Implementation and feasibility of inverse-ratio Airway Pressure Release Ventilation (APRV): Switching from Conventional Ventilation to APRV in Two French ICUs.

Abstract

Background:To evaluate the switching of patients mechanically ventilated on Pressure Support or Volume Control to inverse-ratio Airway Pressure Release Ventilation (APRV) during the COVID-19 pandemic.Methods:We performed a single-center retrospective observational analysis in two ICUs in a tertiary referral university teaching hospital in France. Were included patients with Covid-19 pneumonia requiring invasive ventilation with a PaO2:FiO2 ratio lower than 200 mmHg who performed a 6-hour trial of inverse-ratio APRV.Results:Seventeen consecutive patients who completed a 6-hour APRV trial in April 2020 were included. Three patients who were unable to be maintained on APRV due to an immediate fall in SpO2 were not included. In 12/17 patients (71%), the increase in PaO2:FiO2 ratio was greater than 20%. Mean (± standard deviation) PaO2:FiO2 ratio increased from 126 (± 28) mmHg to 178 (± 53) mmHg after 6 hours of APRV (p<0.001). Two patients presented a decrease in PaO2:FiO2 ratio after 6 hours of APRV. There was no appearance of significant hemodynamic impairment during APRV and an eventual increase in PaCO2 during the first hour of APRV was managed by increasing the respiratory rate (i.e. shortening T-high) and/or increasing tidal volume (i.e. increasing T-low).Conclusions:Switching from Conventional Ventilation (Pressure Support or Volume Assist Control) to inverse-ratio APRV for a 6-hour period in two ICUs that were not previously familiar with this ventilation technique was well tolerated, and associated with a marked improvement in oxygenation. Further studies evaluating inverse-ratio APRV in acute respiratory failure are warranted.Trial registration:NCT04386369

Airway Pressure Release Ventilation for Acute Respiratory Failure Due to Coronavirus Disease 2019: A Systematic Review and Meta-Analysis

“…Only three of the seven included studies 17,20,21 specified their APRV protocol. All of them adapted a personalised approach for setting T low using expiratory flow curve (Table 2).…”

“…Five studies 17,[20][21][22][23] were included in the analysis of PaO 2 / FiO 2 ratio and four studies 17,[21][22][23] were included in the analysis of PaCO 2 . Compared to CMV, APRV was associated with a 33% increase in PaO 2 /FiO 2 ratio (RoM, 1.33; 95%CI, 1.21-1.48; I², 29%) (Figure 5) and a 9% decrease in PaCO 2 (RoM, 0.91; 95% CI, 0.85-0.98; I², 0%) (Figure 6).…”

“…In CMV, a superimposed negative pleural pressure can add to the transpulmonary pressure leading to a significant end-inspiratory stress and hence ventilator induced lung injury. Ibarra-Estrada 17 Jain 18 Zorbas 19 Joseph 20 Koszutski 21 Mahmoud 22 Sathyanarayanan 23 Study The use of other rescue therapies like inhaled pulmonary vasodilators (IPVDs) and prone positioning is another variable which can affect the outcome, but unfortunately was not consistently applied across studies. In ARDS, early prolonged prone positioning improved mortality, 27 while IPVDs improved oxygenation with no reduction of mortality.…”

“…Unfortunately, only three studies followed an APRV protocol. 17,20,21 Koszutski et al 21 and Joseph et al 20 mentioned basic training and intensivists' expertise as studies' limits.…”

“…Of 181 articles screened, seven studies with a combined population of 354 patients satisfied the inclusion criteria (Figure 1), including one RCT, 17 two cohort studies, 18,19 and four beforeafter studies with no control group. [20][21][22][23] All studies were conducted in 2020, including one pre-print 21 and two conference abstracts. 18,23 The authors of the abstracts responded to our request for further details, with one provided us with the full text of the unpublished manuscript.…”