Northern Ontario School of Medicine 1 article published in JoVE Medicine Continuous Venous-Arterial Doppler Ultrasound During a Preload Challenge Jon-Émile S. Kenny1,2, Stanley O. Gibbs2, Delaney Johnston2, Lisa M. Hofer2, Emily Rae2, Geoffrey Clarke2, Joseph K. Eibl1,2,3, Bhanu Nalla1,3, Rony Atoui1,3 1Health Sciences North Research Institute, 2Flosonics Medical, 3Northern Ontario School of Medicine The Frank-Starling-Sarnoff curve is clinically important and describes the relationship between cardiac preload and output. This report illustrates a novel method of simultaneous jugular venous and carotid arterial Doppler velocimetry as transient surrogates of cardiac preload and output, respectively; this approach is enabled by wireless, wearable Doppler ultrasound.