Latest COVID-19 studies look at proning awake patients, residual lung abnormalities

Prone positioning of awake inpatients with COVID-19 reduced intubation but not mortality, according to a meta-analysis published by The BMJ on Dec. 7. It included 17 trials with 2,931 patients (12 trials with low risk of bias, three with some concerns, and two with high risk) and found that awake prone positioning reduced the primary outcome of endotracheal intubation compared with usual care (24.2% vs. 29.8%; relative risk [RR], 0.83 [95% CI, 0.73 to 0.94]), which works out to 55 fewer intubations per 1,000 patients (95% CI, 87 to 19). However, it did not have a statistically significant effect on secondary outcomes, including mortality (15.6% vs. 17.2%), ventilator-free days (difference, 0.97 day), ICU length of stay (−2.1 days), hospital length of stay (−0.09 day), and escalation of oxygen modality (21.4% vs. 23.0%). Adverse events related to awake prone positioning were uncommon in the studies.

The meta-analysis authors concluded that compared to usual care, awake prone positioning reduces the risk of endotracheal intubation in adults with hypoxemic respiratory failure due to COVID-19 but probably has little to no effect on mortality or other outcomes. None of the included trials achieved their targeted durations of prone positioning, they noted. “The intervention may be limited by patient tolerance as data suggest that awake patients may not cope well with long periods of prone positioning. … [T]he benefits of awake prone positioning need to be weighed against the resources and staff needed to ensure safe adherence to the intervention.” The authors called for future research to improve the tolerability of proning and determine its optimal duration.

Another recent study estimated the prevalence of lung abnormalities in patients hospitalized with COVID-19 before or during March 2021. The study, published by the American Journal of Respiratory and Critical Care Medicine on Dec. 1, looked at 209 patients who had been hospitalized with COVID-19 and had a thoracic CT scan performed within 240 days of discharge (median, 119 days). Of these, 166 (79.4%) had residual lung abnormalities with greater than 10% involvement. Thirty-three of these patients underwent repeat CTs at least 90 days later, which did not show significant change in lung reticulations or ground-glass opacities. The study authors estimated the mean weekly change in lung involvement at −0.13% per week (95% CI, −0.20% to −0.05%) for reticulations and −0.13% per week (95% CI, −0.22% to −0.04%) for ground-glass opacities.

They also identified factors associated with the residual abnormalities: an abnormal chest X-ray, a diffusion capacity for carbon monoxide less than 80%, and a need for ventilation during hospitalization. Applying these factors to the portion of their study population who did not have follow-up CTs available (n=3,791), the study authors calculated that up to 11% of patients discharged from hospitalization for COVID-19 could have lung abnormalities. Limitations of the study include that the CT scans were ordered only when clinically indicated, which likely created selection bias. The authors also noted that the functional consequences of the observed abnormalities are still unknown. “At the time of this interim analysis it is not possible to determine whether the observed residual lung abnormalities represent early interstitial lung disease (ILD) with potential for progression, or whether they reflect residual pneumonitis that may be stable or resolve over time,” they wrote.