Continuous, non-invasive technique for measuring blood pressure using impedance plethysmography

An apparatus for non-invasively monitoring blood pressure in an animal, said apparatus comprising:

• an impedance cardiograph that measures thoracic impedance of the animal and determines from the thoracic impedance when a blood volume pulse is emitted from the heart;
• electrocardiograph connected to the impedance cardiograph;
• a sensor which detects when a blood volume pulse occurs at a second location in the animal;
• a timer connected to the impedance cardiograph and the sensor, wherein the timer measures an interval of time which elapses between when a blood volume pulse is emitted from the heart and when a blood volume pulse occurs at the second location;
• and
• a processor which derives tie blood pressure of the animal from the interval of time measured by the timer.

A method for continuously and non-invasively monitoring blood pressure in an animal having a heart, said method comprising:

• measuring thoracic impedance the animal;
• determining from the thoracic impedance when a blood volume pulse is emitted from the heart;
• detecting a blood volume pulse occurring at another location in the animal;
• measuring an interval of time which elapses between when a blood volume pulse is emitted from the heart and occurrence of the blood volume pulse at the other location;
• and
• deriving the blood pressure of the animal from the interval of time measured by the timer.