© Published under licence by IOP Publishing Ltd. Arterial oxygen tension is commonly measured by means of intermittent arterial gas sampling. This technique is unable to detect within-breath oxygen tension changes that may be observed in mechanically ventilated patients, especially in the presence of lung injury. Moreover, it may not afford sufficient time resolution to detect potentially injurious settings of the mechanical ventilation itself. Continuous and rapid arterial oxygen tension measurement could detect within-breath changes in pulmonary gas exchange and offer clinically important feedback for the management of mechanical ventilation therapy in real time. We developed a novel fibre optic intravascular oxygen tension sensor, measured its fast response time in vitro, tested its blood clotting resistance over a period of 24 hours, and its capacity to measure arterial oxygen tension in vivo in a pig model of uninjured lung. This short communication will review the main steps of this collaborative project's progress to date, highlighting the technology's strengths, together with future potential for translation to a clinical scenario.