Sensor adapter cable

Abstract

A sensor adapter cable provides medical personnel with the convenience of utilizing otherwise incompatible optical sensors with multiple blood parameter plug-ins to a physiological monitor, where the plug-ins each have keyed connectors that mechanically lock-out incompatible sensors in addition readers that poll sensor identification components in each sensor so as to electrically lock-out incompatible sensors.

Description

BACKGROUND OF THE INVENTION

Pulse oximetry systems for measuring constituents of circulating blood have gained rapid acceptance in a wide variety of medical applications, including surgical wards, intensive care and neonatal units, general wards, home care, physical training, and virtually all types of monitoring scenarios. A pulse oximetry system generally includes an optical sensor applied to a patient, a monitor for processing sensor signals and displaying results and a patient cable electrically interconnecting the sensor and the monitor. The monitor may be specific to pulse oximetry or may be a multi-parameter monitor that has a pulse oximetry plug-in. A pulse oximetry sensor has light emitting diodes (LEDs), typically one emitting a red wavelength and one emitting an infrared (IR) wavelength, and a photodiode detector. The emitters and detector are typically attached to a finger, and the patient cable transmits drive signals to these emitters from the monitor. The emitters respond to the drive signals to transmit light into the fleshy fingertip tissue. The detector generates a signal responsive to the emitted light after attenuation by pulsatile blood flow within the fingertip. The patient cable transmits the detector signal to the monitor, which processes the signal to provide a numerical readout of pulse oximetry parameters such as oxygen saturation (SpO₂) and pulse rate.

SUMMARY OF THE INVENTION

A sensor adapter cable provides medical personnel with the convenience of utilizing otherwise incompatible sensors with multiple SpO₂ monitors or monitor plug-ins. For example, each monitor plug-in may have a keyed connector that mechanically locks-out incompatible sensors. Further, each sensor may have sensor identification (ID) components that can be read by a pulse oximetry monitor or monitor plug-in so as to electrically lock-out incompatible sensors. The sensor adapter cable advantageously allows the interconnection of these otherwise incompatible devices. In an embodiment, a sensor adapter cable allows the use of any of a Masimo sensor with a ProCal ID, a Masimo sensor with an EEPROM ID and a Nellcor/Philips sensor with an R-cal ID with either of a Masimo SET plug-in or a Philips FAST-SpO2 plug-in to a Philips IntelliVue™ monitor, all available from Philips Medical Systems, Andover, Mass.

A sensor adapter cable has both a mechanical and an electrical interface to a monitor plug-in so as to provide multiple sensor compatibility. In an embodiment, a dual key 8-pin D-shape connector (D8) at one end of an adapter cable provides mechanical compatibility with two-types of plug-in input connectors, as described in U.S. patent application Ser. No. 11/238,634 (Pub No. US2006/0073719 A1) titled Multiple Key Position Plug filed Sep. 29, 2005 and incorporated by reference herein. Further, a family of sensor adapter cables has sensor connector configurations that include MC8, M15 and DB9 connectors, as shown and described below.

The limited pins available on a D8 connector require sharing of pins to accommodate various sensor ID components. For example, an EEPROM sensor ID and a R-cal resistor sensor ID may need to share the same D8 pin. Such an approach, however, creates the potential for the EEPROM to effect the R-cal measurement in Philips FAST equipped devices and for the R-cal voltage drop to effect the ability of Masimo SET equipped devices to read the EEPROM.

An 8-pin dual-key cable which is capable of working correctly with any combination of Philips or Masimo SET equipped SpO2 plug-ins requires the connection of the proper ID component(s) to the SpO2 plug-ins while at the same time electrically disconnecting components that are not used or that could potentially interfere with the connected SpO2 technology. Further, this solution cannot impact the ability of each of the SpO2 technologies to operate correctly across its entire range of sensors and accessories.

One aspect of a sensor adapter cable provides medical personnel with the convenience of utilizing otherwise incompatible optical sensors with multiple blood parameter plug-ins to a physiological monitor. The plug-ins each have keyed connectors that mechanically lock-out incompatible sensors in addition to readers that poll sensor identification components in each sensor so as to electrically lock-out incompatible sensors. The sensor adapter cable has a sensor connector, a plug-in connector, an interconnection cable and a pod. The sensor connector mechanically connects to a predetermined sensor and electrically communicates with sensor electrical elements within the predetermined sensor. The plug-in connector mechanically connects to a predetermined plug-in and electrically communicates with lug-in electrical elements within the predetermined plug-in. An interconnection cable mechanically attaches between and provides electrical communications between the sensor connector and the plug-in connector. A pod is incorporated within the interconnecting cable that electrically interfaces the sensor connector to the plug-in connector.

In various embodiments, the pod has a cut in the interconnection cable that exposes cable wire ends. A circuit board is spliced to the cable wires end. A pre-mold encapsulates the cut, the circuit board, and the cable wire end, and an over-mold envelopes the pre-mode so as to define the pod. The circuit board comprises a first switch that, when closed, connects a resistor ID on the circuit board to the plug-in connector so as to enable a first plug-in attached to the plug-in connector to communicate with a sensor attached to the sensor connector. The circuit board also comprises a second switch that, when closed, connects an EEPROM ID on the circuit board to the plug-in connector so as to enable a second plug-in attached to the plug-in connector to communicate with a sensor attached to the sensor connector. The sensor adapter cable disconnects the resistor ID and the EEPROM ID when the first switch and the second switch are both open. The first switch may incorporate an n-channel MOSFET that turns on in response to a positive control signal from the first plug-in so as to switch in the resistor ID. The second switch may incorporate a p-channel MOSFET that turns on in response to a negative control signal from the second plug-in so as to switch in the EEPROM ID.

Another aspect of a sensor adapter cable is a method of interfacing any of multiple physiological monitor plug-ins to any of multiple optical sensors. An interface cable has a sensor connector on a first end and a plug-in connector on a second end. Resistive and memory IDs are incorporated within the cable. A sensor ID read signal is asserted at the plug-in connector. A particular one of the IDs is presented to the plug-in connector in response to the read signal. In various embodiments, unselected IDs are isolated from the plug-in connector and the selected ID. Switches are integrated with the IDs and are responsive to the read signal so as to connect the selected ID and disconnect the remaining IDs. A first switch is closed and a second switch is opened so as to select either a resistive ID or a memory ID. Both the first switch and the second switch are opened so that the sensor adapter cable functions as a patient cable. A circuit board with the switches and IDs is spliced between a portion of the interface cable conductors. The circuit board is encapsulated into a calibration pod portion of the interface cable.

A further aspect of a sensor adapter cable is a plug-in connector means for connecting to a plug-in module for a physiological monitor. A sensor connector means connects to an optical sensor. An interface cable mechanically and electrically interconnects the plug-in connector means and the sensor connector means. A pod means is integrated with the interface cable for allowing sensors to connected to and be recognized by the plug-in module. In various embodiments, the pod means comprises a circuit board means for splicing sensor IDs into the interface cable. A switching means selectively activates and isolates the sensor IDs so that only a single sensor ID is presented to the plug-in connector. A control means is in communications with the plug-in connector means for making the switching means responsive to a ID read signal from the plug-in module. The pod means further comprises an encapsulation means for enclosing the circuit board means within the pod means, where an encapsulations means embodiment comprises a premold of at least one of an epoxy, HDPE and PVC and an overmold of medical grade PVC.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general block diagram of a physiological parameter monitoring system that incorporates a sensor adapter cable;

FIGS. 2A-B are top, side and end views of a sensor adapter cable embodiment employing a M15 sensor connector and a D8 plug-in connector;

FIGS. 3A-C are a M15 connector end view; a cable schematic and a D8 connector end view, respectively;

FIG. 4 is a detailed schematic of a sensor adapter circuit;

FIGS. 5A-B are top, side and end views of a sensor adapter cable embodiment employing a MC8 sensor connector and a D8 plug-in connector;

FIGS. 6A-C are a MC8 connector end view; a cable schematic and a D8 connector end view, respectively;

FIGS. 7A-B are top, side and end views of a sensor adapter cable embodiment employing a DB9 sensor connector and a D8 plug-in connector;

FIGS. 8A-C are a DB9 connector end view; a cable schematic and a D8 connector end view, respectively;

FIGS. 9A-B are a perspective view and an exploded perspective view, respectively, of a sensor adapter cable pod;

FIGS. 10A-B are a perspective views of a sensor adapter circuit board and cable assembly;

FIG. 10C is a cable-side view of a sensor adapter circuit board;

FIG. 10D are cable prep top and side views; and

FIGS. 11A-C are transparent top, end and front views, respectively, of the pod.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a physiological parameter monitoring system 100 that incorporates a sensor adapter cable 120 or a family of sensor adapter cables so as to interconnect various sensors 110 with parameter processing plug-ins 130 to a physiological monitor 140. The sensors 110 include various types and configurations of optical devices as described above. Sensors typically have ID components that identify the sensor to a plug-in 130 so as to insure compatibility. Examples of ID components include an active component ID 114, such as a memory, or a passive component ID 112, such as one or more resistors having a specified range of values. In a particular embodiment, an active component ID 114 includes an EEPROM and a passive component ID 112 includes a ProCal resistor (Masimo) or an R-cal resistor (Philips/Nellcor).

Also shown in FIG. 1, a sensor adapter cable 120 has a sensor connector 122, a plug-in connector 124, a pod 900 and an interconnecting cable 128. The sensor connector 122 mechanically and electrically interfaces to one or more sensors 112, 114. The plug-in connector 124 interfaces to one or more plug-ins 130. The plug-ins 130, in turn, mechanically and electrically connect with a physiological monitor 140. The sensors 110 provide sensor signals to the plug-ins, which are used to calculate oxygen saturation (SpO2) and pulse rate among other parameters. The monitor 140 controls the plug-in operating modes and displays the parameter calculations accordingly. In an embodiment, the plug-ins are any of Masimo® SET® modules (Masimo Corporation, Irvine, Calif.) or Philips FAST-SpO2 modules, all available from Philips Medical Systems, Andover, Mass. In an embodiment, the physiological monitor is any of various IntelliVue™ monitors also available from Philips. The sensor connector and/or the plug-in connector can be any of various D8, M15, MC8 and DB9 connectors to name a few.

FIGS. 2A-B illustrate a sensor adapter cable embodiment 200 employing a M15 sensor connector 210 and a D8 plug-in connector 10. A cable 20 interconnects the sensor connector 210 and the plug-in connector 10. A pod 900 integrated with the cable 20 contains a sensor adapter circuit 400 (FIG. 4) that insures electrical compatibility between a passive and an active ID 110 (FIG. 1) and a particular plug-in 130 (FIG. 1).

FIGS. 3A-C further illustrate a sensor adapter cable embodiment 200, showing the respective pinouts of the M15 connector 210 and the D8 connector 10. Also shown are the corresponding cable 20 color-coded wires, inner shield and outer shield. Further shown is a sensor adapter circuit 400 and its connections relative to the connectors 10, 210 and cable 20 wires.

FIG. 4 illustrates the sensor adapter circuit 400 having plug-in connections 410 and sensor connections 420. The plug-in connections 410 (J1, J2, J3) connect to the plug-in connector 10 (FIGS. 2-3, 5-6, 7-8). The sensor connections 420 (J4, J5) connect to the sensor connector 210 (FIGS. 2-3); 510 (FIG. 5-6) or 710 (FIGS. 7-8). Table 1 below defines the signal names and associated connections to the plug-in connector pins.

TABLE 1
Adapter Circuit and Plug-in Connector Pinouts
		Reference
	Signal Name	Designation	Plug-in Connector Pin #
	R-TYPE/EEPROM	J2	3
	RCAL/CONTROL	J1	4
	OUTER SHIELD	J3	7

The switch components 430, 440 used in this design (Si2312 and Si2351 or equivalents) are high impedance MOSFET devices that have no impact on R-cal and R-TYPE resistor measurements due to the fact that the MOSFET gates do not require current to activate. When the cable is connected to a Philips FAST equipped device, the RCAL/CONTROL signal will be a positive voltage. The RCAL/CONTROL voltage is 2.9V without a sensor connected and can be as low as 1.1V with the minimum value RCAL resistor of 6.04 KΩ. This is understood to represent the entire range for the RCAL/CONTROL voltage. When the cable is connected to a Masimo XCaI capable SpO2 module, a negative voltage will be applied to RCAL/CONTROL signal. This will turn on Q2 and turn off Q1 which will allow the Masimo system to read the EEPROM contents. Table 2, below, describes how the switches (Q1, Q2) operate.

TABLE 2
Adapter Circuit Switch Truth Table
	RCAL/
SpO2	Control
Module	Signal	Switch Q1	Switch Q2	Comments
Philips	Positive	Closed	Open	Philips FAST
FAST	voltage			module can
				measure RCAL and
				R-TYPE resistors
Masimo	Open (No	Open	Open	Same as patient
ProCal	driving	(Don't	(Don't	cable
Technology	voltage)	care)	care)
Masimo	Negative	Open	Closed	Masimo board will
XCal	voltage			read EEPROM;
Technology				negative voltage will
				be supplied by the
				Masimo board

The n-channel transistor (Q1) 430 was chosen with a very low turn-on threshold (0.85V max) so that it is guaranteed to turn on and switch in the R-TYPE resistor even at the lowest RCAL/CONTROL voltage of 1.1V. The on-resistance of the FET is so low (less than 100 mΩ) that it will not affect the measured R-TYPE resistor value. At the same time, the p-channel FET (Q2) 440 will be turned off since the gate-to-source voltage (Vgs) will be positive. Even in the worst possible case, the Vgs will be −0.3V which is not low enough to turn-on the p-channel device. The minimum turn-on threshold for the p-channel is −0.6V. The purpose of resistors R1 and R2 and ESD protection diodes D1 and D2 are to protect the MOSFET devices. This sensor adapter embodiment ensures proper operation and ample margin in all possible combinations of sensor and device types and therefore meets the design requirements necessary to allow Masimo SET or Philips FAST systems to work correctly with a dual key D8 connector capable of plugging into either type of system.

Resistor R3 of FIG. 4 is a passive ID element on the sensor adapter circuit 400. U1 450 is an EEPROM and is an active ID element on the sensor adapter circuit 400.

FIGS. 5A-B illustrate a sensor adapter cable embodiment 500 employing a MC8 sensor connector 510 and a D8 plug-in connector 10. A cable 20 interconnects the sensor connector 510 and the plug-in connector 10. A pod 900 integrated with the cable 20 contains a sensor adapter circuit 400 (FIG. 4) that insures electrical compatibility between a passive and an active ID 110 (FIG. 1) and a particular plug-in 130 (FIG. 1).

FIGS. 6A-C further illustrate a sensor adapter cable embodiment 500, showing the respective pinouts of the MC8 connector 510 and the D8 connector 10. Also shown are the corresponding cable 20 color-coded wires, inner shield and outer shield. Further shown are the sensor adapter circuit 400 connections relative to the connectors 10, 510 and cable 20 wires.

FIGS. 7A-B illustrate a sensor adapter cable embodiment 700 employing a DB9 sensor connector 710 and a D8 plug-in connector 10. A cable 20 interconnects the sensor connector 710 and the plug-in connector 10. A pod 900 integrated with the cable 20 contains a sensor adapter circuit 400 (FIG. 4) that insures electrical compatibility between a passive and an active ID 110 (FIG. 1) and a particular plug-in 130 (FIG. 1).

FIGS. 8A-C further illustrate a sensor adapter cable embodiment 700, showing the respective pinouts of the DB9 connector 710 and the D8 connector 10. Also shown are the corresponding cable 20 color-coded wires, inner shield and outer shield. Further shown are the sensor adapter circuit 400 connections relative to the connectors 10, 710 and cable 20 wires.

FIGS. 9A-B illustrate a pod 900 that splices the sensor adapter circuit 400 (FIG. 4) into the sensor adapter cable 20. The pod 900 has a overmold 910, a premold 920, a copper foil shield 930, a circuit board 940 and heat-shrink tubing 950. The circuit board 940 provides the sensor adapter circuit 400 (FIG. 4) described above. The board 940 is mounted to the cable 20 and electrically interconnected to the cable wires and outer shield, as described with respect to FIG. 4, above. The premold 920 is manufactured to envelop the circuit board 940 and spliced cable portion. The copper foil shield 930, if used, envelops the premold 920, and the overmold 910 envelops all of the pod 900 components.

FIGS. 10A-D illustrate attachment of the circuit board 940 to the adapter cable 20. Shown is cable preparation (FIG. 10D) for splicing with the circuit board 940 (FIG. 10C). Also shown are preparation of the cable wires (FIG. 10B) and mounting of the circuit board 940 to the cable wires. FIGS. 11A-C further illustrates the assembled pod 900.

A sensor adapter cable has been disclosed in detail in connection with various embodiments. These embodiments are disclosed by way of examples only and are not to be construed as limiting the scope of this disclosure. One of ordinary skill in the art will appreciate many variations and modifications.

Claims

1. A sensor adapter cable provides medical personnel with the convenience of utilizing otherwise incompatible optical sensors with multiple blood parameter plug-ins to a physiological monitor, where the plug-ins each have keyed connectors that mechanically lock-out incompatible sensors in addition to readers that poll sensor identification components in each sensor so as to electrically lockout incompatible sensors, the sensor adapter cable comprising: a sensor connector that mechanically connects to a predetermined sensor and electrically communicates with a plurality of sensor electrical elements within the predetermined sensor;a plug-in connector that mechanically connects to a predetermined plug-in and electrically communicates with a plurality of plug-in electrical elements within the predetermined plug-in;an interconnection cable that mechanically attaches between and provides electrical communications between the sensor connector and the plug-in connector; anda pod, including a circuit board, incorporated within the interconnecting cable that electrically interfaces the sensor connector to the plug-in connector; wherein the pod includes both active and passive identification elements;wherein the circuit board comprises a first switch that, when closed, connects a resistor ID on the circuit board to the plug-in connector so as to enable a first plug-in attached to the plug-in connector to communicate with a sensor attached to the sensor connector, wherein the first switch is one of an n-channel or p-channel MOSFET;wherein the circuit board comprises a second switch that, when closed, connects an EEPROM ID on the circuit board to the plug-in connector so as to enable a second plug-in attached to the plug-in connector to communicate with a sensor attached to the sensor connector, wherein the second switch is the other of an n-channel or p-channel MOSFET.

2. The sensor adapter cable according to claim 1 wherein the pod comprises: a cut in the interconnection cable that exposes a plurality of cable wire ends;the circuit board spliced to the cable wires ends;a pre-mold that encapsulates the cut, the circuit board, and the cable wire end; andan over-mold that envelopes the pre-mode so as to define the pod.

3. The sensor adapter cable according to claim 1 wherein the sensor adapter cable disconnects the resistor ID and the EEPROM ID when the first switch and the second switch are both open.

4. The sensor adapter cable according to claim 1 wherein the first switch turns on in response to a positive control signal from the first plug-in so as to switch in the resistor ID.

5. The sensor adapter cable according to claim 1 wherein the second switch turns on in response to a negative control signal from the second plug-in so as to switch in the EEPROM ID.

6. A method of using a sensor adapter cable for interfacing any of multiple physiological monitor plug-ins to any of multiple optical sensors comprising: providing an interface cable having a sensor connector on a first end and a plug-in connector on a second end, and incorporating a plurality of passive and active memory identifications (IDs) within the cable, wherein the passive ID is at least one resistive ID and the active ID is a memory ID;asserting a sensor ID read signal at the plug-in connector; andselecting a particular one of the IDs to present to the plug-in connector in response to the read signal using one of an n-type MOSFET or a p-type MOSFET for the resistive ID and using the other of an n-type MOSFET or a p-type MOSFET for the memory ID.

7. The method according to claim 6 further comprising isolating unselected IDs from the plug-in connector and the selected ID.

8. The method according to claim 7 wherein the n-type MOSFET and p-type MOSFET are responsive to the read signal so as to connect the selected ID and disconnect the remaining IDs.

9. The method according to claim 8 further comprising closing a first one of the n-type MOSFET or p-type MOSFET and opening a the other of the n-type MOSFET or p-type MOSFET so as to select either a resistive ID or a memory ID.

10. The method according to claim 8 further comprising opening both the n-type MOSFET and p-type MOSFET so that the sensor adapter cable functions as a patient cable.

11. The method according to claim 10 wherein the providing further comprises a circuit board with the n-type MOSFET and p-type MOSFET and IDs spliced between a portion of the interface cable conductors.

12. The method according to claim 11 the circuit board is encapsulated into a calibration pod portion of the interface cable.

13. A sensor adapter cable comprising: a plug-in connector means for connecting to a plug-in module for a physiological monitor;a sensor connector means for connecting to an optical sensor;an interface cable that mechanically and electrically interconnects the plug-in connector means and the sensor connector means; anda pod means integrated with the interface cable for allowing a plurality of sensors to connect to and be recognized by the plug-in module, the pod means including at least passive and active memory identifications (IDs);a switching means for selectively activating and isolating the IDs so that only a single ID is presented to the plug-in connector, wherein the switching means comprises one of an n-type MOSFET or a p-type MOSFET for the at least one of the IDs and the other of an n-type MOSFET or a p-type MOSFET for the at least another of the IDs.

14. The sensor adapter cable according to claim 13 further comprising a control means in communications with the plug-in connector means for making the switching means responsive to a ID read signal from the plug-in module.

15. The sensor adapter cable according to claim 14 wherein the pod means further comprises an encapsulation means for enclosing a circuit board within the pod means.

16. The sensor adapter cable according to claim 15 wherein the encapsulations means comprises: a premold of at least one of an epoxy, HDPE and PVC; andan overmold of medical grade PVC.