Air and oxygen flowmeter confusion

Abstract

We wish to report an episode of air being administered to a critically ill patient rather than oxygen, due to a mix-up with wall-mounted flowmeters. An elderly gentleman in ventricular tachycardia was anaesthetized in a resuscitation area for emergency cardioversion. Afterwards, what was thought to be high flow oxygen was administered via facemask. Mild hypoxaemia (paO2 ~8kPa) persisted, but the cause was unclear until it was noticed that the mask tubing was connected to a piped air flowmeter. Once this was corrected, hypoxaemia improved and the patient suffered no adverse consequences. While there are standards for the design and colour of gas cylinders and pipeline outlets, there are none for flowmeters.1 In this case the error was caused by the anaesthetist (new to the hospital that week) viewing the flowmeter from the side ( Figure 1a) with another mask dangling from above obscuring the label (Figures 1b and c). Figure 1 (A) and (B) Two flowmeters in the resuscitation room: masks are dangling down and obscuring the flowmeter below. (C) When the mask is moved away, the ‘Air’ label becomes obvious The use of non-interchangeable connectors for anaesthetic gases has reduced the potential for administering the wrong gas, but mistakes like this are clearly happening frequently enough for the UK National Patient Safety Agency to issue guidance on the matter.2 They suggested potential solutions including capping air flowmeters, clearer labelling, and that air flowmeters should only be attached when required. Even they recognized that these are weak barriers based on human or administrative actions, which would be inadequate for the safe delivery of other drugs.3 The universal outlets of oxygen and air flowmeters – whether attached to pipeline supplies in hospitals or cylinders in surgeries and ambulances – both accept oxygen mask tubing, and while this persists we believe that this error will be made repeatedly, potentially to the detriment of many patients.