End Tidal CO2 and Masks: Is There a Correlation?

In light of the ongoing COVID-19 pandemic, wearing a mask has become a universal standard as an attempt to reduce the spread of COVID-19. As of 2020, more than half of all U.S. states have implemented a state wide mandated mask policy. There are many schools of thought regarding the benefits and risks of donning a mask to prevent the spread of COVID-19. There is an unproven theory among some that wearing a mask interferes with our natural respiratory function, causing hypoxia, altered mental status and other various health issues. This dangerous perception has led some to believe wearing a mask is harmful, and encourages against wearing a mask in public. This theory, recently refuted by a study investigating oxygen levels while participants wore masks, performed in 2020 encouraged increased compliance with wearing masks. Another study, preformed by evaluated whether gas exchange abnormalities occurred with the use of surgical masks in subjects with and without lung function impairment. The conclusions of the study showed that regardless of lung function impairment, the presence of surgical masks did not impact gas exchange. Additionally, a more recent study concluded that the presence of a facemask did not have a significant change in physiologic parameters while during exercise. Although there is evidentiary support that facemasks do not negatively affect oxygen status and physiologic capacity, there is not strong evidence examining the relationship between ETCO2 and facemasks. The relationship between ETCO2 and facemasks is one of importance because mild decreases in oxygen have much less dangerous effects compared to the effects of rapid accumulations of carbon dioxide. Increases in end tidal carbon dioxide lead to confusion, acidosis and in severe cases, respiratory distress and failure. A study performed in 1989 showed that hypercapnia has greater increases in blood pressure, minute ventilation and sympathetic nerve activity than hypoxia.

In this newly proposed study, healthy volunteers will all wear the same type of three layer surgical mask. Their end tidal carbon dioxide will be measured while at rest without a mask, while resting with a mask and then after walking 100 meters in the mask. While previous studies have focused on changes in oxygen, there is a lack of research dedicated to analyzing end tidal carbon dioxide. This study will hope to show evidence supporting that there is no increase in end tidal carbon dioxide while wearing a mask.