routine clinical data available during initial evaluation. The discrimination of the model was assessed with area under receiver operating curve (AUC). The risk of death from ALI was determined after adjustment for severity of illness and predisposing conditions.

Measurements and main results: Twenty-two hospitals enrolled 5,584 patients at risk. ALI developed a median of 2 (interquartile range 1-4) days after initial evaluation in 377 (6.8%; 148 ALI-only, 229 adult respiratory distress syndrome) patients. The frequency of ALI varied according to predisposing conditions (from 3% in pancreatitis to 26% after smoke inhalation). LIPS discriminated patients who developed ALI from those who did not with an AUC of 0.80 (95% confidence interval, 0.78-0.82). When adjusted for severity of illness and predisposing conditions, development of ALI increased the risk of in-hospital death (odds ratio, 4.1; 95% confidence interval, 2.9-5.7).

Conclusions: ALI occurrence varies according to predisposing conditions and carries an independently poor prognosis. Using routinely available clinical data, LIPS identifies patients at high risk for ALI early in the course of their illness. This model will alert clinicians about the risk of ALI and facilitate testing and implementation of ALI prevention strategies. Clinical trial registered with www.clinicaltrials.gov (NCT00889772).

Figure 1.

Outline of the screening protocol and case ascertainment. ALI = acute lung injury; ARDS = acute respiratory distress syndrome; ED = emergency department.

Figure 2.

Frequency of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) development according to predisposing conditions. The figure depicts the frequency of ALI/ARDS development in subsets of patients with different risk factors. Because the risk factors are not mutually exclusive, the patients who presented with more than one risk factor maybe counted more than once.

Figure 3.

Frequency of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) development according to lung injury prediction score (LIPS) value. The figure depicts the frequency of ALI/ARDS development with different LIPS values. N denotes number of patients in the study who had particular LIPS value.

Figure 4.

Timing of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) development during hospital stay. Lung injury prediction score performance was similar in different subgroup analyses: exclusion of patients who developed ALI/ARDS during the first 24 hours (–24 h) or after 5 days (solid lines); exclusion of patients who developed ALI/ARDS during the first 48 hours (dashed line). The day of admission is marked as Day 0 and the second day as Day 1. The dashed line is at the end of Day 1 (48 h).