The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts


Mark S. Siobal, Leo Bandian, Marwa El Marsafawy, Earl Mangalindan; Anesthesia, SFGH/UCSF, San Francisco, CA

Background: Ventilation with Heliox is available on several ventilator platforms. The rate of heliox cylinder gas consumption is dependent on minute ventilation, the concentration of helium being delivered, and the internal function of the ventilator. We compared heliox cylinder duration using the eVent Medical Inspiration 7i Ventilator to the Viasys Avea Ventilator Method: A single chamber of a Michigan Instruments Test Lung set to a compliance of 60 mL/cm H20 was used with a 7.5 mm endotracheal tube and a R50 resistor. Ventilators were connected to the test lung and set to deliver a Vt = 600mL, RR = 10/min, PEEP = 5, inspiratory flow = 60 L/min with a square wave flow pattern, bias flow of 2.5 L/min, and a FiHe of 70%. E-cylinders of 80/20 heliox were used for the testing. Prior to each test the cylinder pressure was recorded from the digital pressure gage of the heliox cylinder regulator. Each test was timed and ended when the ventilator alarmed for low heliox cylinder pressure. Three full E-cylinders of 80/20 heliox were tested on each ventilator. Results: Cylinder pressures varied between 1500 to 2000 psi therefore the sum of the pressures from the three cylinders varied between 5300 and 5000 psi for the Inspiration 7i and Avea respectively. The sum of the run time minutes from the three test were 177 and 45 minutes, the average cylinder duration was 59 and 15 minutes, and the average cylinder pressure drop was 30 and 111 psi/min for the Inspiration 7i and Avea respectively. Conclusion: Heliox gas consumption determined by cylinder pressure drop is reduced by a factor of 3.7 and cylinder duration is increased by a factor of 3.9 using the eVent Inspiration 7i versus the Viasys Avea during invitro bench testing. Sponsored Research - None