High Frequency Percussive Airway Clearance Utilizing Two Devices in Simulation of Mucous Clearance, Without Spontaneous Breathing, Both With and Without Mechanical Ventilation

Abstract

Background: Several devices exist today for high frequency percussive AWC for invasive and noninvasive patients. Despite several existing devices and some relatively new devices on the market, there were no current bench comparisons. This comparison used 10 mL of simulated mucous (SM) in a balloon, with a 7.5 endotracheal tube connected to Hill-Rom’s Volara and IPV-2C both with and without mechanical ventilation, to look at secretion removal.

Methods: We weighed the balloons with 10 mL of SM (95.5% water with 0.5% TIC Xanthan Gum Fastir) and the rubber band, using a Torbal AGCN200 scale. The Volara was set to Medium CHFO, Peak pressure (PIP) set to 30 cm and CPAP set to 5 cm H₂O. The Volara circuit was attached to the top of the endotracheal tube with the SM-filled balloon attached at the bottom, past the Murphy eye. A rubber band secured it in place. The endotracheal tube was upright and close to a 90 degree angle leading down to the balloon. 6 mL of NSS was nebulized during AWC. After 10 min, the balloon, rubber band, and remaining SM was removed and weighed for comparison on the 4 set-ups. This same process was followed for the IPV-2C. The IPV-2C was set to a high frequency rate of 230 breaths/min with PIP that ranged from 27–30 cm. This information was determined using the pressure line from Percussionaire VDR with measurements displayed on the monitor. We then repeated the steps above for Volara and IPV-2C in-line with the ventilator circuit. Both devices were on the inspiratory limb of an RT380 circuit directly before the Y-piece. Ventilator settings were AC pressure control, set RR 20, PEEP 8 cm H₂O, and total PIP 25 cm.

Results: The SM-filled balloon and rubber band used for the Volara without ventilator weighed in at 11.9785 g. After therapy, it weighed 9.8765 g for a removal of 17.54% of total weight. The SM-filled balloon and rubber band used for the IPV-2C without ventilator weighed in at 11.8604 g. After therapy, it weighed 4.5131 g for a removal of 61.94% of total weight. The SM-filled balloon and rubber band used for the Volara with ventilator weighed in at 11.8067 g. After therapy, it weighed 11.2285 g for a removal of 4.89% of initial weight. The SM-filled balloon and rubber band used for the IPV-2C with ventilator weighed in at 12.2069 g. After therapy, it weighed 5.4525 g for a removal of 55.33% of initial weight.

Conclusions: The Volara with similar settings as the IPV-2C, did not removed as much SM as the IPV-2C did in this bench study. This was true with both invasive ventilation as well as no invasive ventilation.