The Science Journal of the American Association for Respiratory Care

2009 OPEN FORUM Abstracts


Joel M. Brown, John S. Emberger, Rozelle Clark, Victoria Weaver; Respiratory Care, Christiana Care Health System, Newark, DE

Background: Heliox is a therapeutic gas used for the improvement of respiratory distress and to reduce work of breathing in a variety of obstructive airway pathologies. Heliox is traditionally delivered via NRB mask but at times clinicians may be asked provide this gas mixture via mechanical ventilation. The most common concerns with heliox delivery via mechanical ventilation is portability and accurate delivery of volume. The LTV® 1200 (LTV)is a portable turbine driven ICU and transport ventilator that we have used at our facility for the past 3 years. In this study we wanted to determine if the LTV 1200 could accurately deliver Heliox. Method: This bench study was performed using a Michigan Instruments Inc. Dual Adult TTL test lung with the lung compliance set at 50 mL/cm H20 and a 5 cm H20/L/sec fixed airway resistor in line. The Novametrix NICO® Cardiopulmonary Management System (NICO) was used to obtain Vtexh, Insp flow, and PIP data at the test lung. The NICO was calibrated to monitor Heliox 70/30. We obtained a calculated Vtexh and Insp flow by multiplying the data found on the LTV patient monitoring screen by the heliox density factor of 1.6. Heliox 70/30 was supplied to the LTV ventilator via the high pressure oxygen inlet. A new ventilator circuit was used for each trial. The following ventilator setting were used: Volume Assist Control, RR=12, It= 1.0 second, PEEP=5. All data was collected at 6 different tidal volumes (300mL, 400mL, 500mL, 600mL, 700mL, and 800mL). Results: A total of 3 trials were completed with 3 different ventilator circuits. The calculated Vtexh had a direct correlation with the actual Vtexh (R2=0.998). The LTV PIP had a direct correlation with the actual PIP (R2=0.989). The calculated flow had a direct correlation with the actual flow (R2=0.991). The LTV delivered no false alarms and functioned within normal limits throughout the bench study. See Graph#1 for additional results. Conclusion: Our data indicates that the LTV can effectively deliver accurate Vtexh, Insp flow, and PIP when delivering Heliox 70/30 in volume controlled ventilation. Sponsored Research - None

Graph#1: This graph depicts the average values from the three trials. Vt (LTV1200)=Exhaled Vt read on the LTV monitor, Act Vt (NICO)= Exhaled Vt from the NICO at the test lung, Calc Vt (LTV Vt X 1.6)= Exhaled Vt calculated by multiplying the LTV monitor reading by 1.6.

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