Oxygen delivery using self-inflating resuscitation bags.

OBJECTIVE

Oxygen-filled self-inflating resuscitators are used by some as a source of oxygen for spontaneously breathing patients. In this application, the bag is not compressed and oxygen is assumed to flow freely from the patient outlet through a mask positioned loosely over the patient's face. We tested 11 resuscitators to determine the delivery of oxygen from the patient outlet using different inlet flows.

DESIGN

Bench test.

SETTING

A pediatric intensive care unit.

INTERVENTIONS

Patient outlet flow was measured at inlet flows of 5, 10, and 15 L/min at two different orientations of the reservoir valve assembly (upright and inverted).

MEASUREMENTS AND MAIN RESULTS

Patient outlet flow varied between resuscitators but was always less than the inlet flow and, in some cases, was as little as approximately 20% of the inlet flow. As the inlet flow rate was increased, the percentage of outlet flow that a patient received decreased, particularly in the upright position. At inlet flows of 5, 10, and 15 L/min, patient outlet flow ranged from 1.1 to 4.6 L/min, 1.6 to 5.1 L/min, and 2.0 to 6.5 L/min, respectively.

CONCLUSIONS

Self-inflating resuscitators deliver a significantly lower flow of oxygen than the provided inlet flow and should not be relied on to deliver a precise amount of flow of oxygen to spontaneously breathing patients.