Peripheral Oxygen Saturation in Older Persons Wearing Nonmedical Face Masks in Community Settings | Geriatrics | JAMA | JAMA Network
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Table 1.  Baseline Characteristics of Participants
Baseline Characteristics of Participants
Table 2.  Oxygen Saturation Before, While, and After Wearing Nonmedical Face Masks
Oxygen Saturation Before, While, and After Wearing Nonmedical Face Masks
1.
Chu  DK, Akl  EA, Duda  S, Solo  K, Yaacoub  S, Schünemann  HJ; COVID-19 Systematic Urgent Review Group Effort (SURGE) study authors.  Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis.   Lancet. 2020;395(10242):1973-1987. doi:10.1016/S0140-6736(20)31142-9PubMedGoogle ScholarCrossref
2.
Doung-Ngern  P, Suphanchaimat  R, Panjangampatthana  A,  et al.  Case-control study of use of personal protective measures and risk for severe acute respiratory syndrome coronavirus 2 infection, Thailand.   Emerg Infect Dis. 2020;26(11):1973-1987. doi:10.3201/eid2611.203003PubMedGoogle ScholarCrossref
3.
Goodman  J. and Carmichael  F. Coronavirus: “deadly masks” claims debunked. BBC. Posted July 24, 2020. Accessed August 15, 2020. https://www.bbc.com/news/53108405
4.
Centers for Disease Control and Prevention. Considerations for wearing masks: help slow the spread of COVID-19. Updated August 7, 2020. Accessed October 4, 2020. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html
5.
Greenhalgh  T, Javid  B, Matthew  BJ, Inada-Kim  M. What is the efficacy and safety of rapid exercise tests for exertional desaturation in COVID-19. Centre for Evidence-Based Medicine. Posted April 21 2020. Accessed October 4, 2020. https://www.cebm.net/covid-19/what-is-the-efficacy-and-safety-of-rapid-exercise-tests-for-exertional-desaturation-in-covid-19/
6.
Rodríguez-Molinero  A, Narvaiza  L, Ruiz  J, Gálvez-Barrón  C.  Normal respiratory rate and peripheral blood oxygen saturation in the elderly population.   J Am Geriatr Soc. 2013;61(12):2238-2240. doi:10.1111/jgs.12580PubMedGoogle ScholarCrossref
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    3 Comments for this article
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    CO2 Levels
    Mark Emanuele, PhD. | United States Army M.A.R.S.
    Has anyone done a study on whether mask-wearing causes increased levels of CO2 in arterial blood? The fact that the SpO2 levels did not significantly decrease during minimal physical activity while wearing masks, makes me wonder what happens to the CO2 levels in an ABG under the same conditions.

    In addition, I would like to see the results of both SpO2 and CO2 levels with increased physical activity while wearing a mask.
    CONFLICT OF INTEREST: None Reported
    General Impact of RPD
    Mark Dublin, sw engineer | None
    To the previous commenter I'd suggest a recent narrative review of use of respiratory protective devices in healthy volunteers and measures of respiration (1). Most studies used respirators though many 'community' non-medical face coverings add some dead volume like N95.

    Reference

    1. Impact of respiratory protective devices on respiration: Implications for panic vulnerability during the COVID-19 pandemic. J Affect Disord. 2020 Dec 1; 277: 772-778 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7476564/ 
    CONFLICT OF INTEREST: None Reported
    Peripheral Oxygen Saturation in Older Persons Wearing Nonmedical Face Masks in Community Settings
    Marina Clemente Conde, MSc, PhD | University of São Paulo School of Dentistry
    This article raises important considerations about "non-medical" face masks used during the pandemic - assuming that non-medical is referring to non-N95 masks. The three-layer DY95 masks used in this research are the very same used by most medical professionals regularly, including dentists and dental personnel. Dentists have been using this same type of masks on a daily basis, 8-10 hours/day, 5 days/week for decades, and it is, indeed, expected not to affect oxygen saturation.
    We have noticed that, in many countries, due to the costs of the triple layer masks - which have risen due to the pandemic
    - most health centers have approved, for the non-health staff, the use of cloth masks. Many of them are being made of a double layer of regular fabric, generally cotton. Although there are no published data on oxygen saturation in people wearing these fabric masks, most people complain of tiredness, specially when walking long distances, exercising, walking upstairs, etc. The effect of breathing for prolonged times with these masks is similar to the ones observed when one sleeps with the head covered by sheets. In the case of masks, 2 sheets. It would be of great interest if this type of home-made double-layer fabric mask could be investigated as well.
    CONFLICT OF INTEREST: None Reported
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    Research Letter
    October 30, 2020

    Peripheral Oxygen Saturation in Older Persons Wearing Nonmedical Face Masks in Community Settings

    Author Affiliations
    • 1Department of Medicine, McMaster University, Hamilton, Ontario, Canada
    JAMA. Published online October 30, 2020. doi:10.1001/jama.2020.21905

    Based on the evidence that nonmedical face masks prevent the spread of severe acute respiratory syndrome coronavirus 2,1,2 many governments are mandating the wearing of masks in the community. However, fueled partly by claims on social media that masks can cause hypoxia and are therefore dangerous,3 concerns have emerged about the safety of wearing face masks. We examined whether wearing nonmedical face masks was associated with a change in oxygen saturation.

    Methods

    This was a crossover study in which participants self-measured peripheral oxygen saturation (Spo2) before, while, and after wearing a mask. The study protocol was approved by the Hamilton Integrated Research Ethics Board. We included individuals aged 65 years or older and excluded those who had comorbid cardiac or respiratory conditions that could lead to dyspnea or hypoxia at rest or who were unable to remove the mask without assistance.4 Participants were prospectively recruited from a retirement condominium in Ontario between July 27 and August 10, 2020, following approval from the condominium’s board of directors. Residents were contacted by email, and those who were interested were approached to obtain (verbal or written) informed consent.

    To minimize variability, we provided participants with a 3-layer plane-shaped disposable nonmedical face mask with ear loops (Boomcare DY95 model, Deyce Leather Co Ltd) and a portable pulse oximeter (HOMIEE). Instructions on how to correctly wear the mask (to ensure adequate nose and mouth coverage) and measure Spo2 were provided. Participants were instructed to self-monitor and record Spo2 3 times 20 minutes apart for 1 hour before, 1 hour while, and 1 hour after wearing the mask while they were at rest or performing usual activities of daily living at home. Participants were offered opportunities to clarify these instructions.

    We determined whether wearing a face mask would be associated with a decrease of 2% or more in Spo2. A decrease in Spo2 of 3% or more has been previously considered clinically important,5 and for this study, a value of 2% was chosen because older people have lower baseline Spo2.6 For a 2% decrease in Spo2, a standard deviation of 3, α of 5%, and power of 90%, a sample size of 27 participants was required (see the eAppendix in the Supplement for the sample size calculation). For each participant, we calculated the mean of the 3 Spo2 readings for each period (before, while, and after wearing the mask). Pairwise comparisons of these values (while vs before, and while vs after) for each participant were performed, and the paired mean differences (95% CIs) in Spo2 were calculated using GraphPad Prism for Windows (GraphPad Software). The pooled mean Spo2 (95% CI) for all participants was also calculated for each period.

    Results

    Twenty-eight people were approached, 3 declined participation, and 25 participants (mean age, 76.5 years [SD, 6.1 years]; 12 women [48%]) were enrolled. Nine participants (36%) had at least 1 medical comorbidity (Table 1). The pooled mean Spo2 was 96.1% before, 96.5% while, and 96.3% after wearing the mask (Table 2). None of the participants’ Spo2 fell below 92% while wearing masks. The paired mean differences in Spo2 while wearing the mask were minimal when compared with the value before they wore the mask (0.46% [95% CI, 0.06% to 0.87%]) and the value after wearing the mask (0.21% [95% CI, −0.07% to 0.50%]), with both 95% CIs excluding a 2% or more decline in Spo2.

    Discussion

    In this small crossover study, wearing a 3-layer nonmedical face mask was not associated with a decline in oxygen saturation in older participants. Limitations included the exclusion of patients who were unable to wear a mask for medical reasons, investigation of 1 type of mask only, Spo2 measurements during minimal physical activity, and a small sample size. These results do not support claims that wearing nonmedical face masks in community settings is unsafe.

    Section Editor: Jody W. Zylke, MD, Deputy Editor.
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    Article Information

    Corresponding Author: Noel C. Chan, MBBS, C5-116 DBCVRI, 237 Barton St E, Hamilton, ON L8L 2X2, Canada (noel.chan@taari.ca).

    Published Online: October 30, 2020. doi:10.1001/jama.2020.21905

    Author Contributions: Dr Chan had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

    Concept and design: Chan, Hirsh.

    Acquisition, analysis, or interpretation of data: All authors.

    Drafting of the manuscript: Chan, Hirsh.

    Critical revision of the manuscript for important intellectual content: All authors.

    Statistical analysis: Chan, Li.

    Administrative, technical, or material support: Chan, Li.

    Supervision: Chan, Hirsh.

    Conflict of Interest Disclosures: Dr Chan reports receiving a speaker’s fee from Bayer outside of the submitted work. No other disclosures were reported.

    References
    1.
    Chu  DK, Akl  EA, Duda  S, Solo  K, Yaacoub  S, Schünemann  HJ; COVID-19 Systematic Urgent Review Group Effort (SURGE) study authors.  Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis.   Lancet. 2020;395(10242):1973-1987. doi:10.1016/S0140-6736(20)31142-9PubMedGoogle ScholarCrossref
    2.
    Doung-Ngern  P, Suphanchaimat  R, Panjangampatthana  A,  et al.  Case-control study of use of personal protective measures and risk for severe acute respiratory syndrome coronavirus 2 infection, Thailand.   Emerg Infect Dis. 2020;26(11):1973-1987. doi:10.3201/eid2611.203003PubMedGoogle ScholarCrossref
    3.
    Goodman  J. and Carmichael  F. Coronavirus: “deadly masks” claims debunked. BBC. Posted July 24, 2020. Accessed August 15, 2020. https://www.bbc.com/news/53108405
    4.
    Centers for Disease Control and Prevention. Considerations for wearing masks: help slow the spread of COVID-19. Updated August 7, 2020. Accessed October 4, 2020. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html
    5.
    Greenhalgh  T, Javid  B, Matthew  BJ, Inada-Kim  M. What is the efficacy and safety of rapid exercise tests for exertional desaturation in COVID-19. Centre for Evidence-Based Medicine. Posted April 21 2020. Accessed October 4, 2020. https://www.cebm.net/covid-19/what-is-the-efficacy-and-safety-of-rapid-exercise-tests-for-exertional-desaturation-in-covid-19/
    6.
    Rodríguez-Molinero  A, Narvaiza  L, Ruiz  J, Gálvez-Barrón  C.  Normal respiratory rate and peripheral blood oxygen saturation in the elderly population.   J Am Geriatr Soc. 2013;61(12):2238-2240. doi:10.1111/jgs.12580PubMedGoogle ScholarCrossref
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