Changing gas flow during neonatal resuscitation: a manikin study.

INTRODUCTION

When using a T-piece device, resuscitators may try to improve airway pressures by increasing gas flow instead of correcting face mask position.

AIM

To measure the effects of changing gas flow during positive pressure ventilation (PPV) on peak inspiratory pressure (PIP), positive end expiratory pressure (PEEP), expiratory tidal volume (V(Te)) and mask leak.

METHODS

Using a Neopuff T-piece device, 20 neonatal staff members delivered PPV to a modified, leak-free manikin. Resuscitation parameters were recorded. Study A: PPV for 4 min at PIP 30 cm H(2)O and PEEP 5 cm H(2)O. Each minute gas flow was increased (5, 8, 10, and 15 L/min). PIP and PEEP settings were unchanged. Study B: same pressure settings; PPV for 1 min with 5, 8, 10, and 15 L/min in a random order, at a rate of ∼ 60/min. The pressures were adjusted to maintain the same PIP and PEEP after each flow change.

RESULTS

Study A: As gas flow increased (5, 8, 10 and 15 L/min) the median PEEP increased from 4.7 to 26.4 cm H(2)O (p<0.002). Median V(Te) decreased from 10.0 to 0.8 mL (p<0.001). PIP increased slightly from 30 cm H(2)O to 36 cm H(2)O at 15 L/min (p<0.005). Mask leak increased from 14% to 98% (p<0.001) because mask pressure increased. Study B: when PIP and PEEP were maintained there were no significant differences in V(Te) (p=0.42) or mask leak (p=0.51) with changing gas flow.

CONCLUSION

During PPV increasing gas flow dramatically increased PEEP and mask leak and in consequence reduced V(Te). Gas flow should rarely be changed during T-piece resuscitation.