Inaccurate oxygen delivery in some portable liquid oxygen devices

After documenting that the measured flow from a portable liquid oxygen device was different from the set flow and that this difference caused hypoxemia in a patient with chronic obstructive pulmonary disease, we compared the measured and set flows from 23 portable devices supplied by 2 different providers. Nine of 13 devices (69%) from Provider A gave measured flows that differed from the set flows at 14 of 65 (21%) settings (13 devices times 5 flow settings). Three of 10 devices (30%) supplied by Provider B gave measured flows that differed from the set flow in only 5 of 50 (10%) possible settings (10 units times 5 flow settings). Oxygen delivery may be inaccurate from portable liquid systems serviced by some suppliers. This problem may cause patients to become hypoxemic despite using the devices in the prescribed fashion.