Abstract
Time domain analysis of the intracranial pressure (ICP) waveform provides important information about the intracranial pressure-volume reserve capacity. The aim here was to explore whether the tympanic membrane pressure (TMP) waveform can be used to non-invasively estimate the ICP waveform. Simultaneous invasive ICP and non-invasive TMP signals were measured in a total of 28 individuals who underwent invasive ICP measurements as a part of their clinical work up (surveillance after subarachnoid hemorrhage in 9 individuals and diagnostic for CSF circulation disorders in 19 individuals). For each individual, a transfer function estimate between the invasive ICP and non-invasive TMP signals was established in order to explore the potential of the method. To validate the results, ICP waveform parameters including the mean wave amplitude (MWA) were computed in the time domain for both the ICP estimates and the invasively measured ICP. The patient-specific non-invasive ICP signals predicted MWA rather satisfactorily in 4/28 individuals (14%). In these four patients the differences between original and estimated MWA were <1.0 mmHg in more than 50% of observations, and <0.5 mmHg in more than 20% of observations. The study further disclosed that the cochlear aqueduct worked as a physical lowpass filter.
Highlights
Time domain analysis of the intracranial pressure (ICP) waveform provides important information about the intracranial pressure-volume reserve capacity
While ICP usually is assessed by the mean ICP, representing the absolute pressure difference between the outside and inside of the skull cavity, an increasing body of data suggests that the intracranial pressure-volume reserve capacity is better described by the ICP waveform than the mean ICP itself[11,12,13,14,15]
The reason for ICP monitoring was surveillance after subarachnoid hemorrhage in 9 individuals and diagnostic ICP monitoring for cerebrospinal fluid (CSF) circulation disorders of various causes in 19 individuals (Table 1)
Summary
Time domain analysis of the intracranial pressure (ICP) waveform provides important information about the intracranial pressure-volume reserve capacity. The patient-specific non-invasive ICP signals predicted MWA rather satisfactorily in 4/28 individuals (14%). Measurements of ICP require a neurosurgeon to drill a hole in the patient’s skull and advance a catheter into the brain parenchyma, or through the brain tissue and into the ventricular space. This is an invasive procedure, associated with risk of severe complications such as infection and hemorrhage in about 1–2% of patients[4].
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call