Lab Evaluation of Pulmonetic Systems LTV Ventilator with the Datex-Ohmeda INOvent

Background: At our institution we used inhaled nitric oxide (INO) to treat hypoxia and pulmonary hypertension. Most of these patients are on mechanical ventilation. When mechanically ventilated patient requires transportation within the medical center they are frequently placed on the LTV (Pulmonetic Systems, Colton, CA) portable ventilator. The purpose of this study is to determine the effects of using the INOvent (Datex-Ohmeda, Madison, WI) in conjunction with the LTV. We tested for differences in set vs. Indicated volumes, and effects on trigger sensitivity.

Methods: Tidal volume accuracy was investigated by placing a pneumotach (Novametrics VenTrack) between the patient "Y" and a 2 chamber TTL (Michigan Instruments). Inspired and expired volumes were recorded from the VenTrack as well as displayed exp. volumes from the LTV. Volumes from both sources were plotted out on a graph for comparison. Triggering was assessed by attaching the LTV to one side of a double chamber lung with a Puritan Bennett 840 driving the other chamber. Patient effort was simulated by a lift bar on the drive chamber lifting the driven side. Sensitivity levels of 2.4 and 6 lpm, at doses of 0, 5 15, 20, 40, 60 and 80 ppm NO and without the INOvent attached were tested. The flow was measured by placing the VenTrack flow sensor in the expiratory limb of the circuit and identified as the maximum negative deflection immediately before the start of inspiration.

Results: Measured volumes on the VenTrack and LTV correlated well throughout the range of NO doses tested. Volumes increased proportionate to the NO dose. Measured triggering was up to 2 lpm above the set point throughout the range of variables tested. This was easily compensated for by adjustment of the flow trigger.

Conclusions: Our preliminary testing found the LTV ventilator to be compatible with the INOvent.