Airway Pressure Release Ventilation in Acute Respiratory Failure Due to COVID-19: No Role, We Still Need More Data

The authors reply

“…Our results are consistent, as the median P-high was less than 24 cm H 2 O only after day 5, whereas median time of NMB use in APRV was just 57 hours. Contrary to the suggestion of Cheng et al ( 1 ), the proportion of patients receiving NMB in APRV group was not higher than in control group; total time of use was also similar ( 2 ). Consistent with recent guidelines for NMB use in patients with acute respiratory distress syndrome ( 4 ), we aimed to limit NMB to less than or equal to 48 hours; we consider as moot the comparison between our NMB protocol and 9 days of NMB in four of 114 patients (3.5%) of an observational study ( 5 ).…”

“…Cheng et al ( 1 ) suggests our protocol may prolong mechanical ventilation because we assessed readiness to wean when P-high less than or equal to 12 cm H 2 O, unlike their own study in which the P-high criterion was 20 cm H 2 O. However, they reduced P-high bid, whereas we attempted to reduce it thrice daily as tolerated.…”

“…Along our 10 years of experience with APRV, we have also witnessed the phenomenon of “apparent cure,” which consists of rapid improvement in oxygenation leading to a premature decrease of support by clinicians before alveoli have healed, resulting in derecruitment again, as described by Rola et al ( 6 ). This is the reason our weaning protocol is more gradual than suggested by Cheng et al ( 1 ). Therefore, we suspect that the main driver of ventilation length is the speed of lung improvement.…”

“…Based on our center’s prior experience directly measuring the P L , we acknowledged that excessive spontaneous breaths (SBs) during P-high could result in high P L , potentially amplifying lung damage ( 2 ). However, Cheng et al ( 1 ) assume we indicated neuromuscular blocking (NMB) in every case while P-high greater than or equal to 24 cm H 2 O, but this is incorrect. There is no reason to suspect a P L higher than P-high in the absence of SB.…”

“…We thank Cheng et al ( 1 ) for their interest in our study ( 2 ), published recently in Critical Care Medicine , about airway pressure release ventilation (APRV) in patients with COVID-19. It is worth to note that some points had been already addressed in the article ( 2 ).…”