Chest
Original ResearchCritical Care MedicineBilevel vs ICU Ventilators Providing Noninvasive Ventilation: Effect of System Leaks: A COPD Lung Model Comparison
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Materials and Methods
Nine ICU mechanical ventilators and one bilevel ventilator (Table 1) were compared using the ASL5000 lung simulator (IngMar Medical; Pittsburgh, PA) with increasing system leaks. The ASL5000 is a computerized lung simulator consisting of a piston moving inside a cylinder.13 Compliance, resistance, and the inspiratory muscle pressure profile (negative pressure created by respiratory muscles) are set by the user.
Each ventilator evaluated was connected to the ASL5000 by the manufacturer's standard
Baseline Performance
The trigger pressure was smaller for the Esprit, Vision (Respironics), Vela, PB840 (Puritan Bennett; Boulder, CO), and Raphael (Hamilton Medical AG; Rhazuns, Switzerland) ventilators than for the other ventilators (Fig 3). Trigger pressure was greater for the Servo I (Maquet; Solna, Sweden), e360 (Newport), e500, and e500 auto. The time to trigger was shortest for the Esprit (approximately 100 ms) and longest for the iVent (VersaMed; Pearl River, NY) and Esprit Auto-Trak (approximately 160 ms) [
Discussion
The main findings of this study are as follows: (1) at baseline, all ventilators were able to deliver adequate tidal volume, maintain airway pressure, and synchronize with the simulator, without missed efforts or auto-triggering; (2) as the leak was sequentially increased, all ventilators, except for the Vision and the Servo I, needed adjustment of sensitivity and/or inspiratory termination criteria to maintain synchrony, and some ventilators transitioned to backup ventilation; and (3) the
Acknowledgments
Author contributions: All authors contributed to the design of the study, the evaluation of the results, and the writing of the manuscript. Data gathering was primarily preformed by Dr. Ferreira and Mr. Chipman. Data analysis was primarily preformed by Dr. Ferreira.
Financial/nonfinancial disclosures: Dr. Kacmarek has received research grants and honorariums for lecturing from Hamilton Medical, Puritan-Bennett Corp, Respironics Inc. Cardinal Medical, Drager Medical, Newport, and Maquet Medical
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Funding/Support: This study was partially funded by an unrestricted grant from Respironics Inc. Dr. Ferreira was partially funded by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil.
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