2007 OPEN FORUM Abstracts
EFFICIENCY OF HUMID-FLO, A HEAT AND MOISTURE EXCHANGER, WHEN OPERATOR ERROR OCCURS
M. E. Badescu1, T. A. Volsko1, R. L. Chatburn2
INTRODUCTION: Increased resistive work of breathing may occur when a heat and moisture exchanger (HME) becomes obstructed by excessive moisture or airways secretions. The objective of our investigation was to determine the performance characteristics of a new HME with a mode of operation that allows aerosolized medication to be delivered while the device is inline with the ventilator circuit. We hypothesize that resistance through the HME will increase if medicated aerosol therapy is administered when the device is not placed completely in the aerosol delivery mode.
Methods: Constant flow was delivered through the HME at rate of 10 â 50 L/min in aliquots of 10 L/min. Resistance was measured with a u-manometer at baseline and after the administration of a series of six aerosol treatments with normal saline. To evaluate the presence of autoPEEP the HME was placed inline with a standard single limb ventilator circuit, attached to a double lung simulator. The ventilator was operated in the assist control mode and set to deliver a tidal volume of 500 mL. Measurements were obtained at mandatory rates of 10, 15 and 20 breaths per minute. The test lung was set for a compliance of 63 ml/cmH2O and airways resistance of 20 cmH2O/L/sec. Data for autoPEEP measurements were obtained at baseline and after each of the six bland aerosol treatments in the series. Data were analyzed using Excel, and SPSS 9.0. Mean values for resistance were compared by one-way analysis of variance (ANOVA). Statistical significance was established at 0.05.
Results: No difference was noted, p = 0.541, when the mean baseline values for resistance were compared to values obtained after aerosol administration. No autoPEEP was detected.
Conclusions: No significance increase in autoPEEP and resistance in mechanically ventilated patients when operator error occurred and aerosol therapy was administered inline with the Humid-flo HME.