Gas Delivery During Adult Patient Triggered Mechanical Ventilation in New Generation ICU Ventilators

Abstract

Background: New generation ICU ventilators frequently enter the market. To determine the performance of these ventilators they need to be compared to established ICU ventilators. In this study we compared the gas delivery capabilities of the new Nihon Kohden 550 ventilator (NKV 550) to that of the Medtronic PB980 and the Drager V500 ventilators. We hypothesized that if these ventilators were optimally set in pressure support ventilation there would be no differences in trigger response, pressurization time and volume delivery. Methods: Evaluations were performed with the IngMar ASL 5000 computerized lung simulator using a dry circuit and the Fisher & Paykel RT380 adult ventilator circuit. The ASL 5000 was set to simulate normal, COPD and ARDS lung mechanics with two ventilatory drives 1.7 and 6.7 cm H₂O and inspiratory times varying from 500 to 900 milliseconds, ms. Ventilator trigger sensitivity, rise time and termination criteria were optimally set. Each ventilator was set to deliver 5/5, 10/5 and 15/10 cm H₂O pressure support above PEEP. A total of 18 trials were conducted on each ventilator. Each trial lasted 2 min. The last 10 breath of each trial were analyzed. Trigger time (TT, ms), max pressure to trigger (MaxTrigP, cm H₂O), time to max trigger pressure (T-Tpress, ms), trigger pressure time product (PTP, cm H₂O -ms) time to 90% of peak pressure (T90, ms), and tidal volume (V_T, mL) were compared among ventilators using ANOVA for repeated measures. Potentially important clinical differences were defined as a P < .001 and >10% difference among ventilators. Results: Potentially clinically important differences were identified among all variables except tidal volume(see table). Variables differed among ventilators with a P < .001 and >10% difference except for tidal volume. These differences were a result of increased time to trigger during COPD lung mechanics and a low ventilatory drive. Both independently increased time to trigger (data not shown). Conclusions: There are clinically important difference in the performance of the NKV 500, PB 980 and V500 ventilators during adult pressure support ventilation. Disclosures: Robert Kacmarek is a consultant for Medtronic’s and Orange Medical and has received research grants from Medtronic’s and Venner Medical. All other authors report no conflict of interest