GB2130722A - Locating and puncturing an artery - Google Patents

Abstract

Apparatus for locating an artery for puncture comprises a sensor 12 for producing a signal in response to pulsatile blood flow and a plate 10 which is pressed against the patient's skin with slots 14, 16 aligned with the detected artery. The sensor preferably relies on the ultrasonic doppler effect in response to blood flow. A visible or audible indication may be given when the apparatus is adjacent an artery. <IMAGE>

Description

SPECIFICATION Apparatus and method for positioning and puncturing an artery Background of the invention This invention is related to apparatus and methods for positioning and puncturing an artery preparatory to the insertion of a needle or catheter therein.

There are many situations which arise in medical practice, such as insertion of a catheter and withdrawal of blood, which require the puncturing of an artery with a needle or other similar device. Even experienced medical personnel sometimes have difficulty in positioning and puncturing an artery in some patients. It is particularly difficult to locate and puncture an artery in a patient who is obese because the arteries of such a person are not as close to the skin surfaces as the arteries in a person of normal weight. It is also often very difficult to locate and puncture an artery in a person who has very low blood pressure, which often occurs in persons who are extremely ill. Human arteries are normally two to eight millimeters in diameter; and some arteries may be difficult to locate even in a healthy person.

Prior methods for puncturing an artery include only means for determining the approximate position of the artery. Even after a medically trained person has found the patient's artery, puncturing the artery may be difficult, requiring more than one penetration of the patient's skin.

Therefore, there is a need in the art of medical instrumentation for a device which accurately identifies the location of a patient's artery and which retains the artery in position for puncturing.

Summary of the invention Accordingly, the present invention includes means for emitting a signal in response to pulsatile changes in blood flow to ascertain the position of a selected artery and means for holding the artery in position for puncturing.

The signal emitting means is preferably a doppler detector of a type well known in the art for detecting blood flow. A signal processor processes the output signal of the doppler detector to provide a signal for driving a loudspeaker to provide an audible indication that the detector is adjacent an artery and a signal for operating a light which operates intermittently in response to pulsatile blood flow.

The invention includes a plate which provides means for mounting the doppler detector and the light. The plate includes at least one slot for alignment with an artery whose position the doppler detector ascertains. Pressing the plate against the patient's skin with a moderate pressure while an artery is in longitudinal alignment with the slot causes the artery to remain in position in alignment with the slot so that medical personnel may easily puncture the artery with a catheter needle or other similar needle.

The invention is relatively inexpensive and easy to operate so that proficient use thereof requires little specialized training. The invention is useful to both highly trained medical personnel, such as physicians having experience in catheterization techniques, and to personnel, such as paramedicals, having a little experience in such techniques. In addition to being useful in locating an artery preparatory to insertion of a catheter, the invention is useful in positioning and puncturing an artery for withdrawing a blood sample and for other similar purposes. The invention is suitable for use with any patient and is particularly useful in puncturing the arteries of patients who have low blood pressure or whose arteries are not near the surface of the skin.

Brief description of the drawings Figure 1 is a perspective view of the invention; Figure 2 is a plan view of the device of Figure 1; Figure 3 is an elevation and view of the device shown in Figure 2; and Figure 4 is a block diagram of a blood flow detector shown in Figures 1, 2 and 3.

Description of preferred embodiment Figure 1 is a perspective view illustrating the novel structure of the invention. A plate 10 has a blood flow detector 12 imbedded therein between a pair of slots 14 and 1 6. The slots 14 and 16 extend away from the blood flow detector 12 and are generally in coaxial alignment with one another. Figure 2, which is a plan view, illustrates a convenient configuration of the slots 14 and 16.

A handle 18 extends from the plate 1.0 to provide means for conveniently moving the plate over a patient's skin to locate an artery.

The blood flow detector 12 is connected to visual indicator means, such as a light 20. The blood flow detector 12 outputs a signal responsive to pulsatile changes in blood flow to cause the light 20 to produce visible light intermittently when the blood flow detector 12 is adjacent an artery in a patient.

The blood flow detector 12 is also connected to audio indicator means, such as loudspeaker 22, shown in Figure 1. The blood flow detector 12 outputs a signal responsive to pulsatile changes in blood flow to cause the loudspeaker 22 to produce a sound, which trained personnel will understand as being indicative that the blood flow detector 12 is adjacent an artery.

The blood flow detector 12 preferably includes an ultrasonic sensor 24 and a signal processing unit 26 for determining a doppler effect responsive to blood flow. Such devices are well known in the art of medical instrumentation. The blood flow detector 12 may be model number 812, or 841, marketed by Park Electronic Laboratories of Beaverton, Oregon, or other similar device.

To use the invention, a medically trained person moves the plate 10 over the surface of a patient's skin in the vicinity of the artery whose exact location is to be ascertained. By observing the light 20 or by listening to the sound emitted from the loudspeaker 22, the operator locates the artery and aligns the slots 14 and 16 therewith.

The intensity of the sound emitted from the loudspeaker 22 and the brightness of the light 20 increase as the blood flow detector 12 becomes closer to an artery.

Human arteries are typically 2-8 millimeters in diameter. Insertion of a catheter into an artery is ordinarily done through a hollow needle (not shown) having an outer diameter about the same as 18 gauge wire. The slots 14 and 16 have dimensions appropriate for holding an artery in position for puncturing and for allowing the needle to pass through into the artery.

After locating the artery, the operator presses the plate 10 against the patient's body with a moderate pressure to retain the artery in a stabilized position in alignment with a selected slot 14 or 16. After the artery is located and the selected slot 14 or 16 is properly positioned relative to the artery, the operator or other medically trained person punctures the artery with a hollow needle (not shown) to withdraw blood, insert a catheter, or administer other medical treatment.

The plate 10 and handle 18 are preferably made of a transparent plastic material, but may satisfactorily be made of a metal or fiber-adhesive composite material or a combination including plastic, metal, fiber-adhesive composite or other similar material.

The plate 10 may be formed as a single piece with a recess 28 therein for holding the blood flow detector 12, which may be secured within the recess 28 by any convenient means, such as an adhesive material.

The plate 10 may be formed of an upper portion 30 and a lower portion 32 as shown in Figure 3 with the blood flow detector being held between the upper portion 30 and lower portion 32.

Although the present invention has been described with reference to a particular embodiment thereof, it will be understood by those skilled in the art that numerous modifications may be made without departing from the scope of the invention. Accordingly, all modifications and equivalence which are properly within the scope of the appended claims are included in the present invention.

Claims (14)

Claims

1. An apparatus for locating an artery for puncture, comprising: a sensor for emitting a signal in response to pulsatile changes in blood flow to ascertain the position of an artery; and means for positioning said apparatus in alignment with said artery for puncturing.

2. An apparatus according to Claim 1 wherein said sensor includes a doppler detector for producing a signal indicative of pulsatile blood flow.

3. An apparatus according to Claim 2 wherein said sensor includes an indicator responsive to said doppler detector for emitting an audible signal to indicate when said sensor is adjacent to an artery.

4. An apparatus according to Claim 2 or 3 wherein said sensor includes an indicator for producing a visible light in response to said doppler detector to indicate when said sensor is adjacent to an artery.

5. An apparatus according to Claim 4 wherein said visible indicator flashes in use to produce visible light intermittently in response to pulsatile changes in blood flow to indicate when said sensor is adjacent to an artery.

6. An apparatus according to Claim 1 wherein said sensor includes an audible indicator for emitting an audible signal to indicate when said sensor is adjacent to an artery.

7. An apparatus according to Claim 1 or 6 wherein said sensor includes a visible indicator for producing a visible light to indicate when said sensor is adjacent to an artery.

8. An apparatus according to Claim 7 wherein said visible indicator flashes in use to produce an intermittently visible light in response to pulsatile changes in blood flow.

9. An apparatus according to any preceding Claim wherein said positioning means includes a body having at least one slot therein, said slot being formed to position and retain said apparatus in alignment with an artery for puncturing when said body is pressed against the body of a patient with said artery of the patient being in predetermined alignment with said slot.

10. An apparatus according to any of Claims 1 to 8, comprising a base plate having two, substantially co-axial slots therein, said slots each extending part-way across said plate for positioning said apparatus with said slots in alignment with an artery to be punctured; and said sensor in or on said plate between said two slots.

11. A method for locating an artery for puncture, comprising the steps of: determining the position of a selected artery in a patient; placing a slot in a plate in axial alignment with the artery; and pressing the plate against the patient's skin to position the artery in alignment with the slot for puncturing.

12. A method according to Claim 11 wherein the step of determining the position of a selected artery in a patient includes the step of using a doppler detector to produce an audible output in response to pulsatile changes in blood flow.

13. A method according to Claim 11 or 12 wherein the step of determining the position of a selected artery in a patient includes the step of using a doppler detector to produce a visible light output in response to pulsatile changes in blood flow.

14. A method according to Claim 12 or 13, wherein said output increases in intensity as said detector becomes closer to said artery.

1 5. Apparatus for locating an artery for puncture substantially as hereinbefore described with reference to the accompanying drawings.

1 6. A method for locating an artery for puncture substantially as hereinbefore described with reference to the accompanying drawings.