Inducing oscillations in positive end-expiratory pressure improves assessment of cerebrovascular pressure reactivity in patients with traumatic brain injury

Jeanette Tas*, Kirsten D J Bos, Joost le Feber, Erta Beqiri, Marek Czosnyka, Roel Haeren, Iwan C C van der Horst, Sander M J van Kuijk, Ulrich Strauch, Ken M Brady, Peter Smielewski, Marcel J H Aries

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

The cerebral pressure reactivity index (PRx), through intracranial pressure (ICP) measurements, informs clinicians about the cerebral autoregulation (CA) status in adult sedated traumatic brain injury (TBI) patients. Using PRx in clinical practice is currently limited by variability over shorter monitoring periods. We applied an innovative method to reduce the PRx variability by ventilator-induced slow (one minute) positive end-expiratory pressures (PEEP) oscillations. We hypothesized that, as seen in a previous animal model, the PRx variability would be reduced by inducing slow arterial blood pressure (ABP) and ICP oscillations and without other clinically relevant physiological changes.TBI patients were ventilated with a static PEEP for thirty minutes (PRx period) followed by a thirty-minute period of slow (1/minute (0.0167 Hz)) +5 cmH2O PEEP oscillations (induced (ᵅ6;PRx period). Ten TBI patients were included. No clinical monitoring was discontinued and no additional interventions were required during the ᵅ6;PRx period. The PRx variability (measured as the standard deviation (SD) of PRx) decreased significantly during the ᵅ6;PRx period from 0.25 (0.22 - 0.30) to 0.14 (0.09 - 0.17) (p = 0.006). There was a power increase around the induced frequency (1/minute) for both ABP and ICP (p = 0.002). In conclusion, 1/minute PEEP-induced oscillations reduced the PRx variability in TBI patients with ICP levels <22 mmHg. No other clinical relevant physiological changes were observed. Reduced PRx variability might improve CA-guided perfusion management by reducing the time to find 'optimal' perfusion pressure targets. Larger studies with prolonged periods of PEEP-induced oscillations are required to take it to routine use.

Original languageEnglish
Pages (from-to)585-592
Number of pages8
JournalJournal of Applied Physiology
Volume133
Issue number3
Early online date7 Jul 2022
DOIs
Publication statusPublished - Sept 2022

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