Monitoring fetal characteristics by radiotelemetric transmission

• US 5,431,171 A
• Filed: 06/25/1993
• Issued: 07/11/1995
• Est. Priority Date: 06/25/1993
• Status: Expired due to Fees

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Harrison, Michael R., Jennings, Russell W.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Getzow, Scott M.
• Application Number:
  US08/081,139
• Time in Patent Office: 746 Days
• Field of Search: 128/698, 128/736, 128/642, 128/901, 128/733, 128/903, 128/904, 128/675, 128/673, 128/670, 607/902
• US Class Current: 600/511
• CPC Class Codes: A61B 5/0011 Foetal or obstetric data
• CPC Class Codes: Y10S 607/902 Fetal monitoring other than heart rate

Abstract

A fetal monitor is provided for gathering characteristic data such as fetal electrocardiogram, temperature and intra-uterine pressure so that fetal health may be determined during intra-operative and postoperative periods. The fetal monitor comprises a remote sensing unit, the remote sensing unit containing sensors which continually sample fetal temperature and electrocardiogram. A transceiver is housed in the remote sensing unit and outputs the sampled fetal temperature and electrocardiogram signals to an external antenna. A monitoring station is provided for monitoring the fetal temperature and electrocardiogram signals from the antenna. Additionally, a pressure transducer may be housed in the remote sensing unit for continually sampling intra-uterine pressure. This intra-uterine pressure signal in combination with the above signals are utilized to determine fetal health or the onset and progress of parturition.

Claims

1. A fetal monitor and system for measuring characteristics indicative of fetal health, and taking action based upon the health of the fetus is provided, said monitor comprising:

means for sensing a temperature of a fetus and for outputting a fetal temperature signal;

means for sensing an electrocardiogram of said fetus and for outputting a fetal electrocardiogram signal; and

means for receiving said fetal temperature and electrocardiogram signals and for determining the existence of fetal conditions based upon said fetal temperature and electrocardiogram signals.

2. The fetal monitor recited in claim 1, wherein said means for sensing said electrocardiogram of said fetus comprises:

at least one electrocardiogram lead having an exposed distal end, said electrocardiogram lead for receiving electrical signals indicative of a fetal electrocardiogram;

a noise reduction means secured to a proximal end of said electrocardiogram lead; and

an amplification means for amplifying said electrocardiogram signal.

3. The fetal monitor recited in claim 2, wherein said electrocardiogram lead is adapted to be maintained subcutaneously within said fetus for preventing accidental short circuits.

4. The fetal monitor recited in claim 1, wherein said outputting means for said fetal electrocardiogram signal comprises a transceiver.

5. The fetal monitor recited in claim 4, wherein said transceiver is a radio-telemetry transceiver.

6. The fetal monitor recited in claim 1, wherein said means for sensing said temperature of said fetus comprises a temperature sensor which is adapted to be disposed on and in contact with said fetus.

7. The fetal monitor recited in claim 1, wherein said outputting means for said fetal temperature comprises a transceiver.

8. The fetal monitor recited in claim 7, wherein said transceiver is a radio-telemetry transceiver.

9. The fetal monitor recited in claim 1, wherein said means for receiving comprises an antenna.

10. The fetal monitor recited in claim 9, wherein said antenna is a ring retractor antenna.

11. The fetal monitor recited in claim 9, wherein said antenna is a flexible loop of conductive material.

12. The fetal monitor recited in claim 9, wherein said antenna is a finger antenna.

13. The fetal monitor recited in claim 1, wherein said determining means comprises:

a receiver for receiving said fetal electrocardiogram and temperature signals;

a computing means; and

an output means.

14. The fetal monitor recited in claim 13, wherein said computing means comprises a central processor, memory, arithmetic logic unit, and a communications bus for passing said fetal electrocardiogram and temperature signals from said receiver to said output means.

15. The fetal monitor recited in claim 13, wherein said output means comprises a liquid crystal display.

16. The fetal monitor recited in claim 13, wherein said output means comprises a cathode ray tube.

17. The fetal monitor recited in claim 13, wherein said output means comprises a strip chart recorder.

18. The fetal monitor as recited in claim 1, further comprising a means for continually sampling intra-uterine pressure and for outputting a sampled intra-uterine pressure signal.

19. The fetal monitor recited in claim 18, wherein said means for continually sampling intra-uterine pressure comprises:

a pressure transducer; and

a pressure transmission catheter for providing fluid communication between amniotic fluid contained in a uterus and said pressure transducer.

20. The fetal monitor recited in claim 18, wherein said means for sensing intra-uterine pressure comprises a solid state pressure transducer.

21. The fetal monitor recited in claim 1, further comprising an automatic dispensing means for dispensing medication to said fetus upon the existence of a particular fetal condition.

22. The fetal monitor recited in claim 21, wherein said automatic dispensing means comprises:

communications means for communicating with said determining means;

a pump for dispensing said medication;

a reservoir for maintaining said medication for said pump; and

actuation means for receiving a signal from said communications means and for actuating said pump based upon said signal.

23. The fetal monitor recited in claim 22, wherein said communications means comprises a transceiver.

24. The fetal monitor recited in claim 23, wherein said transceiver is a radio-telemetry transceiver.

25. The fetal monitor recited in claim 22, wherein said pump is a piezoelectrically driven micro-pump.

26. The fetal monitor recited in claim 22, wherein said reservoir is a collapsible bag.

27. The fetal monitor recited in claim 21, wherein said automatic dispensing means comprises:

communications means for communicating with said outputting means for said fetal electrocardiogram signal and for communicating with said outputting means for said fetal temperature signal;

a pump for dispensing said medication;

a reservoir for maintaining said medication for said pump; and

actuation means for receiving said fetal electrocardiogram and temperature signals from said communications means and actuating said pump based upon said signals.

28. The fetal monitor recited in claim 1, further comprising an automatic means for dispensing medication to a mother of said fetus upon the existence of a particular fetal condition.

29. The fetal monitor recited in claim 28, wherein said automatic dispensing means comprises:

communications means for communicating with said determining means;

a pump for dispensing said medication to said mother;

a reservoir for maintaing said medication for said pump; and

actuation means for receiving a signal from said communications means and for actuating said pump based upon said signal.

30. The fetal monitor recited in claim 29 wherein said communications means comprises a transceiver.

31. The fetal monitor recited in claim 30 wherein said transceiver is a radio-telemetry transceiver.

32. The fetal monitor recited in claim 29, wherein said pump is a piezoelectrically driven micro-pump.

33. The fetal monitor recited in claim 29, wherein said reservoir is a collapsible bag.

34. The fetal monitor recited in claim 1 further comprising a uterine monitor, said uterine monitor comprising:

means for sensing temperature of a mother and for outputting a sampled maternal temperature signal,

means for sensing electrical activity of a uterine muscle of a mother and for outputting a sampled maternal electromyogram signal, and

means for receiving said maternal temperature and electromyogram signals and for determining the existence of fetal conditions based upon said sampled maternal temperature, maternal electromyogram, fetal temperature, and fetal electrocardiogram.

35. The fetal monitor recited in claim 34, wherein said means for sensing said electromyogram of said mother comprises:

at least one electromyogram lead having an exposed distal end, said electromyogram lead for receiving electrical signals indicative of a maternal uterine electromyogram;

a noise reduction means secured to a proximal end of said electromyogram lead; and

an amplification means for amplifying said electromyogram signal.

36. The fetal monitor recited in claim 35, wherein said electromyogram lead is adapted to be maintained subcutaneously within a uterine wall of said mother for preventing accidental short circuits.

37. The fetal monitor recited in claim 34, wherein said means for sensing temperature of said mother comprises a temperature sensor which is adapted to be disposed on and in contact with a uterine wall of said mother.

38. The fetal monitor recited in claim 34, wherein said outputting means for said maternal electromyogram signal comprises a transceiver.

39. The fetal monitor recited in claim 38, wherein said transceiver is a radio-telemetry transceiver.

40. The fetal monitor recited in claim 34, wherein said sampled maternal temperature, maternal electromyogram, fetal temperature, and fetal electrocardiogram signals are outputted at different frequencies, one frequency for each sampled signal.

41. The fetal monitor recited in claim 34, wherein said outputting means for said maternal temperature signal comprises a transceiver.

42. The fetal monitor recited in claim 41, wherein said transceiver is a radio-telemetry transceiver.

43. The fetal monitor as recited in claim 34, further comprising a means for sensing intra-uterine pressure and for outputting a sampled intra-uterine pressure signal.

44. The fetal monitor recited in claim 43, wherein said means for sensing intra-uterine pressure comprises:

a pressure transducer; and

a pressure transmission catheter for providing fluid communication between amniotic fluid contained in a uterus and said pressure transducer.

45. The fetal monitor recited in claim 43, further comprising a means for receiving said intra-uterine pressure signals and for determining the onset of parturition based upon said sensed maternal temperature, maternal electromyogram, intra-uterine pressure, fetal temperature, and fetal electrocardiogram.

46. The fetal monitor recited in claim 43, wherein said means for sensing intra-uterine pressure comprises a solid state pressure transducer.

47. A fetal monitoring system for measuring characteristics indicative of fetal health, said monitoring system comprising:

a remote sensing unit, said remote sensing unit containing means for sensing temperature of a fetus and for sensing an electrocardiogram of said fetus, said remote sensing unit also housing a transceiver for outputting sampled fetal temperature and electrocardiogram signals, said remote sensing unit maintained within close proximity of said fetus for allowing said fetal temperature to be sampled;

an antenna for receiving said sampled fetal temperature and electrocardiogram signals from said transceiver; and

a monitoring station for monitoring said fetal temperature and electrocardiogram signals, said monitoring station comprising a receiver for receiving said fetal electrocardiogram and temperature signals from said antenna, a computing means for manipulating said fetal electrocardiogram and temperature signals, and an output means for displaying information from said fetal electrocardiogram and temperature signals.

48. The fetal monitor as recited in claim 47, further comprising a means for continually sampling intra-uterine pressure and for outputting a sampled intra-uterine pressure signal.

49. The fetal monitor recited in claim 48, wherein said means for continually sampling intra-uterine pressure comprises:

a pressure transducer; and

a pressure transmission catheter for providing fluid communication between amniotic fluid contained in a uterus and said pressure transducer.

50. The fetal monitor recited in claim 47, wherein said computing means comprises a central processor, memory, arithmetic logic unit, and a communications bus for passing said fetal electrocardiogram and temperature signals from said receiver to said output means.

51. The fetal monitor recited in claim 47, wherein said output means comprises a liquid crystal display.

52. The fetal monitor recited in claim 47, wherein said output means comprises a cathode ray tube.

53. The fetal monitor recited in claim 47, wherein said output means comprises a strip chart recorder.

54. A fetal monitoring system for measuring characteristics indicative of fetal health, said fetal monitoring system comprising:

a fetal monitor, said fetal monitor comprising a means for sensing temperature of a fetus and for outputting a fetal temperature signal, a means for sensing an electrocardiogram of said fetus and for outputting a fetal electrocardiogram signal;

an antenna for receiving said fetal temperature and electrocardiogram signals from said outputting means;

a communications network for allowing the communication of said fetal electrocardiogram and temperature signal to a remote site;

a means for converting said fetal temperature and electrocardiogram signals from said antenna to be compatible with said communications network;

a monitoring station for remotely monitoring said fetal temperature and electrocardiogram signals, said monitoring station comprising a receiver for receiving said fetal electrocardiogram and temperature signals, a computing means for manipulating said fetal electrocardiogram and temperature signals, and an output means for displaying information from said fetal electrocardiogram and temperature signals; and

a means for converting said fetal temperature and electrocardiogram signals from said communications network to be compatible with said monitoring station.

55. The fetal monitor as recited in claim 54, further comprising a means for sensing intra-uterine pressure and for outputting an intra-uterine pressure signal.

56. The fetal monitor recited in claim 55, wherein said means for sensing intra-uterine pressure comprises:

a pressure transducer; and

a pressure transmission catheter for providing fluid communication between amniotic fluid contained in a uterus and said pressure transducer.

57. The fetal monitor recited in claim 55, wherein said means for sensing intra-uterine pressure comprises a solid state pressure transducer.