PERFORMANCE OF PEDIATRIC RESUSCITATION BAGS ASSESSED WITH AN INFANT LUNG SIMULATOR

Many pediatric self-inflating bags are equipped with pressure relief (pop-off) valves to prevent barotrauma. We participated in a resuscitation in which a valve malfunction briefly caused inadequate ventilation. The pop-off valve was seated in an intermediate position between open and closed settings. To investigate this problem, we assessed the performance of several commonly used pediatric self-inflating bags using an infant lung simulator (D, B & M, Redlands, CA). Bags were deflated using a range of inspiratory times (T(I)), delivered tidal volumes, peak proximal airway pressure (P(p)), and peak distal pressure (lung pressure, P(d)). When the pop-off valve was set in the open position, P(p) ranged from 42 cm to 105 cm H2O, although P(d) never exceeded 45 cm H2O. The mean difference between P(p) and P(d) decreased from 14.2 +/- 1.1 cm H2O at T(I) = 0.2 s to 6.1 +/- 0.5 cm H2O at T(I) = 1 s. Inflation of all DMR (disposable) and PMR (nondisposable) bags in the intermediate valve position produced marked air leakage through the valve, with delivered tidal volumes of only 92 +/- 13 mL (DMR) for T(I) < 0.5 s, and unrecordable tidal volumes (< 50 mL) for both DMR and PMR self-inflating bags for T(I) > 0.6 s. A wide range of delivered tidal volumes was observed among all bags examined. We conclude that both DMR and PMR bags can be placed inadvertently in an intermediate valve position that can produce disastrous hypoventilation during resuscitation. Properly positioned pop-off valves are efficient in limiting P(d) to less than 45 cm H2O, despite P(p) measurements in excess of 60-100 cm H2O. Despite nominal delivered tidal volumes set by the manufacturers, a very high variability in delivered tidal volumes was observed among all bag brands.