Effects of wearing N95 and surgical facemasks on heart rate, thermal stress and subjective sensations

Li, Yi; Tokura, Hiromi; Guo, Y. P.; Wong, Arkers Kwan Ching; Wong, Thomas; Chung, Joanne W.Y.; Newton, E.

doi:10.1007/s00420-004-0584-4

Cited by 321 publications

(374 citation statements)

References 7 publications

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“…When worn by patients with TB, on the other hand, we believe that simple surgical masks, rather than the much more expensive N95 respirators, are sufficient to reduce the extent to which patients emit infectious particles. We do not believe that higher-level respirator use by patients with TB is warranted for this purpose due to cost and discomfort (38). Moreover, whereas a better face seal can reduce leakage around the filtration piece of a respirator during inspiration, it is unlikely to substantially resist the air pressure generated by cough, and air is likely to escape around either a surgical mask or respirator, as illustrated by others using real-time optical imaging of air flow patterns during cough (39).…”

Section: Discussionmentioning

confidence: 98%

Surgical Face Masks Worn by Patients with Multidrug-Resistant Tuberculosis

Dharmadhikari

Mphahlele

Stoltz

et al. 2012

Am J Respir Crit Care Med

164

130

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Rationale: Drug-resistant tuberculosis transmission in hospitals threatens staff and patient health. Surgical face masks used by patients with tuberculosis (TB) are believed to reduce transmission but have not been rigorously tested. Objectives: We sought to quantify the efficacy of surgical face masks when worn by patients with multidrug-resistant TB (MDR-TB). Methods: Over 3 months, 17 patients with pulmonary MDR-TB occupied an MDR-TB ward in South Africa and wore face masks on alternate days. Ward air was exhausted to two identical chambers, each housing 90 pathogen-free guinea pigs that breathed ward air either when patients wore surgical face masks (intervention group) or when patients did not wear masks (control group). Efficacy was based on differences in guinea pig infections in each chamber. Measurements and Main Results: Sixty-nine of 90 control guinea pigs (76.6%; 95% confidence interval [CI], 68-85%) became infected, compared with 36 of 90 intervention guinea pigs (40%; 95% CI, 31-51%), representing a 56% (95% CI, 33-70.5%) decreased risk of TB transmission when patients used masks. Conclusions: Surgical face masks on patients with MDR-TB significantly reduced transmission and offer an adjunct measure for reducing TB transmission from infectious patients.Keywords: infection control; multidrug-resistant tuberculosis; transmission; surgical maskOf an estimated 9 million new cases of tuberculosis (TB) in 2008 globally (1), 440,000 were multidrug-resistant TB (MDR-TB) (2), and more than half of those are believed to have occurred in previously untreated patients, the result of transmission of already drug-resistant strains (2). Recent reports of infection with highly drug-resistant strains of Mycobacterium tuberculosis among patients and health care workers illustrate the dire consequences of nosocomial transmission, especially in areas where HIV is endemic (3, 4). Although once believed to arise primarily from unsupervised or erratic treatment of drug-susceptible TB, MDR-TB and extensively drug-resistant TB (XDR-TB) are now known to be transmissible and have emerged as important threats to patients who enter hospitals for drug-susceptible TB (reinfection) or other illnesses, to the clinical staff caring for them, and to occupants of other congregate settings, such as correctional facilities and shelters. One study in Russia found that hospitalization, rather than treatment nonadherence, conferred a sixfold greater relative risk for the acquisition of MDR-TB by patients (5), whereas another study in Latvia revealed that previous hospitalization was a highly significant risk factor for MDR-TB (odds ratio, 18.33; P , 0.002) (6). In addition, health care workers in diverse settings have been shown to be disproportionately exposed to and infected with drugsusceptible and drug-resistant TB (4, 7). TB among health care workers erodes the already limited supply of hospital personnel in many resource-constrained settings, both directly through illness and indirectly through fear of working in such high-risk envi...

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Section: Discussionmentioning

confidence: 98%

Surgical Face Masks Worn by Patients with Multidrug-Resistant Tuberculosis

Dharmadhikari

Mphahlele

Stoltz

et al. 2012

Am J Respir Crit Care Med

164

130

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“…Other studies have also shown increased within-mask temperature for filtering facepiece designs. 27 This may be particularly bothersome to workers, if the respirator is used in a warm humid environment. 25 On the average, women reported higher symptom scores than did men.…”

Section: Discussionmentioning

confidence: 99%

Subjective Response to Respirator Type: Effect of Disease Status and Gender

Harber¹,

Santiago²,

Wu³

et al. 2010

Journal of Occupational &Amp; Environmental Medicine

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“…Difficulty breathing and increased respiratory rates with N95FFR have been heretofore identified. 42,43 As breathing resistance through a respirator increases, less air is drawn through the respirator 44 and hypoventilation occurs that leads to increases in the fraction of expired CO 2 (FECO 2 ), due to a decrement in the volume of expired air, and decreases in the fraction of expired O 2 (FEO 2 ) secondary to greater extraction of oxygen from each breath. 45 Elevated CO 2 levels have also been suggested as one of the reasons why one-third of HCWs who use N95FFR for prolonged periods experience headaches.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the rationale for concurrent use of N95 filtering facepiece respirators with loose-fitting powered air-purifying respirators during aerosol-generating medical procedures

Roberge

2008

American Journal of Infection Control

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The concurrent use of N95 filtering facepiece respirators with powered air-purifying respirators during aerosol-generating medical procedures in patients with severe respiratory pathogens has been promoted as offering additional protection against infectious agents. The purpose of this article is to examine the impact of this additional respiratory equipment upon protection and personal performance. The presumed additive protective effect of an N95 filtering facepiece respirator used concurrently with a powered air-purifying respirator has not been subjected to rigorous scientific investigation. The burden imposed by additional respiratory protective equipment should not be discounted, and the potentially minor contribution to protection may be offset by the negative impact on personal performance. Novel uses of protective equipment occasionally are spawned during crisis situations, but their generalized applicability to healthcare workers should ultimately be evidence-based.

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Effects of wearing N95 and surgical facemasks on heart rate, thermal stress and subjective sensations

Abstract: We discuss how N95 and surgical facemasks induce significantly different temperature and humidity in the microclimates of the facemasks, which have profound influences on heart rate and thermal stress and subjective perception of discomfort.

Cited by 321 publications

References 7 publications

Surgical Face Masks Worn by Patients with Multidrug-Resistant Tuberculosis

Surgical Face Masks Worn by Patients with Multidrug-Resistant Tuberculosis

Subjective Response to Respirator Type: Effect of Disease Status and Gender

Evaluation of the rationale for concurrent use of N95 filtering facepiece respirators with loose-fitting powered air-purifying respirators during aerosol-generating medical procedures

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