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.