1. Serial monitoring of CO2 reactivity following sport concussion using hypocapnia and hypercapnia.
- Author
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Len TK, Neary JP, Asmundson GJ, Candow DG, Goodman DG, Bjornson B, and Bhambhani YN
- Subjects
- Adolescent, Adult, Athletic Injuries epidemiology, Athletic Injuries physiopathology, Blood Flow Velocity, Brain Concussion epidemiology, Brain Concussion physiopathology, Canada epidemiology, Cerebrovascular Circulation, Female, Humans, Hypercapnia physiopathology, Hyperventilation physiopathology, Hypocapnia physiopathology, Male, Monitoring, Physiologic, Recovery of Function, Reproducibility of Results, Ultrasonography, Doppler, Transcranial, Vascular Resistance, Athletic Injuries blood, Brain Concussion blood, Carbon Dioxide blood, Hypercapnia blood, Hyperventilation blood, Hypocapnia blood
- Abstract
Primary Objective: This study examined the effects of mild traumatic brain injury (mTBI) on cerebrovascular reactivity (CVR)., Research Design: A repeated measures design was used to examine serial changes in CVR., Methods and Procedures: Twenty subjects who recently suffered a mTBI were subjected to a respiratory challenge consisting of repeated 20 s breath-holds (BH) and hyperventilations (HV). Testing occurred on days 2 (D2), 4 (D4) and 8 (D8) post-injury as well as a baseline (BASE) assessment (after return-to-play). Transcranial Doppler was used to assess mean cerebral blood velocity (vMCA) and expired gas analysis provided end-tidal carbon dioxide (PETCO2) levels., Results: There was no significant difference in resting vMCA across all testing days for mTBI. No significant differences in PETCO2 were found throughout the testing protocol. A significant effect (p < 0.001) of testing day on vMCA was found during BH and HV challenges for mTBI. Post-hoc analysis revealed significant differences (p < 0.05) in vMCA between D2 and the other testing days., Conclusions: These data suggest that, following mTBI: (1) CVR is not impaired at rest; (2) CVR is impaired in response to respiratory stress; and (3) the impairment may be resolved as early as 4 days post-injury.
- Published
- 2013
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