2005 OPEN FORUM Abstracts
Evaluation of the SureVent Emergency Transport Ventilator
Mark Babic, R.R.T.1, Richard Branson, M.S., R.R.T.2, James K. Stoller, M.D., M.S., F.A.A.R.C.1 1Cleveland Clinic Foundation, Cleveland, Ohio 2University of Cincinnati, Cincinnati, Ohio
Background: In the context of disaster planning for emergency room management, we have recently evaluated a low-cost emergency transport ventilator, the SureVent (Vortran Medical Technology 1, Sacaramento, California).
Methods: The SureVentventilator was evaluated using a Michigan Test Lung (Michigan Instruments, Grand Rapids, Michigan) and an air compressor for the gas source. Airways were simulated using 3 endotracheal tubes (8.0 mm inner diameter) and settings were varied for lung compliance (from 0.1 to 0.2 liters/cm H2O), liter flow (15 liters/min, 20 liters/min, and 40 liters/min) and pressure (20 cm H2O and 30 cm H2O). On the SureVent, liter flow, pressure, and compliance settings determine respiratory rate, tidal volume, and autoPEEP. Tests were conducted with the SureVent set at the lowest and highest achievable respiratory rates.
Results: The graphs summarizes the measured respiratory rate, tidal volume, and autoPEEP produced by various combinations of flow rate, driving pressure, and lung compliance. Notably, as lung compliance decreased, autoPEEP increased. Due to limitations with the Michigan Test Lung, we were unable to obtain data when the SureVent was set at 30 cmH2O and lung compliance at 0.1 L/cmH2O. The tidal volumes at these setting were greater than 2 liters. In making the measurements, we observed that movement of the ventilator was occasionally associated with its stopping or suddenly altering the measured tidal volume (by up to 100 ml).
Conclusions: Our findings identify several shortcomings of the SureVent ventilator, including: 1. Erratic cessation of operation that is position-dependent, 2. Marked variation in tidal volume and autoPEEP when lung compliance was changed, and a concomitant change in the flow rate. While these shortcomings must be understood in the context of the low-cost, low-technology nature of the SureVent ventilator, the variation in tidal volume and autoPEEP with use recommends caution and vigilance for adverse effects of mechanical ventilation, even in disaster management circumstances.