Correction for Blood Pressure Improves Correlation between Cerebrovascular Reactivity Assessed by Breath Holding and 6% CO₂ Breathing

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• 作者：Kiran Prakash ; MD^&lowast ; ; Dinu S. Chandran ; MD^&lowast ; ; Rajesh Khadgawat ; DM^&dagger ; ; Ashok Kumar Jaryal ; MD^&lowast ; ; ^{ashok.jaryal@gmail.com" class="auth_mail} ; Kishore Kumar Deepak ; MD ; PhD^&lowast ;
• 关键词：Cerebrovascular reactivity ; breath holding ; hypercapnia ; breath-holding index ; cerebrovascular conductance index
• 刊名：Journal of Stroke and Cerebrovascular Diseases
• 出版年：April, 2014
• 年：2014
• 卷：23
• 期：4
• 页码：630-635
• 全文大小：206 K

文摘

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Background

Changes in cerebral blood flow velocity to hypercapnia are associated with changes in systemic blood pressure (BP). These confounding BP-dependent changes in cerebral blood flow velocity cause misinterpretation of cerebrovascular reactivity (CVR) results. The objective of the study was to determine the relationship between CVR assessed by breath holding and 6% CO₂ breathing after correcting for聽BP-dependent changes in cerebral blood flow velocity.

Methods

In 33 patients of uncomplicated type 2 diabetes mellitus, CVR was assessed as percentage changes in cerebral blood flow velocity and cerebrovascular conductance index.

Results

Percentage change in cerebral blood flow velocity during breath holding was positively correlated with that of during 6% CO₂ breathing (r聽=聽.35; P聽=聽.0448). CVR during breath holding and 6% CO₂ breathing were better correlated when expressed as percentage changes in cerebrovascular conductance index (r聽=聽.49; P聽=聽.0040). Similarly, breath-holding test results expressed as percentage changes in cerebral blood flow velocity correctly identified only 37.5% of the poor reactors to 6% CO₂ breathing. However, when the breath-holding test results were expressed as percentage changes in cerebrovascular conductance index, 62.5% of the poor reactors to 6% CO₂ breathing were correctly identified indicating a better agreement between the test results obtained by the 2 methods.

Conclusion

Cerebrovascular response to聽breath holding is better correlated with that of 6% CO₂ breathing when changes in cerebral blood flow velocity were corrected for associated changes in BP.