Differences in Ventilator Performance Characteristics and Patient Response

Gerald Moody, Respiratory Care Practitioner, Children’s Medical Center Dallas


Gerald Moody, RRT

In our facility we use two homecare/subacute ventilators, the LTV 1200 and Trilogy 202. We noticed differences in how patients respond clinically between them when applying the exact same ventilator settings. In addition, we noticed that patients transitioning from critical care ventilators to the LTV 1200 and Trilogy 202 ventilators would fail and be placed back on critical care ventilators. We believe that this was due to the equipment not the patient.

To prove this, we bench tested the LTV and Trilogy to compare the accuracy of exhaled Tidal Volume (Vt) readings on each ventilator against delivered Vt as read by the ASL 5000™ Breathing Simulator. We learned that there was large discrepancy of delivered Vt’s between the two ventilators with the identical ventilator settings and that the Trilogy was actually under delivering Vt’s compared to what it was reading/displaying. This correlated with our clinical findings.

The results of our study were presented at the 2013 AARC conference and our abstract, “Accuracy of Exhaled Tidal Volume (Measured and Estimated) of Two Subacute/Homecare Ventilators in Simulated Neonate/Infant Model” received the “2013 Philips Respironics Fellowship in Mechanical Ventilation Award.” Poster Presentation

Additionally, to learn more about the different performance characteristics between these two ventilators, we also tested the effects of rise time settings on peak inspiratory pressures. The results of our tests, “Effects of Rise Time on Peak Inspiratory Pressure of Two Subacute/Home Care Ventilators in a Simulated Neonate/Infant Model” were presented at the 2014 AARC Conference.

Having the ASL 5000 at our disposal enabled us to verify what we suspected clinically and has given us data to prove to our providers and staff that ventilator settings can not simply be transposed from one ventilator to another and be expected to generate the same ventilatory results. It has also allowed us to gain a better understanding of the performance variances and characteristics of our homecare/subacute ventilators.

Having this knowledge has given us the ability to make appropriate ventilator adjustments depending on which ventilator the patient uses. Clinically this translates to faster transition to homecare/subacute ventilators, decreased length of stay, and a higher awareness that a patient’s increased work of breathing may be due to differences in ventilator variances and performance rather than an acute illness or patient condition.