Patent ID: 8808188

Claim:
A system for monitoring a patient's blood pressure, the system comprising: a pressure-delivery system for applying a variable pressure to the patient's arm; a pressure sensor for measuring a time-dependent pressure waveform representing the pressure applied to the patient's arm; a first sensor configured to attach to the patient and generate a first time-dependent waveform representing a flow of blood within the patient; a second sensor configured to attach to the patient and generate a second time-dependent waveform representing contractile properties of the patient's heart; and, a processing component programmed to: i) determine an index pulse transit time (PTT index ) from a separation in time of a first feature of the first time-dependent waveform and a second feature of the second time-dependent waveform; ii) process the pressure, first, and second waveforms as pressure is applied by the pressure-delivery system and determine therefrom a patient-specific slope (m femoral ) representing a relationship between pulse transit time and mean arterial blood pressure in the patient's femoral artery; iii) determine a mean arterial pressure value (MAP INDEX ) from a peak pulse amplitude in the time-dependent pressure waveform; and iv) determine a mean blood pressure value in the patient's femoral artery (MAP femoral ) from a pulse transit time measured from the first and second waveforms (PTT) according to the equation MAP femoral =(m femoral ×PTT)−(m femoral ×PTT INDEX )+MAP INDEX , wherein PTT INDEX represents a pulse transit time determined before PTT.