The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

EFFECTS OF BYPASS HEAT-AND-MOISTURE EXCHANGER ON AEROSOL OUTPUT DURING MECHANICAL VENTILATION.

Andy Doan, David Chang; University of South Alabama, Mobile, AL

BACKGROUND: Bypass heat-and-moisture exchanger (BMHE) has been used to administer small-volume nebulizer (SVN) therapy to mechanically ventilated patients. Unlike the traditional heat-and-moisture exchanger (HME), BHME does not require disconnection of the ventilator circuit for in-line SVN therapy. The purpose of this study was to determine the effectiveness of BHME for administering medicated aerosol therapy via a mechanical ventilator. METHODS: IRB approval was not needed for this bench study. A ventilator (PB-7200) was set up in the laboratory using a volume-controlled mode at a tidal volume of 600 mL, frequency of 15/min, PEEP of 5 cm H2O, peak flow of 60 L/min, FIO2 of 21%. An SVN was connected to a Tee-piece 14” away from the test lung on the inspiratory side of the ventilator circuit. For the experimental data, a BHME was placed between the wye adaptor and the test lung. One unit dose of albuterol sulfate was placed in the SVN running at an air flow rate of 8 L/min. Nebulization continued for one minute after the SVN began to sputter. For the control data, the BHME was removed and the steps followed the similar procedure. Data collection included 10 separate trials on the experimental and control groups. The weight differences of filters for the control and experimental groups were used for t-test analysis. DATA: For the control group without BHME, The mean weight differences for the control (withour BHME) and experimental (with BHME) groups was 0.112 g and 0.09184 g, respectively. The t-test on these 10 pairs of data showed no significant differences (p < 0.05 level). CONCLUSIONS: The aerosol output with a BHME does not show significant difference in comparison to the setup without an HME. Since the BHME allows SVN therapy without breaking the circuit, it should be considered an advantage for mechanically ventilated patients requiring HME and SVN therapy, especially in conditions of high airway pressures or PEEP. Sponsored Research - None