Comparison of two ventilator circuits for Dräger Babylog high-frequency ventilation.
OBJECTIVE
The Dräger Babylog 8000plus ventilator (Dräger Medical Systems, Lübeck, Germany) can provide both conventional and high-frequency ventilation (HFV). Dräger recommends specific circuits for each of these modes. We investigated the performance of the Babylog ventilator in HFV mode when used with the recommended circuits for both conventional and HFV.


METHODS
The Fisher and Paykel RT235 (conventional; Fisher and Paykel Healthcare, Auckland, New Zealand) and Hytrel (HFV; Fisher and Paykel Healthcare) circuits were studied using a 50-mL test lung. Tidal volume, high-frequency minute volume and ventilator alarms were compared at 100 combinations of mean airway pressures (10-16 cm H₂O), frequencies (6-14 Hz) and amplitudes (20-60%).


RESULTS
Tidal volume with the two circuits differed by < 5% for tidal volumes ≤ 2.5 mL. Above this, tidal volumes delivered with the HFV circuit were up to 15% more than that obtained with the conventional ventilation circuit, and high-frequency minute volume differed by up to 30%. With the exception of the highest tidal/minute volumes, the tidal volume delivered using the HFV circuit could also be achieved with adjusted frequency or amplitude when using the conventional circuit. More 'pressure measurement out of range' alarms were noted with the conventional ventilation circuit, particularly at mean airway pressure ≥ 14 cm H₂O and frequency ≤ 10 Hz.


CONCLUSIONS
The conventional ventilation circuit may allow delivery of adequate tidal volume for some infants. Where requirements are higher, the HFV circuit allows the Babylog to deliver higher tidal volumes and higher minute volume, and reduce alarms.
Newborn Services, Royal Women's Hospital Monash, Melbourne, Victoria, Australia. kevin.wheeler@thewomens.org.au
Kevin I
KI
Wheeler
Gregory P
GP
Moore
Colin J
CJ
Morley
Peter G
PG
Davis
D004867:Equipment Design; D006612:High-Frequency Ventilation / Q000295:instrumentation*; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D013990:Tidal Volume