DESCRIPTION

This application claims the benefit of US Provisional patent application Serial No. 61/335,984, filed January 13, 2010, the disclosure of which is incorporated herein by reference.

The present application relates to the medical diagnostic arts. It finds particular application in conjunction with pulse oximetry systems and will be described with particular reference thereto. However, it is to be appreciated that the present application may find other applications, particularly in the diagnosis or monitoring of respiratory, blood, or other medical conditions.

Pulse oximeters are commonly used to monitor characteristics of hemoglobin, particularly to measure oxygen saturation and to monitor pulse rate. Oxygen saturation is commonly measured by determining a ratio of the absorption of two wavelengths of light, typically red and infrared. The relative amount of light of each wavelength absorbed by the blood varies with a level of oxygen saturation.

Typically, light energy from the red and infrared light sources is beamed through a region of the patient containing pulsating vasculature. Any light which is not absorbed is sampled at the opposite side. The signal received at the opposite side is split into red and infrared components, sampled, software filtered, and displayed as a numerical value or as a waveform.

Pulse oximeters can be standalone devices which measure only oxygen saturation or can be integrated with complex medical monitoring systems which measure many physiological properties in addition to oxygen saturation. The sensor includes a multi-pin plug which is configured to fit a corresponding multi-pin socket in the monitor. An integral lead extends from the plug for 2-3 meters to an integrally connected sensor head. The sensor head typically includes a light emitting component which includes a red LED and an infrared LED and a light-receiving unit which includes a photodiode, or the like. Typically, a variety of attaching systems, such as finger clamps, earclips, pressure sensitive adhesive systems, hook and loop fasteners of the Velcro® type, or the like are utilized to secure the sensor head to the patient. One problem the user experiences with such sensors is that they are not interchangeable among manufacturers. Each manufacturer uses a different style of plug, a different arrangement of the pins, and the like. Moreover, some manufacturers use LEDs of different wavelengths, use different LED actuation techniques, and the like. This stifles price competition by limiting medical facilities to purchasing replacement sensor from the original manufacturer. Additionally, this requires the user to maintain more inventory of sensors as well as any attachment accessories. Furthermore, this limitation inconveniences the user by requiring them to remove and replace the sensor when moving patients between departments that may be using pulse oximetry systems from different manufacturers.

The present application proposes a universal sensor which, when used either directly or with a relatively simple adapter, can be plugged into the monitor of a variety of manufacturers providing for standardization within the institution.

In accordance with one aspect, a sensor is provided for a pulse oximetry system. The sensor includes a light emitting unit including a first light emitting element, a second light emitting element, and a third light emitting element. At least one of the light emitting elements emits red light and at least one emits infrared light.

In accordance with another aspect, a pulse oximetry system includes an adapter unit having an adapter plug at one end configured to be received in a socket of a monitor and has a socket at its opposite end configured to receive a sensor plug, the sensor plug and the adapter plug being of different configurations. A sensor unit includes the sensor plug, a light emitting unit for emitting red and infrared light, a light receiving unit for receiving light from the light emitting unit, and a cable. The cable connects the sensor plug with the light emitting unit and the light receiving unit.

One advantage resides in sensor standardization.

Another advantage resides in reduced inventory requirements.

Still further advantages of the present invention will be appreciated to those of ordinary skill in the art upon reading and understand the following detailed description.

The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention.

FIGURE 1 is illustrative of a pulse oximetry system;

FIGURE 2 is a circuit diagram of an oximetry sensor head;

FIGURE 3A illustrates an effective circuit diagram for the LED light emission portion of FIGURE 2 when used in a two-wire alternating polarity configuration;

FIGURE 3B illustrates an effective circuit diagram for the LED portion of FIGURE 2 when operated in a common anode configuration;

FIGURE 4 illustrates a four diode circuit diagram of an oximetry sensor head;

FIGURE 5A illustrates an effective circuit diagram for the LED light emission portion of FIGURE 5 when used in a two-wire alternating polarity configuration;

FIGURE 5B illustrates an effective circuit diagram for the LED portion of FIGURE 5 in a common cathode configuration;

FIGURE 6 is a diagrammatic illustration of the plug or socket portion of the adapter cable of FIGURE 1 ; and,

FIGURE 7 is illustrative of a method of use.

With reference to FIGURE 1, a pulse oximetry monitor 10 may monitor only pulse and blood oxygen saturation levels or maybe a much larger monitor system with many leads that monitor many other physiological conditions as well. The monitor 10 includes a numerical display 12 for displaying blood oxygen saturation and pulse rate values and may also include graphical display 14 for displaying the pulsatile waveform that results from cardiac activity, i.e., a plethysmogram. Optionally, an additional display 16 is provided for displaying other patient data or other physiological information. Of course, the displays 12, 14, 16 and can be integrated into a single display unit which displays numerous different physiological values and waveforms. The monitor 10 further includes a socket 18 configured to receive the plug of a cable connected to a pulse oximetry sensor. The socket may have any one of a variety of configurations as may be selected by the manufacturer of the monitor 10. An adapter cable 20 includes a plug 22 at one end configured to match the socket 18 and a socket 24 at its opposite end configured to receive a plug of a common or universal configuration. A short length of cabling 26 connects the plug and socket.

A pulse oximetry sensor 30 includes a plug 32 of the common or universal configuration which is configured to be received in the socket 24. A length of cabling 34, e.g., 2-3 meters, extends from the common or universal plug 32 to a light emitting unit 36 and a light receiving unit 38 of a sensor head 40. In the y-configuration illustrated in FIGURE 1, the cable branches 42 a short distance before the light emitting unit and the light receiving unit. A mounting strip 44 is provided for adhering the light emitting unit 36 and the light receiving unit 38 in selected locations on opposite sides of a finger, toe, earlobe, or the like. Alternately, a finger clip or the like can be provided to attach the sensor head to the patient.

With continuing reference to FIGURE 1, and further reference to FIGURE 2, the light emitting unit 36 includes three light emitting diodes, a red wavelength light emitting diode 50, a first infrared light emitting diode 52, and a second infrared light emitting diode 54. The red light emitting diode can have any of several wavelengths in the red spectrum, such as 660 nm. The infrared light emitting diodes 52, 54 can have any of a plurality of selected wavelengths in the infrared range, such as 880 nm and 940 nm. The light emitting unit 36 has three leads, a first lead 60, a second lead 62, and a third lead 64. The red diode 50 and the first infrared diode 52 are connected across the first and second leads in an anti-parallel manner. The second infrared diode 54 is connected between the second and third leads in a back-to-back relationship with the red diode.

With reference to FIGURE 3A and continuing reference to FIGURE 2, when a positive potential is applied to the first lead 60, a negative potential or ground is applied to the second lead 62, and the third lead 64 is disconnected, then electricity flows through the first infrared diode 52, causing it to emit infrared light. When a positive potential is applied to the second lead 62 and a negative or ground potential is applied to the first lead 60, the electricity flows through the red diode 50, causing it to emit red light. Due to the anti-parallel relationship of the red diode 50 and the first infrared LED 52, only one of the diodes will be illuminated at a time. Because the second infrared LED 54 is disconnected from the circuit, it will not emit light regardless of the polarity of the potentials applied to leads 60, 62. With continuing reference to FIGURE 2 and further reference to FIGURE 3B, in the common anode mode, to generate a red pulse, a positive potential is applied to the second lead 62 and a negative or ground potential is applied to the first lead 60 and the third lead 64 is disconnected from a negative potential or ground. To generate an infrared pulse, the negative or ground potential is removed from lead 60 and applied to the third lead 64, causing a current flow only through the second infrared LED 54. Note that because the positive potential is applied on lead 62, the first infrared LED 56 cannot be biased to emit light. In this manner, the light emitting circuit 36 can be operated in either a two-wire alternating polarity mode or in a three-wire common anode mode. Moreover, if the first and second infrared LEDs 52, 54 emit light of different wavelengths, then the wavelength of the emitted infrared light can also be selected. Although described with two infrared LEDs and one red LED, it is to be appreciated that two red LEDs and one infrared LED can be used in a like manner.

With continuing reference to FIGURE 2, the light receiving unit 38 includes an opto-electrical component 70, such as a photodiode, which receives light from the LEDs and provides an output across leads 72, 74 indicative of an amount of received light. Additional LEDs or pins of the common or universal plug 32 may be connected with an RF or ground shield 80 to protect the signal from the light detecting unit 38 from potential interference. In the illustrated embodiment, the opto-electrical component receives light that has passed through a section of the patient containing pulsing vasculature. However, sensing light reflected from the vasculature is also contemplated.

In the four LED embodiment of FIGURE 4, like elements are denoted by the same reference number as in FIGURE 2. A second red diode 56 is connected with the second lead 62 and the third lead 64 is an anti-parallel relationship to the infrared diode 54 and in a front-to-front relationship to the infrared diode 52.

This embodiment can be operated as explained in conjunction with FIGURE 3A. Alternately, as illustrated in FIGURE 5A, a positive potential can be applied to the third lead 64 and a negative potential to the second lead with the first lead 60 disconnected causing the infrared LED to emit light. Reversing the polarity on the second and third leads causes the red diode 56 to emit light. By selecting the mode of FIGURE 3A or the mode of FIGURE 5A, different wavelength combinations for the infrared and/or red light can be selected. If the wavelength of both infrared diodes is the same and the wavelength of both red diodes is the same, switching between the modes of FIGURE 3A and FIGURE 5A can be used to double the useful life.

The embodiment of FIGURE 4 can still be operated in the common anode mode as described in conjunction with FIGURE 3B or in a common cathode mode as illustrated in FIGURE 5B. In the common cathode mode, the second lead 62 is connected to the cathode and the red LED 56 is selected by applying a positive potential to the third lead 64 and the infrared LED 52 is selected by applying the positive potential to the first lead 60. These options again provide greater light spectrum selectability and extended life as discussed above.

With reference to FIGURE 6, the plug 22 of the adapter section 20 includes a plurality of pins or contacts 90 configured in accordance with the requirements of the socket 18. The socket 24 includes a plurality of pins or contacts 92 configured to comply with the contact/pin arrangement on the common/universal plug 32. The plug or socket of the adapter 20 can further include an identification device 94 which identifies characteristics of the oximetry sensor, such as wavelengths of the infrared or red diodes, or other operating characteristics. The identification device may have various forms such as a resistor whose resistance value is keyed to the wavelength of the light. Alternately, the identification device can include a non-volatile memory, such as a PROM or the like, which stores the identification information in a digital format and which is digitally readable by the monitor. In other embodiments, an inductive or capacitive identification component can be used. Other digital or analog identification components are also contemplated.

Referring to FIGURE 7 to illustrate use of the oximetry sensor, when the medical facility first converts to the present oximetry sensor, the appropriate adapter unit 20 (if required) for the monitor 10 is plugged into the monitor socket 18 at a step 100. When the monitor is to be used with a patient, the oximetry sensor 30 is wiped down with a liquid disinfectant at a step 102 and plugged into the socket 24 of the adapter 20 at a step 104. The light emitting unit 36 and the light receiving unit 38 are mounted to the patient at step 106. The patient is then monitored 108. After the patient no longer needs a pulse oximetry monitor, the sensor is disconnected, cleaned and disinfected at step 110. The oximetry sensor is now ready to be used with the next patient. Optionally, the cleaned and disinfected oximetry sensor may be placed in sterile packaging at step 112 so that next time the oximetry sensor is used, the first disinfecting step 102 can be bypassed.

The invention has been described with reference to the preferred embodiments. Modifications and alterations may occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be constructed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.