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Different strategies to initiate and maintain hyperventilation: their effect on continuous estimates of dynamic cerebral autoregulation

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posted on 2019-03-22, 10:00 authored by JS Minhas, C Kennedy, TG Robinson, RB Panerai
OBJECTIVE: Capnography is a key monitoring intervention in several neurologically vulnerable clinical states. Cerebral autoregulation (CA) describes the ability of the cerebrovascular system to maintain a near constant cerebral blood flow throughout fluctuations in systemic arterial blood pressure, with the partial pressure of arterial carbon dioxide known to directly influence CA. Previous work has demonstrated dysautoregulation lasting around 30 s prior to the anticipated augmentation of hyperventilation-associated hypocapnia. In order assess to potential benefit of hypocapnic interventions in an acute stroke setting, minimisation of dysregulation is paramount. APPROACH: Hyperventilation strategies to induce and maintain hypocapnia were performed in 61 healthy participants, effects on temporal estimates of dynamic cerebral autoregulation (autoregulation index, ARI) were assessed to validate the most effective strategy for inducing and maintaining hypocapnia. MAIN RESULTS: The extent of initial decrease was significantly smaller in the continuous metronome strategy compared to the delayed metronome and voluntary strategies (▵ARI 0.33  ±  1.18, 2.80  ±  3.33 and 3.69  ±  2.79 respectively, p   <  0.017). SIGNIFICANCE: The use of a continuous metronome to induce hypocapnia rather than the sudden inception of an auditory stimulus appears to reduce the initial decrease in autoregulatory capacity seen in previous studies. Dysautoregulation can be minimised by continuous metronome use during hyperventilation-induced hypocapnia. This advancement in understanding of the behaviour of CA during hypocapnia permits safer delivery of CA targeted interventions, particularly in neurologically vulnerable patient populations.

Funding

JSM is Dunhill Medical Trust Clinical Research Training Fellow (RTF97/0117) at the Department of Cardiovascular Sciences, University of Leicester. TGR is an NIHR Senior Investigator.

History

Citation

Physiol Meas, 2019, 40 (1), pp. 015003

Author affiliation

/Organisation/COLLEGE OF LIFE SCIENCES/School of Medicine/Department of Cardiovascular Sciences

Version

  • AM (Accepted Manuscript)

Published in

Physiol Meas

Publisher

IOP Publishing

eissn

1361-6579

Acceptance date

2018-12-21

Copyright date

2019

Publisher version

https://iopscience.iop.org/article/10.1088/1361-6579/aafab6/meta

Notes

The file associated with this record is under embargo until 12 months after publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.

Language

en

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