Isolation and communication element for a resposable pulse oximetry sensor

1. A sensor comprising:

a connector adapted to electrically communicate with a physiological measurement instrument;

a breakable conductor that transitions from a continuity state to a discontinuity state as the result of sensor wear; and

an isolation and communications element (ICE) having an instrument port and an electrically isolated loop port, said instrument port in communications with said connector and said loop port in communications with said breakable conductor, wherein:

said ICE further comprises a control output responsive to said discontinuity state, said sensor further comprises an electrical component, said ICE being connected in parallel with said connector and said electrical component, and said component being operable from said instrument via said connector according to said control output.

2. The sensor according to claim 1 further comprising a switch in series between said component and said connector, said switch responsive to said control output so as to disconnect said component from said connector.

3. The sensor according to claim 2 wherein said ICE further comprises a converter which supplies DC power to said ICE, said converter connected to said instrument port so as to draw modulated power from said instrument.

4. The sensor according to claim 2 wherein said ICE further comprises:

a processor having an input indicating said discontinuity state and providing said control output in response;

a transceiver in communications with said processor and said instrument port and adapted to transfer a plurality of data items between said instrument and said processor; and

a memory readable and writeable by said processor and adapted to store and retrieve said data items.

5. The sensor according to claim 2 wherein said ICE further comprises:

an opto-isolator driver connected to said loop port and adapted to supply a current to said breakable conductor; and

an opto-isolator receiver connected to said loop port and adapted to receive said current so as to detect said discontinuity state.

6. A sensor comprising:

a connector adapted to electrically communicate with a physiological measurement instrument;

a breakable conductor configured as a current loop that becomes an open circuit as the result of sensor wear, said conductor electrically isolated from said connector;

an electrical component operable from said instrument via said connector said electrical component rendered inoperable in response to said open circuit;

a driver configured to provide a current to said breakable conductor; and

a receiver responsive to said current so as to provide a control output indicating said open circuit, wherein said driver and said receiver are adapted to provide electrical isolation between said conductor and said connector.

7. The sensor according to claim 6 further comprising a switch between said component and said connector, said switch actuated by said control output so as to disconnect said component from said connector.

8. The sensor according to claim 7 wherein said component is an information element readable by said instrument so as to activate said sensor, said switch rendering said information element unreadable when said control output indicates said open circuit.

9. A sensor method comprising the steps of: incorporating a breakable conductor within a sensor to indicate sensor wear;

isolating said conductor from a measurement connector; and

disabling a sensor circuit in response to a discontinuity in said breakable conductor, wherein said isolating step comprises the substeps of:

providing a current for said conductor from an optically isolated driver; and

detecting said current in said conductor by an optically isolated receiver.

10. The sensor method according to claim 9 wherein said disabling step comprises the substeps of:

generating an open circuit output from said receiver when said current is disrupted; and

actuating a switch in response to said open circuit output to disconnect said sensor circuit from said connector.

11. The sensor method according to claim 10 comprising the further steps of:

detecting a communications request at said measurement connector;

actuating said switch in response to said communications request; and

downloading data from said connector to a sensor memory.

12. A sensor configured to connect to a measurement instrument comprising:

a conductive means for indicating sensor wear;

an optical means for isolating said conductive means from said instrument; and

a switching means for disabling a circuit portion of said sensor in response to a discontinuity in said conductive means.

13. The sensor according to claim 12 further comprising a communications means for the transfer of data between said instrument and said sensor.

14. The sensor according to claim 12 further comprising a converter means for drawing power from said instrument and supplying power to said sensor.