key: cord-0991635-3zhh6qtk
authors: Salles-Rojas, Antonio; Guzmán-Valderrábano, Carlos; Madrid, Wilmer A.; González-Molina, Amaury; Silva-Cerón, Mónica; Rodríguez-Hernández, Christian; Salas-Escamilla, Isabel; Castorena-Maldonado, Armando; López-García, Carlos Alberto; Torre-Bouscoulet, Luis; Gochicoa-Rangel, Laura
title: Masking the 6-Minute Walking Test in the COVID-19 Era
date: 2021-06-01
journal: Annals of the American Thoracic Society
DOI: 10.1513/annalsats.202009-1088rl
sha: 8243e0b311c2d5882f0fdf05ba1210492bb1dd18
doc_id: 991635
cord_uid: 3zhh6qtk

nan

distance a subject can walk during the 6-minute walking test (6-MWT) as well as the oxygen saturation (Sp O 2 ), heart rate (HR), dyspnea, and fatigue. The aim of this study was to investigate whether two types of face mask modified the walking distance during the 6-MWT among survivors of COVID-19.

Subjects over 18 years of age who were hospitalized for pneumonia due to a polymerase chain reaction-confirmed diagnosis of COVID-19 who were at least 30 days from discharge were invited to participate; those who could not walk were excluded from the study. It was decided at random (according to a table of random numbers)

This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0/). For commercial usage and reprints, please contact Diane Gern (dgern@thoracic.org).

whether the subject was entered to the surgical or N95 face mask group and whether the first walk was done with or without a face mask. The following two types of face masks were used: the surgical type, which is a pleated spunbond/melt-blown/spunbond nonwoven fabric made from 100% polypropylene (Mds Medical Dress Supplier) and the folding N95 particle face mask, which is made of polypropylene and 3M polyester (model 9010, 3M).

All participants performed two 6-MWTs according to American Thoracic Society/European Respiratory Society standards, with a recovery time of 30 minutes between the two 6-MWTs (7) .

The National Institute of Respiratory Diseases "Ismael Cos ıo Villegas" in M exico City science and bioethics committee approved the study (C16-20), and participants signed the informed consent form. Anthropometric data are presented as means and standard deviations or as number and percentage; Student's t tests, Mann-Whitney U tests, and x 2 tests were used to compare groups. Analysis of variance was used to analyze the results of the 6-MWT with or without the face mask, and Spearman's correlation coefficient (r sp ) and concordance correlation coefficient (CCC) were used to search for associations. Multivariable linear regression analysis was performed to investigate whether the difference walked in meters between both 6-MWTs (with and without face mask [dependent variable]) was predicted by some variables selected by their potential influence in the outcome, such as using or not using the face mask, the type of face mask, the presence of desaturation, the degree of dyspnea and fatigue (10-grade Borg Scale) (8), overweight or obese status, and tobacco use (independent variables). The Enright and colleagues' reference equation, adjusted for body mass index, was used to calculate the percentage predicted for the 6-MWT (9).

We included 77 individuals aged 44 (612) years, with 49 (64%) men. Table 1 shows their general characteristics; 41 (53%) subjects were assigned to the N95 face mask group. Without wearing the face mask, 43 (56%) subjects had a decrease in Sp O 2 of .4%, with 29 (67%) of them experiencing a desaturation event of an Sp O 2 <88% during the 6-MWT. No differences were observed in the meters walked, Sp O 2 , HR, dyspnea, or fatigue, between tests with or without the face mask (surgical or N95) ( Table 2 ). Figure 1 shows the association (r sp 5 0.90, P , 0.001) and agreement (CCC 5 0.94) between the 6-MWT with and without the face mask. The mean difference between the two walks was 20.65 (628) m, as shown in Figure 1B ; the 95% limit of agreement was 255 to 54 m. In 12 (16%) subjects, the difference between walks was .30 m, which was considered the minimum clinically significant limit (MCSL) for changes in the 6-MWT (7) . The multivariable analysis showed that this difference was independent of the type of face mask used (P 5 0.74), presence of desaturation (P 5 0.63), degree of dyspnea before (P 5 0.75) and after (P 5 0.5) the 6-MWT, obesity (P 5 0.89), and tobacco use (P 5 0.93).

When the analysis was conducted according to the type of face mask used during the walk, distances walked with or without face mask were very similar, as follows: with the surgical type face mask, r sp 5 0.91 (P , 0.001), CCC 5 0.94, mean of the differences 5 21.36 (628.7) and 95% confidence interval 5 257.7 to 55 m, whereas with the N95 face mask, r sp 5 0.93 (P , 0.001), CCC 5 0.94, mean of the differences 5 20.02 (627.2), and 95% confidence interval 5 253.4 to 53.3 m.

The main finding of this study is that the mean difference in the 6-MWD when using either a surgical or N95 face mask compared with not wearing a face mask was 20.65 m, with a broad 95% limit of agreement; 84% of the subjects had agreement within MCSL (630 m).

The 6-MWT aims to measure the distance that a subject can walk during 6 minutes in a 30-m corridor (7, (10) (11) (12) . It is indicated in the diagnosis, prognosis, and monitoring of individuals with chronic lung diseases (13) (14) (15) . Although its importance is based on the analysis of the effects of the treatment on the meters walked in 6 minutes, the 6-MWT also allows for measuring the functional status through other parameters, such as the Sp O 2 , HR, dyspnea, fatigue, and blood pressure (7, 13) .

Recently, some authors have suggested the usefulness of the 6-MWT in the initial diagnosis of COVID-19 (16) , for early discrimination of mild from severe cases; however, there are concerns about the likely transmission of COVID-19 via the air to healthcare personnel and individuals with other chronic lung diseases who attend pulmonary function test laboratories (17, 18) . Therefore, new preventive measures have been proposed, one of which is the use of face mask to reduce the risk of infection (16) .

Traditionally, the 6-MWT is performed without a face mask, and the use of a face piece that covers the mouth and nostrils can increase the CO 2 concentrations to 3.0% (60.5%), especially in subjects performing low-intensity exercise (19, 20) . In this sense, using an N95 respirator may be associated with increased breathing effort, sensation of suffocation, and altered results during the 6-MWT. As far as we know, there is only one study that has evaluated the use of a surgical face mask during the 6-MWT (21); these authors found no difference in the meters walked (P 5 0.99) in healthy subjects, and the only significant difference was in the degree of dyspnea (P , 0.001). Our study found that in 84% of the participants, the difference in meters walked was within the MCSL (630 m) (13, (22) (23) (24) , and no differences were obtained in the degree of dyspnea (25). This study has limitations. Although this is a cohort of individuals who recovered from COVID-19, the number of participants in each group could be higher.

Surgical or N95-type face masks can be used during the 6-MWT, especially among those recovering from COVID-19, and the results regarding the meters walked as well as other variables, such as Sp O 2 , HR, and degree of dyspnea, are similar to those obtained without using a face mask.

To the Editor:

During the coronavirus disease (COVID-19) pandemic it has become clear that patients with comorbidities are not only at higher risk of contracting the disease but also to develop serious complications such as acute respiratory distress syndrome (ARDS). A dose-dependent correlation between alcohol consumption and viral infections is well documented (1) and, furthermore, alcohol consumption has been shown to increase the risk of acquiring community infections (2) .

A general increase in the consumption of alcohol has been reported during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic (3). It has been hypothesized that patients with alcohol-related disorders are at an increased risk of COVID-19 (4). However, it remains unknown whether alcohol consumption is associated with a more severe course of COVID-19.

We conducted a cohort study to understand the association of alcohol use and ARDS development using data from ECHOVID-19 (The COVID-19 Echocardiography Study), a prospective multicenter cohort study of 215 hospitalized patients with COVID-19 recruited from eight hospitals in eastern Denmark (March 30 to June 1, 2020). All patients were included consecutively with the investigators blinded to the health status of patients before inclusion. Inclusion criteria for ECHOVID-19 were laboratory-confirmed SARS-CoV-19 infection, age > 18 years, not admitted to an intensive care unit (ICU) at time of inclusion (patients were not excluded if later transferred to the ICU), and being capable of signing a written informed consent. Additional exclusion criteria for this substudy was an unknown history of alcohol consumption (N 5 44).

The primary outcome was ARDS (defined according to the Berlin Criteria) (5) during hospitalization. Severe ARDS, defined as ARDS with an arterial oxygen pressure/fraction of inspired oxygen ratio < 100 mm Hg, was a secondary outcome.

Information on alcohol consumption was obtained by a questionnaire. The exposure was defined as the continuous number of drinks of alcohol per week (12 g ethanol/drink). We used parametric and nonparametric tests to assess differences in baseline characteristics in relation to the outcome. Logistic regression models were used to test and visualize the association between alcohol consumption and the outcomes. A multivariable model was constructed to adjust for potential confounders of ARDS and severe ARDS development. The multivariable model included the variables: age, smoking status (ever-smoker vs. never-smoker), prevalent heart failure, and chronic obstructive pulmonary disease. All participants gave written informed consent, and the study was performed in accordance with the second Declaration of Helsinki and approved by the regional ethics board. The study is registered at Clinicaltrials.gov (NCT04377035).

A total of 171 patients were included in the final sample. The mean age of the study sample was 69 6 13 years and 55% were male. Baseline characteristics of patients progressing to ARDS and patients not developing ARDS are listed in Table 1 . In a univariable model, weekly alcohol consumption was associated with development of ARDS (odds ratio [OR], 1.06; 95% confidence interval [95% CI], 1.01-1.12; P 5 0.015, per 1-drink increase) and severe ARDS (OR, 1.07; 95% CI, 1.02-1.13; P 5 0.009) (Figure 1) . The association between self-reported alcohol consumption and ARDS remained significant after multivariable adjustments (ARDS: OR, 1.05; 95% CI, 1.00-1.10; P 5 0.046, per 1 drink increase; severe ARDS: OR, 1.07; 95% CI, 1.01-1.13; P 5 0.013, per 1 drink increase).

In this study, weekly alcohol consumption was associated with an increased risk of developing ARDS during hospitalization for COVID-19. Higher alcohol consumption is known to be detrimental to health, but it may also be an indicator of psychosocial and socioeconomic challenges. Currently, there does not exist published literature regarding the prognosis after COVID-19 infection according to alcohol consumption. However, before the COVID-19 pandemic, Simou and colleagues conducted a review and metanalysis investigating the association between alcohol consumption and risk of ARDS in hospitalized adults (N 5 177,674) (6) . The authors found that chronic high alcohol consumption significantly increased the risk Clinical trial registered with Clinicaltrials.gov (NCT04377035).

Restoring pulmonary and sleep services as the COVID-19 pandemic lessens: from an Association of Pulmonary, Critical Care, and Sleep Division Directors and

Functional respiratory evaluation in the COVID-19 era: the role of pulmonary function test laboratories

Bioseguridad y prevenci on de infecciones cruzadas durante la realizaci on de estudios de funci on pulmonar

Consensus of Chinese experts on protection of skin and mucous membrane barrier for health-care workers fighting against coronavirus disease 2019

Sociedad Española de Neumolog ıa y Cirug ıa Tor acica SEPAR. Recomendaciones de prevenci on de infecci on por coronavirus en las unidades de funci on pulmonar de los diferentes ambitos asistenciales

SEPAR; 2020

Recommendation from ERS Group 9.1 (Respiratory function technologists /Scientists) Lung function testing during COVID-19 pandemic and beyond

technical standard: field walking tests in chronic respiratory disease

Psychophysical bases of perceived exertion

Reference equations for the six-minute walk in healthy adults

Prueba de caminata de 6 minutos: recomendaciones y procedimientos

ATS Committee on Proficiency Standards for Clinical Pulmonary Function Laboratories. ATS statement: guidelines for the six-minute walk test

Cardiovascular Health Study. The 6-min walk test: a quick measure of functional status in elderly adults

measurement properties of field walking tests in chronic respiratory disease

Clinical correlates and prognostic significance of six-minute walk test in patients with primary pulmonary hypertension. Comparison with cardiopulmonary exercise testing

Pulmonary rehabilitation for chronic obstructive pulmonary disease

Proposed modifications in the 6-minute walk test for potential application in patients with mild COVID-19: a step to optimize triage guidelines

Does spitting in public play a role in transmitting SARS-CoV-2?

Transmission routes of respiratory viruses among humans

Carbon dioxide rebreathing in respiratory protective devices: influence of speech and work rate in fullface masks

Physiological response to alterations in [O2] and [CO2]: relevance to respiratory protective devices

Six-minute-walk test in idiopathic pulmonary fibrosis: test validation and minimal clinically important difference

Interpreting small differences in functional status: the Six Minute Walk test in chronic lung disease patients