Rationale Airway, breathing, circulation assessment The British Thoracic Society recommend assessing airway, breathing and circulation (ABC) as the initial step in assessing an acutely breathless person [British Thoracic Society,2008].Rationale Blood pressure, pulse rate, respiratory rate, temperature, peak expiratory flow rate (PEFR), oxygen saturation and level of consciousness 1 The British Thoracic Society (BTS) recommend that pulse, respiratory rate and oxygen saturation should be measured in all acutely breathless people as an initial step in assessment and that other 'disease specific' measurements should also be carried out [British Thoracic Society, 2008]. 2 Assessment of level of consciousness, blood pressure, heart rate, and temperature are recommended for risk stratification for acute conditions including sepsis, acute asthma, and pneumonia [NICE, 2014; NICE, 2016 ; BTS/SIGN, 2016]. 3 CKS takes the view that the similarity of the recommended methods of assessing risk in widely differing conditions can be taken as evidence that these methods of assessment can reasonably be extrapolated to all people who are acutely ill, whatever the cause, and to people with breathlessness where the cause is unknown.