Design Directions for Calibrating Pulse Oximetry to Skin Color

Pulse Oximeters are medical devices ubiquitous in hospital care, used to indirectly measure heart rate and blood oxygen saturation. Recently, with their essential and widespread use during the Covid-19 pandemic, issues of pulse oximeters systematically overestimating blood oxygen saturation in people with dark skin, delaying treatment and worsening outcomes, has regained attention. Technical solutions that automatically calibrate skin color have been proposed, but few design approaches have explored interactions that foreground the estimative nature of the technology. In this provocation, we present three conceptual proposals for means of manual calibration. They show how a racial, optical, or physiological conception of the human body each lead to different calibration designs that each enable their own mode of (un)desired care. The proposals aim to open design spaces in which manual calibration can be used to deepen understanding of physiology and bias and the workings of medical measuring devices.