麻豆传媒

Two new reports offer conflicting data about the proper use of prone positioning -- a belly-down approach to improve respiration -- in hospitalized, non-intubated patients with COVID-19.

One study, which was nonrandomized, suggested that the intervention is useless and may actually be harmful. The other, a randomized controlled trial, linked proning to a reduced risk of intubation but not to a mortality benefit.

What should clinicians do? Considering the evidence that's available about non-intubated patients, "it is unclear which patients will benefit, how long they need to be proned, and if proning masks disease progression delaying further interventions," said Peter Sottile, MD, of the University of Colorado Anschutz Medical Campus in Aurora, co-author of a accompanying the first study, which was published in .

Miguel Ángel Ibarra Estrada, MD, of the University of Guadalajara in Mexico, the lead author of the second study, which was presented this week at the Society of Critical Care Medicine's virtual , told 麻豆传媒 that "awake prone positioning is an effective measure, as this is a no-cost and safe procedure."

The non-randomized, controlled study, by Edward Tang Qian, MD, of Vanderbilt University Medical Center in Nashville, and colleagues, tracked 501 patients with COVID-19 and hypoxia who were not on mechanical ventilation (mean age 61, 56.7% male). Of those, 258 underwent prone positioning and were found to be more likely to have worse outcomes than the usual-care group at 5 days (adjusted OR 1.63, 95% CI 1.16-2.31) and to show no signs of clinical improvement.

However, the commentary noted the relatively short amount of time that patients spent in the prone position (mean of 4.2 hours), along with other limitations. "Concerns related to study design weaken the strength of [the] conclusions," Sottile and co-authors wrote.

Ibarra Estrada and colleagues randomly assigned 216 patients with COVID-19 and hypoxia to prone positioning and 214 to standard care. All patients were receiving oxygen through high-flow nasal cannula. (The study by Qian and co-authors included patients who received oxygen in various ways other than mechanical ventilation.)

The intubation rate was lower in the proned patients compared with those who had standard care (30% vs 43%, respectively; RR 0.70, 95% CI 0.54-0.90, P=0.006), and there was no statistically significant difference in mortality (33% vs 37%; RR 0.89, 95% CI 0.69-1.15, P=0.3), Ibarra Estrada reported.

Based on the statistical trend, "there is a high probability" the mortality difference would have been significant if recruitment had continued, he said, noting that the study was stopped because proning showed a clear benefit.

The team linked treatment failure to less daily time proned (i.e., less than 7.7 hours), higher respiratory rate at enrollment, and decrease in respiratory rate less than 3 bpm after the first session of proning.

Proning caused back pain in 7.4% of patients and dislodged intravenous lines in 6.5%. "Tolerance of patients is frequently limited due to pain, anxiety, body habitus, comorbidities, etc.," which can limit the amount of time that patients can be proned, Ibarra Estrada said.

He noted that the study is the largest randomized controlled trial of proning in non-intubated patients with COVID-19 and was included in a recent meta-analysis that found that awake proning reduced the need for intubation among patients receiving advanced respiratory support.

Sottile told 麻豆传媒 it's clear that "intubated patients with moderate to severe acute respiratory distress syndrome should be considered for prone positioning unless contraindications to proning exist."

But the situation is murky for non-intubated patients, he added. "It is still unclear if awake prone positioning improves mortality in patients with acute hypoxic respiratory failure, such as COVID. It remains unclear if the improvement in oxygenation masks the progression of lung injury and delays potentially life-saving interventions such as intubation and mechanical ventilation with low tidal volume ventilation or actually improves the disease progression."