Ferreira JC, Chipman DW, Hill NS, Kacmarek RM.; Chest August 2009 136:448–456; published ahead of print May 8, 2009
Background: Noninvasive positive pressure ventilation (NPPV) modes are currently available on bi-level and ICU ventilators. However, little data comparing the performance of the NPPV modes on these ventilators is available.
Methods: In an experimental bench study the ability of 9 ICU ventilators to function in the present of leaks were compared to a bi-level ventilator using the IngMar ASL5000 lung simulator set at a compliance of 60 mL/cmH(2)O, inspiratory resistance of 10 cmH(2)O/L/s, expiratory resistance of 20 cmH(2)O/ L/s and a respiratory rate of 15 breaths/min. All ventilators were set at 12 cm H(2)O pressure support and 5 cm H(2)O PEEP. Data were collected at baseline and at 3 customized leaks.
Main results: At baseline, all ventilators were able to deliver adequate tidal volumes, maintain airway pressure and synchronize with the simulator, without missed efforts or auto-triggering. As the leak was increased, all ventilators (except the Vision and Servo i) needed adjustment of sensitivity or cycling criteria to maintain adequate ventilation and some transitioned to back-up ventilation. Significant differences in triggering and cycling were observed between the Servo i and the Vision.
Conclusions: The Vision and Servo i were the only ventilators that required no adjustments as they adapted to increasing leaks. There were differences in performance between these two ventilators, although the clinical significance of these differences is unclear. Clinicians should be aware that in the presence of leaks, most ICU ventilators require adjustments to maintain an adequate tidal volume.