The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

COMPARISON OF MEAN EXPIRED CO2 MEASUREMENTS USING THE EVENT INSPIRATION 7I VENTILATOR VOLUMETRIC CAPNOGRAPHY VS THE RESPIRONICS NICO2 MONITOR.

Mark S. Siobal, Leo Bandian; Anesthesia, SFGH/UCSF, San Francisco, CA

Background: Calculation of VD/VT requires a mean expired CO2 (PeCO2) measurement. The eVent Medical Inspiration 7i ventilator is equipped with integrated volumetric CO2 monitoring and calculates PeCO2. We compared PeCO2 from the Inpsiration 7i Ventilator measurements and compared it to PeCO2 measurements from the Respironics NICO2 monitor during simulated ventilation. The Inspiration 7i ventilator evaluated was equpied with a PeCO2 feature not yet available use in the USA. Method: The Inpsiration 7i ventilator set to Vt = 500mL, RR = 10, PEEP = 10 cm H2O, Insp. Time = 0.75 sec., Insp. Flow = 50 L/min, and FiO2 = .50 was attached to a single chamber of a Michigan Instruments Test Lung. The ventilator flow sensor and mainstream CO2 sensor, and the NICO2 monitor combined CO2 / flow sensor were calibrated and attached between the ventilator circuit and test lung chamber. 100% CO2 bleed-in to the test lung chamber was adjusted until an end tidal CO2 (ETCO2) of 35 mm Hg was displayed on the NICO2 monitor. PeCO2 calculated by NICO2 monitor and PeCO2 calculated from the ventilator measurements were recorded. Ventilation of the test lung was then changed in increments of 1 L/min by increasing the RR by 2 breaths per minute increments up to a RR of 30. PeCO2 calculated by the NICO2 monitor and PeCO2 calculated from the ventilator measurements were recorded at each step after a 5 minute stabilization period. The proximal and distal position of the ventilator CO2 sensor, and the NICO2 combined CO2 / flow sensor were then reversed and the measurements were repeated. A total of 22 measurements were recorded and compared. Results: There was a very strong correlation between Inpsiration 7i ventilator and NICO2 monitor measurements of PeCO2 (r = 0.998, r squared = 0.996, p < 0.0001) with minimal bias and excellent precision (+ 0.5 ± 0.9 mm Hg). Conclusion: PeCO2 calculated by the Inpsiration 7i ventilator are in strong agreement with PeCO2 measurements from the NICO2 monitor during simulated ventilation. In-vivo comparison of the two PeCO2 measurements needs to be validated. Sponsored Research - None