Outcomes and complications of intracranial pressure monitoring in acute liver failure: A retrospective cohort study

Objective: To determine if intracranial pressure monitor placement in patients with acute liver failure is associated with significant clinical outcomes. Design: Retrospective multicenter cohort study. Setting: Academic liver transplant centers comprising the U.S. Acute Liver Failure Study Group. Patients: Adult critically ill patients with acute liver failure presenting with grade III/IV hepatic encephalopathy (n = 629) prospectively enrolled between March 2004 and August 2011. Intervention: Intracranial pressure monitored (n = 140) versus nonmonitored controls (n = 489). Measurements and Main Results: Intracranial pressure monitored patients were younger than controls (35 vs 43 yr, p < 0.001) and more likely to be on renal replacement therapy (52% vs 38%, p = 0.003). Of 87 intracranial pressure monitored patients with detailed information, 44 (51%) had evidence of intracranial hypertension (intracranial pressure > 25 mm Hg) and overall 21-day mortality was higher in patients with intracranial hypertension (43% vs 23%, p = 0.05). During the first 7 days, intracranial pressure monitored patients received more intracranial hypertension-directed therapies (mannitol, 56% vs 21%; hypertonic saline, 14% vs 7%; hypothermia, 24% vs 10%; p < 0.03 for each). Forty-one percent of intracranial pressure monitored patients received liver transplant (vs 18% controls; p < 0.001). Overall 21-day mortality was similar (intracranial pressure monitored 33% vs controls 38%, p = 0.24). Where data were available, hemorrhagic complications were rare in intracranial pressure monitored patients (4 of 56 [7%]; three died). When stratifying by acetaminophen status and adjusting for confounders, intracranial pressure monitor placement did not impact 21-day mortality in acetaminophen patients (p = 0.89). However, intracranial pressure monitor was associated with increased 21-day mortality in nonacetaminophen patients (odds ratio, ~ 3.04; p = 0.014). Conclusions: In intracranial pressure monitored patients with acute liver failure, intracranial hypertension is commonly observed. The use of intracranial pressure monitor in acetaminophen acute liver failure did not confer a significant 21-day mortality benefit, whereas in nonacetaminophen acute liver failure, it may be associated with worse outcomes. Hemorrhagic complications from intracranial pressure monitor placement were uncommon and cannot account for mortality trends. Although our results cannot conclusively confirm or refute the utility of intracranial pressure monitoring in patients with acute liver failure, patient selection and ancillary assessments of cerebral blood flow likely have a significant role. Prospective studies would be required to conclusively account for confounding by illness severity and transplant.