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Continuous monitoring of cerebrovascular reactivity through pulse transit time and intracranial pressure.

Publication ,  Journal Article
Liu, X; Gadhoumi, K; Xiao, R; Tran, N; Smielewski, P; Czosnyka, M; Hetts, SW; Ko, N; Hu, X
Published in: Physiological measurement
January 2019

Cerebrovascular reactivity (CR) is a mechanism that maintains stable blood flow supply to the brain. Pressure reactivity index (PRx), the correlation coefficient between slow waves of invasive arterial blood pressure (ABP) and intracranial pressure (ICP) has been validated for CR assessment. However, in clinical ward, not every subarachnoid hemorrhage (SAH) patient has invasive ABP monitoring. Pulse transit time (PTT), the propagation time of a pulse wave travelling from the heart to peripheral arteries, has been suggested as a surrogate measure of ABP. In this study, we proposed to use PTT instead of invasive ABP to monitor CR.Forty-five SAH patients with simultaneous recordings of invasive ABP, ICP, oxygen saturation level (SpO2) and electrocardiograph (ECG) were included. PTT was calculated as the time from the ECG R-wave peak to the onset of SpO2. PTT based pressure reactivity index (tPRx) was calculated as the correlation coefficient between slow waves of PTT and ICP. Wavelet tPRx (wtRx) was calculated as the cosine of wavelet phase shift between PTT and ICP. Meanwhile, PRx and wPRx were also calculated using invasive ABP and ICP as input.The result showed a negative relationship between PTT and ABP (r  =  -0.58, p   <  0.001). tPRx negatively correlated with PRx (r  =  -0.51, p   =  0.003). Wavelet method correlated well with correlation method demonstrated through positive relationship between wPRx and PRx (r  =  0.82, p   <  0.001) as well as wtPRx and tPRx (r  =  0.84, p   <  0.001).PTT demonstrates great potential as a useful tool for CR assessment when invasive ABP is unavailable. Key points • Pulse transit time (PTT), defined as the propagation time of a pulse wave travelling from the heart to the peripheral arteries, has been proposed as a surrogate measure of ABP. The relationship between PTT and ABP in SAH patients remains unknown. • Cerebrovascular reactivity (CR) assessment through PTT has advantages over invasive ABP, as it avoids bleeding and infection risk, and can be used outside of the ICU. • We introduced a new method to assess CR using PTT and ICP through correlation based method and wavelet based method. • We found that beat-to-beat PTT was negatively related with invasive ABP in SAH patients. A significant linear relationship exists between PTT-based CR parameter and a well validated method, PRx. PTT demonstrates great potential as a useful tool for CR assessment when invasive ABP is unavailable in SAH patients.

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Published In

Physiological measurement

DOI

EISSN

1361-6579

ISSN

0967-3334

Publication Date

January 2019

Volume

40

Issue

1

Start / End Page

01LT01

Related Subject Headings

  • Wavelet Analysis
  • Subarachnoid Hemorrhage
  • Pulse Wave Analysis
  • Monitoring, Physiologic
  • Middle Aged
  • Male
  • Intracranial Pressure
  • Humans
  • Female
  • Cerebrovascular Circulation
 

Citation

APA
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ICMJE
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Liu, X., Gadhoumi, K., Xiao, R., Tran, N., Smielewski, P., Czosnyka, M., … Hu, X. (2019). Continuous monitoring of cerebrovascular reactivity through pulse transit time and intracranial pressure. Physiological Measurement, 40(1), 01LT01. https://doi.org/10.1088/1361-6579/aafab1
Liu, Xiuyun, Kais Gadhoumi, Ran Xiao, Nate Tran, Peter Smielewski, Marek Czosnyka, Steven W. Hetts, Nerissa Ko, and Xiao Hu. “Continuous monitoring of cerebrovascular reactivity through pulse transit time and intracranial pressure.Physiological Measurement 40, no. 1 (January 2019): 01LT01. https://doi.org/10.1088/1361-6579/aafab1.
Liu X, Gadhoumi K, Xiao R, Tran N, Smielewski P, Czosnyka M, et al. Continuous monitoring of cerebrovascular reactivity through pulse transit time and intracranial pressure. Physiological measurement. 2019 Jan;40(1):01LT01.
Liu, Xiuyun, et al. “Continuous monitoring of cerebrovascular reactivity through pulse transit time and intracranial pressure.Physiological Measurement, vol. 40, no. 1, Jan. 2019, p. 01LT01. Epmc, doi:10.1088/1361-6579/aafab1.
Liu X, Gadhoumi K, Xiao R, Tran N, Smielewski P, Czosnyka M, Hetts SW, Ko N, Hu X. Continuous monitoring of cerebrovascular reactivity through pulse transit time and intracranial pressure. Physiological measurement. 2019 Jan;40(1):01LT01.
Journal cover image

Published In

Physiological measurement

DOI

EISSN

1361-6579

ISSN

0967-3334

Publication Date

January 2019

Volume

40

Issue

1

Start / End Page

01LT01

Related Subject Headings

  • Wavelet Analysis
  • Subarachnoid Hemorrhage
  • Pulse Wave Analysis
  • Monitoring, Physiologic
  • Middle Aged
  • Male
  • Intracranial Pressure
  • Humans
  • Female
  • Cerebrovascular Circulation