System and Method for Mitigating the Effects of Tissue Blood Volume Changes to Aid in Diagnosing Infiltration or Extravasation in Animalia Tissue

Abstract

A system including a sensor and a device coupled to the sensor. The sensor is configured to detect in Animalia tissue (i) a first electromagnetic radiation extinction dominated by absorption of a first wavelength and (ii) a second electromagnetic radiation extinction dominated by scattering of a second wavelength. The device is configured to aid in diagnosing at least one of infiltration and extravasation in the Animalia tissue based on the first and second electromagnetic radiation extinctions detected by the sensor.

What is claimed is: 
     
         1 . A system to aid in diagnosing at least one of infiltration and extravasation in Animalia tissue, the system comprising:
 a sensor configured to emit first and second signals entering the Animalia tissue and to detect third and fourth signals exiting the Animalia tissue, the first signal having a peak wavelength between 800 nanometers and 1,050 nanometers, the second signal having a peak wavelength between 560 nanometers and 660 nanometers, the third signal including a portion of the first signal that is at least one of reflected, scattered and redirected from the Animalia tissue, and the fourth signal including a portion of the second signal that is at least one of reflected, scattered and redirected from the Animalia tissue; and   a device coupled to the sensor and configured to (i) detect infusate accumulation over time in the Animalia tissue based on the third signal and (ii) detect tissue blood volume changes in the Animalia tissue based on the fourth signal, the device being configured to output a notice based on distinguishing between the infusate accumulation and the tissue blood volume changes.   
     
     
         2 . The system of  claim 1  wherein the notice comprises one of (i) an infiltration/extravasation examination of the Animalia tissue is indicated and (ii) an infiltration/extravasation examination of the Animalia tissue is contraindicated. 
     
     
         3 . The system of  claim 1  wherein the device comprises an analog-to-digital converter configured to (i) represent the third signal with a first sequence of values and (ii) represent the fourth signal with a second sequence of values. 
     
     
         4 . The system of  claim 3  wherein the device comprises a processor coupled to the analog-to-digital converter, the processor being configured to (i) compute normalized values of the first and second sequences of values, (ii) compare the normalized values of the second sequence of values with a threshold value, and (iii) compare corresponding normalized values of the first and second sequences of values. 
     
     
         5 . The system of  claim 4  wherein the threshold value is 0.90. 
     
     
         6 . The system of  claim 4  wherein the device comprises an indicator coupled to the processor, the indicator being configured to output the notice when (i) the normalized values of the second sequence of values are less than the threshold value and (ii) the normalized values of the first sequence of values are greater than the corresponding normalized values of the second sequence of values. 
     
     
         7 . A system comprising:
 a sensor configured to detect infusate accumulation over time in Animalia tissue and to detect tissue blood volume change in the Animalia tissue;   a device coupled to the sensor and being configured to aid in diagnosing at least one of infiltration and extravasation in the Animalia tissue based on distinguishing between (i) infusate accumulation detected by the sensor and (ii) tissue blood volume change detected by the sensor.   
     
     
         8 . The system of  claim 7  wherein the sensor comprises an emitter and a detector. 
     
     
         9 . The system of  claim 8  wherein the emitter is configured to emit first and second signals, the first signal is sensitive to the infusate accumulation and the second signal is sensitive to the tissue blood volume change, the detector is configured to detect third and fourth signals, the third signal includes a portion of the first signal that is at least one of reflected, scattered and redirected from the Animalia tissue, and the fourth signal includes a portion of the second signal that is at least one of reflected, scattered and redirected from the Animalia tissue. 
     
     
         10 . The system of  claim 9  wherein the first and third signals comprise electromagnetic radiation at a first peak wavelength, and the second and fourth signals comprise electromagnetic radiation at a second peak wavelength. 
     
     
         11 . The system of  claim 10  wherein the first peak wavelength is in a first range of peak wavelengths between 930 nanometers and 960 nanometers, and the second peak wavelength is in a second range of peak wavelengths between 570 nanometers and 620 nanometers. 
     
     
         12 . A method to aid in diagnosing at least one of infiltration and extravasation in the Animalia tissue, the method comprising:
 coupling a sensor to the Animalia tissue, the sensor:
 detecting a first signal correlating to infusate accumulation in the Animalia tissue; and 
 detecting a second signal correlating to tissue blood volume in the Animalia tissue; and 
   coupling a device to the sensor, the device distinguishing between infusate accumulation and tissue blood volume changes.   
     
     
         13 . The method of  claim 12 , comprising notifying an infiltration/extravasation examination of the Animalia tissue is contraindicated based on (i) the device evaluating that infusate is not accumulating in the Animalia tissue and (ii) the device evaluating that tissue blood volume is changing in the Animalia tissue. 
     
     
         14 . The method of  claim 12 , comprising notifying an infiltration/extravasation examination of the Animalia tissue is indicated based on (i) the device evaluating that infusate is accumulating in the Animalia tissue and (ii) the device evaluating that tissue blood volume is changing in the Animalia tissue. 
     
     
         15 . The method of  claim 12  wherein (i) detecting infusate accumulation includes the sensor transmitting a first signal entering the Animalia tissue, the first signal has a peak wavelength between 800 nanometers and 1,050 nanometers; (ii) detecting tissue blood volume change includes the sensor transmitting a second signal entering the Animalia tissue, and the second signal having a peak wavelength between 570 nanometers and 620 nanometers; (iii) evaluating whether infusate is accumulating includes the sensor receiving a third signal exiting the Animalia tissue, the third signal includes a portion of the first signal that is at least one of reflected, scattered and redirected from the Animalia tissue; and (iv) evaluating whether tissue blood volume is changing includes the sensor receiving a fourth signal exiting the Animalia tissue, the fourth signal includes a portion of the second signal that is at least one of reflected, scattered and redirected from the Animalia tissue. 
     
     
         16 . The method of  claim 15 , comprising notifying an infiltration/extravasation examination of the Animalia tissue is contraindicated when (i) infusate is not accumulating based on the device evaluating the third signal and tissue blood volume is changing based on the device evaluating the fourth signal or (ii) infusate is not accumulating based on the device evaluating the third signal and tissue blood volume is not changing based on the device evaluating the fourth signal. 
     
     
         17 . The method of  claim 15 , comprising notifying an infiltration/extravasation examination of the Animalia tissue is indicated when (i) infusate is accumulating based on the device evaluating the third signal and tissue blood volume is changing based on the device evaluating the fourth signal or (ii) infusate is accumulating based on the device evaluating the third signal and tissue blood volume is not changing based on the device evaluating the fourth signal. 
     
     
         18 . A system to aid in diagnosing at least one of infiltration and extravasation in Animalia tissue, the system comprising:
 a sensor including—
 a housing including a surface configured to confront an epidermis of the Animalia tissue; 
 a first waveguide being partially disposed in the housing and configured to transmit first and second signals that enter the Animalia tissue through the epidermis, the first signal having a peak wavelength between 800 nanometers and 1,050 nanometers, and the second signal having a peak wavelength between 570 nanometers and 620 nanometers; and 
 a second waveguide being partially disposed in the housing and configured to transmit third and fourth signals that exit the Animalia tissue through the epidermis, the third signal including a portion of the first signal that is at least one of reflected, scattered and redirected from the Animalia tissue, and the fourth signal including a portion of the second signal that is at least one of reflected, scattered and redirected from the Animalia tissue; 
   a dressing being configured to couple the sensor to the epidermis;   a device being configured to evaluate the third and fourth signals, the device including—
 an optics bench including a first light emitting diode, a second light emitting diode and a photodiode, the first light emitting diode being configured to emit the first signal transmitted by the first waveguide, the second light emitting diode being configured to emit the second signal transmitted by the first waveguide, and the photodiode being configured to detect the third and fourth signals transmitted by the second waveguide; 
 a processor coupled to the optics bench, the processor being configured to (i) compute normalized values of the third and fourth signals, (ii) compare the normalized value of the third signal with a threshold value, and (iii) compare the normalized values of the third and fourth signals; and 
 an indicator coupled to the processor, the indicator being configured to output a notice when (i) the normalized value of the third signal is less than the threshold value and (ii) the normalized value of the fourth signal is greater than the normalized value of the third signal; and 
   a cable coupling the sensor and the device, the cable including portions of the first and second waveguides.   
     
     
         19 . The system of  claim 18  wherein the peak wavelengths of the first and third signals are between 930 nanometers and 960 nanometers. 
     
     
         20 . The system of  claim 18  wherein the peak wavelengths of the first and third signals are centered about 940 nanometers, and the peak wavelengths of the second and fourth signals are centered about 610 nanometers. 
     
     
         21 . The system of  claim 18  wherein the peak wavelengths of the second and fourth signals generally correspond to an isosbestic point of oxyhemoglobin and deoxyhemoglobin. 
     
     
         22 . The system of  claim 18  wherein the peak wavelengths of the second and fourth signals are centered about 586 nanometers. 
     
     
         23 . The system of  claim 18  wherein the first waveguide includes a plurality of emission optical fibers and the second waveguide includes a plurality of detection optical fibers. 
     
     
         24 . The system of  claim 23  wherein the cable comprises a sheath cincturing the pluralities of emission and detection optical fibers. 
     
     
         25 . The system of  claim 18  wherein the dressing comprises a fitting having first and second arrangements, the first arrangement being configured to retain the housing with respect to the epidermis, and the second arrangement being configured to release the housing from the first arrangement. 
     
     
         26 . The system of  claim 25  wherein the dressing comprises a body coupled to the fitting and configured to prevent contiguous engagement between the housing and the epidermis. 
     
     
         27 . The system of  claim 18  wherein the threshold value is not greater than 0.95. 
     
     
         28 . The system of  claim 18  wherein the threshold value is 0.90. 
     
     
         29 . The system of  claim 18  wherein the processor is configured to evaluate the third signal for infusate accumulation over time in the Animalia tissue and to evaluate the fourth signal for changing tissue blood volume in the Animalia tissue. 
     
     
         30 . The system of  claim 18  wherein the notice comprises an aid to diagnosing at least one of infiltration and extravasation in the Animalia tissue. 
     
     
         31 . The system of  claim 18  wherein the first waveguide includes an emitter face configured to confront the epidermis, the second waveguide includes a detector face configured to confront the epidermis, and the surface cinctures the emitter and detector faces. 
     
     
         32 . The system of  claim 31  wherein the housing comprises an electromagnetic radiation energy absorber configured to generally absorb portions of the first, second, third and fourth signals that (i) are at least one of reflected, scattered and redirected from the Animalia tissue, and (ii) impinge on the surface. 
     
     
         33 . The system of  claim 31  wherein each individual point of the emitter end face is disposed a minimum distance not less than 3 millimeters from each individual point of the detector end face, and each individual point of the emitter end face is disposed a maximum distance not more than 5 millimeters from each individual point of the detector end face. 
     
     
         34 . The system of  claim 18  wherein the cable includes a plug and the optics bench includes a transceiver configured for consistent optical coupling with the plug, the transceiver includes a common enclosure for the first light emitting diode, the second light emitting diode, and the photodiode. 
     
     
         35 . The system of  claim 18  wherein the device comprises a shell generally encasing first and second printed circuit boards, the optics bench is mounted on the first printed circuit board, the processor is mounted on the second printed circuit board, and the second printed circuit board is spaced from the first printed circuit board. 
     
     
         36 . The system of  claim 18  wherein the device comprises a temperature sensor coupled to the processor. 
     
     
         37 . A system to aid in diagnosing at least one of infiltration and extravasation in Animalia tissue, the system comprising:
 a sensor including—
 a housing including a surface configured to confront an epidermis of the Animalia tissue; 
 a first waveguide being partially disposed in the housing and configured to transmit first and second signals that enter the Animalia tissue through the epidermis, the first signal having a peak wavelength between 800 nanometers and 1,050 nanometers, and the second signal having a peak wavelength between 570 nanometers and 620 nanometers; and 
 a second waveguide being partially disposed in the housing and configured to transmit third and fourth signals that exit the Animalia tissue through the epidermis, the third signal including a portion of the first signal that is at least one of reflected, scattered and redirected from the Animalia tissue, and the fourth signal including a portion of the second signal that is at least one of reflected, scattered and redirected from the Animalia tissue; 
   a dressing being configured to couple the sensor to the epidermis;   a device being configured to evaluate the third and fourth signals, the device including—
 an optics bench including a first light emitting diode, a second light emitting diode and a photodiode, the first light emitting diode being configured to emit the first signal transmitted by the first waveguide, the second light emitting diode being configured to emit the second signal transmitted by the first waveguide, and the photodiode being configured to detect the third and fourth signals transmitted by the second waveguide; 
 a processor coupled to the optics bench, the processor being configured to (i) activate and deactivate the first and second light emitting diodes during each of a plurality of cycles, (ii) sample the third and fourth signals during each of the plurality of cycles, (iii) compute normalized values of individual third and fourth signal samples for each of the plurality of cycles, (iv) fit an equation to ordered pairs of the normalized values for each cycle in a first collection of the plurality of cycles, and (v) compare the equation to ordered pairs of the normalized values for each cycle in a second collection of the plurality of cycles; 
 an indicator coupled to the processor, the indicator being configured to output a notice when (i) the ordered pairs of the second collection number more than a first threshold value, (ii) the ordered pairs of the second collection are perpendicularly spaced a displacement from the equation, (iii) the displacement corresponds to a change in the normalized values of the third signal samples that is greater than a second threshold value, and (iv) the displacement corresponds to a change in the normalized values of the fourth signal samples that is less than the change in the normalized values of the third signal samples; and 
   a cable coupling the sensor and the device, the cable including portions of the first and second waveguides.   
     
     
         38 . The system of  claim 37  wherein the peak wavelengths of the first and third signals are between 930 nanometers and 960 nanometers. 
     
     
         39 . The system of  claim 37  wherein the peak wavelengths of the first and third signals are centered about 940 nanometers, and the peak wavelengths of the second and fourth signals are centered about 610 nanometers. 
     
     
         40 . The system of  claim 37  wherein the peak wavelengths of the second and fourth signals generally correspond to an isosbestic point of oxyhemoglobin and deoxyhemoglobin. 
     
     
         41 . The system of  claim 37  wherein the first waveguide includes a plurality of emission optical fibers and the second waveguide includes a plurality of detection optical fibers. 
     
     
         42 . The system of  claim 37  wherein the dressing comprises a fitting having first and second arrangements, the first arrangement being configured to retain the housing with respect to the epidermis, and the second arrangement being configured to release the housing from the first arrangement. 
     
     
         43 . The system of  claim 42  wherein the dressing comprises a body coupled to the fitting and configured to prevent contiguous engagement between the housing and the epidermis. 
     
     
         44 . The system of  claim 37  wherein a first rate of activating and deactivating the first light emitting diode is between 0.3 Hertz and 60 Hertz. 
     
     
         45 . The system of  claim 37  wherein a second rate of activating and deactivating the second light emitting diode is between 24 Hertz and 120 Hertz. 
     
     
         46 . The system of  claim 37  wherein a first rate of activating and deactivating the first light emitting diode is 5 Hertz and a second rate of activating and deactivating the second light emitting diode is 60 Hertz. 
     
     
         47 . The system of  claim 37  wherein the equation comprises one of a first-degree polynomial function and a second-degree polynomial function. 
     
     
         48 . The system of  claim 37  wherein the first threshold value is 300. 
     
     
         49 . The system of  claim 37  wherein the second threshold value is 0.05. 
     
     
         50 . The system of  claim 37  wherein the processor is configured to evaluate the third signal for infusate accumulation over time in the Animalia tissue and to evaluate the fourth signal for changing tissue blood volume in the Animalia tissue. 
     
     
         51 . The system of  claim 37  wherein the notice comprises an aid to diagnosing at least one of infiltration and extravasation in the Animalia tissue. 
     
     
         52 . The system of  claim 37  wherein the first waveguide includes an emitter face configured to confront the epidermis, the second waveguide includes a detector face configured to confront the epidermis, and the surface cinctures the emitter and detector faces. 
     
     
         53 . The system of  claim 52  wherein the housing comprises an electromagnetic radiation energy absorber configured to generally absorb portions of the first, second, third and fourth signals that (i) are at least one of reflected, scattered and redirected from the Animalia tissue, and (ii) impinge on the surface. 
     
     
         54 . The system of  claim 52  wherein each individual point of the emitter end face is disposed a minimum distance not less than 3 millimeters from each individual point of the detector end face, and each individual point of the emitter end face is disposed a maximum distance not more than 5 millimeters from each individual point of the detector end face. 
     
     
         55 . The system of  claim 37  wherein the cable includes a plug and the optics bench includes a transceiver configured for consistent optical coupling with the plug, the transceiver includes a common enclosure for the first light emitting diode, the second light emitting diode, and the photodiode. 
     
     
         56 . The system of  claim 37  wherein the device comprises a shell generally encasing first and second printed circuit boards, the optics bench is mounted on the first printed circuit board, the processor is mounted on the second printed circuit board, and the second printed circuit board is spaced from the first printed circuit board. 
     
     
         57 . A system to aid in diagnosing at least one of infiltration and extravasation in Animalia tissue, the system comprising:
 a sensor including—
 a housing including a surface configured to confront an epidermis of the Animalia tissue; 
 a first waveguide being partially disposed in the housing and configured to transmit first and second signals that enter the Animalia tissue through the epidermis, the first signal having a peak wavelength between 800 nanometers and 1,050 nanometers, and the second signal having a peak wavelength between 570 nanometers and 620 nanometers; and 
 a second waveguide being partially disposed in the housing and configured to transmit third and fourth signals that exit the Animalia tissue through the epidermis, the third signal including a portion of the first signal that is at least one of reflected, scattered and redirected from the Animalia tissue, and the fourth signal including a portion of the second signal that is at least one of reflected, scattered and redirected from the Animalia tissue; 
   a dressing being configured to couple the sensor to the epidermis;   a device being configured to evaluate the third and fourth signals, the device including—
 an optics bench including a first light emitting diode, a second light emitting diode and a photodiode, the first light emitting diode being configured to emit the first signal transmitted by the first waveguide, the second light emitting diode being configured to emit the second signal transmitted by the first waveguide, and the photodiode being configured to detect the third and fourth signals transmitted by the second waveguide; 
 a processor coupled to the optics bench, the processor being configured to (i) compute normalized values of the third and fourth signals, (ii) compute a predicted signal based on the normalized values of the fourth signal, and (iii) compare the predicted signal and the normalized values of the third signal; 
 an indicator coupled to the processor, the indicator being configured to output a notice when (i) the predicted signal is less than a first threshold value and (ii) the predicted signal and the normalized values of the third signal diverge less than a second threshold value; and 
   a cable coupling the sensor and the device, the cable including portions of the first and second waveguides.   
     
     
         58 . The system of  claim 57  wherein the peak wavelengths of the first and third signals are between 930 nanometers and 960 nanometers. 
     
     
         59 . The system of  claim 57  wherein the peak wavelengths of the first and third signals are centered about 940 nanometers, and the peak wavelengths of the second and fourth signals are centered about 610 nanometers. 
     
     
         60 . The system of  claim 57  wherein the peak wavelengths of the second and fourth signals generally correspond to an isosbestic point of oxyhemoglobin and deoxyhemoglobin. 
     
     
         61 . The system of  claim 57  wherein the first waveguide includes a plurality of emission optical fibers and the second waveguide includes a plurality of detection optical fibers. 
     
     
         62 . The system of  claim 57  wherein the first waveguide includes an emitter face configured to confront the epidermis, the second waveguide includes a detector face configured to confront the epidermis, and the surface cinctures the emitter and detector faces. 
     
     
         63 . The system of  claim 62  wherein the housing comprises an electromagnetic radiation energy absorber configured to generally absorb portions of the first, second, third and fourth signals that (i) are at least one of reflected, scattered and redirected from the Animalia tissue, and (ii) impinge on the surface. 
     
     
         64 . The system of  claim 62  wherein each individual point of the emitter end face is disposed a minimum distance not less than 3 millimeters from each individual point of the detector end face, and each individual point of the emitter end face is disposed a maximum distance not more than 5 millimeters from each individual point of the detector end face. 
     
     
         65 . The system of  claim 57  wherein the dressing comprises a fitting having first and second arrangements, the first arrangement being configured to retain the housing with respect to the epidermis, and the second arrangement being configured to release the housing from the first arrangement. 
     
     
         66 . The system of  claim 57  wherein the device comprises a memory. 
     
     
         67 . The system of  claim 66  wherein the memory is configured to store an equation and the processor is configured to compute the predicted signal based on the equation and the fourth signal. 
     
     
         68 . The system of  claim 66  wherein the memory is configured to store a look-up table and the processor is configured to compute the predicted signal based on the look-up table and the fourth signal. 
     
     
         69 . The system of  claim 57  wherein the first threshold value is 0.95. 
     
     
         70 . The system of  claim 57  wherein the second threshold value is 0.05. 
     
     
         71 . The system of  claim 57  wherein the processor is configured to evaluate the third signal for infusate accumulation over time in the Animalia tissue and to evaluate the fourth signal for changing tissue blood volume in the Animalia tissue. 
     
     
         72 . The system of  claim 57  wherein the notice comprises an aid to diagnosing at least one of infiltration and extravasation in the Animalia tissue. 
     
     
         73 . The system of  claim 57  wherein the cable includes a plug and the optics bench includes a transceiver configured for consistent optical coupling with the plug, the transceiver includes a common enclosure for the first light emitting diode, the second light emitting diode, and the photodiode. 
     
     
         74 . The system of  claim 57  wherein the device comprises a shell generally encasing first and second printed circuit boards, the optics bench is mounted on the first printed circuit board, the processor is mounted on the second printed circuit board, and the second printed circuit board is spaced from the first printed circuit board. 
     
     
         75 . The system of  claim 57  wherein the device comprises a temperature sensor coupled to the processor.