Minute Ventilation Limitations of Two Field Transport Ventilators

Knowledge of transport ventilator performance impacts patient safety. This study compared minute ventilation (V_E) of the MOVES and Uni-Vent 731 when ventilating the VentAid Training Test Lung with compliance (C) ranging from 0.02 to 0.10 L/cm H₂O and three different airway resistances (R) (none, Rp5, or Rp20). Tidal volume (V_T) was 800 ± 25 mL. Respiratory rate was increased to ventilator's maximum or until auto-PEEP > 5 cm H₂O. Respiratory parameters were recorded with the RSS 100HR Research Pneumotach. Data were reported as median (interquartile range). Peak inspiratory pressure (PIP) of the Uni-Vent and MOVES ranged from 22.3 (22.2-22.5) to 82.6 (82.2-83.2) and 20.8 (20.6-20.9) to 50.6 (50.2-50.9) cm H₂O, respectively. V_E of the Uni-Vent and MOVES ranged from 17.7 (17.7-17.7) to 31.5 (31.5-31.5) and 11.3 (10.5-11.3) to 20.2 (19.7-20.5) L/min, respectively. Linear regression demonstrated strong, negative correlation of V_E with PIP for the MOVES (V_E [L/min] = 26 - 0.31 × PIP [cm H₂O], r = -0.97) but weak, positive correlation for the Uni-Vent (r = 0.05). Uni-Vent V_E exceeded MOVES V_E under each test condition (p = 0.0002). If patient V_E requirements exceed those predicted by the MOVES regression equation, then using the Uni-Vent should be considered.