Intracranial pressure monitoring in severe traumatic brain injury: results from the American College of Surgeons Trauma Quality Improvement Program

Abstract

Although existing guidelines support the utilization of intracranial pressure (ICP) monitoring in patients with traumatic brain injury (TBI), the evidence suggesting benefit is limited. To evaluate the impact on outcome, we determined the relationship between ICP monitoring and mortality in centers participating in the American College of Surgeons Trauma Quality Improvement Program (TQIP). Data on 10,628 adults with severe TBI were derived from 155 TQIP centers over 2009-2011. Random-intercept multilevel modeling was used to evaluate the association between ICP monitoring and mortality after adjusting for important confounders. We evaluated this relationship at the patient level and at the institutional level. Overall mortality (n=3769) was 35%. Only 1874 (17.6%) patients underwent ICP monitoring, with a mortality of 32%. The adjusted odds ratio (OR) for mortality was 0.44 [95% confidence interval (CI), 0.31-0.63], when comparing patients with ICP monitoring to those without. It is plausible that patients receiving ICP monitoring were selected because of an anticipated favorable outcome. To overcome this limitation, we stratified hospitals into quartiles based on ICP monitoring utilization. Hospitals with higher rates of ICP monitoring use were associated with lower mortality: The adjusted OR of death was 0.52 (95% CI, 0.35-0.78) in the quartile of hospitals with highest use, compared to the lowest. ICP monitoring utilization rates explained only 9.9% of variation in mortality across centers. Results were comparable irrespective of the method of case-mix adjustment. In this observational study, ICP monitoring utilization was associated with lower mortality. However, variability in ICP monitoring rates contributed only modestly to variability in institutional mortality rates. Identifying other institutional practices that impact on mortality is an important area for future research.

FIG. 1.

Forest plot of adjusted odds ratios (ORs) of death after severe traumatic brain injury at the different hospital quartiles of intracranial pressure (ICP) monitoring use. Quartile 4 has the highest rate of ICP monitoring and quartile 1 (the reference) has the lowest. Dotted line represents the odds of dying at the reference quartile (quartile 1). CI, confidence interval. *ORs were estimated using a random-intercept multilevel model with hospital-specific ICP monitoring rate (categorized into quartiles) as the main exposure and in-hospital mortality as the outcome of interest. Patient-level covariates were age, gender, comorbid illnesses, Glasgow Coma Scale motor score, Abbreviated Injury Scale score for body region head, hypotension on admission, type of intracranial lesion, mechanism of injury, and type of insurance. Hospital-level covariates were volume of traumatic brain injury patients per center, teaching status, and number of hospital beds.