Assessment of a Non-Invasive Brain Pulse Monitor to Measure Intra-Cranial Pressure Following Acute Brain Injury

Barry Dixon; Jessica M Sharkey; Elliot J Teo; Sally A Grace; Jacqui S Savage; Andrew Udy; Paul Smith; Jack Hellerstedt; John D Santamaria

doi:10.2147/MDER.S398193

Assessment of a Non-Invasive Brain Pulse Monitor to Measure Intra-Cranial Pressure Following Acute Brain Injury

Med Devices (Auckl). 2023 Jan 24:16:15-26. doi: 10.2147/MDER.S398193. eCollection 2023.

Authors

Barry Dixon^{1

2

3}, Jessica M Sharkey¹, Elliot J Teo^{1

2}, Sally A Grace¹, Jacqui S Savage¹, Andrew Udy⁴, Paul Smith^{5

6}, Jack Hellerstedt¹, John D Santamaria²

Affiliations

¹ Cyban Pty Ltd, Melbourne, VIC, Australia.
² Department of Critical Care Medicine, St Vincent's Hospital, Melbourne, Australia.
³ Department of Medicine, University of Melbourne, Melbourne, Vic, Australia.
⁴ Department of Critical Care Medicine, The Alfred Hospital, Melbourne, Australia.
⁵ Department of Neurosurgery, St Vincent's Hospital, Melbourne, Australia.
⁶ University of Melbourne Medical School, Melbourne, Vic, Australia.

Abstract

Background: Intracranial pressure (ICP) monitoring requires placing a hole in the skull through which an invasive pressure monitor is inserted into the brain. This approach has risks for the patient and is expensive. We have developed a non-invasive brain pulse monitor that uses red light to detect a photoplethysmographic (PPG) signal arising from the blood vessels on the brain's cortical surface. The brain PPG and the invasive ICP waveform share morphological features which may allow measurement of the intracranial pressure.

Methods: We enrolled critically ill patients with an acute brain injury with invasive ICP monitoring to assess the new monitor. A total of 24 simultaneous invasive ICP and brain pulse monitor PPG measurements were undertaken in 12 patients over a range of ICP levels.

Results: The waveform morphologies were similar for the invasive ICP and brain pulse monitor PPG approach. Both methods demonstrated a progressive increase in the amplitude of P2 relative to P1 with increasing ICP levels. An automated algorithm was developed to assess the PPG morphological features in relation to the ICP level. A correlation was demonstrated between the brain pulse waveform morphology and ICP levels, R²=0.66, P < 0.001.

Conclusion: The brain pulse monitor's PPG waveform demonstrated morphological features were similar to the invasive ICP waveform over a range of ICP levels, these features may provide a method to measure ICP levels.

Trial registration: ACTRN12620000828921.

Keywords: acute brain injury; intracranial pressure; monitoring; non-invasive; photoplethysmography.

Grants and funding

The research was supported by a grant from the Biomedtech Horizons Program part of the Medical Research Future Fund of the Australian Government.