Delivery of titrated oxygen via a self-inflating resuscitation bag

Aim

To investigate whether titration of inspired oxygen can be achieved through adjustment of oxygen flow into a self-inflating resuscitation bag with a reservoir of a type used in standard ambulance practice.

Methods

In a series of bench experiments, oxygen was delivered via a flow metre to a 1500 ml self-inflating resuscitation bag with a 2500 ml reservoir bag and connected to a test lung. The oxygen concentration delivered to the test lung by manual inflation of the resuscitation bag was measured using an anaesthetic machine while the delivered tidal volume was measured using a respirometer. The delivered oxygen concentration was measured at flows of 0.5, 2, 6, 12 and 15 l min⁻¹ for tidal volumes of 300, 600, and 900 ml with bag inflation rates of 10, 20 and 30 min⁻¹.

Results

A wide range of delivered oxygen concentrations ranging between 24% and 99.5% were achieved with different oxygen flows, tidal volumes, and inflation rates. Overall, the mean delivered oxygen concentration increased significantly with each of the increments of oxygen flow tested (p < 0.001 for all comparisons).

Conclusions

Effective titration of oxygen delivery can be achieved using adjustment of oxygen flow with a standard self-inflating resuscitation bag and reservoir.