Introduction: Intrapulmonary percussive ventilation (IPV) is an airway clearance therapy (ACT) that delivers high frequency, low tidal volume percussive breaths to facilitate lung recruitment, mobilize secretions, improve gas exchange, and treat and prevent atelectasis. While studies support its safety, efficacy, and benefit, few have described its impact on lung physiology during invasive mechanical ventilation (IMV). This study aims to assess the effect of IPV on lung compliance in a heterogeneous group of invasively ventilated children. We hypothesized that lung compliance would improve following a single treatment. Methods: This is an ongoing single center, prospective observational pilot study in a 37-bed PICU. Patients ≤18 years old on conventional IMV and receiving IPV as per the clinical team are eligible for inclusion. The primary outcome is dynamic compliance (Cdyn) and secondary outcome is static compliance (Cstat), whenever attainable. Subjects are enrolled within 24 hours of initiating IPV, and compliance is measured 15 minutes before, 15 minutes after, and 3 hours after a treatment. Results: This interim analysis includes 19 patients with a median age of 6.9 years. 21% were previously healthy, while the remainder had comorbidities, most commonly a neurologic disorder (53%). 11 had cuffed endotracheal tubes and 8 had tracheostomies (7 cuffed). 5 met criteria for pediatric acute respiratory distress syndrome (PARDS). 90% were prescribed additional ACTs, most commonly albuterol (88%), 3% saline (65%), and ipratropium (41%), and 53% were co-administered with IPV. There was no significant percent change from baseline Cdyn at 15 minutes (5.5%, p=0.246) or 3 hours (5.8%, p=0.353), nor was there a difference within the PARDS subgroup at 15 minutes (12.9%, p=0.125). We also found no difference in Cstat at 15 minutes (10.1%, p=0.25) or 3 hours (7.8%, p=0.50). Conclusions: This interim analysis does not show a significant improvement in lung compliance following a single IPV treatment in a heterogeneous group of invasively ventilated children, although differences may not have been detected due to small sample size. It is also possible that changes in compliance would be more appreciable with multiple IPV treatments over time.
Cummings et al. (Sun,) studied this question.