Prone positioning did not appear to provide benefit, and was actually associated with worsening hypoxia, in awake hospitalized patients with COVID-19, a new trial found.
The pragmatic trial, conducted in 2020, included 501 patients with acute hypoxemic respiratory failure and COVID-19 infection who were treated at two U.S. academic medical centers and had not received mechanical ventilation. All were receiving oxygen by standard low-flow nasal cannula, high-flow nasal cannula, or noninvasive positive-pressure ventilation to maintain an oxygen saturation of 89% or higher. Half of the patients were encouraged by practitioners to use prone positioning as often and consistently as they were able, while the other half were not given any specific direction on positioning. Results were published by JAMA Internal Medicine on April 18.
According to nursing observations, patients in the intervention group spent a median of 4.2 hours (interquartile range, 1.8 to 6.7 hours) in the prone position per day compared with 0 hours (interquartile range, 0 to 0.7 hour) per day in the usual care group. At study day 5, the prone positioning group had a significantly lower result on the study's primary outcome, which measured worsening hypoxemia using the World Health Organization ordinal scale (adjusted odds ratio, 1.63; 95% credibility interval, 1.16 to 2.31). However, the groups did not show any significant difference on that outcome at study day 14 or 28, or on the secondary endpoints of mortality, hospital length of stay, ventilator-free days, or progression to mechanical ventilation.
The results indicate “that a universal recommendation of awake prone positioning for the care of patients with COVID-19–associated hypoxemia who are not yet receiving mechanical ventilation may worsen clinical outcomes and cause harm,” said the authors, who offered a number of possible explanations. These include that early prone positioning may accelerate the progression of lung damage or may improve oxygenation but obscure the natural progression of disease, causing delays in other therapies. Switching positions could also dislodge oxygen support, they noted.
The study authors listed a number of limitations to the trial, including the absence of blinding or a comparison of oxygen saturation before, during, and after prone positioning. An accompanying editorial said that “concerns related to study design weaken the strength of their conclusions” but also concluded that the results show “caution is warranted” about extrapolating research results from one patient population to another, such as has been done with the benefits of prone positioning in mechanically ventilated patients with COVID-19.