key: cord-1010618-tvda8rcb
authors: Prud’homme, Eloi; Trigui, Youssef; Elharrar, Xavier; Gaune, Marie; Loundou, Anderson; Lehingue, Samuel; Boyer, Arnaud; Lefebvre, Laurent; Dols, Anne-Marie; Chanez, Pascal; Papazian, Laurent; Forel, Jean-Marie
title: Effect of Prone Positioning on the respiratory support of non-intubated patients with COVID-19 and acute hypoxemic respiratory failure: A retrospective matching cohort study.
date: 2021-01-29
journal: Chest
DOI: 10.1016/j.chest.2021.01.048
sha: 2f0b8325ba678ccda6d32f54ff22e08cb3eb9b43
doc_id: 1010618
cord_uid: tvda8rcb

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1 Effect of Prone Positioning on the respiratory support of non-intubated patients with COVID-19 and acute hypoxemic respiratory failure: A retrospective matching cohort study.

Eloi Prud'homme, MD 1 *; Youssef Trigui, MD 2 ; Xavier Elharrar, MD 2 ; Marie Gaune, MD 3 ; Anderson Loundou, PhD 4 ; Samuel Lehingue, MD 5 ; Arnaud Boyer, MD 6 ; Laurent Lefebvre, MD 7 ; Anne-Marie Dols, MD 8 ; Pascal Chanez, MD, PhD 3 ; Laurent Papazian, MD, PhD 1, 9 ; Jean-Marie Forel, MD 1 

We designed an exposed/non-exposed bicentric retrospective matched cohort study to assess the effectiveness of PP for patients hospitalized outside Intensive Care Unit (ICU) with COVID-19 requiring oxygen.

All consecutive patients hospitalized from March 20 th to April 20 th , 2020, in Aix-en-Provence Hospital and Marseille University Hospital, France, were screened for eligibility. Inclusion criteria were: age over 18, hypoxemic respiratory failure requiring oxygen supplementation, by either conventional oxygen therapy or high flow nasal cannula (HFNC), and PCR-confirmed SARS-CoV-2. The study received approval by the appropriate IRB (n° MR 3514070520).

Two treatment strategies were compared: awake PP for at least 3 hours a day during three consecutive days (PP group) and no instruction regarding positioning or no tolerance of PP during hospitalization (no-PP group). Each PP session had a minimum duration of 1 hour and a maximum duration of 12 hours, for a minimum total PP duration of 3 hours per day. Position of the patient and duration of PP sessions were monitored by the medical and paramedical team every 3 hours. The oxygen supplementation strategy was to initiate first oxygen therapy, second HFNC, third pressure support with non-invasive ventilation (NIV), and finally invasive mechanical ventilation (IMV).

It was a retrospective analysis of patient medical records from admission to day 14.

The primary outcome of the study was the "upgrading of oxygen delivery method" evaluated on day 14 (D14) and defined by reaching at least 6L/min with a doubling of the initial oxygen flow for usual oxygen supplementation, or initiating HFNC, or initiating NIV or IMV. The secondary outcome was death at D14.

Difference testing between groups was performed using the two-tailed t test, Mann-Whitney U test, or chi-square tests as appropriate. To determine the relative risk of "upgrading the oxygen delivery method" due to PP, we performed a propensity score analysis to adjust for imbalances in baseline characteristics between patients with and without PP. Using the overall population (n=168), we developed a logistic regression model to derive a propensity score for PP (used as a binary value).

The variables relevant to the model were selected from the univariate analyses (p value < 0.20) or and from their clinical relevance and were as following: 1) center; 2) age; 3) sex; 4) smoking history; 

A total of 414 confirmed COVID-19 patients were admitted during the study period. Two hundred forty-six patients did not meet inclusion criteria (192 did not require oxygen supplementation, 31

refused the use of their data and 23 had incomplete files). Among the 168 patients eligible for analysis, 48 received PP for at least 3h a day for three days and 120 did not. After performing a propensity score matching, 96 patients were analyzed (48 patients in each group). All patients receiving PP were successfully matched with a patient without PP ( 

This retrospective, bicentric study done on 96, awake, non-intubated, spontaneously breathing COVID-19 patients with acute hypoxemic respiratory failure requiring oxygen supplementation showed that PP for at least three hours a day during three consecutive days prevented the upgrading of oxygen delivery method on D14 after hospital admission compared to no instruction regarding prone positioning or no tolerance of PP during hospitalization.

These results are consistent with findings from previous small studies of PP in non-intubated patients with improvement in oxygenation and a trend to improve clinical outcomes 4, 5, [8] [9] [10] .

The study has several limitations. First, although we used robust statistical techniques for adjustment, treatment was not randomly assigned, and patients were instructed for PP according to J o u r n a l P r e -p r o o f 5 the physician in charge. Second, the reasons for the lack of a significant effect on death or intubation remain uncertain but the sampling size was suboptimal to answer these questions and the study was not powered nor planned to assess the effect on mortality. Third, it was a retrospective collection of data from patient hospitalized in medical ward who were not monitored that's why we did not evaluate oxygenation response neither tolerance during PP session.

PP for at least 3 hours a day during three consecutive days may be associated with a clinical benefit by preventing the upgrading of oxygen delivery method. These results need to be confirmed with further randomized prospective studies.

J o u r n a l P r e -p r o o f

Clinical Course and Outcomes of 344 Intensive Care Patients with COVID-19

Prone Positioning in Severe Acute Respiratory Distress Syndrome

Prone Position for Acute Respiratory Distress Syndrome. A Systematic Review and Meta-Analysis. Annals of the

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

Respiratory Parameters in Patients With

After Using Noninvasive Ventilation in the Prone Position Outside the Intensive Care Unit

Lower mortality of COVID-19 by early recognition and intervention: experience from Jiangsu Province

CT image visual quantitative evaluation and clinical classification of coronavirus disease (COVID-19)

Efficacy and safety of early prone positioning combined with HFNC or NIV in moderate to severe ARDS: a multi-center prospective cohort study

Feasibility and physiological effects of prone positioning in non-intubated patients with acute respiratory failure due to COVID-19 (PRON-COVID): a prospective cohort study. The Lancet Respiratory Medicine

Prone and Lateral Positioning in Spontaneously Breathing Patients With COVID-19 Pneumonia Undergoing Noninvasive Helmet CPAP Treatment

SpO2/FiO2 at admission (mean, sd) 299 (±45)

CRP (mg/l) (mean, sd) 116 (±94)