The Science Journal of the American Association for Respiratory Care

2001 OPEN FORUM Abstracts

A COMPARISON OF TWOHOME CARE CPAP SYSTEMS FOR MANAGEMENT OF INFANTS WITH TRACHEAL AND/OR BRONCHIALMALACIA

Tom Blackson, BS, RRT, ChristianaCare Health System, John Rendle, AS, RRT, Tim Cox, BS, RRT, A.I. DuPont Hospitalfor Children

Purpose: The purpose of thisstudy was to evaluate two CPAP systems used for the home care management ofan infant population of patients with airways compromised due to tracheal and/orbronchial malacia.

Design: A bench model wasdeveloped using a drive ventilator to power one side of a Michigan test lungin order to simulate the breathing pattern of an infant. The drive side of thetest lung was connected via the manufacturer supplied ?bar? to slave the patientside to the drive side of the test lung. A 3.7 mm ID tracheostomy tube, alongwith a #20 parabolic resistor, was used on the patient side of the test lungin order to simulate a common artificial airway size and a ?best circumstance?airway resistance. The patient side of the lung simulator mimicked a patientbreathing at a respiratory rate of 30 breaths/min and a tidal volume of 50 ml.Four CPAP levels, (2.5, 5.0, 7.5, and 10.0 cm H2O), were used forthe comparison. Two different flow generators were employed, (device #1 &#2). The same external PEEP valves were used for both device evaluations. Afree flow, zero PEEP, circuit was used as the control for each CPAP device.Values for total circuit flow, tidal volume, peak flow, minute volume, and extrinsicPEEP were obtained at each experimental PEEP level and control condition. Arepresentative sample of the data collected is shown below for the extremesof PEEP settings as well as for the zero PEEP control.

Device #1

CircuitFlow L/min

VTexpired Patient mlMVPatient L/min PIFPatient L/minPEEPSet cm H2O PEEPmonitor cm H2O
37.9 low 391.213.100.38
79.5 high24 0.810.102.75
30.6 low 471.414.12.52.5
53.6 high42 1.313.32.52.9
35.8 low 421.313.010.0 10.7
46.3 high38 1.112.310.010.9

 

Device #2

CircuitFlow L/min

VTexpired Patient mlMVPatient L/min PIFPatient L/minPEEPSet cm H2O PEEPmonitor cm H2O
12.9 Low 40 1.213.3 0 0
30.7 high 40 1.213.400

12.5 low

50 1.513.9 2.52.4

28.1 high

611.815.2 2.5 1.6

2.4 low

521.6 13.810.07.8

11.6 high

46

1.4 12.5 10.09.8

Conclusion: Selection ofa home CPAP device may produce different patient responses despite standardizationof the PEEP valve and patient drive to breathe. This may result in clinicallysignificant differences in gas exchange and lung mechanics in the patient populationin question. Further evaluation is indicated.

OF-01-216

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