Continuous Monitoring Reveals Minimal Physiologic Response to Cerebrospinal Fluid Drainage: A Pilot Study

Background and Purpose: Clinical practice regarding external ventricular drain (EVD) management and intracranial pressure (ICP) measurement frequency varies substantially. This study explores ICP dynamics associated with cerebrospinal fluid (CSF) drainage from EVDs. Methods: We measured ICP in three patients using continuous data acquisition (CDA) during 10 minutes of ICP monitoring, 3 minutes of CSF drainage, and 10 minutes of ICP monitoring. Results: The mean ICP during the 10 minutes prior to CSF drainage (13.9 [3.9] mmHg) was statistically significantly different than the mean observed during the postdrain period (14.7 [3.8] mmHg; p < .0001). The mean ICP 1 minute before drainage was 14.8 (95% confidence interval [CI] [10, 19.6]) and 14 (95% CI [11.4, 16.7]) after 3 minutes of CSF drainage (p < .0001). Conclusion: Despite being statistically significant, the measured impact of CSF drainage was not clinically meaningful. Using CDA, we were able to identify a precise trend in ICP change over time.