Background Awake prone positioning (APP) is widely used in the management of patients with coronavirus disease (COVID-19). The primary objective of this study was to compare the outcome of COVID-19 patients who received early versus late APP. Methods Post hoc analysis of data collected for a randomized controlled trial (ClinicalTrials.gov NCT04325906). Adult patients with acute hypoxemic respiratory failure secondary to COVID-19 who received APP for at least one hour were included. Early prone positioning was defined as APP initiated within 24 h of high-flow nasal cannula (HFNC) start. Primary outcomes were 28-day mortality and intubation rate. Results We included 125 patients (79 male) with a mean age of 62 years. Of them, 92 (73.6%) received early APP and 33 (26.4%) received late APP. Median time from HFNC initiation to APP was 2.25 (0.8–12.82) vs 36.35 (30.2–75.23) hours in the early and late APP group (p < 0.0001), respectively. Average APP duration was 5.07 (2.0–9.05) and 3.0 (1.09–5.64) hours per day in early and late APP group (p < 0.0001), respectively. The early APP group had lower mortality compared to the late APP group (26% vs 45%, p = 0.039), but no difference was found in intubation rate. Advanced age (OR 1.12 [95% CI 1.0–1.95], p = 0.001), intubation (OR 10.65 [95% CI 2.77–40.91], p = 0.001), longer time to initiate APP (OR 1.02 [95% CI 1.0–1.04], p = 0.047) and hydrocortisone use (OR 6.2 [95% CI 1.23–31.1], p = 0.027) were associated with increased mortality. Conclusions Early initiation (< 24 h of HFNC use) of APP in acute hypoxemic respiratory failure secondary to COVID-19 improves 28-day survival. Trial registration ClinicalTrials.gov NCT04325906.

Inhaled epoprostenol (iEPO) has been utilized to improve oxygenation in mechanically ventilated subjects with severe hypoxemia, but the evidence for iEPO via high-flow nasal cannula (HFNC) is rare. Following approval by the institutional review board, this retrospective cohort study evaluated subjects who received iEPO via HFNC for more than 30 min to treat severe hypoxemia comorbid with pulmonary hypertension or right heart dysfunction between July 2015 and April 2018. A total of 11 subjects were enrolled in the study of whom 4 were male (36.4%), age 57.5 ± 22.1 years, and APACHE II score at ICU admission was 18.5 ± 5.7. Ten subjects had more than three chronic heart or lung comorbidities; seven of them used home oxygen. After inhaling epoprostenol, subjects’ SpO2/FIO2 ratio improved from 107.5 ± 26.3 to 125.5 ± 31.6 (p = 0.026) within 30–60 min. Five subjects (45.5%) had SpO2/FIO2 improvement >20%, which was considered as a positive response. Heart rate, blood pressure, and respiratory rate were not significantly different. Seven subjects did not require intubation, and seven subjects were discharged home. This retrospective study demonstrated the feasibility of iEPO via HFNC in improving oxygenation. Careful titration of flow while evaluating subjects’ response may help identify responders and avoid delaying other interventions. This study supports the need for a larger prospective randomized control trial to further evaluate the efficacy of iEPO via HFNC in improving outcomes.

No abstract

Background: Aerosol delivery via high-flow nasal cannula (HFNC) has attracted clinical interests in recent years. However, both HFNC and nebulization are categorized as aerosol generating procedures (AGPs). In-vitro studies raised concerns that AGPs had high transmission risk. Very few in-vivo studies examined fugitive aerosols with HFNC and nebulization via HFNC, and effective methods to mitigate aerosol dispersion are unknown.Method: Two HFNC devices (Airvo2 and Vapotherm) with or without a vibrating mesh nebulizer (VMN) were compared; HFNC alone, surgical mask over HFNC interface, and HFNC with face tent scavenger were used in a random order for nine healthy volunteers. Fugitive aerosol concentrations at sizes of 0.3-10 μm were continuously measured by particle sizers placed at one and three feet from participants. On a different day, six of the nine participants received six additional nebulizer treatments via VMN or small volume nebulizer (SVN) with mouthpiece with/without an expiratory filter or facemask. In-vitro simulation was employed to quantify inhaled dose with VMN via Airvo2 and Vapotherm.Results: Compared to baseline, neither HFNC device generated higher aerosol concentrations.Compared to HFNC alone, VMN via Airvo2 generated higher 0.3-1.0 μm particles (all p<.05) but VMN via Vapotherm did not. Concentrations of 1.0-3.0 μm particles with VMN via Airvo2 were similar with VMN and a mouthpiece/facemask but lower than SVN with a mouthpiece/facemask (all p<.05). Placing a surgical mask over HFNC during nebulization reduced 0.5-1.0 μm particles (all p<.05) to levels similar to the use of a nebulizer with mouthpiece and expiratory filter. In-vitro the inhaled dose with VMN via Airvo2 was 6 times higher than VMN via Vapotherm.

No abstract