The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

MECHANICAL VENTILATORS IN THE HOT ZONE: EFFECTS OF A CBRN FILTER ON PATIENT PROTECTION AND BATTERY LIFE.

Thomas Blakeman1, Dario Rodriquez2, Peter Toth1, Richard Branson1; 1Department of Surgery, University of Cincinnati, Cincinnati, OH; 2Center for Sustainment of Trauma and Readiness Skills (CSTARS), Cincinnati, OH

Introduction: In a contaminated environment, respiratory protection for ventilated patients can be achieved by attaching a chemical, biological, radiological, or nuclear (CBRN) filter to the air intake port of the ventilator. We evaluated the effect of a CBRN filter on battery duration and patient protection of four ventilators (CareFusion LTV-1000, Impact 754 and 731, and Newport HT-50) in the laboratory. Methods: Each ventilator was attached to a test lung. Ventilator settings were; assist control (AC) mode, respiratory rate 35 bpm, tidal volume 450 ml, positive end-expiratory pressure (PEEP) 10 cm H2O, inspiratory time 0.8 seconds, and FIO2 0.21. Each ventilator was operated with and without the filter until the battery was fully discharged. We also evaluated the ventilators’ ability to route all gas through the CBRN filter during simulated breath triggering and analyzed the pressures required to breathe through the anti-asphyxiation valve of a failed device. Results: The range of battery life varied widely across different ventilator models (99.8 – 562.6 minutes). There was no significant difference in battery life (p < 0.01) when operating with or without the CBRN filter attached. The difference in battery duration for the devices with and without the filter: LTV-0.4 min., Impact 754-3.6 min., Impact 731- 4.1 min., and HT 50-10.9 min. The peak negative pressure required to breathe though the failed device was -4 cm H2O to -9 cm H2O. Only the Impact 731 routed all inspired gases through the CBRN filter when patient demand outstripped inspiratory flow. Figure below shows gas inspired through the anti-asphyxia valve in a CO2 rich environment demonstrating entrainment of room air during normal ventilation operation. Conclusions: Duration of operation from the internal battery was not altered by attachment of the CBRN filter. The use of a CBRN filter is necessary for protection of ventilated patients when environmental contamination is present, although conditions exist where all gas does not pass through the filter with some ventilators under normal operating conditions, leaving the patient’s airway exposed to the contaminated environment. Sponsored Research - None