TY - JOUR T1 - Variability of Tidal Volume in Patient-Triggered Mechanical Ventilation in ARDS JF - Respiratory Care DO - 10.4187/respcare.05415 SP - respcare.05415 AU - Sophie Perinel-Ragey AU - Loredana Baboi AU - Claude Guérin Y1 - 2017/08/01 UR - http://rc.rcjournal.com/content/early/2017/08/01/respcare.05415.abstract N2 - BACKGROUND: Limiting tidal volume (VT) in patients with ARDS may not be achieved once patient-triggered breaths occur. Furthermore, ICU ventilators offer numerous patient-triggered modes that work differently across brands. We systematically investigated, using a bench model, the effect of patient-triggered modes on the size and variability of VT at different breathing frequencies (f), patient effort, and ARDS severity.METHODS: We used a V500 Infinity ICU ventilator connected to an ASL 5000 lung model whose compliance was mimicking mild, moderate, and severe ARDS. Thirteen patient-triggered modes were tested, falling into 3 categories, namely volume control ventilation with mandatory minute ventilation pressure control ventilation, including airway pressure release ventilation (APRV); and pressure support ventilation. Two levels of f and effort were tested for each ARDS severity in each mode. Median (first-third quartiles) VT was compared across modes using non-parametric tests. The probability of VT > 6 mL/kg ideal body weight was assessed by binomial regression and expressed as the odds ratio (OR) with 95% CI. VT variability was measured from the coefficient of variation.RESULTS: VT distribution over all f, effort, and ARDS categories significantly differed across modes (P < .001, Kruskal–Wallis test). VT was significantly greater with pressure support (OR 420 mL, 95% CI 332–527 mL) than with any other mode except for variable pressure support level. Risk for VT to be > 6 mL/kg was significantly increased with spontaneous breaths patient-triggered by pressure support (OR 19.36, 95% CI 12.37–30.65) and significantly reduced in APRV (OR 0.44, 95% CI 0.26–0.72) and pressure support with guaranteed volume mode. The risk increased with increasing effort and decreasing f. Coefficient of variation of VT was greater for low f and volume control-mandatory minute ventilation and pressure control modes. APRV had the greatest within-mode variability.CONCLUSIONS: Risk of VT > 6 mL/kg was significantly reduced in APRV and pressure support with guaranteed volume mode. APRV had the highest variability. Pressure support with guaranteed volume could be tested in patients with ARDS. ER -