RELIABILITY AND RESPONSE TIME OF THREE PATIENT TRIGGERED INFANT VENTILATORS

Abstract

We compared the reliability and response time (RT) of three patient triggered infant ventilators in 10 healthy adult rabbits. Ventilation was randomly assigned to a Bear Cub Enhancement Module (CEM), Infrasonics star Sync, and Draegar Babylog 8000 in both the synchronized intermittent mandatory ventilation (SIMV) and assist-control (A/C) modes. All studies were repeated at ventilator flow rates of 6 and 12 1pm, and at 3 sensitivity settings (except Star sync). Rabbits were lightly anesthetized and tracheostomized; airway flow and pressure, and pleural pressure were recorded. RT was measured from the start of each spontaneous breath to the onset of each triggered ventilator breath (N=250±50 breaths). Ventilator breaths occurring >200 msec after the start of spontaneous breaths or during early expiration were considered trigger failures and were excluded from analysis for RT. RT (mean±SD) and failure rate at maximum sensitivity and 12 1pm were compared by ANOVA: RT of each ventilator was the same at 6 and 12 1pm in both modes. RT of star Sync was shorter than Bear CEM, and Bear CEM was shorter than Babylog on both modes (p<.01). Decreasing trigger sensitivity by 2 settings increased RT of both Bear CEM and Babylog by 60%. The Babylog failed consistently on SIMV but not at all on A/C.