Intracranial pressure-monitoring systems in children with traumatic brain injury: combining therapeutic and diagnostic tools

Abstract

Objective: To compare the correlation of intracranial pressure (ICP) measurement and time to detection of ICP crises (defined as ICP ≥ 20 mm Hg for ≥ 5 mins) between an intraparenchymal (IP) monitor and external ventricular drain (EVD) in children for whom continuous cerebrospinal fluid diversion was used as a therapy for severe traumatic brain injury.

Setting: Academic, pediatric intensive care unit.

Design: Retrospective review of a prospectively collected pediatric neurotrauma database.

Patients: Children with severe traumatic brain injury (Glasgow Coma Scale score of ≤ 8) who underwent ICP monitoring with both IP and EVD techniques were studied. In cohort 1 (n = 58), hourly ICP measurements were extracted from the medical record; in cohort 2 (n = 4), ICP measurements were collected every minute by an automated data-collection system.

Measurements and main results: The mean absolute difference in ICP (|N5ICP|N5) and intraclass correlation coefficients were calculated. Timing to detection of ICP crises was analyzed. Data were expressed as mean ± sem. For cohort 1, 7,387 hrs of data were analyzed; 399 hrs (23,940 mins) were analyzed for cohort 2. In cohort 1, the |N5ICP|N5 was 3.10 ± 0.04 mm Hg (intraclass correlation coefficients = 0.98, p < .001). The |N5ICP|N5 in cohort 2 was 3.30 ± 0.05 mm Hg (intraclass correlation coefficients = 0.98, p < .001). In cohort 2, a total of 75 ICP crises were observed. Fifty-five (73%) were detected first by the IP monitor, of which 35 were not identified by the EVD monitor. Time between IP and EVD detection of a crisis was 12.60 ± 2.34 mins.

Conclusion: EVD and IP measurements of ICP were highly correlated, although intermittent EVD ICP measurements may fail to identify ICP events when continuously draining cerebrospinal fluid. In institutions that use continuous cerebrospinal fluid diversion as a therapy, a two-monitor system may be valuable for accomplishing monitoring and therapeutic goals.

Figure 1

a. Representative graphs of intracranial pressure (ICP) measurements in a patient in Cohort 2. Data were obtained by the automated collection system (Bedmaster Ex, Excel Medical). The top graph represents measurements made by the external ventricular drain (EVD) monitor; the bottom graph represents measurements made by the intraparenchymal (IP) monitor. In this particular patient, both monitors demonstrate consistent and timely detection of ICP crises (solid black arrows). b. Representative graphs of intracranial pressure (ICP) measurements in a patient in Cohort 2. Data were obtained by the automated collection system (Bedmaster Ex, Excel Medical). The top graph represents measurements made by the external ventricular (EVD) monitor; the bottom graph represents measurements made by the intraparenchymal (IP) monitor. ICP crises are identified by solid black arrows. In contrast to Figure 1a, the EVD monitor fails to detect several significant ICP crises identified by the IP monitor (dashed line arrows).

Figure 1

a. Representative graphs of intracranial pressure (ICP) measurements in a patient in Cohort 2. Data were obtained by the automated collection system (Bedmaster Ex, Excel Medical). The top graph represents measurements made by the external ventricular drain (EVD) monitor; the bottom graph represents measurements made by the intraparenchymal (IP) monitor. In this particular patient, both monitors demonstrate consistent and timely detection of ICP crises (solid black arrows). b. Representative graphs of intracranial pressure (ICP) measurements in a patient in Cohort 2. Data were obtained by the automated collection system (Bedmaster Ex, Excel Medical). The top graph represents measurements made by the external ventricular (EVD) monitor; the bottom graph represents measurements made by the intraparenchymal (IP) monitor. ICP crises are identified by solid black arrows. In contrast to Figure 1a, the EVD monitor fails to detect several significant ICP crises identified by the IP monitor (dashed line arrows).

Figure 2

Description of ICP (intracranial pressure) crisis detection in Cohort 2 by monitoring method. External ventricular drain (EVD) monitors and intraparenchymal (IP) monitors were used to measure ICP in all subjects.