Flow rate computer adjunct for use with an impedance plethysmograph and method
System for determining characteristics of blood flow Patent #: 3996925
ApplicationNo. 06/393429 filed on 06/29/1982
US Classes:600/484, Detecting respiratory condition600/483, Simultaneously detecting cardiovascular condition and diverse body condition600/504, Measuring blood flow in body portion other than heart600/506, By detecting electrical impedance of body portion600/507, By detecting volume of body portion600/508, Heart600/533, Measuring respiratory flow impedance or lung elasticity600/538, Measuring breath flow or lung capacity600/547Measuring electrical impedance or conductance of body portion
ExaminersPrimary: Smith, Jerry
Assistant: MacDonald, Allen R.
Attorney, Agent or Firm
International ClassesA61B 5/08 (20060101)
G06F 17/00 (20060101)
AbstractThe invention provides apparatus and methods for using the electrical bioimpedance measurements to monitor parameters associated with blood flow in a segment of body tissue. The invention eliminates the effect of respiration from the thoracic impedance as a function of time to provide a signal indicative of pulsatile thoracic impedance changes continuously. The pulsatile thoracic impedance signal is processed to produce signals indicative of the ventricular ejection time and the maximum rate of change of pulsatile thoracic impedance which are used in a microprocessor to calculate the volume of blood pumped per stroke according to an improved systolic upstroke equation.