The efficacy of oxygen wafting using different delivery devices, flow rates and device positioning

Background: Oxygen "wafting" provides a non-contact oxygen alternative for uncooperative paediatric patients in the emergency department (ED). The aim of this study was to identify the combination of oxygen delivery device, flow rate and device positioning that delivers the highest concentration of wafted oxygen. Methods: ED nursing staff were surveyed to determine current oxygen wafting practice. A simulated patient and oxygen sensor were used to compare wafted oxygen concentrations for six delivery devices in various positions and oxygen flow rates. Results: Only oxygen tubing and the paediatric non-rebreather mask consistently delivered wafted oxygen concentrations above 30%. The paediatric non-rebreather held below the face produced concentrations ranging from 26.1% (10 cm) to 39.8% (5 cm). At 15 L/min, tubing held in front of the face produced concentrations ranging from 31.2% (15 cm) to 56.7% (5 cm); reducing the flow rate to 6–8 L/min had no meaningful effect on the delivered oxygen concentration. When tubing was used below the face, flow rates between 6 and 8 L/min produced somewhat higher concentrations than 15 L/min (5 cm: 36.3% vs. 30.9%). Conclusions: When delivering oxygen by wafting, the highest oxygen concentrations are achieved when positioning tubing 5–15 cm in front of the face or positioning tubing or a paediatric non-rebreather mask 5–10 cm below the face at 10–15 L/min flow. This should be considered when using oxygen wafting in the ED