Cerebrovascular Responses to O 2 -CO 2 Exchange Ratio under Brief Breath-Hold Challenge in Patients with Chronic Mild Traumatic Brain Injury
Year: 2021
Type: article
Study design: Observational Study
Abstract: Breath-by-breath O 2 -CO 2 exchange ratio (bER) is a respiratory gas exchange (RGE) metric, which is the ratio of the changes in the partial pressure of O 2 (ΔPO 2 ) to CO 2 (ΔPCO 2 ) between endinspiration and end-expiration, has been demonstrated to characterize the cerebrovascular responses to breath-hold challenge in healthy individuals. We aimed to explore if bER could characterize cerebrovascular responses in patients with chronic mild traumatic brain injury (mTBI) under breath-hold challenge. We also investigated the correlation between bER and the severity of post-concussion symptoms. Blood-oxygenation-level-dependent (BOLD) images were acquired using functional magnetic resonance imaging (fMRI) on eleven patients with chronic mTBI and eleven controls without brain injury history when performing a breath-hold task. Time series of RGE metrics of ΔPO 2 , ΔPCO 2 , and bER were computed, and their cross-correlation with regional change in BOLD (ΔBOLD) was calculated. Symptom burden was assessed using the Rivermead Post Concussion Questionnaire (RPQ), and its correlation with RGE changes was also measured. Compared with controls, a diffuse decrease in the correlation between regional ΔBOLD and bER was found in the brain of mTBI patients (p fdr <0.05). No significant difference was found between patients and controls for the correlation of regional ΔBOLD with ΔPO 2 and ΔPCO 2 . The averaged changes in bER (ρ=0.79, p=0.01) and ΔPO 2 (ρ=0.70, p=0.03) in breath-hold epochs decreased with increased symptom severity indicated by RPQ scores. Our imaging and symptom severity findings suggest that bER can be used to characterize cerebrovascular responses to breath-hold in mTBI patients. RGE may contribute to the post-concussive symptom severity.
Source: Journal of Neurotrauma
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: green
Funders: Massachusetts General Hospital, Centre d'Imagerie BioMédicale, National Institutes of Health, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, National Institute of Biomedical Imaging and Bioengineering, National Center for Research Resources, National Center for Complementary and Integrative Health
OpenAlex ID: W3175311714