WO2012040630A1

WO2012040630A1 - Infiltration detection device

Info

Publication number: WO2012040630A1
Application number: PCT/US2011/053090
Authority: WO
Inventors: Rafael V. Andino
Original assignee: Venetec International, Inc.
Priority date: 2010-09-24
Filing date: 2011-09-23
Publication date: 2012-03-29

Abstract

Systems and methods are provided herein for measuring a property of the tissue of a patient. The systems and methods detect infiltration of the tissue based on changes to the measured property of the tissue.

Description

INFILTRATION DETECTION DEVICE

RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Serial No. 61/386,357, filed September 24, 2010, and U.S. Provisional Patent Application Serial No. 61/386,363, filed September 24, 2010, each of which are hereby expressly incorporated by reference in their entireties.

BACKGROUND

Field of the Invention

[0002] This invention relates to a system for detecting infiltration of a medical article in the vasculature of a patient. More particularly, this invention relates to a sensor system configured to detect infiltration.

Description of the Related Art

[0003] Healthcare providers routinely require access to the vasculature of a patient for delivery or withdrawal of fluids to or from the patient's bloodstream. When such access is required over any period of time, it is common to introduce a catheter or similar medical article into the bloodstream of the patient to provide reusable access, for instance in order to deliver medication and/or fluids directly into the bloodstream of the patient. During introduction of such a medical article, or through movement of the medical article after placement, it is possible, that the catheter may be placed in the wrong position. Accordingly, fluid may be introduced in the tissue surrounding the vasculature of a patient as opposed to into the blood stream. The accumulation of substances, such as fluid introduced from a catheter, in a tissue in amounts excess of normal is referred to as infiltration. It may be desirable to monitor the patient for infiltration, such as, at the point of insertion of a catheter.

SUMMARY

[0004] The devices, systems, and methods of the present disclosure have several features, no single one of which is solely responsibly for its desirable attributes. Without limiting the scope of this invention as expressed by the claims which follow, its more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled "Detailed Description of Certain Embodiments," one will understand how the features of this disclosure provide several advantages over other medical devices.

[0005] One aspect is an infiltration detection device. The device comprises a sensor configured to measure a property of a tissue of a patient. The device further comprises a processor configured to detect infiltration of the tissue of the patient based at least in part on a change of the measured property of the tissue.

[0006] Another aspect is a detection device. The device comprises a sensor configured to measure a property of an environment surrounding a tip of a medical device. The device further comprises a processor configured to detect the location of the tip of the medical device in a body of a patient based at least in part on the measured property.

[0007] Another aspect is a method for measuring tissue infiltration. The method comprises measuring a value for a property of a tissue. The method further comprises determining whether infiltration of the tissue has occurred based at least in part on the measured value of the property of the tissue.

[0008] Another aspect is a method for determining placement of a medical device. The method comprises measuring a value of a property of an environment where a tip of the medical device is located in a body. The method further comprises determining a relative location of the tip in the body based at least in part on the measured value of the property of the environment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIGURE 1A is a perspective view of an embodiment of an infiltration detection device according to a preferred embodiment of the present invention.

[0010] FIGURE IB is a perspective view of the infiltration detection device from FIGURE 1A placed on a patient's skin.

[0011] FIGURE 2 is a perspective view of another embodiment of an infiltration detection device and a control device according to the present invention. [0012] FIGURE 3A is a cross-section through a tip of the infiltration device from FIGURE 2.

[0013] FIGURE 3B is another cross-section through a tip of another embodiment of the infiltration device from FIGURE 2.

[0014] FIGURE 4 is a flowchart of one embodiment of a process for measuring tissue for infiltration performed by the device of FIGURE 1 A or FIGURE 2.

[0015] FIGURE 5 is a flowchart of one embodiment of a process for measuring placement of the device of FIGURE 2.

[0016] FIGURE 6 illustrates a block diagram of an embodiment of the circuitry of the control device of FIGURE 1 A or FIGURE 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The following description and the accompanying figures, which describe and show the preferred embodiments, are made to demonstrate several possible configurations that an infiltration detection device can take to include various aspects and features of the invention. Some of the illustrated embodiments are shown with a controller that can be utilized by a health care provider to monitor signals from a sensor placed on the tissue of a patient. The illustration of the infiltration detection device in this context is not intended to limit the disclosed aspects and features of the invention to the specified embodiments or to usage only with the illustrated controller. Those of skill in the art will recognize that the disclosed aspects and features of the invention are not limited to any particular application.

[0018] The preferred embodiments of the present invention advantageously provide an infiltration detection device for monitoring infiltration of the tissue of a patient. The infiltration detection device preferably has a sensor configured to be placed in a catheter which is inserted in the skin of a patient or on the skin of the patient for detecting a property of the tissue. The infiltration device further preferably has a controller that allows a user to use the infiltration device to monitor the tissue of a patient for infiltration.

[0019] To facilitate a complete understanding of the illustrated embodiment, the remainder of the detailed description describes the medical article with reference to the attached figures, wherein like elements among the embodiments are referenced with like numerals throughout the following description.

[0020] Embodiments of the infiltration devices disclosed herein may be employed on or below the patient's skin. For example, FIGURE 1A is a perspective view of an embodiment of an external infiltration detection device 100A. The infiltration device 100 A includes an embodiment of a sensor 105. In one embodiment, the sensor 105 of the infiltration detection device 100A is configured to measure a property of the tissue of the patient when placed on or near the skin of the patient as shown in FIGURE IB. The sensor 105 may generate a signal based on the measurement of the property and send the signal to a control device 110 for analysis as described below. The signal may be transmitted continuously or periodically. Alternatively, the control device 110 may interrogate the sensor 105 to determine the measurement of the property.

[0021] In one embodiment, the sensor 105 is configured to measure a property of the tissue of the patient (e.g., the reflectivity of wavelengths of light on the surface of the tissue). The measured property may change due to infiltration of the tissue. For example, the reflectivity of tissue of a patient under normal conditions may be different than the reflectivity of infiltrated tissue. The sensor 105 may generate a signal based on the measurement of the property. For example, the sensor 105 may comprise a light emitting diode (LED) and a photoresistor that changes resistance based on the light incident the photoresistor. The LED directs light incident the skin of the patient, and the photoresistor receives and reacts to the reflected light. The conduction of the photoresistor may be measured via a circuit as is known by a person having ordinary skill in the art. The circuit may be located, for example, in the control device 110. The change in conduction corresponds to a change in reflectivity of the tissue. The change of reflectivity, such as a change greater than a threshold value, may indicate that infiltration of the tissue has occurred. For example, the conduction of the photoresistor when the sensor 105 is placed on the tissue of the patient where it is known that infiltration has not occurred can be used as a baseline measurement and stored in the control device 110. The measurement of the baseline can be repeated for a number of patients and a function of the multiple measurements (e.g., average) can be used as the baseline measurement. Alternatively, the baseline measurement can be measured specifically for an individual patient. Further, the conduction of the photoresistor when the sensor 105 is placed on the tissue of the patient where it is known infiltration has occurred can be measured for one or several different patients and compared to the baseline measurement by the control device 110. A threshold value can then be determined (e.g., the difference between an average infiltration measurement and the average baseline measurement) by the control device 110. Accordingly, the device 100A can be calibrated. When values are measured by the sensor 105 that are different than normal tissue and are approximately greater than the baseline measurement by the threshold value or equal to values associated with infiltrated tissue (e.g., greater than the threshold value), the control device 110 determines that infiltration has occurred. In one embodiment, the measurement of conduction of the photoresistor corresponding to blue light and/or red light being the predominant wavelength reflecting off of the tissue of the patient may indicate infiltration has occurred.

[0022] FIGURE 2 is a perspective view of an embodiment of an internal infiltration detection device 100B employed under the patient's skin. The infiltration detection device 100B may comprise a medical article such as a catheter 102. The catheter 102 may comprise a hollow elongated cylindrical wall defining a lumen and a tip 107. The infiltration detection device 100B further includes an embodiment of a sensor 109. The sensor 109 may be located in a wall of the catheter 102 in the region of the tip 107 as shown in FIGURE 3 A. Alternatively, the sensor 109 may be located in the lumen defined by the catheter 102 in the region of the tip 107 as shown in FIGURE 3B.

[0023] In one embodiment, the sensor 109 is configured to measure a property of the tissue of the patient. The sensor 109 may generate a signal based on the measurement of the property and send the signal to a control device 115 for analysis similar to as described above with respect to sensor 105 and control device 110. Alternatively, the control device 115 may interrogate the sensor 109.

[0024] In another embodiment, the sensor 109 of the infiltration detection device 100B is configured to measure a property of the environment where the tip 107 of the catheter 102 is located to determine whether the tip 107 is properly positioned in the body. The value of the measured property may change based on where in the body the tip 107 is located. For example, the chemical constituency of different locations of the body may differ. For instance, the oxygen concentration in a vein may be different than the oxygen content in tissue surrounding the vein. Therefore, by measuring a property of the location of the tip 107, it may be determined whether the tip 107 is inserted in a vein or in the tissue surrounding the vein. Further, by monitoring changes in the property, such as while the catheter 102 is being inserted into a vein, it may be possible to determine when the tip 107 has left one portion of the body and entered another portion of the body, such as leaving the surrounding tissue and entering the vein, and vice versa. By determining where the tip 107 is located, it can be determined whether fluid is being introduced to the correct area of the patient (e.g., the vein) as opposed to some other tissue so as to prevent infiltration.

[0025] The sensor 109 may generate a signal based on the measurement of the property and send the signal to a control device 115 for analysis as described below. For example, in one embodiment, the sensor 109 may comprise a biosensor such as a dark- type electrode. The biosensor may detect an analyte (e.g., glucose or certain cytokines) through a chemical reaction with the analyte. As the analyte reacts, a current is produced in the biosensor. The level of current may be indicative of the level of analyte present. The level of analyte may be correlated to the portion of the body where the tip 107 is located. For example, the inside of a vein may have a higher glucose concentration than the surrounding tissue. Accordingly, an increase in current levels of the biosensor while the catheter 102 is inserted in the body may correspond to the tip 107 moving from the surrounding tissue into the vein.

[0026] By monitoring where the tip 107 is located, infiltration of the surrounding tissue can be avoided by stopping the introduction of fluid through the catheter 102 if the tip 107 is located in the wrong portion of the body. Further, other properties may be measured at the tip 107 that indicate where the tip 107 is located. In another example, the device 100B may use the sensor 109 to measure properties of the tissue to determine whether or not infiltration has occurred such as described above with respect to the device 100A, and as described in embodiments below.

[0027] The location of the sensor 109 is not limited to the tip 107 of the catheter 102 and may be located at any location along the length of the catheter 102. For example, the sensor 109 may be located in a hub of the catheter 102. The sensor 109 may accordingly measure properties of fluid (e.g., blood) passing through the catheter 102, such as the properties of fluids discussed above. For example, the sensor 109 may measure one or more of temperature, pH, presence and/or concentration of enzymes, presence and/or concentration of an analyte (e.g., glucose or certain cytokines), etc. The measured properties may be used to determine the location of the tip 107 and/or whether infiltration has occurred as described above and as described below.

[0028] In one embodiment, the sensor 105 and/or sensor 109 may comprise an optical sensor, such as a light sensor (e.g., a light emitting diode (LED) sensor). In one embodiment, the optical sensor may comprise an LED sensor configured to emit light from an LED. The light may reflect off of the tissue of the patient. The LED sensor may further be configured for use as a photodiode in a circuit. The LED sensor may then measure the wavelength and/or amplitude of the light reflected off of the tissue of the patient. In another embodiment, the optical sensor may measure a change in color (i.e., wavelength) of light reflected from the tissue of the patient using other known techniques. The measured value may be compared to a threshold value to determine whether infiltration has occurred as discussed above.

[0029] In at least one embodiment, where the sensor 109 comprises an optical sensor, the measured value is compared to a threshold value to determine where the tip 107 is located in the body. For example, the wavelength and/or amplitude of light reflected in the tissue surrounding the vein of the patient may differ from the wavelength and/or amplitude of light reflected in the vein of the patient. Further, the wavelength and/or amplitude of light reflected can be measured in the vein when it is known the tip 107 is properly placed in the vein and when it is known the tip 107 is mislocated. The measurements can be made for a single patient or several patients similar to as discussed above with respect to device 100 A. Accordingly, the control device 115 can be calibrated. When values are measured that are different than those inside the vein and are approximately equal to values associated with tissues surrounding the vein, the control device 115 provides an indication that the tip 107 is located in the incorrect portion of the body. [0030] In another embodiment, the sensor 105 and/or sensor 109 may comprise an electromagnetic sensor. The sensor may comprise two electrodes. An electromagnetic wave may be passed between the two electrodes and through the tissue. As infiltration of the tissue occurs, more fluid enters the tissue. The increased fluid in the tissue may increase the resistance (impedance) of the tissue. Accordingly, properties of the tissue may be measured (e.g., resistance of the tissue). The measured value may be compared to a threshold value to determine whether infiltration has occurred. The threshold value may be determined similar to how the device calibration is described above with respect to the photoresistor. Properties of known tissues, both infiltrated and non-infiltrated, may be measured and recorded. When values are measured that are different than normal tissue and are approximately equal to values associated with infiltrated tissue, the device 100A and/or 100B determines that infiltration has occurred. The determination may be in the form of an audible or visual indication to the healthcare provider.

[0031] In at least one embodiment, where the sensor 109 comprises an electromagnetic sensor, the measured values may be used to determine a position of the tip 107. The measured value may be compared to previously recorded values to determine where the tip 107 is located. The previously recorded values may be measured similarly to how the device calibration is described above with respect to the biosensor. Properties of known portions of the body may be measured and recorded. When values are measured that are different than those inside the vein and are approximately equal to values associated with tissues surrounding the vein, the control device 115 determines that the tip 107 is located in the incorrect portion of the body.

[0032] In yet another embodiment, the sensor 105 and/or sensor 109 may comprise a mechanical sensor. In the embodiment of the sensor 105, the mechanical sensor may detect the pressure on the surface of the tissue (e.g., surface tension of the tissue). In the embodiment of the sensor 109, the mechanical sensor may detect a pressure or resistance applied to the tip 107 from, for example, the tissue. For example, the mechanical sensor may apply a force to the tissue and measure the amount of resistance of the tissue. In another example, the mechanical sensor may comprise a piezoelectric sensor, such as a piezoelectric disk. The piezoelectric sensor may be placed on the surface of the tissue, and as pressure increases in the tissue, the force of the pressure causes the piezoelectric sensor to deform. The deformation of the piezoelectric sensor changes the resistance of the piezoelectric sensor and generates a voltage. The voltage and/or the resistance of the piezoelectric sensor may be measured. The measured value may be compared to a threshold value to determine whether infiltration has occurred. The threshold value may be measured similar to how the device calibration is described above with respect to the photoresistor. Properties of known tissues, both infiltrated and non-infiltrated, may be measured and recorded. When values are measured that are different than normal tissue and are approximately equal to values associated with infiltrated tissue, the device 100A and/or 100B determines whether infiltration has occurred.

[0033] In one embodiment, where the sensor 109 comprises a mechanical sensor, the measured values may be used to determine a position of the tip 107. For example, as the tip 107 passes through different types of materials the properties of those materials may differ. For example, the vein may be stiffer and/or denser than surrounding tissue. Accordingly, the resistance or pressure exerted by the materials as the tip 107 is pushed through the various materials may change. By monitoring the change in pressure at the tip 107 as the catheter 102 is inserted into a vein, it can be determined where the tip 107 is located. For example, the pressure recorded may increase significantly as the tip 107 is pushed through the wall of a vein, and then decrease when the tip 107 enters the interior of the vein. Further, if the tip 107 moves out of the interior of the vein, the pressure changes again. By measuring the change in pressure as the catheter 102 is inserted, it can be determined where the tip 107 is located.

[0034] In a further embodiment, the sensor 105 and/or sensor 109 may comprise a sonar sensor. The sonar sensor may comprise a piezoelectric transducer configured to emit a sound wave toward the tissue. Further, the transducer may receive the sound waves and create an electrical pulse corresponding to the reflected wave. The shape of the wave may be compared to a base line wave to determine whether infiltration has occurred. The baseline may be measured similar to how the device calibration is described above with respect to the photoresistor. Properties of known tissues, both infiltrated and non-infiltrated, may be measured and recorded. When values are measured that are different than normal tissue and are approximately equal to values associated with infiltrated tissue, the device 100A and/or 100B determines whether infiltration has occurred.

[0035] In at least one embodiment, where the sensor 109 comprises a sonar sensor, the measured values could be used to determine the location of the tip 107. For example, the measured value may be compared to previously recorded values to determine where the tip 107 is located. The previously recorded values may be measured similarly to how the device calibration is described above with respect to the biosensor. Properties of known portions of the body may be measured and recorded. When values are measured that are different than those inside the vein and are approximately equal to values associated with tissues surrounding the vein, the control device 115 determines whether the tip 107 is located in the incorrect portion of the body.

[0036] In a further embodiment, the sensor 105 and/or the sensor 109 may comprise a temperature sensor, such as a thermistor. The temperature sensor may be used to measure a temperature of the tissue to determine whether infiltration of the tissue has occurred. For example, a baseline temperature of the tissue may be measured when it is known infiltration has not occurred, for example before any fluid is introduced into the patient. The baseline may be measured similar to how the device calibration is described above with respect to the photoresistor. A measured increase in the temperature may indicate infiltration occurred. For example, the measured temperature change may be compared to a threshold value to determine whether infiltration has occurred. The threshold value may be measured similar to how the device calibration is described above with respect to the photoresistor. Properties of known tissues, both infiltrated and non-infiltrated, may be measured and recorded. When values are measured that are different than normal tissue and are approximately equal to values associated with infiltrated tissue, the device 100A and/or 100B determines that infiltration has occurred.

[0037] In yet a further embodiment, the sensor 109 may comprise an integrated sensor that detects some property of the environment where the tip 107 is located such as temperature, pH, presence and concentration of enzymes, etc. Accordingly, properties of the body portion may be measured. The measured value may be compared to a threshold value to determine where the tip 107 is located. The previously recorded values may be measured similarly to how the device calibration is described above with respect to a photoresistor. Properties of known portions of the body may be measured and recorded. When values are measured that are different than those inside the vein and are approximately equal to values associated with tissues surrounding the vein, the control device 115 determines that the tip 107 is located in the incorrect portion of the body.

[0038] Referring to Figure 1, the sensor 105 may further be in communication with a control device 110. The sensor 105 and the control device 110 may be in communication via any appropriate wired or wireless link, such as a direct wire link, BLUETOOTH®, IEEE 802.1 la/b/g, etc. The control device may be configured to monitor signals from the sensor 105. For example, the control device 110 may comprise a processor (such as processor 610 shown in FIGURE 6) in communication with the sensor 105. The processor may be configured to control the sensor 105. The processor may further be configured to receive a signal from the sensor 105 and determine whether tissue infiltration has occurred. For example, the processor may be configured to cause an LED of the sensor 105 to emit light by sending an electrical signal to the LED. Further, the processor may be configured to pass a current through a photoresistor of the sensor 105 via a circuit formed between the processor and the photoresistor. The processor may then measure the resistance of the photoresistor via the circuit. If the resistance changes by a threshold value, the processor may determine that infiltration has occurred.

[0039] The control device 110 may comprise a switch on a housing of the control device 110. The switch may be placed in an off position when the processor and sensor 105 are not measuring a property of the tissue. The switch may be placed in an initialization position to measure a base value of the property of the tissue. The base value is the value of the property of the tissue before infiltration has occurred. The processor may measure the base value of the property of the tissue when the switch is in the initialization position. The measured base value may then be stored in a memory of the control device 110. The switch may also be placed in a measure position. The processor may measure the value of the property of the tissue when the switch is in the measure position. Further, the processor may compare the measure value to the base value to determine whether infiltration of the tissue has occurred. An indicator of the control device 110 may be used to indicate whether infiltration has occurred or not. For example, the indicator may comprise an LED. The LED may be controlled by the processor to turn green if infiltration has not occurred. Further, the LED may be controlled by the processor to turn red if infiltration has occurred. One of ordinary skill in the art will recognize other indicators may be used such as a liquid crystal display (LCD) that displays text indicating the condition of the tissue.

[0040] The sensor 105 and control device 110 may be used to measure a property of the tissue of a patient before infiltration has occurred. For example, a property of the tissue of a patient may be measure prior to a catheter being placed into the tissue. The measured value of the property acts as a baseline to compare subsequent measurements. The property of the tissue may then be measured at various times to determine whether infiltration has occurred. For example, the tissue may be measured after the catheter has been inserted and fluid is introduced to determine whether initial placement of the catheter is improper. Additionally, the tissue may be measured periodically to detect infiltration which may occur due to movement of the catheter after placement. For example, the tissue may be measured by medical personnel at regular check up intervals of a patient. A change in the measure property might be a sign of infiltration. The amount of change in the property required to be a sign of infiltration is based on the property being measured. The amount of change required may be determined by measuring tissue properties before and after infiltration and determining what values of those properties correspond to infiltrated tissue and non- infiltrated tissue. A threshold value may be determined based on the measured values and stored in the memory of the control device 110.

[0041] Referring to Figure 2, the sensor 109 may further be in communication with a control device 115. The sensor 109 and the control device 115 may be in communication via any appropriate wired or wireless link, such as a direct wire link, BLUETOOTH®, IEEE 802.1 la/b/g, etc. The control device may be configured to monitor signals from the sensor 109. For example, the control device 115 may comprise a processor (such as processor 610 shown in FIGURE 6) in communication with the sensor 109. The processor may be configured to control the sensor 109. The processor may further be configured to receive a signal from the sensor 109 and determine whether tissue infiltration has occurred and/or determine the location of the tip 107. For example, the processor may be configured to cause an LED of the sensor 109 to emit light by sending an electrical signal to the LED. Further, the processor may be configured to pass a current through a photoresistor of the sensor 109 via a circuit formed between the processor and the photoresistor. The processor may then measure the resistance of the photoresistor via the circuit. If the resistance changes by a threshold value, the processor may determine that infiltration has occurred. Additionally or alternatively, if the measured resistance is not the same as the resistance of the desired location of the tip 107, the processor may determine that the tip 107 is located in the wrong portion of the body.

[0042] The control device 115 may comprise a switch on a housing of the control device 115. The switch may be placed in an off position when the processor and sensor 109 are not measuring a property of the tissue. The switch may be placed in an initialization position to measure a base value of the property of the tissue. The base value is the value of the property of the tissue before infiltration has occurred or the value of the property of the environment where it is desired to locate the tip 107. The processor may measure the base value of the property of the tissue when the switch is in the initialization position. The measured base value may then be stored in a memory of the control device 115. The switch may also be placed in a measure position. The processor may measure the value of the property of the tissue when the switch is in the measure position. Further, the processor may compare the measure value to the base value to determine whether infiltration of the tissue has occurred and/or to determine whether tip 107 is located in the wrong portion of the body. An indicator of the control device 115 may be used to indicate whether infiltration has occurred or not and/or whether the tip 107 is located in the wrong portion of the body. For example, the indicator may comprise an LED. The LED may be controlled by the processor to turn green if infiltration has not occurred and/or the tip 107 is located in the correct portion of the body. Further, the LED may be controlled by the processor to turn red if infiltration has occurred and/or to the tip 107 is located in the wrong portion of the body. One of ordinary skill in the art will recognize other indicators may be used such as a liquid crystal display (LCD) that displays text indicating the condition of the tissue.

[0043] The sensor 109 and control device 115 may be used to measure a property of the tissue of a patient before infiltration has occurred. For example, a property of the tissue of a patient may be measure prior to a catheter being placed into the tissue. The measured value of the property acts as a baseline to compare subsequent measurements. The property of the tissue may then be measured at various times to determine whether infiltration has occurred. For example, the tissue may be measured after the catheter has been inserted and fluid is introduced to determine whether initial placement of the catheter is improper. Additionally, the tissue may be measured periodically to detect infiltration which may occur due to movement of the catheter after placement. For example, the tissue may be measured by medical personnel at regular check up intervals of a patient. A change in the measure property might be a sign of infiltration. The amount of change in the property required to be a sign of infiltration is based on the property being measured. The amount of change required may be determined by measuring tissue properties before and after infiltration and determining what values of those properties correspond to infiltrated tissue and non- infiltrated tissue. A threshold value may be determined based on the measured values and stored in the memory of the control device 115.

[0044] Further, the sensor 109 and control device 115 may be used to measure a property of the environment where the tip 107 is located. For example, a property of the vein of a patient may be measured after the catheter 102 is inserted in the vein. The measured value of the property acts as a baseline to compare subsequent measurements. The property of the environment where the tip 107 is located may then be measured at various times to determine whether the tip 107 has moved to a different portion of the body. For example, the tip 107 may move outside of the vein. The property may be measured periodically to detect if the tip 107 has moved out of the vein. For example, the property may be measured by medical personnel at regular check up intervals of a patient. A change in the measured property might be a sign of improper placement of the catheter tip 107. The amount of change in the property, which would indicate that the tip 107 is improperly placed, will vary depending on the measured property. The amount of change required may be determined by measuring properties at proper placement points and at improper placement points.

[0045] One embodiment of a process 400 of measuring tissue for infiltration using the device 100A and/or the device 100B is described below with respect to FIGURE 4. At a step 420, the control device 110 and/or the control device 115 is activated. Further at a step 430, the sensor 105 and/or the sensor 109 measures a property of the tissue. Next at a step 440, the processor of the control device 110 and/or the control device 115 compares the measured value of the property of the tissue against a baseline value. At a determining step 450, the processor determines whether infiltration of the tissue has occurred based on the comparison of the measured value of the property of the tissue and the baseline value.

[0046] One embodiment of a process 500 of determining the placement of a catheter 102 is shown with respect to FIGURE 5. At a first step 520, the control device 115 is activated. Further at a step 530, the sensor 109 measures a property of the environment where the tip 107 is located. Next at a step 540, the processor 610 of the control device 115 compares the measured value of the property against a baseline value. At a determining step 550, the processor 610 determines whether the tip 107 is located at the correct position in the body based on the comparison of the measured value of the property and the baseline value.

[0047] Figure 6 illustrates a block diagram of an embodiment of the circuitry of the control device 110 and/or the control device 115. The control device 110/115 comprises a processor 610 in data communication with a memory 620. The processor 610 is further in data communication with a communications controller 630. Although described separately, it is to be appreciated that functional blocks described with respect to the control device 110/115 need not be separate structural elements. For example, the processor 610 and memory 620 may be embodied in a single chip.

[0048] The processor 610 can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any suitable combination thereof designed to perform the functions described herein. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0049] The processor 610 can be coupled, via one or more buses, to read information from or write information to memory 620. The processor may additionally, or in the alternative, contain memory, such as processor registers. The memory 620 can include processor cache, including a multi-level hierarchical cache in which different levels have different capacities and access speeds. The memory 620 can also include random access memory (RAM), other volatile storage devices, or non-volatile storage devices. The storage can include hard drives, optical discs, such as compact discs (CDs) or digital video discs (DVDs), flash memory, floppy discs, magnetic tape, and Zip drives.

[0050] The processor 610 is also coupled to an input device 640 and an output device 650 for, respectively, receiving input from and providing output to, a user of the control device 110/115 . Suitable input devices include, but are not limited to, a switch, a keyboard, buttons, keys, switches, a pointing device, a mouse, a joystick, a remote control, an infrared detector, a video camera (possibly coupled with video processing software to, e.g., detect hand gestures or facial gestures), a motion detector, or a microphone (possibly coupled to audio processing software to, e.g., detect voice commands). Suitable output devices include, but are not limited to, visual output devices, including displays and printers, audio output devices, including speakers, headphones, earphones, and alarms, and haptic output devices, including force-feedback game controllers and vibrating devices.

[0051] The processor 610 is further coupled to a communication controller 630. The communication controller 630 prepares data generated by the processor 610 for wired or wireless transmission to another device such as the sensor 105. The communications controller 630 also received wired or wireless transmissions from another device such as the sensor 105. The communications controller 630 can include a transmitter, receiver, or both. In other embodiments, the transmitter and receiver are two separate components. The communications controller 630, can be embodied as a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any suitable combination thereof designed to perform the functions described herein.

[0052] The various illustrative logical blocks, modules, and circuits described in connection with the examples disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0053] The methods or algorithms described in connection with the examples disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC.

[0054] Of course, it is to be understood that not necessarily all such objectives or advantages may be achieved in accordance with any particular embodiment using the systems described herein. Thus, for example, those skilled in the art will recognize that the systems may be developed in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objectives or advantages as may be taught or suggested herein.

[0055] Furthermore, the skilled artisan will recognize the interchangeability of various features from different embodiments. Although these techniques and systems have been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that these techniques and systems may be extended beyond the specifically disclosed embodiments to other embodiments and/or uses and obvious modifications and equivalents thereof. Additionally, it is contemplated that various aspects and features of the invention described can be practiced separately, combined together, or substituted for one another, and that a variety of combination and subcombinations of the features and aspects can be made and still fall within the scope of the invention. Thus, it is intended that the scope of the systems disclosed herein disclosed should not be limited by the particular disclosed embodiments described above.

Claims

WHAT IS CLAIMED IS:

1. An infiltration detection device comprising:

a sensor configured to measure a property of a tissue of a patient; and a processor configured to detect infiltration of the tissue of the patient based at least in part on a change of the measured property of the tissue.

2. The infiltration device of Claim 1, wherein the measured property comprises the optical reflectivity of the tissue.

3. The infiltration device of Claim 2, wherein the optical reflectivity of the tissue comprises a wavelength of light reflected from the tissue.

4. The infiltration device of Claim 1, wherein the measured property comprises the pressure of the tissue.

5. The infiltration device of Claim 1, wherein the measured property comprises a response to an electromagnetic wave of the tissue.

6. The infiltration device of Claim 1, wherein the measured property comprises a response to a sound wave of the tissue.

7. The infiltration device of Claim 1, wherein the measured property comprises a temperature of the tissue.

8. A detection device comprising:

a sensor configured to measure a property of an environment surrounding a tip of a medical device; and

a processor configured to detect the location of the tip of the medical device in a body of a patient based at least in part on the measured property.

9. The detection device of Claim 13, wherein the measured property comprises the optical reflectivity of the environment surrounding the tip of the medical device.

10. The detection device of Claim 13, wherein the measured property comprises the pressure of the environment surrounding the tip of the medical device.

11. The detection device of Claim 13, wherein the measured property comprises a response to an electromagnetic wave of the environment surrounding the tip of the medical device.

12. The detection device of Claim 13, wherein the measured property comprises a chemical constituency of the environment surrounding the tip of the medical device.

13. A method for measuring tissue infiltration, the method comprising:

measuring a value for a property of a tissue; and

determining whether infiltration of the tissue has occurred based at least in part on the measured value of the property of the tissue.

14. The method of Claim 13, further comprising comparing the measured value to a baseline value of the tissue.

15. The method of Claim 13, wherein the property comprises the optical reflectivity of the tissue.

16. The method of Claim 13, wherein the property comprises the pressure of the tissue.

17. The method of Claim 13, wherein the property comprises a response to an electromagnetic wave of the tissue.

18. The method of Claim 13, wherein the property comprises a response to a sound wave of the tissue.

19. The method of Claim 13, wherein the property comprises a temperature of the tissue.

20. A method for determining placement of a medical device, the method comprising:

measuring a value of a property of an environment where a tip of the medical device is located in a body; and

determining a relative location of the tip in the body based at least in part on the measured value of the property of the environment.

21. The method of Claim 20, further comprising comparing the measured value to a baseline value of the environment in the body.

22. The method of Claim 20, wherein the property comprises the optical reflectivity of the environment surrounding the tip of the medical device.

23. The method of Claim 20, wherein the property comprises the pressure of the environment surrounding the tip of the medical device.

24. The method of Claim 20, wherein the property comprises a response to an electromagnetic wave of the environment surrounding the tip of the medical device.

25. The method of Claim 20, wherein the property comprises a chemical constituency of the environment surrounding the tip of the medical device.