Face masks don’t limit oxygen intake, thermometers might be inaccurate
THIS week’s a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, focuses on examining the links between a sleeping disorder and severe cases of COVID-19, the inherent inaccuracy of non-touch thermometers and dispelling myths surrounding face masks and oxygen intake.
MASKS DON’T AFFECT LUNGS
The average face mask may be uncomfortable but does not limit the flow of oxygen to the lungs, even in people with severe lung diseases, researchers say.
They tested the effect of wearing surgical masks on gas exchange – the process by which the body adds oxygen to the blood while removing carbon dioxide – in 15 healthy physicians and 15 military veterans with severely impaired lungs via a quick-paced six-minute walk on a flat, hard surface.
Oxygen and carbon dioxide levels in the blood were measured before and after the walking test. Neither the healthy doctors nor the patients with diseased lungs showed any major changes in gas exchange measurements after the walking test or up to 30 minutes later.
Mask discomfort is likely not due to rebreathing of carbon dioxide and decreases in oxygen levels, the researchers reported in the journal Thorax. Instead, masks may be causing discomfort by irritating sensitive facial nerves, warming inhaled air, or inducing feelings of claustrophobia.
Any such discomfort should not cause safety concerns, researchers said, as that could contribute to the reduction of “a practice proven to improve public health.”
SLEEP APNEA INCREASES RISK
A common sleep disorder appears to put COVID-19 patients at higher risk for critical illness, a new study finds.
Using Finnish national databases, researchers found that while the rates of infection with the new coronavirus were the same for people with and without obstructive sleep apnea (OSA), among people who did become infected, those with OSA had a five-fold higher risk of hospitalization.
When people with OSA are asleep, their breathing stops briefly and then restarts, often multiple times during the night. OSA is associated with health problems like obesity, high blood pressure, heart disease and diabetes, but was linked with a higher risk for severe COVID-19 even after researchers took all these other factors into account.
The study cannot prove that OSA caused more severe outcomes. But in a paper posted on medRxiv ahead of peer review, researchers advise doctors evaluating patients with suspected or confirmed coronavirus infection to recognize that the sleep disorder is a risk factor for severe COVID-19.
THERMOMETERS AND INACCURACY
Non-contact infrared thermometers, long used in children and now being used to screen for fever in public places, may not accurately measure body temperature in adults, a small study suggests.
The devices are held a short distance from the forehead. Because they never touch the skin, they help prevent transmission of germs and do not need to be sterilized after each use.
In a study of 265 adults at two hospitals, Australian researchers compared infrared thermometers with “temporal artery” thermometers, which are rubbed across the forehead. When body temperatures were below 37.5 degrees Celsius (99.5 degrees Fahrenheit), the devices yielded similar results. But for higher body temperatures, the non-contact thermometers “demonstrated poor accuracy,” with greater discrepancies as temperatures rose, according to a report published on Friday in the American Journal of Infection Control. As only 37 study participants had a fever, larger studies are needed to confirm these findings, researchers said. Meanwhile, they added, when an infrared thermometer shows a temperature above 37.5 degrees Celsius in an adult, it might be wise to get a direct measurement with a thermometer than makes contact with the body.