The Science Journal of the American Association for Respiratory Care

2011 OPEN FORUM Abstracts

TIDAL VOLUME PRECISION DURING NEONATAL VOLUME-TARGETED, SPONTANEOUS MODES WITH A LARGE ETT LEAK IN AN ERRATICALLY BREATHING INFANT LUNG MODEL.

Rob DiBlasi, Kendra Smith, Dave Crotwell, John Salyer; Seattle Children's Hospital, Seattle, WA

BACKGROUND: Volume-targeted spontaneous modes of ventilation are gaining acceptance for use in premature infants to provide consistent tidal volume (VT) delivery. We evaluated 4 commonly used neonatal ventilator's ability to maintain target VT with changes in patient breathing patterns and respiratory effort with a large ETT leak. We hypothesized there would be no difference in the delivered VT between ventilator brands under these conditions. METHODS: Three each of 3 brands of neonatal ventilators were tested and a single unit of a fourth brand, using respective volume-targeted spontaneous modes, including: 1) GE Carestation; 2)PB 840(N=1); 3) Drager VN500; and 4) Carefusion Avea (Machine volume and new Prototype mode). The ventilators were set at VT=5 mL, Back-up RR 40 breaths/min, PEEP 5 cmH2O, and FIO2 0.21 and gases were humidified at 37 degree C for twenty minutes prior to testing. When available, the ventilator was set to limit excessive volume delivery at 125-130% of the set VT. The Ingmar ASL 5000 ventilator was configured using a customized breath sequence (n=155) consisting of erratic, spontaneous and apneic breathing patterns coupled with ongoing changes in mechanics and breathing effort. Each ventilator was attached to the ASL 5000 with a 2.5 mm ID endotracheal tube. Breath to breath VT delivery was measured using ASL software version 3.2 for the entire breath sequence. Customary descriptive statistics were calculated for delivered VT including coefficient of variation. Mean differences between brands were tested for statistical significance using ANOVA with significance established as P < 0.05. The precision of VT delivery was calculated using coefficient of variation (CV). RESULTS: Figure 1 shows the descriptive statistics and distribution of delivered tidal volumes for all ventilators tested. There were significant differences reported between ventilator brands (p < 0.01) and we would characterize these performance differences as clinically important. CONCLUSION/DISCUSSION: There may be clinically relevant differences in these neonatal volume-targeted, spontaneous breathing modes that are based on how well the ventilator measures tidal volume and regulates inspiratory pressure to achieve a tidal volume target in the presence of a large endotracheal tube leak Sponsored Research - Some of the ventilators provided for this study were done so by GE, Covidien, and Drager.