Intracranial Pressure Monitoring Practice, Treatment, and Effect on Outcome in Aneurysmal Subarachnoid Hemorrhage

Background: Intracranial pressure (ICP) monitoring and its management in aneurysmal subarachnoid hemorrhage (aSAH) is variable worldwide. The present study aimed to explore the practice of ICP monitoring, its variability across countries, and the association with 6-month outcomes in aSAH. Methods: This was a preplanned subanalysis of SYNAPSE-ICU, a multicenter, international, prospective, observational cohort study focused on patients diagnosed with aSAH. We evaluated the variability in ICP monitoring across countries through a logistic regression model adjusted for case-mix and considered countries as a random effect. The association between ICP probe insertion and 6-month mortality and a poor neurological outcome, defined as an Glasgow Outcome Score Extended ≤ 4, was assessed by using a propensity score approach. Results: A total of 423 patients with aSAH from 92 centers across 32 countries were included in this analysis. ICP monitoring was used in 295 (69.7%) patients. Significant between-country variability in ICP insertion was observed, with an incidence ranging between 4.7% and 79.9% (median odd ratio 3.04). The median duration of ICP monitoring was 12 days (first quartile [Q1] through third quartile [Q3] range 8–18), with an overall daily median ICP value of 14 mm Hg (Q1–Q3 10–19) and a median maximum value of 21 mm Hg (Q1–Q3 16–30). Patients monitored with ICP received more aggressive therapy treatments compared with non-monitored patients (therapy intensity level, TIL, score 10.33 [standard deviation 3.61] vs. 6.3 [standard deviation 4.19], p < 0.001). In more severe patients, ICP monitoring was significantly associated with better 6-month outcome (poor neurological outcome: odds ratio 0.14, 95% confidence interval 0.02–0.53, p = 0.0113; mortality: hazard ratio 0.25, 95% confidence interval 0.13–0.49, p < 0.0001). However, no significant effect was observed in patients with both reactive pupils. Conclusions: Our cohort demonstrated high variability in ICP insertion practice among countries. A more aggressive treatment approach was applied in ICP-monitored patients. In patients with severe aSAH, ICP monitoring might reduce unfavorable outcomes and mortality at 6 months.