2007 OPEN FORUM Abstracts
EVALUATION OF CONTINUOUS POSITIVE PRESSURE DEVICES WITH A PRESSURE RELEASE OPTION
L. Haan1, S. Woodland1, L. Johnatakis1
Background: Traditional CPAP machines deliver a continuous set pressure during inspiration and expiration. Newer machines that allow for a decrease in pressure at the onset of expiration are now being used; the algorithm for this pressure change varies by manufacturer. This decrease in pressure was evaluated on two different machines, each set at three different CPAP levels and each of the optional pressure release levels. The Respironics Remstar Pro C Flex (C Flex) has a pressure drop at the start of expiration based on expiratory flow and the C-Flex setting. ResMed S8 Elite with EPR (EPR) uses three comfort levels to determine the degree by which pressure will drop, in cm H2O, throughout expiration.
Method: The C Flex and the EPR were attached to the Hans Rudolph Electronic Breathing Simulator (HR 1101). HR 1101 settings: resistance 10 cm H2O/L/sec; compliance 20 mL/cm H2O; respiratory rate 12 breaths per minute; amplitude 5 cm H2O; target volume 3000 mL. EPR and CFlex settings: CPAP 5, 10 and 15 cm H2O with C Flex and EPR settings of 1, 2 and 3 at each CPAP setting. The low pressure was averaged over 5 breaths.
Machine, CPAP pressure setting, C-Flex or EPR setting, average low pressure. Respironics Remstar Pro CFlex 5 cmH20,1, 4.3 cmH20; ResMed S8 Elite EPR 5 cmH20,1, 3.9 cmH20; CFlex 5 cmH20, 2, 4.0 cmH20; EPR 5 cmH20, 2, 3.9 cmH20; CFlex 5 cmH20, 3, 3.7 cmH20; EPR 5 cmH20, 3, 3.9 cmH20; CFlex 10 cmH20, 1,9.5 cmH20;EPR 10 cmH20, 1, 9.6 cmH20; CFlex 10 cmH20,2, 8.9 cmH20; EPR 10 cmH20, 2, 9.8 cmH20; CFlex 10 cmH20,3, 8.5 cmH20; EPR 10 cmH20, 3, 9.8 cmH20; CFlex 15 cmH20, 1, 14.6 cmH20; EPR 15 cmH20, 1, 14.7 cmH20; CFlex 15 cmH20, 2, 14.5 cmH20; EPR 15 cmH20, 2, 14.7 cmH20: CFlex 15 cmH20, 3, 14.1cmH20; EPR 15 cmH20, 3, 14.7 cmH20.
Conclusion: The two CPAP machines resulted in different averaged low pressures during the expiratory phase despite the test settings being the same. Some of the pressure release settings make little or no difference. The differences may be due to the way the two different algorithms respond.