The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

CAN ANYONE TELL ME THE OSCILLATORY TROUGH PRESSURE(OTP)?

Jeffrey W. Wright, Kevin Crezee; Respiratory Care, Primary Childrens Medical Center, Salt Lake City, UT

Introduction: From the beginning many users of the HFOV have wondered what pressures existed within the HFOV circuit during the ventilators negative deflection (OTP). An equation has been developed to determine the OTP of the operating HFOV. The formula is a variation of the Mean Airway Pressure equation (See equation block). Purpose: Test and authenticate the accuracy of the HFOV set parameters. Use multiple parameters on the HFOV to authenticate the accuracy of the OTP equation. Testing: To determine the actual OTP and the displayed settings of the CareFusion High Frequency Oscillatory Ventilator A model a Certifier FA Plus Test System by Trust Science Innovation was utilized. The HFOV A was assembled and performance/calibration completed. The Certifier FA Plus set-up, calibrated and adapted to monitor pressures at the temperature probe port at the patient wye on the HFOV circuit. Multiple ventilator parameters were manipulated to determine the accuracy of the OTP equation and the displayed settings of the HFOV. The MAP and AMP would remain constant as several HTZ rate and Bias flow changes were made. With each change the results were recorded. (See Data Table 1) The MAP and AMP would then be altered. Again, the MAP and AMP would remain constant while several HTZ rate and Bias flow changes were made. Results: It was verified that the AMP is Delta P within +- 2 cm in 98% of the displayed HFOV AMP tested. The average measured MAP was found to be about a 1/2 cm less that displayed set with the 2 HFOV A devices used in testing. The HTZ rate on average was found to be within 15 cycles per minute of set, although with the higher HTZ the gap was larger. (See Data Table 1) The OTP equation was shown to be accurate within 93.8% of the results being captured within +or - 1.5 cm of measured OPT. (See Data Table 2) Conclusion: The OTP equation is accurate to within 1.5 cm 93.8% of the recorded values, and the displayed values on the HFOV are accurate to an acceptable range. Sponsored Research - None