The Science Journal of the American Association for Respiratory Care

2011 OPEN FORUM Abstracts

PERFORMANCE OF FOUR VENTILATOR CIRCUITS, A BENCH STUDY.

Matthew Davis, Maria Madden, Pete Saunders; Respiratory Care, UMMC/Shock Trauma, Nottingham, MD

BACKGROUND Ventilator circuit compressibility and compliance varies between circuits. These values create compressible volume loss and may adversely affect ventilator performance. METHODS & MATERIALS The four ventilator circuits used were: Airlife Volume Ventilator, Fisher & Paykel Evaqua, Maquet non-compliant and a heated non-complaint circuit. The two ventilators used were: Maquet Servo-I and Drager Evita XL. We measured compressibility by setting tidal volume to 200 mL, flow of 40LPM, turning the high pressure alarm to max, occluding the end of the patient wye and then cycling the ventilator. Compressibility = Volume/pressure. We then used the drager circuit test for compliance and resistance values. The circuits were attached to a maquet rubber test lung and run through a series of test. We also added a five pound weight to the test lung to simulate decreased lung compliance. CONCLUSION The two non-compliant circuits had better compressibility and circuit compliance values however the change in volume delivered was not clinically significant. The ventilator circuits did not affect the time constants, work of breathing or measured compliance values.The changes in inspiratory and expiratory airway resistance were nominal. The authors of this abstract believe further research is needed to prove whether ventilator circuit compliance affects patient outcomes.
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