Low versus high gas flow rate for respiratory support of infants at birth: a manikin study

Abstract

Background: Neonatal resuscitation guidelines do not specify the gas flow rate during mask ventilation.

Aim: Investigating the effect of gas flow rates on pressures, volumes delivered and mask leak.

Methods: Flow 5 and 10 liters/min were tested. In study part 1, pressure ranges were measured when ventilating an intubated manikin with a Neopuff®. In study part 2, pediatric staff mask-ventilated a manikin (peak inflation pressure (PIP) 30 cm H(2)O, positive end expiratory pressure (PEEP) 5 cm H(2)O). We measured pressures, expired tidal volume (V(Te)) and mask leak.

Results: Study part 1:an intubated manikin was ventilated with flow 5 versus 10 liters/min: range in PEEP was 0.4-3.6 and 2-14 cm H(2)O, respectively, maximum PIP was 73 cm H(2)O with both flow rates. Study part 2: when mask ventilation was given with flow 5 versus 10 liters/min: leak decreased (24% (8-85) vs. 80% (34- 94); p < 0.0001), V(Te) increased (6.7 (5.1-7.8) vs. 4.7 (2.4-7.0) ml; p < 0.001), PEEP decreased (3.1 (0.8) vs. 3.7 (0.7) cm H(2)O; p < 0.001), PIP was similar (28.1 (2.7) vs. 28.0 (2.3) cm H(2)O; NS). Large leaks decreased V(Te) and PEEP during both flow rates, PIP only with flow 5 liters/min.

Conclusion: A low flow rate during neonatal mask ventilation may be a good alternative approach in reducing mask leak, provided that inflation time and flow rate warrants set pressures. Only large leaks seem to influence delivered pressures and volumes. Before resuscitation guidelines are advised, more studies on gas flow rates are needed.