Maximum FIO2 in minimum time depending on the kind of resuscitation bag and oxygen flow

Objective To analyze what FIO₂ can be reached, and how long it takes using the different autoinflated resuscitation bags and increasing oxygen flows.Design Experimental analysis on the effect of three different models of autoinflated resuscitation bag and increasing oxygen flows in the final FIO_2, and time spent to reach it.Setting Laboratory, with a gas analyzer and a lung simulator to measure inspired FIO₂.Interventions Simulated cardiopulmonary resuscitation. Three different autoinflated resuscitation bags were studied; A, the classic one with oxygen delivery directly into the bag, without reservoir, B, a new one without the reservoir device; and C, a new one with the reservoir device properly implemented. Increasing oxygen flows were administered until FIO₂ stabilized.Results With model A the maximum FIO₂ reached was 0.73 in 70 s using a 20 l/min oxygen flow. With model B the maximum FIO₂ reached was 0.65 in 90 s using a 20 l/min oxygen flow. The best FIO₂ (0.99) was reached using model C in 55 s with 12 l/min oxygen flow. In the three models a high correlation between oxygen flow and FIO₂ was found (r>0.8).Conclusions It is mandatory to use model C resuscitation autoinflated bag with 12 l/min of oxygen flow during the resuscitation maneuvers. Using another autoinflated bag model, maximum oxygen flows (i.e., 20 l/min) are needed. The resuscitation autoinflated bags showed less effectiveness when they were not properly assembled.