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

To analyze what FIO2 can be reached, and how long it takes using the different autoinflated resuscitation bags and increasing oxygen flows.

Experimental analysis on the effect of three different models of autoinflated resuscitation bag and increasing oxygen flows in the final FIO2, and time spent to reach it.

Laboratory, with a gas analyzer and a lung simulator to measure inspired FIO2.

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.

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).

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.