Positioning method for pulse oximetry fetal sensor

• US 5,961,452 A
• Filed: 10/20/1997
• Issued: 10/05/1999
• Est. Priority Date: 08/22/1990
• Status: Expired due to Fees

• Current Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Inventors: Chung, Christopher, McNamara, Helen M.
• Primary Examiner(s): Dvorak, Linda C.
• Assistant Examiner(s): YARNELL, BRYAN KEITH
• Application Number:
  US08/954,303
• Time in Patent Office: 715 Days
• Field of Search: 600/310, 600/313, 600/322, 600/323, 600/338, 600/339, 600/341, 600/342, 600/376, 600/473, 600/476, 600/478
• US Class Current: 600/338
• CPC Class Codes: A61B 5/1076 for measuring dimensions inside body cavities, e.g. using catheters A61B3/1005 takes precedence
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1464 specially adapted for foetal tissue

Abstract

An intrauterine pulse oximetry apparatus and method are provided to measure fetal blood oxygen saturation at sites in a preferred region on the fetus. The sensor of the apparatus is attached to a stiff cable which can be inserted into the uterus past the presenting part and transcervical region of the fetus. The cable may have visual and tactile markings by which the user, without seeing or feeling the sensor, can guide it to an appropriate site on the fetus and for use in determining the depth of the sensor in the vagina.

Claims

1. A positioning method comprising:

providing a pulse oximetry apparatus having a substantially stiff tube such that the tube remains rigid enough under its own weight to be inserted unsupported into a vagina;

providing a sensor at an insertion end of the stiff tube;

inserting the sensor into the vagina;

advancing the sensor through a cervix into a uterus;

placing the sensor on the fetus in a region beyond the reach of a user in physical contact with the fetus without additional means for securing the sensor to a fetal skin; and

using visual markings on the stiff tube to indicate a depth of the sensor in said vagina.

2. A positioning method comprising:

providing a pulse oximetry apparatus having a substantially stiff tube such that the tube remains rigid enough under its own weight to be inserted unsupported into a vagina;

providing a sensor at an insertion end of the stiff tube;

inserting the sensor into the vagina;

advancing the sensor through a cervix into a uterus;

placing the sensor on the fetus in a region beyond the reach of a user in physical contact with the fetus without additional means for securing the sensor to a fetal skin; and

using a tactile marking on the stiff tube to indicate a depth of the sensor in said uterus.

3. A positioning method comprising:

providing a pulse oximetry apparatus having a substantially stiff tube such that the tube remains rigid enough under its own weight to be inserted unsupported into a vagina;

providing a sensor at an insertion end of the stiff tube;

inserting the sensor into the vagina;

advancing the sensor through a cervix into a uterus;

placing the sensor on the fetus in a region beyond the reach of a user in physical contact with the fetus without additional means for securing the sensor to a fetal skin; and

using a tactile marking on the stiff tube to indicate a location of the sensor on the fetal head.

4. A positioning method comprising:

providing a pulse oximetry apparatus having a substantially stiff tube such that the tube remains rigid enough under its own weight to be inserted unsupported into a vagina;

providing a sensor at an insertion end of the stiff tube;

inserting the sensor into the vagina;

advancing the sensor on the fetus in a region beyond the reach of a user, beyond a presenting part of the fetus and beyond a transcervical region; and

determining a depth of the sensor in a uterus.