Continuous high-frequency oscillation therapy in invasively ventilated pediatric subjects in the critical care setting

BACKGROUND: Continuous high-frequency oscillation (CHFO) creates a pressure gradient in the small airways that accelerates expiratory flow. The intended use of CHFO therapy is to facilitate secretion removal and treat atelectasis. Our objective was to assess the feasibility, safety, and efficacy of CHFO in the mechanically ventilated pediatric population. METHODS: After institutional review board approval, we retrospectively reviewed medical records of mechanically ventilated children treated with CHFO (the MetaNeb system) at our institution from July 1, 2007 through August 31, 2012. Patients supported with extracorporeal membrane oxygenation were excluded. We evaluated changes in ventilator settings in subjects with ventilator data documented within 6 h pre- and post-treatment. We evaluated arterial blood gas (ABG) results for individual treatments, comparing ABG results within 8 h pre-therapy to ABG results within 3 h post-treatment. Oxygen index and P_aO2/F_IO2 were calculated. Demographic data, blood pressure, heart rate, and development of new air leak while being treated with CHFO were recorded. Pre- and post-CHFO measurements were compared using Wilcoxon signed-rank testing. RESULTS: Our cohort included 59 invasively ventilated subjects. Median age was 2 y (range 1 month to 19 y), and median weight was 14 kg (2−81 kg). We evaluated data on 528 total treatments (range per subject 1−39 treatments). Peak inspiratory pressure significantly decreased with CHFO, whereas other parameters, including P_aCO2 and breathing frequency, remained stable. There was no significant change in systolic blood pressure, diastolic blood pressure, or heart rate following treatment with CHFO. One subject (2%) developed a clinically insignificant pneumothorax during CHFO. CONCLUSIONS: CHFO is feasible and seems safe in our cohort of mechanically ventilated pediatric subjects. The rate of pneumothorax was consistent with that seen in similar pediatric ICU populations. These preliminary results suggest that CHFO may be beneficial by improving lung compliance in pediatric subjects with secretion-induced atelectasis. Prospective clinical studies are needed to further evaluate the clinical efficacy and safety of CHFO in children receiving invasive mechanical ventilation.