Mask wearing showed no negative oxygenation, hemodynamic changes in patients with COPD

Oct 10, 2023

Kim SH, et al. Ann Am Thorac Soc. 2023;doi:10.1513/AnnalsATS.202206-551RL.

Kim SH, et al. Ann Am Thorac Soc. 2023;doi:10.1513/AnnalsATS.202206-551RL.

Wearing a KF80 mask while exercising and performing daily activities did not impact oxygenation and hemodynamic factors in adults with mild to moderate COPD, according to study results published in Annals of the American Thoracic Society.

"We did not observe any impairment in oxygenation or serious changes in hemodynamic parameters while our participants wore KF80 masks," Sang-Heon Kim, MD, PhD, of Hanyang University College of Medicine, and colleagues wrote. "Although we did not measure the end-tidal carbon dioxide or respiratory rate, these findings suggest that wearing masks does not have serious adverse effects on respiratory function and cardiovascular hemodynamics, even during strenuous exercise."

In a single-center prospective randomized crossover study, Kim and colleagues evaluated 30 adults (median age, 71 years; 96.7% men) with mild to moderate COPD in Seoul, South Korea, to determine how face masks effect oxygen saturation and hemodynamic responses when they work out and conduct daily activities.

Researchers tested for these outcomes with use of the KF80 mask, which is similar to the European FFP1 mask, with a "0.6 m particle filtration rate of at least 80%," according to researchers.

To evaluate changes with mask wearing, researchers collected patients’ oxygen saturation, heart rate, systolic and diastolic blood pressure, electrocardiogram and echocardiography before they exercised on a treadmill with a mask on. The same factors were then measured during/after exercise.

Additionally, researchers had the patients wear a mask for 24 hours while they conducted their daily activities to see how heart rate, systolic and diastolic blood pressure and electrocardiogram changed from baseline through ambulatory blood pressure and Holter monitoring.

Oxygen saturation and hemodynamic responses during exercise and daily activities were also evaluated without wearing a mask in all patients.

Compared with baseline measurements of oxygen saturation, researchers found significant reductions after exercise both with a mask (baseline median, 96%; interquartile range [IQR], 94-97 vs. after, 91%; IQR, 86-93; P = .001) and without a mask (baseline, 96%; IQR, 95-97 vs. after, 91%; IQR, 86-94; P = .001), and both phases resulted in the same lowest percentage of oxygen saturation.

In a subgroup analysis, those with less than 5% of oxygen saturation changes while exercising (n = 14) did not significantly differ from those with an at least 5% change (n = 16) when evaluating how wearing masks differed between both sets of adults.

In terms of hemodynamic factors during exercise, testing with a mask and without a mask both showed heart rates above baseline (P < .001 for both) and comparable maximum heart rates at peak exercise, according to researchers.

While working out on the treadmill, researchers did not observe any instances of a significant decrease in blood pressure or electrocardiogram changes in the patients.

Researchers did see a significant reduction when measuring diastolic dysfunction following exercise with a mask on (before, 9.3; IQR, 7.8-13.3 vs. after, 8.5; IQR, 7.4-10.6); however, they wrote that this "does not imply the presence of a relaxation abnormality or a significant hemodynamic compromise."

Looking at changes in hemodynamic variables during daily activities when wearing a mask vs. not wearing a mask, blood pressure and heart rate did not significantly vary based on mask wearing, according to researchers.

Researchers note the presence of several limitations in this study including only testing with the KF80 mask, population made up of nearly all men, population of only those with mild to moderate COPD and a lack of assessment on the long-term consequences of mask wearing.

Despite these limitations, the results offer important insight on the effects of mask wearing.

"The findings of this prospective randomized crossover study suggest that wearing a face mask does not have serious effects on oxygenation and cardiovascular hemodynamics in patients with mild to moderate COPD," Kim and colleagues wrote. "Thus, the protective benefits of wearing masks with regard to infection prevention appear to outweigh the risks."

Andrew J. Gangemi, MD

Since the start of the pandemic, personal protective equipment (PPE) has been a cornerstone in limiting community spread. While there were initial concerns of increased risk of severe respiratory failure among patients with COPD, cohort studies such as those from the Losartan Effects on Emphysema Progression (LEEP) trial found no increase in all-cause hospitalizations among patients and a decrease in COPD-specific hospitalizations. Furthermore, this patient cohort exhibited resilience to the social distancing and isolation imposed by the pandemic with low rates of anxiety and depression throughout the pandemic.

In this small study, Kim and colleagues examined the impact of masks on exercise tolerance and hemodynamics among mild to moderate COPD patients, both during in-lab protocolized exercise testing and during daily activities using a crossover design. KF80 masks, with an 80% filtration rate for particles 0.6 µm in size, were used which should conceivably reduce airflow to a more clinically significant degree than standard surgical masks. However, they found no significant differences in the baseline and peak-exercise oxygen saturations, mean and maximal heart rate, or blood pressure parameters in either short term stress testing or in longer term outpatient monitoring. These findings are consistent with previous small studies testing oxygenation and ventilation during simple pulmonary exercise testing in both healthy subjects and severe COPD subjects. Even after 30 minutes of wearing an N95 mask (which by comparison has a 95% filtration rate for particles 0.1 µm to 0.3 µm in size), there were no significant differences in heart rate response to exercise or gas exchange as determined both noninvasively using pulse oximetry and end-tidal CO2 and invasively using arterial blood gas sampling.

The strengths of this current study include a crossover design as well as the prolonged monitoring period during the home phase. Furthermore, patients were tested using a Bruce protocol which stresses the cardiopulmonary system to a greater degree than a simple 6-minute walk test and should better capture significant impairments in ventilation. Unfortunately, based on the reported data we cannot extrapolate changes in minute ventilation that could explain the perception of dyspnea for patients wearing masks. This current study also did not quantify breathlessness, such as with the Borg dyspnea scale, to correlate the physiologic observations to subjective dyspnea. Several putative physiologic effects of wearing PPE may explain the reported discomfort from masks aside from air flow resistance, such as rises in inspired air temperature and increases in dead space with local CO2 entrainment exert neural feedback effects.

This study supports prior data failing to show any major impairments of masks on airflow or gas exchange among COPD patients. PPE reduces not only the spread of COVID-19 but other respiratory viral illnesses, likely contributing to the reduction in non-COVID-19-related COPD exacerbations during the pandemic. When encouraging patients to adhere to masking protocols, these findings can help assure them that perceived discomfort is not accompanied by dangerous drops in gas exchange.

References:

Zhang WZ, et al. Chronic Obstr Pulm Dis. 2022;doi:10.15326/jcopdf.2022.0287.

Kim SH, et al. Ann Am Thorac Soc. 2023;doi:10.1513/AnnalsATS.202206-551RL.

Samannan R, et al. Ann Am Thorac Soc. 2021;doi:10.1513/AnnalsATS.202007-812RL.

Huo S, et al. Build Environ. 2021;doi:10.1016/j.buildenv.2021.108261.