Fig. 1
From: The 30-year evolution of airway pressure release ventilation (APRV)
Comparison of APRV pressure waveforms. Artistic depiction of airway pressure waveforms, all of which were defined as APRV, illustrating the significant variability in what has been defined as an APRV breath. Stock in 1987 used 60 % CPAP with TLow of 1.27 s and a respiratory rate (RR) of 20 [2]. Davis in 1993 used a similar %CPAP, but decreased the RR by prolonging THigh and TLow [3]. Gama de Abreau in 2010 simulated conventional ventilation with a prolonged TLow and short THigh [4]. Finally, Roy in 2013 used a very brief adaptive TLow and large THigh with 90 % CPAP [5]. Of note, though the ventilator pressure is set at zero, this does not reflect true pressure as the brief TLow prevents full deflation of the lung, and thus prevents end-expiratory pressure from reaching zero. Figures a–c are examples of fixed-APRV (F-APRV) and figure d of personalized APRV (P-APRV)