The Science Journal of the American Association for Respiratory Care
INTRODUCTION: Intrapulmonary Percussive Ventilation (IPV) is a therapy designed to re-expand areas of atelectasis, facilitate removal of secretions, increase aerosol particle deposition, and improve gas exchange. This study was a follow-up to our previous pilot data showing that IPV was associated with improvement in atelectasis. Our purpose was to test the hypothesis that IPV, when given via artificial airway, is superior to chest physiotherapy (CPT; clapping and vibration) in improving atelectasis and static compliance.
Methods: We enrolled 13 subjects from our Pediatric Intensive Care Unit who were intubated and mechanically ventilated and who had radiographic evidence of atelectasis. Atelectasis was quantified from routine chest radiographs by two blinded observers (radiologist and physician) using an ordinal scale as follows: 4 = complete collapse of two or more segments or lobes, 3 = complete collapse of one segment or lobe, 2 = partial collapse of two or more segments or lobes, 1 = partial collapse of one or segment or lobe and, 0 = complete resolution of collapse. Patients with fever or positive secretion cultures were excluded. Patients were randomized to conventional chest physiotherapy (CPT; clapping and vibration) or IPV (Intrapulmonary Percussionator Ventilator, IPV-1, F.M. Bird Corp). IPV treatments were given with 6 mL normal saline solution at 15-30 cm H20 (equal to peak pressures on the ventilator) using frequencies of 180-220 cycles per minute. Both treatments were delivered every four hours and lasted about 10 minutes. Static compliance (pre and post treatment) was measured with a CO2SMO+ (Novametrix Medical Systems Inc.) using an inspiratory hold to obtain plateau pressure during mechanical ventilation (using a Siemens Servo 900C) with tidal volumes of 6-10 mL/kg. Differences in median values were compared with the Mann-Whitney Rank Sum Test with significance set at p
Results: The median age of patients in the study was 3.1 years (range 1.5 months to 14 years). ET tube size ranged from 3.0 uncuffed to 7.0 cuffed, but 4.0 uncuffed was most common. The median duration of treatment for CPT was 7 days (range 4-8); median duration for IPV was 2.5 days (range 2-14). No side effects of either treatment were noted in any patient. Data below are reported as medians:
|Compliance (cm H2O)||2.4||2.0||0.55||5.0||5.3||0.72|
CONCLUSION: This controlled clinical trial has shown that IPV is associated with a significant and clinically important improvement in atelectasis, whereas conventional CPT is not. Neither treatment improved respiratory system compliance. IPV is a safe and effective method of airway clearance that can be used on patients with artificial airways and seems to be superior to conventional clapping and vibration.