Comparison of airway pressure release ventilation (APRV) versus biphasic positive airway pressure (BIPAP) ventilation in COVID-19 associated ARDS using transpulmonary pressure monitoring.

BACKGROUND

APRV has been used for ARDS in the past. Little is known about the risk of ventilator- induced lung- injury (VILI) in APRV vs. BIPAP in the management of in COVID19-associated ARDS (CARDS). This study aimed to compare transpulmonary pressures (TPP) in APRV vs. BIPAP in CARDS in regard to lung protective ventilator settings.

METHODS

This retrospective, monocentric cohort study (ethical approval: 21-1553) assessed all adult ICU- patients with CARDS who were ventilated with BIPAP vs. APRV and monitored with TPP from 03/2020 to 10/2021. Ventilator-settings / -pressures, TPP, hemodynamic and arterial blood gas parameters were compared in both modes.

RESULTS

20 non- spontaneously breathing patients could be included in the study: Median TPPendexpiratory was lower / negative in APRV (-1.20mbar; IQR - 4.88 / +4.53) vs. positive in BIPAP (+ 3.4mbar; IQR + 1.95 / +8.57; p < .01). Median TPPendinspiratory did not differ. In APRV, mean tidal- volume per body- weight (7.05 ± 1.28 vs. 5.03 ± 0.77 ml; p < .01) and mean airway- pressure (27.08 ± 1.67 vs. 22.68 ± 2.62mbar; p < .01) were higher. There was no difference in PEEP, peak-, plateau- or driving- pressure, compliance, oxygenation and CO2- removal between both modes.

CONCLUSION

Despite higher tidal- volumes / airway-pressures in APRV vs. BIPAP, TPPendinspiratory was not increased. However, in APRV median TPPendexpiratory was negative indicating an elevated risk of occult atelectasis in APRV- mode in CARDS. Therefore, TPP- monitoring could be a useful tool for monitoring a safe application of APRV- mode in CARDS.