Method and circuit for storing and providing historical physiological data

1. An oximeter sensor, comprising:

a light emitting element configured to emit light;

a light detector configured to receive the light, wherein the oximeter sensor is configured to operate in transmittance mode and the light emitting element is positioned relative to the light detector to facilitate operation in the transmittance mode;

a probe configured to contact an external surface of a patient and to provide an impedance measurement to an oximeter monitor; and

a memory storing data relating to whether the impedance measurement represents adequate contact with the patient, wherein the memory is configured to provide the data to the oximeter monitor for comparison to the impedance measurement to determine if the impedance measurement represents adequate contact between the oximeter sensor and the patient.

2. The oximeter sensor of claim 1 , wherein the probe comprises two electrodes.

3. A method of manufacturing an oximeter sensor, comprising:

coupling a light emitting element to the oximeter sensor;

coupling a light detector to the oximeter sensor, wherein the oximeter sensor is configured to operate in transmittance mode and the light emitting element is positioned relative to the light detector to facilitate operation in the transmittance mode;

coupling a probe to the oximeter sensor, the probe configured to contact a patient on an external surface and to provide an impedance measurement to an oximeter monitor; and

installing a memory storing data relating to whether the impedance measurement represents adequate contact with the patient, wherein the memory is configured to provide the data to the oximeter monitor for comparison to the impedance measurement to determine if the impedance measurement represents adequate contact between the oximeter sensor and the patient.

4. The method of claim 3 , comprising installing two electrodes on the oximeter sensor.

5. An oximeter system, comprising:

an oximeter sensor configured to be placed externally on a patient and to operate in a transmittance mode, the oximeter sensor comprising:

a light emitting element configured to emit light;

a light detector configured to receive the light;

a probe configured to externally contact a patient and to provide an impedance measurement; and

a memory storing data relating to whether the impedance measurement represents adequate contact with the patient; and

an oximeter monitor, comprising:

a drive circuit configured to provide signals to circuitry of the oximeter sensor;

a receiving circuit configured to receive the impedance measurement from the probe and to receive the data from the memory; and

a circuit configured to compare the data to the impedance measurement to determine if the impedance measurement represents adequate contact between the oximeter sensor and the patient.

6. The system claim 5 , wherein the probe comprises two electrodes.

7. An oximeter monitor, comprising:

a drive circuit configured to provide signals to circuitry of an oximeter sensor configured to operate in transmittance mode;

a receiving circuit configured to receive information from a probe of the oximeter sensor placed externally on a patient, the information including an impedance measurement determined by the probe;

a data circuit configured to receive data relating to whether the impedance measurement is indicative of adequate contact with the patient from a memory of the oximeter sensor; and

a circuit configured to compare the data to the impedance measurement to determine if the impedance measurement represents adequate contact between the oximeter sensor and the patient.

8. The oximeter monitor of claim 7 , wherein the probe comprises two electrodes

9. A method of monitor operation, comprising:

providing signals to circuitry of an oximeter sensor that is configured to couple to an external surface of a patient and to operate in transmittance mode;

receiving information from a probe of the oximeter sensor located on the external surface of the patient, the information comprising an impedance measurement;

receiving data from a memory of the oximeter sensor, the data relating to whether the impedance measurement is indicative of adequate contact with the patient; and

comparing the data to the impedance measurement to determine if the oximeter sensor is in adequate contact with the patient.

10. A method of operating an oximeter sensor, comprising:

projecting light from a light emitting element;

receiving the light with a light detector, wherein the light emitting element is configured to operate in transmittance mode and the light emitting element is positioned relative to the light detector to facilitate operation in the transmittance mode;

measuring a level of impendence with a probe placed on an external surface of a patient;

maintaining data in a memory of the oximeter sensor relating to whether the impedance measurement represents adequate contact with the patient; and

providing the impedance measurement and the data to an oximeter monitor for comparison to determine if the oximeter sensor is in adequate contact with the patient.

11. The method of claim 10 , comprising powering electrodes to facilitate measuring the level of impendence.