Background: Intrapulmonary percussive ventilation (IPV) provides benefits of promoting pulmonary hygiene, treating secretion-related atelectasis, and potential alveolar recruitment in clinical practice. Recently, continuous high-frequency oscillation (CHFO) has been introduced with a similar mechanism in IPV, which provides high-frequency minibursts of gas delivery to loosen and mobilize secretions in patients with mechanical ventilation. There is limited evidence on effectiveness of secretion mobilization in IPV or CHFO superimposed with mechanical ventilation. The purpose of this bench study is to compare the effectiveness of IPV or CHFO in secretion movement during pediatric mechanical ventilation. Methods: A breathing simulator, Active Servo Lung 5000 (ASL 5000), a was programmed to simulate a pediatric patient with passive breathing connected to a 4-mm endotracheal tube (ETT) and a ventilator on pressure-controlled continuous mandatory ventilation with set-point targeting scheme (PC-CMVs) mode superimposed on IPV or CHFO device. 0.2 mL of secretion simulant was instilled into the mid-portion of the ETT marked at 9-11 cm. Each experiment was performed for 10 min and repeated 10 times for control, IPV, and CHFO group. After each experiment among three groups, the direction and minimal distance of secretion movement between pre- and post-trial, and the range of secretion distribution were recorded and analyzed. Results: Overall, all three groups moved the direction of secretion movement toward to the simulator. The lengths of secretion dispersion were 5.60 5.30-6.08 cm in the control group, 8.65 8.30-9.25 cm in the IPV group, and 6.95 6.50-7.05 cm in the CHFO group (P < .001). The minimal displacements of secretion were 0.95 0.875-1.50 cm in the control group, 0.40 0.30-0.60 cm in the IPV group, and 0.50 0.28-0.73 cm in the CHFO group (P < .001). However, there was no significant difference on the minimal displacement of secretion between the IPV group and the CHFO group. Conclusions: In the pediatric patient with positive pressure ventilation model, all three groups moved the secretion blocked in the ETT toward to the lower airway. Compared to the control group, both IPV and CHFO groups had less minimal displacement of secretion toward to the lower airway. IPV may have a better effect in airway clearance than CHFO.
Liu et al. (Sun,) studied this question.