OBJECTIVE: Prehospital guidelines state that monitoring should match in-hospital standards, but consensus on the use of arterial blood gases (ABGs) and arterial lines remains unclear. The aim was to perform a systematic literature review and survey of UK helicopter emergency medical services (HEMS) use and perceptions of ABGs and arterial lines. METHODS: A systematic literature review was conducted for arterial lines and ABGs and prehospital care. Additionally, two questionnaires were distributed to all UK HEMS (questionnaire 1: current clinical practice and questionnaire 2: clinicians' opinions). RESULTS: From 1,028 results, 13 studies (10 ABGs and 3 arterial lines) were included, demonstrating it is feasible to obtain ABGs and place arterial lines in the prehospital setting. There were concerns about practical difficulties for ABGs and the time taken for arterial lines. Survey responses were obtained from all UK HEMS (N = 22). Six services carry equipment for performing ABGs and nine services for arterial lines. Clinicians expressed concerns relating to the time taken to perform both procedures, but most believed it would allow better monitoring and more targeted treatment. CONCLUSION: The evidence of benefit for both procedures remains poor. Overall, there may be clinical benefits, but these are likely to be patient specific and require further investigation.