The use of the Laerdal infant resuscitator results in the delivery of high oxygen fractions in the absence of a blender

BACKGROUND: High oxygen increases morbidity and mortality. Current guidelines in Neonatal Resuscitation Programme (NRP) state if self-inflating bags are used with an input FiO2 of 1.0 without an oxygen reservoir a delivered safe FiO2 of approximately 0.40 is achieved. This conflicts with manufacturer findings (Laerdal infant resuscitator (LIR)). We assessed FiO2 delivery by the LIR, varying oxygen reservoir (OR) use, ventilation and input flowrates. METHODS: A test lung was connected to the LIR and oxygen analyzer. FiO2 delivery was measured under these four conditions: LIR plus OR and FiO2 1.0 or FiO2 0.40; LIR minus OR and FiO2 of 1.0 and 0.40. Variations of ventilation patterns in random order, assessed tidal volumes (from 20 and 40mL), ventilation rates (from 30, 40 and 60breaths/min), and input flowrates (from 1, 3, 5, 8, and 10Lpm). A wash-out period of 1min of ventilation was followed by measure of FiO2 during manual ventilation. RESULTS: The measured FiO2 with the LIR delivered the same source FiO2 under all experimental conditions for flowrates of 5Lpm and greater; irrespective of the OR presence or absence. At flowrates of 1 and 3Lpm, FiO2 was lower, with and without the reservoir, but the reservoir was visibly identified as not filled. CONCLUSION: Our findings support the manufacturers performance specification that high input FiO2 results in high delivered FiO2 with/without an OR. These results dispute the 2006 NRP guidelines that state "in the absence of a reservoir (oxygen) the delivered oxygen is reduced to about 40%".