Acute lung injury in a neurosciences critical care unit

Introduction

Acute lung injury (ALI) may complicate neurological illness, but the mechanisms and outcomes of ALI in this setting are poorly understood. We hypothesized that ALI is linked to severity of neurological illness, mechanical ventilation (MV) parameters, and outcomes in brain-injured patients.

Methods

We identified consecutive patients admitted over a 2-year period to a tertiary hospital neurosciences critical care unit and requiring MV for >48 hours. ALI was determined using AECC criteria. Univariable and multivariable predictors of ALI and of mortality were assessed.

Results

We evaluated 124 patients with head trauma (34 patients), intracerebral hemorrhage (29 patients), subarachnoid hemorrhage (25 patients), ischemic stroke (12 patients), and other brain disorders (24 patients). The primary indication for MV was neurological (impaired consciousness, seizures, intracranial hypertension) in 89 patients, respiratory failure in 22 patients, surgery in 10 patients, and other in three patients. ALI developed in 36 patients (29%) a mean (SD) of 2.7 (1.8) days after initiation of MV. Neither ALI risk factors (pneumonia, aspiration, sepsis, trauma, transfusion, pancreatitis) or neurological insult severity (Glasgow Coma Scale on admission, absence of brainstem reflexes) were significantly associated with ALI. Tidal volumes and positive end-expiratory pressures on days 1 and 2 of MV were not significantly different in patients with and without ALI. Fifty-two patients (42%) died during hospitalization, and independent predictors of death were admission with intracerebral hemorrhage (OR = 4.3, 95% CI = 1.5–12.2), absence of corneal reflex (OR = 5.0, 95% CI = 1.2–20.0), and circulatory shock (OR = 6.2, 95% CI = 1.9–20.9). There was no independent association between ALI and mortality.

Conclusion

ALI developed in nearly one-third of patients undergoing MV following either traumatic or nontraumatic brain injury. The postulated relationships between ALI and MV parameters, neurological severity of illness, and short-term mortality were not confirmed in this population.