A device operable to calculate a physiological parameter characteristic of a health condition of a human subject includes a finger cuff that is wearable on the subjects finger and operable to measure the patients peripheral blood pressure waveform. A memory unit stores the measured peripheral blood pressure waveform, and an adjustable pressure transfer function, which includes at least one adjustable characteristic. The patients cardiac output is estimated based on the stored measured peripheral blood pressure waveform, and the pressure transfer function is then adjusted based on that estimated cardiac output. The subjects aortic blood pressure waveform is then reconstructed from the stored peripheral blood pressure waveform and the adjusted pressure transfer function. A computing unit then calculates the physiological parameter from the reconstructed aortic blood pressure waveform.
