Adult ICU ventilators to provide neonatal ventilation: a lung simulator study

Traditionally, specific ventilators have been manufactured to only provide neonatal mechanical ventilation. However, many of the current generation of ICU ventilators also include a neonatal mode.

Using the IngMar ASL5000 lung simulator the Puritan Bennett 840, the Maquet Servo i, the Viasys AVEA, the GE Engström, the Drager Evita XL and Babylog 8000 Plus were evaluated during assisted ventilation in the pressure assist/control mode. Three lung mechanics were set: resistance 50 cmH(2)O/L/s, compliance 2 mL/cmH(2)O; resistance 100 cmH(2)O/L/s, compliance 1 mL/cmH(2)O; and resistance 150 cmH(2)O/L/s, compliance 0.5 mL/cmH(2)O. A maximum negative pressure drop of 4 and 7 cmH(2)O was achieved during simulated inspirations. Each ventilator was evaluated with PEEP 5 cmH(2)O, peak pressure 20 cmH(2)O and inspiratory time 0.3 s and with PEEP 10 cmH(2)O, peak pressure 30 cmH(2)O and inspiratory time 0.4 s. Each ventilator setting was then repeated with a leak of 0.3 L/min at a constant pressure of 5 cmH(2)O.

Overall each of the 5 ICU ventilators responded faster or greater than the Babylog with respect to: pressure to trigger (except the Servo i), time to trigger (except the Evita XL), time between trigger and return of pressure to baseline, time from start of breath to 90% of peak pressure (except the Avea) and pressure time product of breath activation. Expiratory tidal volume was also greater with all ICU ventilators except the Avea. Variation in mechanics, leak, PEEP and muscular effort had little effect on these differences.

All ICU ventilators tested were able to at least equal the performance of the Babylog 8000 Plus on all variables evaluated.