Fetal cardiac monitoring utilizing umbilical blood flow parameters and heartbeat information

• US 5,749,831 A
• Filed: 06/23/1997
• Issued: 05/12/1998
• Est. Priority Date: 06/23/1997
• Status: Expired due to Fees

• Current Assignee: Baker, Donald A.
• Original Assignee: Baker, Donald A.
• Inventors: Baker, Donald A.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): SCHAETZLE, KENNEDY
• Application Number:
  US08/880,352
• Time in Patent Office: 323 Days
• Field of Search: 600/301, 600/304, 600/407, 600/437, 600/438, 600/453, 600/454, 600/483, 600/504, 600/455, 600/511, 600/528, 600/364
• US Class Current: 600/301
• CPC Class Codes: A61B 8/02 Measuring pulse or heart rate
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/0866 involving foetal diagnosis; pre-natal or peri-natal diagnosis of the baby
• CPC Class Codes: A61B 8/463 characterised by displaying multiple images or images and diagnostic data on one display composite display in devices for short-range imaging with acoustic waves G01S7/52074

Abstract

Methods and systems for monitoring to assess the health of a fetus being carried within a mother. The methods include sensing fetal heart information using a fetal heart sensor; determining at least one fetal heart rate measure from the fetal heart rate information; detecting umbilical flow information relating to the flow of blood within the umbilical; deriving at least one umbilical flow indicator from at least the umbilical flow information; and analyzing the fetal heartbeat measure and umbilical flow measure to produce at least one fetal health parameter. The systems include the heartbeat sensor, umbilical flow detector, and a processor which allows analysis of the information obtained from the sensor and detector to provide an indication of fetal health.

Claims

1. A method for monitoring to assess at least one fetal health parameter associated with a fetus being carried within an expectant mother, comprising the steps:

placing at least one fetal heart sensor at an appropriate position relative to the mother for sensing fetal heartbeat information emanating from a fetal heart beating within the fetus;

sensing fetal heartbeat information using the at least one fetal heart sensor;

determining at least one fetal heartbeat measure from the fetal heartbeat information;

positioning at least one umbilical flow detector at an appropriate position relative to the mother to detect umbilical blood flow information, said umbilical blood flow information indicating flow of blood within an umbilical cord which extends between the fetus and a placenta carried within the mother, said positioning occurring so as to allow detection of the umbilical blood flow information at an umbilical target location which is distal from a fetal umbilicus whereat the umbilical cord attaches to the fetus;

detecting umbilical blood flow information from the umbilical target location using the at least one umbilical flow detector;

deriving at least one umbilical flow measure from the umbilical blood flow information detected in said detecting step;

analyzing said at least one fetal heartbeat measure and said at least one umbilical flow measure to produce said at least one fetal health parameter.

2. The method of claim 1 and further comprising comparing said at least one fetal health parameter to at least one baseline fetal health parameter measured previously in time in a manner similar to said at least one fetal health parameter to determine at least one fetal health parameter change.

3. The method of claim 1 wherein said determining at least one fetal heartbeat measure includes determining fetal heart rate produced by the fetal heart.

4. The method of claim 1 wherein said determining at least one fetal heartbeat measure includes determining systolic duration of fetal heartbeats produced by the fetal heart.

5. The method of claim 1 wherein said determining at least one fetal heartbeat measure includes determining a period of time associated with the first heart sound produced by the fetal heart.

6. The method of claim 1 wherein said determining at least one fetal heartbeat measure includes determining a period of time associated with the second heart sound produced by the fetal heart.

7. The method of claim 1 wherein said deriving at least one umbilical flow measure includes deriving at least one estimate of fetal blood flow velocity.

8. The method of claim 1 wherein said deriving at least one umbilical flow measure includes deriving at least one estimate of maximum fetal blood flow velocity ejected from the fetal heart.

9. The method of claim 1 wherein said deriving at least one umbilical flow measure includes deriving at least one estimate of fetal blood flow acceleration or deceleration.

10. The method of claim 1 wherein said deriving at least one umbilical flow measure includes deriving at least one estimate of fetal blood flow acceleration associated with ejection of fetal blood from the fetal heart.

11. The method of claim 1 wherein said deriving at least one umbilical flow measure includes deriving at least one estimate of fetal blood flow deceleration associated with deceleration of fetal blood within the umbilical cord.

12. The method of claim 1 wherein said analyzing includes determining mean aortic acceleration.

13. The method of claim 1 wherein said analyzing includes determining acceleration rate.

14. The method of claim 1 wherein said analyzing includes determining a systole acceleration time period which is a period of time for which fetal blood flow from the fetal heart is experiencing an increasing velocity.

15. The method of claim 1 wherein said analyzing includes:

determining a systole acceleration time period which is a period of time for which fetal blood flow from the fetal heart is experiencing an increasing velocity;

determining at least one estimate of maximum systolic velocity which is a maximum fetal blood flow velocity ejected from the fetal heart;

determining a mean aortic acceleration which is the maximum systolic velocity divided by the systole acceleration period.

16. The method of claim 15 wherein said analyzing includes comparing multiple mean aortic accelerations determined at various fetal heart rates.

17. The method of claim 15 wherein said analyzing includes comparing multiple acceleration rates determined at various fetal heart rates.

18. The method of claim 15 wherein said analyzing includes comparing multiple mean aortic accelerations determined at various fetal heart rates to determine a fetal heart rate at which said mean aortic acceleration rate is at a minimal value.

19. The method of claim 15 wherein said analyzing includes comparing multiple mean aortic acceleration determined at various fetal heart rates to at least one baseline mean aortic acceleration rates measured previously in time to determine at least one fetal health parameter change.

20. The method of claim 15 wherein said analyzing includes comparing multiple acceleration rates determined at various fetal heart rates to at least one baseline acceleration rate measured previously in time to determine at least one fetal health parameter change.

21. The method of claim 1 wherein said analyzing includes comparing systolic and diastolic flow velocities detected in said detecting step.

22. The method of claim 1 wherein said analyzing includes comparing systolic and diastolic periods of time.

23. The method of claim 1 wherein said analyzing includes comparing pulse transit times for a plurality of umbilical blood flow pulses.

24. The method of claim 1 wherein said analyzing includes determining an ejection time period which is a period of time during which blood is ejected from the fetal heart.

25. The method of claim 1 wherein said at least one fetal health parameter includes an index which relates to fetal cardiac oxygen consumption.

26. The method of claim 1 wherein said at least one fetal health parameter includes a systole velocity profile which indicates velocity of fetal blood flow over a systolic period;

and further comprising comparing said systole velocity profile to at least one baseline systole velocity profile measured previously in time to determine at least one fetal health parameter change.

27. The method of claim 1 wherein said analyzing includes consideration of an inotropic index of performance against a chronotropic index of performance to produce said at least one fetal health parameter which is dependent upon both said inotropic index and said chronotropic index.

28. A method for monitoring to assess at least one fetal health parameter associated with a fetus being carried within an expectant mother, comprising the steps:

determining at least one fetal heartbeat measure from fetal heartbeat information sensed from a fetal heart beating within the fetus;

positioning at least one umbilical flow detector at an appropriate position relative to the mother to detect umbilical blood flow information, said umbilical blood flow information indicating flow of blood within an umbilical cord which extends between the fetus and a placenta carried within the mother, said positioning occurring so as to allow detection of the umbilical blood flow information at an umbilical target location which is distal from a fetal umbilicus whereat the umbilical cord attaches to the fetus;

detecting umbilical blood flow information from the umbilical target location using the at least one umbilical flow detector;

deriving at least one umbilical flow measure from the umbilical blood flow information detected in said detecting step;

analyzing said at least one fetal heartbeat measure and said at least one umbilical flow measure to produce said at least one fetal health parameter.

29. A fetal monitoring system for monitoring a fetus carried within a mother, the system comprising:

at least one fetal heart sensor for sensing fetal heartbeat information;

at least one umbilical flow detector for detecting umbilical blood flow information which indicates flow of blood within an umbilical cord which extends between the fetus and a placenta carried by the mother;

at least one processor connected to receive said fetal heartbeat information from the at least one fetal heartbeat sensor, and connected to receive umbilical flow information from the at least one umbilical flow detector, said at least one processor deriving therefrom at least one fetal health parameter.

30. The system of claim 29 wherein said at least one fetal heartbeat sensor comprises at least one acoustical sensor.

31. The system of claim 29 wherein said at least one fetal heartbeat sensor comprises at least one ultrasonic heartbeat sensor subsystem.

32. The system of claim 29 wherein said at least one umbilical flow detector comprises an ultrasonic flowmeter.

33. The system of claim 29 wherein said at least one umbilical flow detector comprises a gated, pulsed-wave Doppler flowmeter.

34. The system of claim 29 wherein said at least one processor comprises a programmable microprocessor which is programmed to analyze said fetal heartbeat information and said umbilical flow information to determine said at least one fetal health parameter.

35. The system of claim 29 wherein said at least one fetal heartbeat sensor comprises at least one acoustical sensor;

and said at least one umbilical flow detector comprises an ultrasonic flowmeter.

36. The system of claim 29 wherein:

said at least one fetal heartbeat sensor is an ultrasonic sensor which sensing fetal heart sounds;

said at least one umbilical flow sensor comprises a gated, pulsed-wave Doppler flowmeter;

said processor comprises a programmable microprocessor which is programmed to analyze said fetal heartbeat information and said umbilical flow information into said at least one fetal health parameter.