18.05.2020

Use of Prone Positioning in Nonintubated Patients With COVID-19 and Hypoxemic Acute Respiratory Failure

Therapeutic PulmonologyAnesthesia-intensive care
Elharrar X et al
JAMA

Main result

  •     Inclusion of 24 consecutive COVID-19 patients with mean age of 66 years, 67% male, 23% obese, 26% hypertensive. In this sample, 33% of patients required at least 4L of O2 with a mean respiratory rate of 18.
  •     17% of patients did not tolerate prone position for more than 1 hour and 21% between 1 and 3 hours.
  •     Before the prone position, mean PaO2 was 72.8 and PaCO2 was 34.1 vs. 91 and 32.8 respectively during the prone position and 77.6 and 32.3 after the prone position.
  •     25% of patients responded well to prone position (difference of 21.3 mmHg, p=0.006), 40% of those who had been in prone position for more than 3 hours and 13% had a lasting effect after prone position (p=0.53).
  •     No major complications found, but 42% of patients had back pain.
  •     21% of patients required mechanical ventilation during the 10-day follow-up.

Takeaways

  •  The prone position in non-intubated COVID-19 patients is fairly well tolerated (63% of cases).
  •  Oxygenation increased in only 25% of cases and was not maintained after the prone position in the majority of cases.
  • The prone position therefore appears to temporarily improve the respiratory situation but requires further studies to confirm and quantify the effect.

Strenght of evidence Weak

- Pseudo-experimental before-after study on small sample
- A single episode of prone position of unknown duration.
- No assessment of improvement in clinical symptomatology other than respiratory, biological or radiological signs.
- No a priori calculation of the number of subjects required and power visibly too low for the secondary judgement criteria.
- No consideration of the period as a random adjustment factor and no adjustment for potential confounding factors.
- Choice of the main judging criterion and the 20% threshold not justified

Objectives

Evaluate the feasibility, efficacy and safety of the prone position in COVID-19 patients awake in the non-intensive care unit.

Method

  •     Monocentric pre-post prospective study conducted in France (Aix-en-Provence)
  •     Consecutive inclusion of confirmed awake, non-intubated, spontaneously ventilated COVID-19 patients with acute hypoxemic respiratory failure requiring oxygen therapy and compatible CT scans.
  •     Blood gas is performed before the prone position, during, 6 and 12 hours after the supine position.
  •     Maintaining the same oxygen therapy device and FiO2 during the study
  •     10-day patient follow-up
  •     Primary endpoint = the proportion of good responders is defined as a 20% increase in Pa02 before and during the prone position.
  •     Secondary endpoints = variation in PaO2 and PaCO2, proportion of patients supporting the prone position for at least one hour and at least 3 hours (feasibility) and proportion of persistent responders defined by a PaO2 increase of at least 20% between before and after.
  •     Statistics: no headcount calculation, analysis by Wilcoxon test with p-value of 0.01 as threshold to take into account the inflation of the alpha risk (Bonferroni method)

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