Paradoxical Hypocapnia While Wearing a Facemask: A Novel Cause of Orthostatic Intolerance - A Case Report

Abstract

Previous studies with facemasks have shown significant respiratory effects, including increased breathing resistance, CO2 rebreathing due to CO2 accumulation in the facemask cavity leading to hypercapnia, and decreased inhaled O2 concentration. These changes may lead to a number of symptoms like dyspnea, headache, sweating, and dizziness. In the present case report a patient is described with similar symptoms while wearing a facemask, but with the opposite effect: a hyperventilatory hypocapnic response, leading to orthostatic intolerance symptoms. A 34 year old female patient was examined with symptoms while wearing a facemask in public. She was studied in the supine position. First, end-tidal CO2 and cerebral flow measurements, using extracranial Doppler imaging, were obtained without facemask. Thereafter, after 10 minutes of wearing a facemask, measurements were repeated. While wearing the facemask, the end-tidal CO2 decreased from 35 mmHg without the facemask to 28 mmHg with the facemask, respiration rate increased from 10 to 15 breath/min and cerebral blood flow decreased from 565 ml/min to 419 ml/min, a 26% reduction while wearing the facemask. These changes were accompanied by her typical orthostatic intolerance symptoms while wearing the facemask in public As shown in this patient, wearing a facemask cannot only cause hypercapnia, as has been previously described, but may also cause hypocapnia, leading to a cerebral blood flow reduction and orthostatic intolerance symptoms.