US20200306507A1 - Electronic guidewire detector for catheter insertion - Google Patents
Electronic guidewire detector for catheter insertion Download PDFInfo
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- US20200306507A1 US20200306507A1 US16/368,464 US201916368464A US2020306507A1 US 20200306507 A1 US20200306507 A1 US 20200306507A1 US 201916368464 A US201916368464 A US 201916368464A US 2020306507 A1 US2020306507 A1 US 2020306507A1
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Definitions
- the present invention is directed to a detecting the presence of a guidewire for use with a catheter, and, in one embodiment, to a detector for detecting that a guidewire for use with a central venous catheter (CVC) has been accidentally left in place during a medical procedure or operation.
- CVC central venous catheter
- a “central venous catheter” also known as a “central line,” “central venous line,” or “central venous access catheter,” is a catheter placed into a large vein.
- Catheters such as the known 3 lumen catheter of FIG. 1 , can be placed in veins in the neck (internal jugular vein), chest (subclavian vein or axillary vein), groin (femoral vein), or through veins in the arms (also known as a peripherally inserted central catheters (PICC) line). It is used to administer medication or fluids that are unable to be taken by mouth or would harm a smaller peripheral vein, obtain blood tests (specifically the “central venous oxygen saturation”), and to measure central venous pressure.
- FIGS. 2A and 2B illustrate catheters having been inserted into patients.
- FIG. 3A illustrates a three lumen (or three-segment) catheter that has corresponding caps for closing off the “ports” or openings of the catheter.
- a guidewire is a thin, flexible, medical wire inserted into the body to guide a larger instrument, such as a catheter, central venous line, or feeding tube.
- the materials used to make guidewires have varied over the years but today they primarily consist of stainless steel and Nitinol (nickel titanium). Not all of a guidewire is placed into a patient as the guidewire must be retrievable after insertion of the catheter.
- the phrase “the patient side of the guidewire” will be used to refer to at least the end of the guidewire that is inserted into the patient. The other end will be called “the caregiver end”.
- the blood vessel is penetrated with a hollow needle and a guidewire is then advanced through the needle into the vessel.
- the needle is removed, leaving the wire in place, and the catheter is advanced over exposed or caregiver end of the guidewire until the first part or caregiver end of the wire extends outside the back of the catheter.
- the catheter is advanced into proper position within the vessel. Once the catheter is in place the guidewire is grabbed by the caregiver side and removed and discarded—leaving the catheter in place.
- FIG. 1 is an illustration of an exemplary, known 3 lumen catheter prior to insertion into a patient
- FIG. 2A is an illustration of a catheter as used when inserted into a patient
- FIG. 2B is a picture of a patient into whom a catheter has been inserted
- FIG. 3A is an illustration of a 3 lumen catheter with its corresponding caps for closing off the ports of the catheter;
- FIG. 3B is an illustration of a 3 lumen catheter where one of the caps has been replaced with a detector according to a first embodiment of the invention
- FIG. 4A is a perspective view of the detector of FIG. 3B where the cover of the detector surrounds the internal circuitry of the detector;
- FIG. 4B is a partial exploded side view of the detector
- FIG. 4C is a top view of the detector of FIG. 4A where the cover of the detector has been removed for illustrative purposes to expose the internal circuitry;
- FIG. 4D is a front view of the detector of FIG. 4A where the switch activator can been seen;
- FIG. 4E is an enlarged view of the switch activator (e.g., a spring surrounding a plunger) shown within the cap of FIG. 4D ;
- the switch activator e.g., a spring surrounding a plunger
- FIG. 4F is a partial exploded view of the detector (including separated cap and spring plunger system for additional clarity) of FIG. 4A to show the inter-relationship between the spring plunger system, the cap and the circuit board switch of the detector;
- FIG. 4G is a partial underside view of the detector (showing a light transmitter, a light guide and two light detectors) of FIG. 4A to show the inter-relationship between the light transmitter, the light guide and the two light detectors and the controller mounted on the circuit board of the detector);
- FIG. 4H is a partial exploded view of the upper portion of the circuit board of the detector when the spring plunger system abuts the switch mounted to the circuit board of the detector;
- FIG. 4I is a partial underside view of the detector showing the light transmitter and the two light detectors mounted to the underside of the circuit;
- FIG. 4J is an enlarged view of the light guide and the two light detectors of FIG. 4B ;
- FIG. 5A is an illustration of a detector according to a second embodiment described herein;
- FIG. 5B is a partially exposed view of the circuit board inside the housing of the detector of FIG. 5B ;
- FIG. 6 is a graph showing the spectral characteristic of blood
- FIG. 7 is a block diagram of a simple encoder
- FIGS. 8A-8D combined are a flowchart showing how the detector tracks the progress of a guidewire through the detector.
- the present invention is directed to a design of a detector for use with a guidewire to reduce the incidence of guidewires accidently being left inside patients after the placement of central venous (and other) catheters and/or left inside a patient after removal of the catheter (at the end of an operation or other medical procedure).
- a detector can be placed on or integrated with a portion of a catheter to detect the presence and/or removal of a guidewire.
- the detector can provide doctors, nurses and/or other medical professionals with at least one of a visual indication or an audible indication of the location of the guidewire relative to a reference point (e.g., a location close to a port or the port hub) of the catheter. As shown in FIG.
- the detector can be created in the form of a larger cap for one of the ports (e.g., the red port (‘distal port’)).
- the detector could be incorporated into this plastic port hub (Y-Connector) without departing from the teachings herein.
- the detector 100 includes a cap 110 for connecting to the catheter but providing a guidewire passage 115 there through.
- the detector 100 further includes a housing 120 mechanically connected to the cap 110 that surrounds the internal circuitry of the detector 110 .
- the housing 120 also has three illumination sections ( 130 A- 130 C) which allow a number of conditions detected by the detector 110 to be indicated to the medical professionals utilizing the detector 100 .
- Illumination sections 130 A- 130 C can be of the same or different types and can include, but are not limited to, (a) windows for allowing lights from interior bulbs or LEDs to be seen from outside the housing 120 , (b) bulbs, or (c) LEDs.
- Each illumination section can be of a single color or multiple colors to indicate a number of conditions as discussed below.
- the conditions may be indicated by turning on and off illumination sections, and/or by changing a frequency of blinking of illumination sections.
- the detector 100 may include a speaker (e.g., a piezoelectric speaker) (not shown) for audibly indicating one or more conditions.
- the detector 100 can detect and indicate to the medical professionals a number of conditions for a guidewire initially inserted into the catheter either from the patient side or the caregiver side.
- the detector 100 can sense conditions including, but not limited to: (1) the guidewire has not yet been inserted through the housing, (2) the guidewire has been inserted through the housing but has not yet been removed through the housing, (3) the guidewire has been both inserted through the housing and properly removed from the housing, (4) the guidewire has been inserted through the housing but has moved into an unsafe location, and (5) the guidewire has been inserted through the housing but has been left in the patient—i.e. it has not returned out the correct side.
- the conditions can be indicated using one or more illuminations sections and/or a speaker.
- the system could include a small digital display that could show the length of guidewire that is in the body at any given time.
- the detector indicates when the guide wire is in each of three locations by illuminating the LEDs according to:
- the detector indicates when the guide wire is in each of four locations by illuminating the LEDs and utilizing the speaker according to:
- the detector may include a grabbing mechanism (e.g., a spring-loaded pinching device or a metal that changes shape when electricity is applied to it) that can be triggered in one or both of either of the last two states described above.
- a grabbing mechanism e.g., a spring-loaded pinching device or a metal that changes shape when electricity is applied to it
- the detector would attempt to “grab” the guidewire before it is no longer within the detector.
- a grabbing device may be placed inside the tube in which the guidewire is passing or adjacent to the tube but having sufficient force to alter the shape of the tube such that the guidewire is grabbed.
- the detector includes a display (e.g., such a 7 or 9 segment LED digit display, an LCD with back-light, or a number of LED bars) (not shown) and further includes a detector for determining (and displaying the distance the guidewire has been advanced through the detector.
- a display e.g., such a 7 or 9 segment LED digit display, an LCD with back-light, or a number of LED bars
- the detector for determining (and displaying the distance the guidewire has been advanced through the detector. This has many practical applications to the doctor placing the wire, helping them gauge the distance the wire is now in the body. By knowing the distance, the doctor can put the wire in to the exact length of the catheter—without having to over compensate. It is always better to have just enough length in the body but not too much as the extra length only adds to the potential for unnecessary puncture of the vein wall during insertion. Pushing the guidewire in unnecessarily far also could lead to disruption of the heart's normal rhythm.
- the display can give an actual distance of the length traveled by the guidewire, and the detector can give a warning (e.g., an audible alarm, a flashing of the display, or a change in the back-light color) when the guidewire is getting too close to the end.
- a warning e.g., an audible alarm, a flashing of the display, or a change in the back-light color
- the detector includes red and green LEDs 130 B and 130 C where the red LED 130 B turns on upon power up; the green LED 130 C turns on when the detector detects that the wire has entered; the green LED 130 C turns off when the detector detects the wire exit; the red LED 130 B blinks if the guidewire comes out the wrong direction (meaning a possible situation of a catheter pulling off the guidewire and the guidewire having been left in the body); and the red LED 130 B turns off when wire exits out the correct direction.
- the fourth embodiment is further configured with a blue LED 130 A such as shown in FIG. 4A .
- the blue LED 130 A illuminates when both ends of the wire exit out the correct direction in the correct order—signifying everything is good. This would stay on until the battery dies many hours later allowing visual confirmation at any time later. (If needed, screwing the cap off and then back on could reset the detector.)
- the detector 100 can detect whether a guidewire already in a patient is properly inserted and removed from the catheter.
- the detector detects the location of the guidewire during its progress. For example, the detector detects when the caregiver-side the guidewire first enters into the detector (as detected by a first sensor at a first location). The detector then detects whether caregiver-side of the guidewire passes all the remaining sensors and whether the patient-side end of the guidewire passes each of the sensors too—indicating that the guidewire has been properly removed.
- FIGS. 4B-4J One illustrative configuration of the internal components of the detector 100 of FIG. 4A is shown in FIGS. 4B-4J .
- the internal components within the housing 120 include: (a) surface mounts LED 135 A, 135 B, and 135 C, (b) a guidewire passage tube 200 that connects (e.g., using a friction fit) to the cap 110 and is concentric with the guidewire passage 115 , (c) light sensors 210 A and 210 B, (d) light tube 220 , (e) battery 250 , (f) spring system 260 , (g) switch 270 , (h) light guide 275 , (i) light transmitter 280 ( FIG.
- the battery 250 is preferably a lithium coin battery as shown. Most lithium coin cell batteries lose less than 3% of their energy each year in standby, thus giving it an excellent shelf life. The 30 mAh of energy of a CR927 is anticipated to power such a detector 100 for many hours longer than would be needed for a typical catheter insertion during surgery.
- guidewire passage tube should be understood to include shapes other than cylindrical.
- the tube may, for example, have a rectangular external cross-section where it meets the light detectors to better allow the transfer of the light from the LEDs in the direction toward the light detectors.
- the controller 300 may be any one or a combination of: an application specific integrated circuit (ASIC), a one-time programmable logic array (e.g., a PLD using fuses), a reprogrammable logic array (e.g., a field programmable gate array (FPGA), a generic array of logic (GAL), or a logic array programmed using electrically erasable memory, flash memory, ferroelectric memory, random access memory, and/or static random access memory), and a digital computer processor with memory (including memory internal to the processor, such as electrically erasable memory, flash memory, ferroelectric memory, random access memory, and/or static random access memory, as well as memory external to the processor including electrically erasable memory, flash memory, ferroelectric memory, random access memory, and/or static random access memory).
- ASIC application specific integrated circuit
- the detector 100 can utilize a number of different guidewire sensor systems for detecting the location and/or direction of the guidewire relative to the detector 100 .
- the sensing is accomplished by turning on (or pulsing it at a high rate) the light transmitter 280 (e.g., a red LED).
- the light from the light transmitter 280 is passed through the light tube 220 and into the light guide 275 and directed at two or more points on a guidewire passage tube 200 (e.g., a clear plastic or glass tube) running substantially the length (in the direction of motion of the guidewire) of the detector (e.g., half-an-inch apart) and coincident with the path of the guidewire.
- a guidewire passage tube 200 e.g., a clear plastic or glass tube
- the light detectors 290 A and 290 B there are two light detectors 290 A and 290 B on the bottom side of the circuit board which can see the light of the light transmitter 280 having traveled along the light guide 275 .
- the light detectors 290 A and 290 B would detect a portion of the red light having passed through the guidewire passage tube 200 when no guidewire is present in the guidewire passage tube 200 .
- the intensity drops significantly allowing the corresponding light detector 290 A and/or 290 B to know the guidewire is at that location.
- the sensor system can detect not only the presence of the guidewire but its direction of travel as well. Any color light may work, but preferably light in the 630 nm to 700 nm range is used because this shade of red transmits well through blood with little (or at least manageable) attenuation by the blood, as shown in FIG. 6 .
- blood looks red because it absorbs the frequencies of visible light corresponding to all of the colors except red. Therefore, red light passes through the thumb easily. Green light, however, is pretty much completely absorbed.
- the guidewire is in the form of steel spring.
- a magnetic field would be disturbed if it moved between a magnet and a sensor using a magnetometer or linear Hall effect device.
- a series of repeating bars can be printed on the wire and detected by an encoder as the wire moves by a corresponding set of sensors (as shown in FIG. 7 ).
- the distance the wire has traveled—as well as the direction can be calculated.
- the direction of travel is determined by noting which channel produces an output first.
- any other reflective method using light, acoustic or other waves
- the detector 100 is powered on by screwing the cap 110 onto the port (thereby compressing the spring plunger system 260 and causing the distal end thereof to contact and activate the switch 270 ).
- FIG. 4D shows a front view of the cap 110 with the spring plunger system 260 protruding there through.
- FIG. 4E shows the enlarged portion of FIG. 4D that corresponds to the spring system 260 protruding through the cap 110 .
- FIG. 4F shows an exploded view of the detector 100 where the spring system 260 has not yet been placed within the cap 110 .
- a guidewire with a series of bumps at known (e.g., regular or irregular) distances is used with the detector.
- the detector in such a configuration utilizes a sensor that detects the bumps (e.g., by detecting a decreased amount of light as the bump passes the sensor or using at a narrow internal portion having at least one strain gauge that flexes due to contact with the bumps).
- the detector can count the bumps to determine how far the guidewire moves in each direction.
- two closely spaced detectors are used to determine a direction of the guidewire based on the relative order in which the strain gauges are activated. By using a known correlation between the number of bumps, the detector can display to a medical professional how far the guidewire has been inserted into the patient and how much it has been “backed up” as it is being pulled out.
- a detector having two internal sensors can determine the status of the guidewire relative to the sensors of the detector 100 attached to or integrated with the catheter.
- the detector 100 starts in state 00 b (that is 00 in binary), where the more significant bit corresponds to the caregiver-side and the less significant bit corresponds to the patient-side.
- the sensor detects the presence of the guidewire at its location by a “1” signal and indicates the absence of sensing the guidewire at its location by a “0” signal.
- the reverse polarity for the signals could be used as well.
- each sensor would then have a corresponding state bit. For example, assuming the most significant bit corresponds to the caregiver-side and the least significant bit corresponds to the patient-side, a state of 1100 b would represent that the patient-side end of the guidewire is half way into the detector, a state of 0011 b would represent that the caregiver-side end of the guidewire is half way into the detector, a state of 0000 b would represent that no portion of the guidewire is in the detector yet (or anymore), and a state of 1111 b would represent that there is guidewire at each of the sensor locations.
- Step S 800 (where the initial state of the LED(s) is turned on)
- Step S 810 indicates that there is a change in the patient-side sensor
- control passes to Step S 815 which corresponds to State 01 b .
- the detector changes the LED(s) to indicate (e.g., using a Yellow LED and turning off the Green LED) that the guidewire has entered from the patient-side and is expected to be pulled out the caregiver-side after the catheter has been inserted into the patient.
- the discussion of guidewire entering from the patient-side and that is to be pulled out the caregiver-side after the catheter has been inserted into the patient will be now provided with respect for FIGS. 8A and 8B .
- step S 805 the detector would have processed the logic for a guidewire entering from the caregiver-side and that is both pushed in and pulled out the caregiver-side after the catheter has been inserted into the patient, as described with respect to FIGS. 8C and 8D .
- the detector enters a loop (steps S 815 , S 820 , and S 825 ) to determine whether there a next change detected by the sensors. If there are no changes, then the detector continues the loop (while the guidewire should be advancing toward the caregiver. If step S 820 detects that the patient-side detector changes, then the guidewire has backtracked toward the patient, and control passes to step S 825 where the detector signals to the caregiver that the guidewire prematurely left the patient side (e.g., by utilizing a signal via an LED or audibly).
- step S 830 detects that the guidewire has advanced to the caregiver-side
- step S 835 FIG. 8B
- the detector sets its state to State 11 b (corresponding to the patient-side and caregiver-sides both detecting the presence of the guidewire).
- the detector can further provide visual feedback (e.g., by setting an LED) or audio feedback to let the caregiver know how far the guidewire has progressed (or the LED can remain in the same illumination condition as in the previous state).
- step S 835 the detector again enters a loop (S 835 , S 840 , and S 850 ) where it waits for a change in one of the detectors. If step S 840 determines that there is a change in the caregiver-side detector, the control passes to step S 845 to enable the detector to alert the caregiver that the guidewire reversed back towards the patient. The caregiver may have intended this if the guidewire became caught, and the caregiver may silence the alarm using a reset button (not shown).
- step S 850 detects that the guidewire has advanced so that it is no longer present on the patient side, then the caregiver has inserted the catheter into the patient and has begun the process of removing the wire. As such, control passes to step S 855 .
- the detector sets its state to State 10 b (corresponding to only the caregiver-side detector detecting the presence of the guidewire).
- the detector can further provide visual feedback (e.g., by setting an LED to flashing Yellow instead of solid yellow, or by setting the LED to fast flashing yellow instead of slow flashing yellow in State 11 b ) or audio feedback to let the caregiver know how far the guidewire has progressed (or the LED can remain in the same illumination condition as in the previous state).
- step S 855 the detector again enters a loop (S 855 , S 860 , and S 870 ) where it waits for a change in one of the detectors. If step S 860 determines that there is a change in the patient-side detector, the control passes to step S 865 to enable the detector to alert the caregiver that the guidewire reversed back towards the patient. The caregiver may have intended this if the guidewire became caught, and the caregiver may silence the alarm using a reset button (not shown).
- step S 870 detects that the guidewire has advanced so that it is no longer present on the caregiver side, then the caregiver has removed the guidewire from the patient. As such, control passes to step S 875 .
- step S 875 the detector sets its state to State 00 b .
- the detector provides visual feedback (e.g., by setting an LED to Green) and/or audio feedback to let the caregiver know the guidewire has been successfully removed.
- step S 805 detects a change in the caregiver-side before a change in the patient side
- the detector processes the logic for a guidewire entering from the caregiver-side that is both pushed in and pulled out the caregiver-side after the catheter has been inserted into the patient, as described with respect to FIGS. 8C and 8D .
- the steps of FIGS. 8C and 8D perform a series of loops (loop1: S 880 , S 885 , and S 900 ; loop2: S 905 , S 910 , and S 920 ; and S 925 , S 930 , and S 935 ).
- the logic is expecting to find that the guidewire progresses from the caregiver side, past the patient side and into the patient, and then is removed from the patient, clearing the patient-side detector and then clearing the caregiver-side detector before signaling that the catheter has been properly removed from the patient. If an unexpected change in guidewire location is determined in step S 885 , then the detector can alert the caregiver and the caregiver can signal if it was intended (e.g., because of a caught guidewire).
- step S 910 detects that the guidewire has cleared the caregiver-side, then an alarm is indicated to let the caregiver know that it has lost the caregiver end of the wire and that corrective action is immediately needed.
- the detector may include a grabbing mechanism (e.g., a spring-loaded pinching device or a metal that changes shape when electricity is applied to it) that can be triggered to attempt to “grab” the guidewire before it is no longer within the detector.
- a grabbing device may be placed inside the tube in which the guidewire is passing or adjacent to the tube but having sufficient force to alter the shape of the tube such that the guidewire is grabbed.
- step S 930 it is possible that the caregiver must back the guidewire out to past the patient-side detector because the guidewire got caught but that the caregiver is going to try again. So, control can pass from step S 930 to S 905 without causing an alarm. In at least one alternate configuration, the steps S 825 , S 845 , S 865 , and S 890 could have performed the same process of returning to the proper previous corresponding state without raising an alarm (assuming that the caregiver intended to partially retract the guidewire). Once the guidewire is removed past the caregiver-side detector, control passes to step S 940 which indicates that the guidewire was successfully removed.
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Abstract
Description
- The present invention is directed to a detecting the presence of a guidewire for use with a catheter, and, in one embodiment, to a detector for detecting that a guidewire for use with a central venous catheter (CVC) has been accidentally left in place during a medical procedure or operation.
- A “central venous catheter” (CVC), also known as a “central line,” “central venous line,” or “central venous access catheter,” is a catheter placed into a large vein. Catheters, such as the known 3 lumen catheter of
FIG. 1 , can be placed in veins in the neck (internal jugular vein), chest (subclavian vein or axillary vein), groin (femoral vein), or through veins in the arms (also known as a peripherally inserted central catheters (PICC) line). It is used to administer medication or fluids that are unable to be taken by mouth or would harm a smaller peripheral vein, obtain blood tests (specifically the “central venous oxygen saturation”), and to measure central venous pressure.FIGS. 2A and 2B illustrate catheters having been inserted into patients.FIG. 3A illustrates a three lumen (or three-segment) catheter that has corresponding caps for closing off the “ports” or openings of the catheter. - More than 50 million surgical procedures were performed in the United States. As part of some of those procedures, central venous catheters are inserted into patients. Before a catheter is placed into a patient, a guidewire must be inserted in the blood vessel to act as a guide for the catheter. The guidewire has become an integral part of a growing number of medical procedures with its use steadily increasing and expanding into more and more medical specialties, particularly as non-invasive procedures have been developed. The market for guidewires is now global and growing. Market data shows this market to be about $1 billion globally each year and growing at a CAGR of 8.2%.
- A guidewire is a thin, flexible, medical wire inserted into the body to guide a larger instrument, such as a catheter, central venous line, or feeding tube. The materials used to make guidewires have varied over the years but today they primarily consist of stainless steel and Nitinol (nickel titanium). Not all of a guidewire is placed into a patient as the guidewire must be retrievable after insertion of the catheter. As used herein, the phrase “the patient side of the guidewire” will be used to refer to at least the end of the guidewire that is inserted into the patient. The other end will be called “the caregiver end”.
- As discussed above, during placement of a central venous catheter, the blood vessel is penetrated with a hollow needle and a guidewire is then advanced through the needle into the vessel. The needle is removed, leaving the wire in place, and the catheter is advanced over exposed or caregiver end of the guidewire until the first part or caregiver end of the wire extends outside the back of the catheter. Then, while holding the wire in place so that it does not move, the catheter is advanced into proper position within the vessel. Once the catheter is in place the guidewire is grabbed by the caregiver side and removed and discarded—leaving the catheter in place.
- The most common complications of central venous catheters are infection and damage to surrounding structures. A less common but more serious complication is the accidental failure to remove the guidewire after placement and at times after the operation is complete—leaving the guidewire fully retained within the body. Despite the rare occurrence (approx. 1 per 3,000 placements), these retained guidewires cause significant potential harm to the patient including more surgeries, more lengthy hospital stays, additional medical problems, and potentially death. That 1:3,000 number correlates to over 2,000 occurrences annually in the US alone. Mortality rates with retained guidewires is as high as 1 in 5.
- There are detailed procedures in place to assure that guidewires are never inadvertently left in patients. These include checklists, instrument counts, and careful training. Nonetheless, these events continue to happen due to human error. The most common cause is catheter advancement into the body over the wire before the guidewire is threaded the entire length of the catheter so that the lagging or caregiver end of the wire can be gripped by the user and held in place during advancement. Consistent factors noted in many investigations include operator fatigue, distractions, emergency situations, and inexperience. These human factors cause safety steps to be forgotten or skipped in the interest of expediency or deviated from due a confluence of uncommon events. Almost all safety steps in place require the operator to perform various safety checklists even though human factors often reduce their reliability. Very little safety engineering has been done to modify equipment and reduce the potential for human error.
- An exemplary set of steps for installing a known catheter is provided below. (The same or similar procedures are used for many other types of operations in which a guidewire is used to place a catheter.)
-
- 1. A needle is inserted into the blood vessel at a location on the body where the catheter is to be placed.
- 2. Guidewire is pushed through the needle into the blood vessel.
- 3. Guidewire continues to be pushed into the blood vessel to the appropriate depth so that the guidewire remains in the vessel once the needle is removed.
- 4. The needle is removed over the exposed or caregiver end of the guidewire while leaving the guidewire in place.
- 5. A catheter is advanced over the exposed or caregiver end of the guidewire and into position so that the leading tip of the catheter is completely in the blood vessel.
- 6. The guidewire is grabbed by its caregiver end and removed through the catheter and discarded, leaving the catheter in proper position.
- 7. The catheter is secured in place with sutures and/or adhesive dressing to maintain proper position.
- The following description, given with respect to the attached drawings, may be better understood with reference to the non-limiting examples of the drawings, wherein:
-
FIG. 1 is an illustration of an exemplary, known 3 lumen catheter prior to insertion into a patient; -
FIG. 2A is an illustration of a catheter as used when inserted into a patient; -
FIG. 2B is a picture of a patient into whom a catheter has been inserted; -
FIG. 3A is an illustration of a 3 lumen catheter with its corresponding caps for closing off the ports of the catheter; -
FIG. 3B is an illustration of a 3 lumen catheter where one of the caps has been replaced with a detector according to a first embodiment of the invention; -
FIG. 4A is a perspective view of the detector ofFIG. 3B where the cover of the detector surrounds the internal circuitry of the detector; -
FIG. 4B is a partial exploded side view of the detector; -
FIG. 4C is a top view of the detector ofFIG. 4A where the cover of the detector has been removed for illustrative purposes to expose the internal circuitry; -
FIG. 4D is a front view of the detector ofFIG. 4A where the switch activator can been seen; -
FIG. 4E is an enlarged view of the switch activator (e.g., a spring surrounding a plunger) shown within the cap ofFIG. 4D ; -
FIG. 4F is a partial exploded view of the detector (including separated cap and spring plunger system for additional clarity) ofFIG. 4A to show the inter-relationship between the spring plunger system, the cap and the circuit board switch of the detector; -
FIG. 4G is a partial underside view of the detector (showing a light transmitter, a light guide and two light detectors) ofFIG. 4A to show the inter-relationship between the light transmitter, the light guide and the two light detectors and the controller mounted on the circuit board of the detector); -
FIG. 4H is a partial exploded view of the upper portion of the circuit board of the detector when the spring plunger system abuts the switch mounted to the circuit board of the detector; -
FIG. 4I is a partial underside view of the detector showing the light transmitter and the two light detectors mounted to the underside of the circuit; -
FIG. 4J is an enlarged view of the light guide and the two light detectors ofFIG. 4B ; -
FIG. 5A is an illustration of a detector according to a second embodiment described herein; -
FIG. 5B is a partially exposed view of the circuit board inside the housing of the detector ofFIG. 5B ; -
FIG. 6 is a graph showing the spectral characteristic of blood; -
FIG. 7 is a block diagram of a simple encoder; and -
FIGS. 8A-8D combined are a flowchart showing how the detector tracks the progress of a guidewire through the detector. - The present invention is directed to a design of a detector for use with a guidewire to reduce the incidence of guidewires accidently being left inside patients after the placement of central venous (and other) catheters and/or left inside a patient after removal of the catheter (at the end of an operation or other medical procedure). In particular, a detector can be placed on or integrated with a portion of a catheter to detect the presence and/or removal of a guidewire. The detector can provide doctors, nurses and/or other medical professionals with at least one of a visual indication or an audible indication of the location of the guidewire relative to a reference point (e.g., a location close to a port or the port hub) of the catheter. As shown in
FIG. 3B , the detector can be created in the form of a larger cap for one of the ports (e.g., the red port (‘distal port’)). Alternatively, the detector could be incorporated into this plastic port hub (Y-Connector) without departing from the teachings herein. - One illustrative embodiment of the
detector 100 described herein is illustrated inFIG. 4A . Thedetector 100 includes acap 110 for connecting to the catheter but providing aguidewire passage 115 there through. Thedetector 100 further includes ahousing 120 mechanically connected to thecap 110 that surrounds the internal circuitry of thedetector 110. In the illustrated embodiment, thehousing 120 also has three illumination sections (130A-130C) which allow a number of conditions detected by thedetector 110 to be indicated to the medical professionals utilizing thedetector 100.Illumination sections 130A-130C can be of the same or different types and can include, but are not limited to, (a) windows for allowing lights from interior bulbs or LEDs to be seen from outside thehousing 120, (b) bulbs, or (c) LEDs. Each illumination section can be of a single color or multiple colors to indicate a number of conditions as discussed below. The conditions may be indicated by turning on and off illumination sections, and/or by changing a frequency of blinking of illumination sections. Alternatively, or in addition to the illumination sections, thedetector 100 may include a speaker (e.g., a piezoelectric speaker) (not shown) for audibly indicating one or more conditions. - In general, the
detector 100 can detect and indicate to the medical professionals a number of conditions for a guidewire initially inserted into the catheter either from the patient side or the caregiver side. Starting with a guidewire inserted initially from the caregiver side, thedetector 100 can sense conditions including, but not limited to: (1) the guidewire has not yet been inserted through the housing, (2) the guidewire has been inserted through the housing but has not yet been removed through the housing, (3) the guidewire has been both inserted through the housing and properly removed from the housing, (4) the guidewire has been inserted through the housing but has moved into an unsafe location, and (5) the guidewire has been inserted through the housing but has been left in the patient—i.e. it has not returned out the correct side. The conditions can be indicated using one or more illuminations sections and/or a speaker. In addition to light and audible notifications—the system could include a small digital display that could show the length of guidewire that is in the body at any given time. - For example, in a first embodiment with two
illuminations sections FIGS. 5A and 5B ) corresponding to red and green LEDs, respectively, the detector indicates when the guide wire is in each of three locations by illuminating the LEDs according to: -
- (Red off, Green off): Guidewire not inserted yet or inserted and properly removed;
- (Red off, Green on): Guidewire has been inserted and not yet properly removed and has not moved into an unsafe position (e.g., the caregiver-side end of the guidewire has entered into the detector)
- (Red on, Green off): Guidewire has gone too far and is now past the last of all the sensors in the detector and fully on the body side of the detector such that there is potentially a problem.
- In a second embodiment with two
illuminations sections -
- (Red off, Green off): Guidewire not inserted yet or inserted and properly removed;
- (Red off, Green on): Guidewire has been inserted and not yet properly removed and has could have moved into an unsafe position (e.g., the caregiver-side end of the guidewire has entered into the detector to a point beyond the first of at least three sensors in the detector)
- (Red flashing, Green on, speaker beeping): Guidewire has gone nearly too far and is now in danger of going fully on the body side (e.g., to a point beyond at least two sensors of at least three sensors but has not gone beyond the last sensor).
- (Red on, Green on, speaker on continuous tone): Guidewire has gone too far and is now fully on the body side and potentially fully into the body (e.g., to a point beyond the last sensor of the detector).
- To further aid in preventing the guidewire from going too far into the patient, the detector may include a grabbing mechanism (e.g., a spring-loaded pinching device or a metal that changes shape when electricity is applied to it) that can be triggered in one or both of either of the last two states described above. In such a configuration, the detector would attempt to “grab” the guidewire before it is no longer within the detector. Such a grabbing device may be placed inside the tube in which the guidewire is passing or adjacent to the tube but having sufficient force to alter the shape of the tube such that the guidewire is grabbed.
- In a third embodiment, the detector includes a display (e.g., such a 7 or 9 segment LED digit display, an LCD with back-light, or a number of LED bars) (not shown) and further includes a detector for determining (and displaying the distance the guidewire has been advanced through the detector. This has many practical applications to the doctor placing the wire, helping them gauge the distance the wire is now in the body. By knowing the distance, the doctor can put the wire in to the exact length of the catheter—without having to over compensate. It is always better to have just enough length in the body but not too much as the extra length only adds to the potential for unnecessary puncture of the vein wall during insertion. Pushing the guidewire in unnecessarily far also could lead to disruption of the heart's normal rhythm. In such a configuration, the display can give an actual distance of the length traveled by the guidewire, and the detector can give a warning (e.g., an audible alarm, a flashing of the display, or a change in the back-light color) when the guidewire is getting too close to the end.
- In a fourth embodiment, the detector includes red and
green LEDs red LED 130B turns on upon power up; thegreen LED 130C turns on when the detector detects that the wire has entered; thegreen LED 130C turns off when the detector detects the wire exit; thered LED 130B blinks if the guidewire comes out the wrong direction (meaning a possible situation of a catheter pulling off the guidewire and the guidewire having been left in the body); and thered LED 130B turns off when wire exits out the correct direction. - In a fifth embodiment, the fourth embodiment is further configured with a
blue LED 130A such as shown inFIG. 4A . In such a configuration, theblue LED 130A illuminates when both ends of the wire exit out the correct direction in the correct order—signifying everything is good. This would stay on until the battery dies many hours later allowing visual confirmation at any time later. (If needed, screwing the cap off and then back on could reset the detector.) - Alternatively, the
detector 100 can detect whether a guidewire already in a patient is properly inserted and removed from the catheter. In such a situation, when the catheter is initially placed on the caregiver-side of the guidewire and advanced toward the patient (for insertion of the catheter into the patient), the detector detects the location of the guidewire during its progress. For example, the detector detects when the caregiver-side the guidewire first enters into the detector (as detected by a first sensor at a first location). The detector then detects whether caregiver-side of the guidewire passes all the remaining sensors and whether the patient-side end of the guidewire passes each of the sensors too—indicating that the guidewire has been properly removed. - One illustrative configuration of the internal components of the
detector 100 ofFIG. 4A is shown inFIGS. 4B-4J . In addition to the components of thedetector 100 discussed above with respect toFIG. 4A , the internal components within the housing 120 (formed from anupper shell portion 125A and alower shell portion 125B which may snap together or be screwed together) include: (a) surface mountsLED guidewire passage tube 200 that connects (e.g., using a friction fit) to thecap 110 and is concentric with theguidewire passage 115, (c) light sensors 210A and 210B, (d) light tube 220, (e)battery 250, (f)spring system 260, (g)switch 270, (h)light guide 275, (i) light transmitter 280 (FIG. 4G ), (j)light detectors FIG. 4G ), and (k) a controller 300 (e.g., die-bonded to the pc board and covered by an epoxy dot) (FIG. 4G ). Thebattery 250 is preferably a lithium coin battery as shown. Most lithium coin cell batteries lose less than 3% of their energy each year in standby, thus giving it an excellent shelf life. The 30 mAh of energy of a CR927 is anticipated to power such adetector 100 for many hours longer than would be needed for a typical catheter insertion during surgery. As used herein, “guidewire passage tube” should be understood to include shapes other than cylindrical. The tube may, for example, have a rectangular external cross-section where it meets the light detectors to better allow the transfer of the light from the LEDs in the direction toward the light detectors. Thecontroller 300 may be any one or a combination of: an application specific integrated circuit (ASIC), a one-time programmable logic array (e.g., a PLD using fuses), a reprogrammable logic array (e.g., a field programmable gate array (FPGA), a generic array of logic (GAL), or a logic array programmed using electrically erasable memory, flash memory, ferroelectric memory, random access memory, and/or static random access memory), and a digital computer processor with memory (including memory internal to the processor, such as electrically erasable memory, flash memory, ferroelectric memory, random access memory, and/or static random access memory, as well as memory external to the processor including electrically erasable memory, flash memory, ferroelectric memory, random access memory, and/or static random access memory). - The
detector 100 can utilize a number of different guidewire sensor systems for detecting the location and/or direction of the guidewire relative to thedetector 100. In a first configuration of the guidewire sensor system, the sensing is accomplished by turning on (or pulsing it at a high rate) the light transmitter 280 (e.g., a red LED). The light from thelight transmitter 280 is passed through the light tube 220 and into thelight guide 275 and directed at two or more points on a guidewire passage tube 200 (e.g., a clear plastic or glass tube) running substantially the length (in the direction of motion of the guidewire) of the detector (e.g., half-an-inch apart) and coincident with the path of the guidewire. In the illustrated configuration, there are twolight detectors light transmitter 280 having traveled along thelight guide 275. Using a red LEDlight transmitter 280, thelight detectors guidewire passage tube 200 when no guidewire is present in theguidewire passage tube 200. However, when the guidewire is blocking the transmissions—the intensity drops significantly allowing the correspondinglight detector 290A and/or 290B to know the guidewire is at that location. Because thelight detectors FIG. 6 . In general, blood looks red because it absorbs the frequencies of visible light corresponding to all of the colors except red. Therefore, red light passes through the thumb easily. Green light, however, is pretty much completely absorbed. - Alternate sensor systems also can be used. In one alternate configuration, the guidewire is in the form of steel spring. Thus, a magnetic field would be disturbed if it moved between a magnet and a sensor using a magnetometer or linear Hall effect device. Alternatively, a series of repeating bars (or other optical codes) can be printed on the wire and detected by an encoder as the wire moves by a corresponding set of sensors (as shown in
FIG. 7 ). By using standard mathematical functions, the distance the wire has traveled—as well as the direction can be calculated. By using two offset sensors, the direction of travel is determined by noting which channel produces an output first. In yet another configuration, any other reflective method (using light, acoustic or other waves) can be used to detect the presence of the guidewire. - In one configuration, the
detector 100 is powered on by screwing thecap 110 onto the port (thereby compressing thespring plunger system 260 and causing the distal end thereof to contact and activate the switch 270).FIG. 4D shows a front view of thecap 110 with thespring plunger system 260 protruding there through.FIG. 4E shows the enlarged portion ofFIG. 4D that corresponds to thespring system 260 protruding through thecap 110.FIG. 4F shows an exploded view of thedetector 100 where thespring system 260 has not yet been placed within thecap 110. - In yet another embodiment, a guidewire with a series of bumps at known (e.g., regular or irregular) distances is used with the detector. The detector in such a configuration utilizes a sensor that detects the bumps (e.g., by detecting a decreased amount of light as the bump passes the sensor or using at a narrow internal portion having at least one strain gauge that flexes due to contact with the bumps). The detector can count the bumps to determine how far the guidewire moves in each direction. In one such configuration, two closely spaced detectors are used to determine a direction of the guidewire based on the relative order in which the strain gauges are activated. By using a known correlation between the number of bumps, the detector can display to a medical professional how far the guidewire has been inserted into the patient and how much it has been “backed up” as it is being pulled out.
- As shown in
FIGS. 8A-8D , a detector having two internal sensors can determine the status of the guidewire relative to the sensors of thedetector 100 attached to or integrated with the catheter. Starting with step S800 inFIG. 8A , when thedetector 100 is initially powered on, thedetector 100 starts in state 00b (that is 00 in binary), where the more significant bit corresponds to the caregiver-side and the less significant bit corresponds to the patient-side. For each of the steps described below, the sensor detects the presence of the guidewire at its location by a “1” signal and indicates the absence of sensing the guidewire at its location by a “0” signal. As would be appreciated by those of skill in the art, the reverse polarity for the signals could be used as well. Moreover, although the discussion below assumes two sensors in thedetector 100, additional sensors can be utilized to be able to detect where within the detector an end of the guidewire is located. Each sensor would then have a corresponding state bit. For example, assuming the most significant bit corresponds to the caregiver-side and the least significant bit corresponds to the patient-side, a state of 1100b would represent that the patient-side end of the guidewire is half way into the detector, a state of 0011b would represent that the caregiver-side end of the guidewire is half way into the detector, a state of 0000b would represent that no portion of the guidewire is in the detector yet (or anymore), and a state of 1111b would represent that there is guidewire at each of the sensor locations. - After control passes from Step S800 (where the initial state of the LED(s) is turned on), control passes to step S805 where a first sensor detects if there is a change in the state of the caregiver-side (from no guidewire present to guidewire present). If not, then control passes to step S810 where a second sensor detects if there is a change in the state of the patient-side (from no guidewire present to guidewire present). If not, then control returns to step S800 (or to step S805 if the LEDs do not need to be refreshed).
- If step S810 indicates that there is a change in the patient-side sensor, then control passes to Step S815 which corresponds to
State 01b. In that state, the detector changes the LED(s) to indicate (e.g., using a Yellow LED and turning off the Green LED) that the guidewire has entered from the patient-side and is expected to be pulled out the caregiver-side after the catheter has been inserted into the patient. The discussion of guidewire entering from the patient-side and that is to be pulled out the caregiver-side after the catheter has been inserted into the patient will be now provided with respect forFIGS. 8A and 8B . However, had step S805 detected a change first, then the detector would have processed the logic for a guidewire entering from the caregiver-side and that is both pushed in and pulled out the caregiver-side after the catheter has been inserted into the patient, as described with respect toFIGS. 8C and 8D . - Having set itself to
State 01b, the detector enters a loop (steps S815, S820, and S825) to determine whether there a next change detected by the sensors. If there are no changes, then the detector continues the loop (while the guidewire should be advancing toward the caregiver. If step S820 detects that the patient-side detector changes, then the guidewire has backtracked toward the patient, and control passes to step S825 where the detector signals to the caregiver that the guidewire prematurely left the patient side (e.g., by utilizing a signal via an LED or audibly). The caregiver may have intended this if the guidewire became caught, and the caregiver may silence the alarm using a reset button (not shown) such that the detector returns to its previous corresponding state (i.e.,State 01b for step S825). If instead step S830 detects that the guidewire has advanced to the caregiver-side, then control passes to step S835 (FIG. 8B ). In step S835, the detector sets its state to State 11b (corresponding to the patient-side and caregiver-sides both detecting the presence of the guidewire). The detector can further provide visual feedback (e.g., by setting an LED) or audio feedback to let the caregiver know how far the guidewire has progressed (or the LED can remain in the same illumination condition as in the previous state). - From step S835, the detector again enters a loop (S835, S840, and S850) where it waits for a change in one of the detectors. If step S840 determines that there is a change in the caregiver-side detector, the control passes to step S845 to enable the detector to alert the caregiver that the guidewire reversed back towards the patient. The caregiver may have intended this if the guidewire became caught, and the caregiver may silence the alarm using a reset button (not shown).
- If instead step S850 detects that the guidewire has advanced so that it is no longer present on the patient side, then the caregiver has inserted the catheter into the patient and has begun the process of removing the wire. As such, control passes to step S855. In step S835, the detector sets its state to State 10b (corresponding to only the caregiver-side detector detecting the presence of the guidewire). The detector can further provide visual feedback (e.g., by setting an LED to flashing Yellow instead of solid yellow, or by setting the LED to fast flashing yellow instead of slow flashing yellow in State 11b) or audio feedback to let the caregiver know how far the guidewire has progressed (or the LED can remain in the same illumination condition as in the previous state).
- From step S855, the detector again enters a loop (S855, S860, and S870) where it waits for a change in one of the detectors. If step S860 determines that there is a change in the patient-side detector, the control passes to step S865 to enable the detector to alert the caregiver that the guidewire reversed back towards the patient. The caregiver may have intended this if the guidewire became caught, and the caregiver may silence the alarm using a reset button (not shown).
- If instead step S870 detects that the guidewire has advanced so that it is no longer present on the caregiver side, then the caregiver has removed the guidewire from the patient. As such, control passes to step S875. In step S875, the detector sets its state to
State 00b. The detector provides visual feedback (e.g., by setting an LED to Green) and/or audio feedback to let the caregiver know the guidewire has been successfully removed. - As discussed above, if step S805 detected a change in the caregiver-side before a change in the patient side, then the detector processes the logic for a guidewire entering from the caregiver-side that is both pushed in and pulled out the caregiver-side after the catheter has been inserted into the patient, as described with respect to
FIGS. 8C and 8D . Similar to the steps described with respect toFIGS. 8A and 8B , the steps ofFIGS. 8C and 8D perform a series of loops (loop1: S880, S885, and S900; loop2: S905, S910, and S920; and S925, S930, and S935). The logic is expecting to find that the guidewire progresses from the caregiver side, past the patient side and into the patient, and then is removed from the patient, clearing the patient-side detector and then clearing the caregiver-side detector before signaling that the catheter has been properly removed from the patient. If an unexpected change in guidewire location is determined in step S885, then the detector can alert the caregiver and the caregiver can signal if it was intended (e.g., because of a caught guidewire). - However, if step S910 detects that the guidewire has cleared the caregiver-side, then an alarm is indicated to let the caregiver know that it has lost the caregiver end of the wire and that corrective action is immediately needed. As discussed above, to further aid in preventing the guidewire from going too far into the patient, the detector may include a grabbing mechanism (e.g., a spring-loaded pinching device or a metal that changes shape when electricity is applied to it) that can be triggered to attempt to “grab” the guidewire before it is no longer within the detector. Such a grabbing device may be placed inside the tube in which the guidewire is passing or adjacent to the tube but having sufficient force to alter the shape of the tube such that the guidewire is grabbed.
- As shown in step S930, it is possible that the caregiver must back the guidewire out to past the patient-side detector because the guidewire got caught but that the caregiver is going to try again. So, control can pass from step S930 to S905 without causing an alarm. In at least one alternate configuration, the steps S825, S845, S865, and S890 could have performed the same process of returning to the proper previous corresponding state without raising an alarm (assuming that the caregiver intended to partially retract the guidewire). Once the guidewire is removed past the caregiver-side detector, control passes to step S940 which indicates that the guidewire was successfully removed.
- While certain configurations of structures have been illustrated for the purposes of presenting the basic structures of the present invention, one of ordinary skill in the art will appreciate that other variations are possible which would still fall within the scope of the appended claims.
Claims (21)
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US10118020B2 (en) * | 2011-12-07 | 2018-11-06 | Traumatek Solutions B.V. | Devices and methods for endovascular access and therapy |
US11094223B2 (en) * | 2015-01-10 | 2021-08-17 | University Of Florida Research Foundation, Incorporated | Simulation features combining mixed reality and modular tracking |
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