Respiratory Parameters Using Advanced Airways During In-hospital Cardiac Arrest

The investigators aim to investigate the real life volumes of air delivered to the lungs when rescuers deliver these breaths by hand as part of resuscitation attempts during cardiac arrest. The study will compare the volumes achieved using different devices which are routinely used to provided an airway during routine cardiac arrest care. Volumes will be measured using a small non intrusive device which sits in the airway circuit and measures flow of air in real time. The patients chosen for this study will be those already recruited to an ongoing trial (AIRWAYS-3) assessing the outcomes for patients suffering in hospital cardiac arrest based on airway device used.