Background and purpose: Because neuroimaging is rarely readily available, long-term monitoring of intracranial pressure (ICP) in neurological/ neurosurgical patients during ventilator weaning and early neurorehabilitation currently relies on clinical observation. Pupilometry and multimodal neurosonography are evaluated for follow-up monitoring in this prospective study.
Methods: During weaning and early neurorehabilitation, sonographic neuromonitoring was used to noninvasively examine the ICP of patients. It made it possible to measure the width of the third ventricle, the possibility of a midline shift, the flow velocities of the middle cerebral artery, and the diameters of the bilateral optic nerve sheaths. The size and reactivity of the pupils were measured with quantitative pupillometry. As controls, we used data from clinical follow-up, ICP measurements from a spinal tap, and other neuroimaging results.
Results: During a mean observation period of 21 days, 17 patients-11 with intracranial hemorrhage, four with encephalopathies, and two with ischemic stroke-were examined for ICP changes using neurosonography and pupillometry. 354 out of 980 analyses, or 36.1%, produced pathological findings. Pathological values without a clear clinical correlate were found during follow-up in 15 of 17 patients (88.2%). Neurosonography was used to identify clinically relevant changes in ICP in two patients (11.8%). The absence of clinical improvement was highly predicted by abnormal pupillometry results.
Conclusion: Pupilometry can only detect rapid ICP changes in acute neurointensive care, whereas multimodal neurosonography may be a noninvasive method for long-term ICP assessment. With a large number of pathological but nonsignificant findings, the study also demonstrates typical pitfalls in neuromonitoring. The effect of detected subtle changes in ICP on neurological outcome should be confirmed by additional controlled studies.