Background: Intrapulmonary percussive ventilation (IPV) provides benefits promoting pulmonary hygiene, treating secretion-related atelectasis, and potential alveolar recruitment in clinical practice. Similar to IPV, continuous high-frequency oscillation (CHFO) delivers high-frequency minibursts of gas during mechanical ventilation and benefits intubated patients from pulmonary hygiene and alveolar recruitment. The concerns of potential lung injury from higher volume or pressure delivery limit the application of IPV or CHFO in clinical practice. Thus, the purpose of this study is to compare patient-ventilation interaction and pressure delivery between IPV and CHFO superimposed on mechanical ventilation. Methods: An Active Servo Lung 5000 (ASL 5000) simulator was programmed to simulate a pediatric patient (resistance of 60 L/min/s and compliance of 9 mL/cm H2O) with maximal muscle pressure of 10 cm H2O connected to a ventilator on pressure-controlled continuous mandatory ventilation with set-point targeting scheme (PC-CMVs) mode superimposed on IPV or CHFO device. Asynchrony index (AI) was calculated by total asynchrony events divided by total breaths over the 10-min experiments. Peak inspiratory pressure (PIP), mean airway pressure (MAP), auto-PEEP, inspiratory tidal volume (VTi), and expiratory tidal volume (VTe) were recorded and analyzed. Results: 348 breaths and 933 breaths were recorded in the IPV group and the CHFO group, respectively. PIP, MAP, auto-PEEP, VTi, and VTe at baseline were 19.71 ± 0.05 cm H2O, 9.73 ± 0.03 cm H2O, 1.80 ± 0.04 cm H2O, 66.13 ± 0.96 mL, and 66.13 ± 1.24 mL, respectively. Mean VT errors ranged from -96% to 998% in two groups. Calculated AI in the IPV group and the CHFO group were 0.6% and 62.5% respectively. PIP, MAP, and autoPEEP in both groups were significantly higher than values at baseline. VTi, and VTe in both groups were significantly lower than values at baseline. MAP and auto-PEEP were significantly higher in the IPV group than in the CHFO group. Conclusions: High VT errors were reported when applying high-frequency airway clearance techniques superimposed on mechanical ventilation. Compared to mechanical ventilation along, both IPV and CHFO superimposed on mechanical ventilation delivered higher MAP, and autoPEEP. Although CHFO led to more asynchrony events, IPV maintained higher MAP and autoPEEP than CHFO, which might be more beneficial in alveolar recruitment. Further investigation will be needed for the effects of secretion movements.
Liu et al. (Sun,) studied this question.