The Science Journal of the American Association for Respiratory Care

1998 OPEN FORUM Abstracts

LABORATORY EVALUATION OF TWO TRANSPORT VENTILATORS

Teresa A. Volsko, BS, RRT, Robert L. Chatbum, RRT, Enrique R. Grisoni, MD University Hospitals Health Systems, Cleveland, Ohio

INTRODUCTION: Mechanical ventilators are often used during transport of critically ill patients. It has been suggested that transport ventilators should deliver stable tidal volumes (within 10% of set) in the face of changing pulmonary mechanics, to ensure adequate ventilation (Resp Care 1992;37:775-795). The purpose of this study was to determine if the transport ventilators evaluated met this criterion under both low and high load conditions.

Methods: Two transport ventilators, the Hamilton Max and Biomed Crossvent 4 were evaluated. A single compartment lung model (TTL, Michigan Instruments) was used to simulate high load (C = 0.02 L/cm H_{2}O, R = 20 cm H_{2}O/L/s), and low load (C = 0.1 L/cm H_{2}O, R = 5 cm H_{2}O/L/s) conditions. The model was disconnected for the baseline no load condition. The same standard nondisposable patient circuit was used on each ventilator. To measure V_{T} delivery, a Bicore flow transducer was placed inline between the TTL and ventilator circuit, after calibration verification with a 500 mL syringe. For each set V_{T} (0.05 L, 1.0 L and 1.5 L) three measurements were obtained for each load. Acceptable performance was judged as volume delivery within 10 % of target. Results: The results for each combination of V_{T} and load are shown in the figure (mean values only, standard deviation too small to show on scale). Dotted lines represent accuracy intervals defined as ┬▒ 10 % of target volume.

(See original for figure)

Conclusions: Both ventilators performed acceptably under no load and low load levels. The Hamilton Max ventilator did not perform within the defined limits at high load. Exhaled V_{T} monitoring during transport may be indicated to ensure adequate V_{T} delivery in patients with low compliance and/or high resistance.

The 44th International Respiratory Congress Abstracts-On-Disk®, November 7 - 10, 1998, Atlanta, Georgia.

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