The Science Journal of the American Association for Respiratory Care

1997 OPEN FORUM Abstracts

LABORATORY EVALUATION OF THE PRESSURE AND VOLUME DELIVERY OF THE INTRAPULMONARY PERCUSSIVE VENTILATOR (IPV).

Robert S. Campbell RRT, James J. Lawson* RRT, Richard D. Branson RRT, Jay A. Johannigman MD, Fred A. Luchette MD, Kenneth Davis Jr. MD. Department of Surgery, University of Cincinnati Medical Center, Cincinnati, OH; * Respiratory Care Department, Kettering Medical Center, Kettering, OH.

BACKGROUND: The Intrapulmonary Percussive Ventilator (IPV) (Percussionaire Corp) is a pneumatic positive pressure device used to enhance secretion clearance and recruit lung volume. IPV utilizes a sliding venturi to create a percussive (pulsatile) flow waveform at a frequency between 100 and 240 cycles per minute at driving pressures (DP) of 20 to 50 psig. We evaluated the pressure and volume delivery of the IPV in a lung model. METHOD: An IPV was powered with 50 psig source gas and connected to one chamber of test lung (TTL, Michigan Instruments) via a simulated trachea (imatrach, Mallinckrodt). TTL settings included compliance (C) of 0.03 and 0.06 L/cmH_{2}O and resistance (R)of 5 and 20 cmH_{2}O/L/sec. The DP of the IPV was set to 30, 40, and 50 psig with "percussion" set at 50% of the scope of the control. Pressure was measured proximal to the trachea and within the test lung and volume was integrated from the flow signal measured between the trachea and test lung using a Fleisch pneumotach. Peak lung pressure, pressure amplitude in the proximal airway, time (T) to attain a pressure equilibrium in the lung, and tidal volume (V_{T}) were measured and recorded. Breaths were manually actuated for 10 seconds and 5 breaths at each setting were averaged. P and V_{T} at each DP were compared using ANOVA, p < 0.05 was considered significant. Results: Table 1 reveals the P, T to pressure equilibration, and V_{T} at C (0.03) and R (20) at each DP tested. Mean pressure amplitude in the proximal airway was 40.3, 28.7, and 23.4 cmH_{2}O with DP of 50, 40, and 30 psig, respectively.

Table 1

50 psig 40 psig 30 psig

P (cmH_{2}O) 21.3 ± 1.3 16.1 ± 1.2* 10.0 ± 1.1*#

T to equil (sec) 5.9 ± 0.5 5.1 ± 0.4 3.7 ± 0.3*#

V_{T} (mL) 750 ± 46 536 ± 34* 323 ± 31*#

*=p < 0.05 vs. 50 psig, # =p < 0.05 vs. 40 psig

CONCLUSION: Pressure delivery to the lung during IPV is within a safe and clinically acceptable range at all DP tested. Delivered V_{T} is dependent on set DP and lung C and varies only slightly with changing R. T to pressure equilibrium increases as R, DP, and C increase. Actuation times of greater than 5 seconds are recommended to attain maximal volume recruitment.

OF-97-131

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