Objective: Intracranial hypertension has been reported as a prognostic factor in the poor outcome of spontaneous intracerebral with intraventricular hemorrhage (ICH, IVH). Intracompartmental pressure gradients may exist around focal ICH and IVH and may adversely affect tissue perfusion. EVD position is an important determinant of IVH removal efficiency with thrombolytics which may impact accuracy of intracranial pressure (ICP) measures.
Methods: We report the time course of ICP in 109 subjects from the CLEAR III trial, who had pragmatic placement of 2 or more simultaneous EVDs with documented ICP recordings every 4 hours for up to 10 days. We performed analysis of ICP differences by EVD side ipsilateral vs. contralateral to dominant IVH volume and assessed discordant readings of potential clinical significance to decision-making.
Results: Mean (SD) age was 60 (10) years, with mean ICH and IVH volume of 9.1 (8.1) and 39 (25.5) mL respectively. Simultaneous EVD placement on opposite ventricle sides was performed in 109 subjects with mean (SD) of 57(28) paired ICP readings; EVD placement on same ventricle side was performed in 10 subjects with mean 20(32) paired ICP readings. For opposite side EVDs, mean ICP was significantly higher in EVDs placed ipsilateral to dominant volume of IVH vs. in contralateral EVDs: 11.9 vs. 10.9 mmHg (p=0.004), whereas for same side EVDs, mean ICP was higher in EVDs placed contralateral to dominant IVH volume vs. ipsilateral: 12.3 vs. 9.1 mmHg (p<0.001). EVDs placed contralateral to dominant IVH in subjects with opposite side cranial EVD placement were significantly less likely to report ICP >30 mmHg than EVDs placed ipsilateral to dominant IVH (Odds ratio=0.41; 95% CI: 0.20-0.84; p=0.02). Differences in ICP between opposite side EVDs were significant for ICH volume >10mL, modified Graeb score>18, age<60, percent IVH removal at end of treatment, obstruction of third ventricle at EOT, and intraventricular saline assignment (vs. alteplase)
Conclusions: We report that occasional pressure gradients exist within the intraventricular cavity in patients with spontaneous IVH and have implications in the interpretation of ICP recordings. In view of the importance of bilateral EVD usage to optimize clearance of IVH, and minimize the occurrence of raised ICP, consideration must be given to location of intraventricular catheters in relationship to these clinical objectives.