Attempting to prevent hyperoxaemia after out-of-hospital resuscitation

Survival to discharge in the UK after an out-of-hospital cardiac arrest is significantly lower than in other similarly developed countries (7.3% in the UK compared with the rest of Europe at 11.7%). One modifiable factor that could be contributing to this is the oxygen administered by paramedics after a successful out-of-hospital resuscitation. Randomised controlled trials on the topic are limited, and most research is observational and often does not differentiate according to the location of the cardiac arrest, leading to conflicting results. Overall, hyperoxaemia may be beneficial for the patient after a successful resuscitation until a critical level is reached; in the prehospital setting, it is not always possible to measure PaO2 as this is outside of the scope of practice of a paramedic in the UK. Above a critical level, excess oxygen becomes damaging and worsens patient outcomes. After a successful resuscitation, where possible, paramedics should consider titrating a patient's oxygenation to a peripheral oxygen saturation of 94–98% unless a more accurate measurement, such as point-of-care arterial blood gas results are available to guide titration.