Certain respiratory support techniques may lower COVID-19 mortality in low-income countries

Key takeaways:

• During the pandemic, standard oxygen therapy and noninvasive ventilation were commonly used in Uganda.
• Mortality was high with noninvasive ventilation and low with standard oxygen therapy.

Standard oxygen therapy and high-flow nasal oxygen along with awake prone positioning were associated with lower COVID-19-associated mortality in a low-income country, according to results published in CHEST.

Further, use of advanced respiratory support was linked to elevated mortality among adults with COVID-19-related acute respiratory distress syndrome receiving treatment in Uganda, results showed.

“The 28-day all-cause mortality of this cohort was high, particularly in patients with moderate or severe COVID-19-assosciated ARDS, as well as in those receiving [noninvasive ventilation] or [invasive mechanical ventilation],” Arthur Kwizera, MBChB, MMed, senior lecturer in anesthesiology and critical care at Makerere University College of Health Sciences in Uganda, and colleagues wrote.

In a multicenter, prospective, observational study in Uganda, Kwizera and colleagues assessed 499 adults (mean age, 54 years; 68.1% men) with COVID-19-related ARDS to determine commonly used respiratory support techniques during September 2020 through February 2021 of the COVID-19 pandemic in a low-income country.

Nearly half (n = 247) of the total cohort had moderate COVID-19-associated ARDS, whereas the rest had either mild (n = 137) or severe (n = 115) ARDS. Additionally, 38.9% of patients were admitted to the ICU, which meant the remaining patients received treatment elsewhere, “underlining the lack of ICU capacity in the country,” researchers wrote.

The most frequently used first-line respiratory support technique was standard oxygen therapy for 37.3% of patients, followed by noninvasive ventilation (23.4%), invasive mechanical ventilation (17.6%), CPAP (11.6%) and high-flow nasal oxygen (10%).

When grouped by disease severity, use of standard oxygen therapy, CPAP, noninvasive ventilation and invasive mechanical ventilation differed significantly between the three severity levels.

For example, 73% of patients with mild ARDS received standard oxygen therapy, compared with only 26.3% of those with moderate ARDS and 18.3% of those with severe ARDS (P < .001).

Further, noninvasive ventilation and invasive mechanical ventilation were used for more patients with moderate (26.7%; 20.6%) and severe (34.8%; 27%) ARDS vs. mild ARDS (8%; 4.4%; P < .001 for both), according to researchers.

For 19.8% of patients, researchers found that the selected technique needed to be escalated. Patients with moderate or severe ARDS more frequently had CPAP, noninvasive ventilation and invasive mechanical ventilation as the highest support technique used, whereas those with mild ARDS more frequently had standard oxygen therapy as their most advanced support technique.

At 28 days, a little over half (51.9%) of patients died, most of whom had severe (75.7%) or moderate (62.3%) ARDS vs. mild ARDS (13.1%; P < .001).

Researchers further found high 28-day mortality rates among those treated with invasive mechanical ventilation (83.9%), noninvasive ventilation (61.1%) and CPAP (58.3%). In contrast, mortality was lower with use of high-flow nasal oxygenation (31.9%) and standard oxygen therapy (19.9%; P < .001).

Mortality rates also were higher among those patients who required escalation of their respiratory support (81.8% vs. 44.5%: P < .001).

Notably, prone positioning (n = 79) was also linked to reduced mortality compared with no proning (40.5% vs. 54%; P = .027).

Researchers found heightened odds for in-hospital death with noninvasive ventilation (OR = 6.31; 95% CI, 2.29-17.37) and invasive mechanical ventilation (OR = 8.08; 95% CI, 3.52-18.67) vs. standard oxygen therapy.

“The multiple logistic regression analysis suggested that this association may be explained partly by disease severity, but also highlighted an independent association between mechanical ventilation, particularly [invasive mechanical ventilation], and mortality,” the researchers wrote. “The fact that patients with COVID-19-associated ARDS receiving [invasive mechanical ventilation] were sedated routinely and usually were ventilated in controlled methods made them exquisitely vulnerable to power cuts and interruptions of pressurized oxygen supply, both of which occurred on multiple occasions during the study period. In addition, limited human and material resources in non-ICU and ICU wards may have contributed to the very high mortality rates we observed.”

Other significant risk factors for mortality included oxygen saturation to FIO₂ ratio (OR = 0.99; 95% CI, 0.98-0.99) and respiratory rate (OR = 1.07; 95% CI, 1.03-1.12), both at admission.

“Although our data are observational, they suggest that the use of [standard oxygen therapy] and [high-flow nasal oxygenation] therapy as well as awake prone positioning are associated with a lower mortality resulting from COVID-19-associated ARDS in a resource-limited setting,” Kwizera and colleagues wrote.