Continuous prolonged prone positioning in COVID-19-related ARDS: a multicenter cohort study from Chile
Authors: Cornejo Rodrigo A. , Montoya Jorge , Gajardo Abraham I. J. , Graf Jerónimo , Alegría Leyla , Baghetti Romyna , Irarrázaval Anita , Santis César , Pavez Nicolás , Leighton Sofía , Tomicic Vinko , Morales Daniel , Ruiz Carolina , Navarrete Pablo , Vargas Patricio , Gálvez Roberto , Espinosa Victoria , Lazo Marioli , Pérez-Araos Rodrigo A. , Garay Osvaldo , Sepúlveda Patrick , Martinez Edgardo , Bruhn Alejandro ,   the SOCHIMI Prone-COVID-19 Group, Rossel Nicole , Martin María José , Medel Juan Nicolás , Oviedo Vanessa , Vera Magdalena , Torres Vicente , Montes José Miguel , Salazar Álvaro , Muñoz Carla , Tala Francisca , Migueles Mariana , Ortiz Claudia , Gómez Felipe , Contreras Luis , Daviu Itzia , Rodriguez Yurimar , Ortiz Carol , Aquevedo Andrés , Parada Rodrigo , Vargas Cristián , Gatica Miguel , Guerrero Dalia , Valenzuela Araceli , Torrejón Diego 
Published: November 2022

Abstract
Background
Prone positioning is currently applied in time-limited daily sessions up to 24 h which determines that most patients require several sessions. Although longer prone sessions have been reported, there is scarce evidence about the feasibility and safety of such approach. We analyzed feasibility and safety of a continuous prolonged prone positioning strategy implemented nationwide, in a large cohort of COVID-19 patients in Chile.

Methods
Retrospective cohort study of mechanically ventilated COVID-19 patients with moderate-to-severe acute respiratory distress syndrome (ARDS), conducted in 15 Intensive Care Units, which adhered to a national protocol of continuous prone sessions  ≥ 48 h and until PaO2:FiO2 increased above 200 mm Hg. The number and extension of prone sessions were registered, along with relevant physiologic data and adverse events related to prone positioning. The cohort was stratified according to the first prone session duration: Group A, 2–3 days; Group B, 4–5 days; and Group C, > 5 days. Multivariable regression analyses were performed to assess whether the duration of prone sessions could impact safety.

Results
We included 417 patients who required a first prone session of 4 (3–5) days, of whom 318 (76.3%) received only one session. During the first prone session the main adverse event was grade 1–2 pressure sores in 97 (23.9%) patients; severe adverse events were infrequent with 17 non-scheduled extubations (4.2%). 90-day mortality was 36.2%. Ninety-eight patients (24%) were classified as group C; they exhibited a more severe ARDS at baseline, as reflected by lower PaO2:FiO2 ratio and higher ventilatory ratio, and had a higher rate of pressure sores (44%) and higher 90-day mortality (48%). However, after adjustment for severity and several relevant confounders, prone session duration was not associated with mortality or pressure sores.

Conclusions
Nationwide implementation of a continuous prolonged prone positioning strategy for COVID-19 ARDS patients was feasible. Minor pressure sores were frequent but within the ranges previously described, while severe adverse events were infrequent. The duration of prone session did not have an adverse effect on safety.