Factors influencing intracranial pressure monitoring guideline compliance and outcome after severe traumatic brain injury

Objective: To determine adherence to Brain Trauma Foundation guidelines for intracranial pressure monitoring after severe traumatic brain injury, to investigate if characteristics of patients treated according to guidelines (ICP+) differ from those who were not (ICP-), and whether guideline compliance is related to 6-month outcome. Design: Observational multicenter study. Patients: Consecutive severe traumatic brain injury patients (>= 16 yrs, n = 265) meeting criteria for intracranial pressure monitoring. Measurements and Main Results: Data on demographics, injury severity, computed tomography findings, and patient management were registered. The Glasgow Outcome Scale Extended was dichotomized into death (Glasgow Outcome Scale Extended = 1) and unfavorable outcome (Glasgow Outcome Scale Extended 1-4). Guideline compliance was 46%. Differences between the monitored and nonmonitored patients included a younger age (median 44 vs. 53 yrs), more abnormal pupillary reactions (52% vs. 32%), and more intracranial pathology (subarachnoid hemorrhage 62% vs. 44%; intraparenchymal lesions 65% vs. 46%) in the ICP+ group. Patients with a total intracranial lesion volume of similar to 150 mL and a midline shift of similar to 12 mm were most likely to receive an intracranial pressure monitor and probabilities decreased with smaller and larger lesions and shifts. Furthermore, compliance was low in patients with no (Traumatic Coma Databank score I -10%) visible intracranial pathology. Differences in case-mix resulted in higher a priori probabilities of dying (median 0.51 vs. 0.35, p < .001) and unfavorable outcome (median 0.79 vs. 0.63, p < .001) in the ICP+ group. After correction for baseline and clinical characteristics with a propensity score, intracranial pressure monitoring guideline compliance was not associated with mortality (odds ratio 0.93, 95% confidence interval 0.47-1.85, p = .83) nor with unfavorable outcome (odds ratio 1.81, 95% confidence interval 0.88-3.73, p = .11). Conclusions: Guideline noncompliance was most prominent in patients with minor or very large computed tomography abnormalities. Intracranial pressure monitoring was not associated with 6-month outcome, but multiple baseline differences between monitored and nonmonitored patients underline the complex nature of examining the effect of intracranial pressure monitoring in observational studies. (Crit Care Med 2012; 40:1914-1922)