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.