Newborn self-inflating manual resuscitators: precision robotic testing of safety and reliability

A controlled bench test was undertaken to determine the performance variability among a range of neonatal self-inflating bags (SIB) compliant with current International Standards Organisation (ISO).

Use of SIB to provide positive pressure ventilation during newborn resuscitation is a common emergency procedure. The United Nations programmes advocate increasing availability of SIB in low-income and middle-income nations and recommend devices compliant with ISO. No systematic study has evaluated variance in different models of neonatal SIB.

20 models of SIB were incrementally compressed by an automated robotic device simulating the geometry and force of a human hand across a range of precise distances in a newborn lung model. Significance was calculated using analysis of variance repeated measures to determine the relationship between distance of SIB compression and delivered ventilation. A pass/fail was derived from a composite score comprising: minimum tidal volume; coefficient of variation (across all compression distances); peak pressures generated and functional compression distance.

Ten out of the 20 models of SIB failed our testing methodology. Two models could not provide safe minimum tidal volumes (2.5-5 mL); six models exceeded safety inflation pressure limit >45 cm H₂O, representing 6% of their inflations; five models had excessive coefficient of variation (>30% averaged across compression distances) and three models did not deliver inflation volumes >2.5 mL until approximately 50% of maximum bag compression distance was reached. The study also found significant intrabatch variability and forward leakage.

Compliance of SIBs with ISO standards may not guarantee acceptable or safe performance to resuscitate newborn infants.