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A scoping review protocol on brain PaCO2 levels at altitude
Hanna Tang1,2, Laurel Charlesworth1,2,3, Manoj Lalu3,4
1Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Ontario, Canada.
Plos One
|January 14, 2025
Summary
Aeromedical transport may worsen ischemic stroke by altering blood gases at high altitudes. This review maps literature on altitude-related changes in PaCO2 to inform future stroke care guidelines.
Area of Science:
- Neurology
- Aerospace Medicine
- Physiology
Background:
- Aeromedical transfers for ischemic stroke are increasing.
- The impact of altitude changes on cerebral perfusion is poorly understood.
- Hypoxia at high altitudes may decrease PaCO2, causing cerebral vasoconstriction and worsening stroke burden.
Purpose of the Study:
- To map existing literature on PaCO2 changes with altitude.
- To identify research gaps regarding altitude's effect on cerebral ischemia.
- To provide a foundation for guidelines on optimal aeromedical transport altitudes for stroke patients.
Main Methods:
- Scoping review following Joanna Briggs Institute methodology.
- Systematic search of MEDLINE, Embase, Web of Science, and Cochrane Library.
- Duplicate screening, full-text review, and data extraction by two independent investigators.
Main Results:
- This section will present findings on the current literature regarding PaCO2 changes at different altitudes.
- Quantitative data will be summarized using descriptive statistics.
- Qualitative data will be synthesized in tabular format, with frequency data presented in a histogram.
Conclusions:
- Current literature on altitude-induced PaCO2 changes in ischemic stroke patients is limited.
- Further research is needed to understand cerebral autoregulation during aeromedical transport.
- This review will highlight literature availability to guide future research and clinical recommendations.
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