The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

A NOVEL METHOD FOR INTEGRATING A LUNG ANALOG INTO A CADAVER FOR RELIABLE VOLUME MEASUREMENT DURING POSITIVE-PRESSURE MASK TESTING.

Andrew J. Mazzoli1, Phillip Coule2; 1Respiratory Therapy, Medical College of Georgia, Augusta, GA; 2Emergency Medicine, Medical College of Georgia, Augusta, GA

BACKGROUND: The cadaver model is frequently used to simulate live subjects. However, large, repetitive tidal volumes can alter or damage the lungs, thus altering performance characteristics. Lung analogs allow for reliable repetitive volume changes with little or no alteration in the system, but lack anatomical similarity to live subjects. We describe a novel integration of a lung analog into a cadaver to gain the advantages of both in positive-pressure mask testing. METHOD: To test two different types of positive pressure masks in the cadaver model while reliably measuring volumes delivered and leaked, the authors integrated a Michigan Instruments TTL, (Grand Rapids, MI) into a fresh, un-embalmed cadaver through the use of a retrograde tracheostomy technique. A tracheotomy was performed and a #8 endotracheal tube was placed with the distal tip directed cephalad toward the larynx. The tube was then sutured in place and the incision was closed tightly around the tube. The cuff was inflated and checked for leaks. The proximal end of the endotracheal tube was directed toward the lateral chest taped in place (See Figure 1). Tubing was attached to the 15 mm adapter and then to a vane-type spirometer. Another piece of tubing was used to attach the spirometer to the lung analog. Nineteen volunteers tested both an intra-oral and a conventional mask on the face of the cadaver. Tidal volumes of .5 L, 1.0 L, and 1.5 L were delivered to the masks by a ventilator set on volume control at a rate of twenty breaths per minute for two minutes. A total of at least 4,560 breaths were delivered to the integrated model. RESULTS: The masks were applied to the face of the cadaver by the volunteers with varying degrees of success, in keeping with what would be expected in the live subject. Volume delivered to the lung analog and volume leaked past the masks were easily and reliably observed. The cadaver was returned to the anatomy laboratory, minimally altered, to be used for future study. CONCLUSION: This novel approach provided the advantages of both the cadaver and the lung analog in positive-pressure mask testing. This approach may be valuable in testing other devices that are applied to the face or upper airway where volume measurement is important. Although not measured in this study, adapters could easily be placed in-line to measure pressure in this model. This technique might also prove suitable for use in the animal model. Sponsored Research - NuMask Intraoral masks were supplied by NuMask, Inc. for use in the study mentioned in this abstract. Figure 1.