New studies on combating COVID-19 clusters, conserving oxygen, and using telehealth

One hospital team described how they dealt with a surge of hospital-onset COVID-19 and clusters of cases caused by the omicron variant in an article published by Clinical Infectious Diseases on Feb. 7. The incidence of hospital-onset cases rose from 0.0 per 1,000 patient-days in November 2021 to 0.5 per 1,000 in December to 3.0 per 1,000 from Jan. 1 to 15, 2022. In response, the hospital developed a protocol for COVID-19 clusters, defined as three or more new cases on a unit within a three-day period: All patients on affected units were placed on enhanced precautions (N95 respirator, eye protection, gloves, and gowns) regardless of SARS-CoV-2 status, and all uninfected patients were tested for COVID-19 daily. Room sharing was discouraged, and visitors were permitted but required to wear masks, gowns, gloves, and eye protection. The response was applied to two infection clusters, and additional infections on the units were identified by unit-wide testing triggered by the cluster protocol, but no new cases developed on the units in the next 10 days. The authors noted that their findings do not prove the intervention stopped spread but that the hospital's clusters “abated rapidly compared to previous reports of hospital-based SARS-CoV-2 clusters,” suggesting “the potential benefits of universal N95 respirators and daily patient testing to prevent healthcare-associated SARS-CoV-2 infections.”

Another small study offered strategies to more efficiently deliver oxygen to patients with COVID-19 on low-flow nasal cannula. The trial in a Belgian hospital randomized 24 patients to receive nasal cannula alone, covered by a surgical face mask, or covered by a double-trunk mask (an aerosol mask in which two tubes have been fixed in each of the side holes). Results were published by the Journal of General Internal Medicine on Feb. 8. Based on arterial blood gases taken after 30 minutes, the arterial partial pressure of oxygen increased significantly with the double-trunk mask (mean change, 40 mm Hg; P<0.001), but also to some extent with the surgical face mask (mean change, 20 mm Hg; P=0.04) compared to nasal cannula alone. Oxygen output was also reduced with the surgical face mask (median reduction, 1.5 L/min) or the double-trunk mask (median reduction, 3.3 L/min) (P<0.001 vs. control for both). The study authors concluded that either strategy improves arterial oxygenation and reduces oxygen consumption but recommended that “the double-trunk mask (patent-free) should be favored over the surgical facemask, regardless of the nasal cannula oxygen flow, because of the more favorable blood oxygen level response.” They noted that its components are inexpensive and can be replaced or reused after daily cleaning.

Finally, a study published by the Journal of General Internal Medicine on Feb. 7 looked at use of telehealth for patients hospitalized with COVID-19. It included 2,200 COVID-19 patients from four hospitals in an integrated health system; 51.9% had at least one telehealth visit during hospitalization, with a median of three visits in this group. The study found that telehealth visit use was significantly associated with patient race, ethnicity, admission source, payer, month of admission, and site of care. Compared to patients at the system's academic hospital, patients at one community hospital had twice as many telehealth visits and patients at two other community hospitals had less than a third as many. “Local culture and the possibility of implicit bias likely contributed to variation in telehealth adoption,” the authors said. “Future research should explore variation in inpatient telehealth use and whether differences are associated with patient outcomes.”