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Updated: Mar 20, 2026

MRI Mapping of Cerebrovascular Reactivity via Gas Inhalation Challenges
Published on: December 17, 2014
A 47-year-old woman with hypercapnia and altered mental status
1Division of Pulmonary, Critical Care, and Sleep Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
Abstract:
Permissive hypercapnia is a commonly used ventilator strategy in attempt to improve refractory hypoxemia. The rationale of such practice is based on the assumption that hypercapnia, although associated with altered mental status, is well tolerated. Here, we report a case in which the altered mental status caused by hypercapnia is underlined by a life-threatening mechanism. The case indicates the severity of hypercapnia may have been mistakenly overlooked in the past.
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