CO2 Levels Behind and in Front of Different Protective Mask Types

Akhondi, Hossein; Kaveh, Sassan; Kaufman, Kimball; Danai, Tina; Ayutyanont, Napatkamon

doi:10.36518/2689-0216.1321

Cited by 1 publication

(2 citation statements)

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“…The retracted 2021 study ( Christakis & Fontanarosa, 2021 ) and a similar 2022 study ( Akhondi et al, 2022 ) detract from the safety of masking by using CO2 meters to focus on gas levels behind masks, comparing those levels to standards meant for a surrounding environment. Claims are made that clinical symptoms of hypercapnia will ensue, while avoiding any measurement of a PaCO2 analogue or oxygen saturation.…”

Section: Discussionmentioning

confidence: 99%

“…Research into that topic was limited, with physiologic studies on mask-wearing pediatric subjects especially rare, and none compared the relative effects between children and adults. Yet in 2021 and 2022, four peer reviewed publications claimed that masking was physiologically harmful, with one evaluating the effect of masking on children ( Christakis & Fontanarosa, 2021 ; Elbl et al, 2021 ; Kisielinski et al, 2021 ; Akhondi et al, 2022 ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Physiologic effects of surgical masking in children versus adults

Brooks

Layman

Willis

2023

PeerJ

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Background Surgical masks remain a focal part of the CDC guidelines to decrease COVID-19 transmission. Evidence refuting significant effects of masking on ventilation is mostly limited to small studies, with a paucity of studies on children, and none comparing children to adults. Methods A total of 119 subjects were enrolled (71 adults, 49 children) in a prospective interventional study with each subject serving as their own mask-free control. End tidal CO2 (ETCO2), inspired CO2 (ICO2), and respiratory rate were measured by nasal cannula attached to an anesthesia machine D-fend module. Pulse oximetry and heart rate were also followed. After the mask-free period, an ASTM Level 3 disposable surgical mask was donned and 15 min of mask-worn data were collected. Results A steady state was confirmed for ETCO2 and ICO2 over the masked period, and mean ICO2 levels rose significantly (p < 0.001) after masking in all age groups. The increase in ICO2 for the 2- to 7-year-old group of 4.11 mmHg (3.23–4.99), was significantly higher (p < 0.001) than the final ΔICO2 levels for both the 7- to 14-year-old group, 2.45 mmHg (1.79–3.12), and adults, 1.47 mmHg (1.18–1.76). For the pediatric group there was a negative, significant correlation between age and ΔICO2, r = −0.49, p < 0.001. Masking resulted in a statistically significant (p < 0.01) rise in ETCO2 levels of 1.30 mmHg in adults and 1.36 mmHg in children. The final respective ETCO2 levels, 34.35 (33.55–35.15) and 35.07 (34.13–36.01), remained within normal limits. Pulse oximetry, heart rate, and respiratory rate were not significantly affected. Discussion The physiology of mechanical dead space is discussed, including the inverse relationship of subject age vs ICO2. The methodology and results are compared to previously published studies which detracted from the physiologic safety of surgical masking. Conclusions The wearing of a surgical mask results in a statistically significant rise in ICO2 and a smaller rise in ETCO2. Because ETCO2 and other variables remain well within normal limits, these changes are clinically insignificant.

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Section: Discussionmentioning

confidence: 99%