MXPA00007638A

MXPA00007638A - Fluid sampling device with retractable needle.

Info

Publication number: MXPA00007638A
Application number: MXPA00007638A
Authority: MX
Inventors: Michael J Botich
Original assignee: Mdc Invest Holdings Inc
Priority date: 1998-02-05
Filing date: 1999-02-05
Publication date: 2002-04-24
Also published as: PL342257A1; WO1999044660A1; EP1053038A1; JP2002505162A; CN1294525A; AU2589099A; CA2319508A1; AU736394B2; EP1053038A4; BR9907642A

Abstract

A method for withdrawing a fluid sample from a patient is disclosed comprising the steps of: a) providing a sampling device (10) having a housing (20) and a needle (40) having a sharpened tip for piercing the skin of the patient; b) withdrawing fluid from the patient into the housing; c) retracting the needle so that the sharpened tip of the needle is enclosed within the housing; and d) expelling the fluid from the housing after the needle is retracted.

Description

FLUID SAMPLING APPARATUS WITH RETRACTABLE NEEDLE.

Field of the Invention The present apparatus refers to the field of medical devices for fluid sampling. More specifically, the present invention relates to said medical devices having a refractory needle, so that the apparatus becomes safe after use. In particular, the present invention relates to an apparatus for drawing blood from a patient, wherein after use the needle is refracted so that the contaminated needle is stored in said apparatus, avoiding accidental contact with said contaminated needle.

Antecedents of the Invention.

The present invention relates to a type of medical device that is used to take a blood sample from the arteries. Collection of blood from the arteries is commonly performed in emergency room facilities, as well as in hospitals to perform tests for various conditions, such as blood oxygen levels and p H. Commonly used standard devices are covered with Heparin to prevent the accumulation of blood and the fit between the plunger of substances and the barrel is loose enough to allow the blood pressure of the arteries to move the piston according to the apparatus according to the blood of the arteries. These requirements complicate the reaction of the needle.

Summary of the Invention.

In light of the interior the present invention provides an apparatus and method for collecting fluid samples from a patient. The apparatus comprises a cover, a plunger sliding in the cover and a needle having a sharp tip for piercing a patient. The needle is operated to pierce the skin of a patient. The patient fluid is collected in a fluid chamber that is inside the cover. After the sample has been collected, the needle is refracted inside the cover so that it is stored at the sharp point. Once the needle is refracted, a couple of series prevent the sample from leaking from the fluid chamber. In addition, the seals are preferably placed to prevent air from entering the fluid chamber after the needle is refracted. Subsequently the fluid can be expelled from the fluid chamber, displacing the plunger that is inside the cover.

Brief Description of the Drawings.

The above summary, as well as the detailed description that follows the preferred embodiment, may be better understood when read together with the drawings that follow, in which: Figure 1 is a top view of a medical device for fluid sampling that has a retractable needle; Figure 2 is a side view of a medical device for fluid sampling shown in Figure 1; Figure 3A is a side view of the apparatus shown in Figure 1, illustrating the apparatus before use; Figure 3B is a side view of the apparatus shown in Figure 3A, illustrating the apparatus after a quantity of fluid has been removed; Figure 3C, is a side view of the apparatus shown in Figure 3A, illustrating the apparatus with needle in a retracted position; Figure 3D is a side view of the apparatus shown in Figure 3A, illustrating the apparatus after the fluid sample has been ejected; Figure 4 is a side view of a second embodiment of a medical device for fluid sampling having a retractable needle; Figure 5A is a side view of the apparatus shown in Figure 4, illustrating the apparatus before use; Figure 5B is a side view of the apparatus shown in Figure 5A, illustrating the apparatus after a quantity of fluid has been removed; Figure 5C, is a side view of the apparatus shown in Figure 5A, illustrating the apparatus with the needle in a retracted position. Figure 5D, is a side view of the apparatus shown in Figure 5A, illustrating the apparatus after the fluid sample has been ejected; Figure 6 is a side view of a third embodiment of a medical device for fluid sampling having a retractable needle; Figure 7A is a side view of the apparatus shown in Figure 6, which illustrates the apparatus before use; Figure 7B is a side view of the apparatus shown in Figure 7A, illustrating the apparatus after a quantity of fluid has been removed; Figure 7C, is a side view of the apparatus shown in Figure 7A, which illustrates the apparatus with the diver separated from the plunger; Figure 7D is a side view of the apparatus shown in Figure 7A, illustrating the apparatus with the needle in a retracted position; Figure 8 is a side view of a fourth embodiment of a medical device for fluid sampling having a retractable needle; Figure 9 is an enlarged fragmentary sectional view of the apparatus shown in Figure 8; Figure 10 is a cross-sectional view of the apparatus shown in Figure 9, taken along line 10-10; Figure 11, is a side view of the apparatus shown in Figure 8, illustrating the apparatus with the needle in a refracted position; Figure 12A is a schematic side view of a combination syringe and needle assembly. removable Figure 12B is a side view of the apparatus shown in Figure 12A illustrating the assembly of the needle attached to the syringe; Figure 12C, is a side view of the apparatus shown in Figure 12A, illustrating the needle in a retracted position; Figure 1 3A is a side view of a second embodiment of the removable needle assembly; and Figure 13B, is a side view of the needle assembly shown in Figure 13A, illustrating the needle in a retracted position.

Detailed Description of the Invention. Referring to the drawings and specifically to Figures 1 through 3D, an apparatus for fluid sampling is generally designated, with the number 10. The apparatus 10 comprises a barrel 20 and a needle 40 projecting forward from the Front end of the barrel. A piston 30 slides in the barrel 20. The fluid is shown through the needle. For example, the apparatus can be used to make a quantity of fluid in a patient. The needle 40 pierces the skin of a patient, and the blood of the patient remains inside the barrel 20. It is an elongated hollow cover generally in cylindrical form. The front end of the barrel 20 forms a small diameter nose piece 22. The nose piece 22 is used, forming a standard Luer-type lifting accessory. The nose piece 22 is generally closed, having an opening for receiving the needle 40. The plunger 30 has a hollow front stem 31. An elastomeric diver 32 is attached to the forward end of the stalk of plunger 31. The piston 32 forms a fluid-tight seal with the inner wall of the barrel 20. The stem is formed integrally with the rear part of the plunger, which is an elongated hollow cylindrical part, which forms a chamber for the needle 34 that receives the needle after it is retracted. The rear end of the needle chamber is closed, to prevent the needle from being moved backwards from the needle chamber. At the front end of the chamber for the needle 34, an actuator 36 is formed. The actuator is generally frustoconical, and is shaped to contribute in a matching manner to a needle retainer 50 that holds the needle releasably.

The needle 40 includes a side port 42 formed in the side wall of the needle. In addition, the rear end of the needle is plugged in. The needle is positioned so that the lateral port 42 is located in front of the diver. An invariable plunger is formed in the barrel between the diver 32 and the front end of the barrel 20. Therefore, the fluid flowing through the needle is discharged through the lateral port 42 which is in the fluid chamber between the diver 32 and the nose 22.

The needle 40 is operable between a projection position, in which the sharp tip of the needle projects forward of the nose 22 of the barrel 20, and a retracted position in which the needle is stored within the barrel. A spring 60 surrounds the needle 40, tilting the needle back towards the retracted position. The needle retainer 50 releasably retains the needle 40 in the projection position, against the inclination of the spring 60. When the actuator 36 engages the needle retainer 50, the needle retainer releases the needle 40, allowing the spring drives the needle backwards into the chamber for the needle 34.

The needle retainer 50 is rigidly connected to the barrel 20, so that the needle retainer is axially fixed relative to the barrel. The inner wall of the barrel 20 includes a rest that forms a seat 25 for receiving the needle retainer 50. As shown in Figure 1, the needle retainer 50 comprises a pair of connecting clips 58 that form a fastening or friction fit adjustment with the seat 25 that is on the barrel wall. The connecting clips 58 project through a pair of slots 38 which are located in the side walls of the plunger 30. The slot allows the plunger to be moved axially relative to the needle retainer. The needle retainer 50 includes at least one tab or latch 52 for releasably retaining the needle. In this example, the tabs 52 are attached to the needle by UV curable epoxy. Alternatively, a block may be attached to the needle and the tongue may support the block to retain the needle against further axial displacement. The forward end of the tongues forms a raised actuation surface 56 that contributes to the raised actuator 36 that is in the plunger. When the plunger is moved backward, the actuator 36 engages the raised actuation surface 56 of the needle retainer, wedging the tabs apart. The tongues are displaced radially out of the gear with the needle. The spring then urges the needle backwards into the chamber for the needle 34. The needle retainer 50 further includes a cover for the spring 54 projecting forward from the tongue 52. The forward end of the spring cover 54, forms a bearing surface against which the forward end of the spring 60 bears. The end of the spring can support the needle retainer 50. The piston 32 includes a pierceable septum that forms a liquid-tight seal with the outer surface of the needle, to prevent fluid from leaking from the barrel into the plunger 30. In addition, the projection position, the needle pierces a nose seal 24 placed inside the nose 22 of the barrel. The nose seal forms a liquid-tight seal with the outer surface of the needle to prevent fluid from leaking out of the barrel through the nose 22. The apparatus can be designed to operate in two different ways. In the first form, the plunger is extracted to form a fluid chamber of a particular volume. Subsequently the needle is inserted into a patient and blood flows through the needle and into the barrel, filling the fluid chamber. When the apparatus is designed to be used in this manner, hydrophobic ventilation is included to prevent an air pocket from forming to the apparatus, which could impede the flow of blood into the fluid chamber. Ventilation is permeable to air, but is not permeable to blood. Ventilation allows air from the fluid chamber to be discharged from a fluid chamber, as blood enters the fluid chamber, but prevents blood from leaking from the fluid chamber.

Alternatively, the apparatus 10 may be configured to operate in a manner such that blood pressure backs the plunger so that blood enters the fluid chamber. During this event, the plunger is moved forward so that the piston is placed on the front end of the barrel, engaging the front wall of the barrel. Subsequently, the needle is introduced into the patient and the blood flows into the barrel, displacing the piston 32 backwards so that the blood enters the barrel. When the apparatus is designed to be used in such a manner, it does not need ventilation to vent the air from the fluid chamber. In addition, the piston of the barrel wall is lubricated to reduce friction between the barrel piston and thus facilitate the movement of the plunger.

Referring to the figures of 3A - 3D, the device operates as indicated below. In Figure 3A, the apparatus is shown before being used. The needle 40 is inserted into a blood vessel of the patient, and blood flows into the fluid chamber located in the barrel, as shown in Figure 3B. Referring to Figure 3C, the plunger is subsequently displaced axially backwards, so that the actuator 36 engages the needle retainer 50, displacing the tab 52 radially outwards, to release the needle. Subsequently, the spring 60 urges the needle backwards from the needle chamber so that it is stored with the barrel. After the needle retracts, the septum of the diver that was inserted by the needle is sealed again to prevent blood from leaking into the plunger. In addition, the nose seal 24 is sealed again, to prevent blood from seeping through the nose 22. In this way, the sample is sealed inside the fluid chamber against contact with air. Referring now to Figure 3D, after the needle is retracted, the sample can be discharged from the syringe so that the sample can be folded. The sample can be discharged by moving the plunger forward. By moving the diver forward, enough liquid pressure is created to expel the liquid through the hole in the membrane of the nose seal that was formed by the needle. Referring now to Figures 4 through 5D, a second embodiment 10 of a fluid sampling apparatus is shown. Apparatus 1 10 includes a barrel 120 and a retractable needle 140 projecting forward of the barrel. A plunger 130 slides in the barrel. After a sample of fluid was collected in the apparatus, the needle is retracted in the barrel, so that the needle is stored to avoid accidental contact with said contaminated needle. Once the needle is retracted, the fluid is sealed inside a fluid chamber that is in the barrel. Subsequently, the fluid sample is discharged, so that the sample can be tested. Plunger 1 30 includes a hollow stem 132. An elastomeric diver 132 is removably attached to the front end of the stem. The piston forms a fluid-proof seal with the inside of the barrel. Preferably, a hydrophobic plug 136 extends through the piston, providing ventilation for the vessels located in the fluid chamber between the diver and the forward end of the barrel. An annular base projecting in or detent ring 125 limits the axial displacement backwards of the diver. Once the diver engages with the stop ring 125, the continuous backward movement of the plunger separates the diver from the plunger.

The stem of the plunger projects forward of the portion of the rear part of the plunger, which is an elongated hollow portion generally cylindrical, which forms a chamber for the needle 134. The stem 132 is also hollow, forming a front chamber 137 for receiving the rear end of the needle when said needle 140 is placed in the retracted position. The front end of the front chamber is smaller in diameter than a block 146 attached to the rear end of the needle. In this form, at the moment of the displacement towards the back of the plunger, the inner wall of the front chamber 137 engages with the block 146 that is in the needle, driving the needle backwards. It, in turn, moves the needle out of the gear with the needle retainer 150, so that the continuous backward movement of the plunger retracts back the needle. The front end of the barrel 120 forms a reduced diameter nose 122. The needle projects forward of the nose 122 in the projection position. In this position, the needle passes through an opening that is at the front end of the diver. The front opening in the diver is smaller in diameter than the needle, so that the piston forms a fluid-tight seal around the outside of the needle. A needle retainer 150 removably holds the needle in the projection position. In this example, the needle retainer comprises a pair of receptacles 152 that contribute and engage a spherical retainer attached to the needle.

The apparatus 120 operates as indicated below. Referring to Figure 5A, apparatus 1 10 is shown before use. The plunger 130 is displaced backward to provide a fluid chamber that receives the fluid sample. The needle is then inserted into the patient's artery. Blood flows through the needle in the fluid chamber through a side port 142 that is located on the needle to collect the sample, as shown in Figure 5B. Referring to Figure 5C, once the sample is collected the plunger is displaced backwards to separate the diver from the plunger. The plunger is moved further back to retract the needle into the barrel. Referring to Figure 5D, later the sample can be ejected, driving the plunger forward to engage the diver again and subsequently driving the diver forward.

Referring now to figures 6 through 7, a third embodiment of a medical device for fluid sampling is illustrated. The apparatus includes a barrel 220 and a retractable needle 240 projecting from the front end of the barrel. A plunger 230 slides in the barrel. Once the sample is collected from the patient, the needle retracts into the barrel to store the contaminated needle.

The barrel is generally cylindrical and hollow. The plunger 230 includes an elastomeric diver 234 which forms a fluid-tight seal with the inner wall of the barrel. The plunger 230 is hollow, having a front chamber 239 that covers the spring before the needle is retracted, and a chamber for the rear needle 237 that receives the needle after it is retracted. A spring 260 surrounding the needle tilts the needle back to the retracted position. The spring is positioned around the needle 240 between a fixed spring block 228 and a needle block 244 connected to the trailing end of the needle. The spring block 228 is fixedly attached to the barrel 220. Therefore, the slot 233 is formed in the side portion of the plunger 230 to provide a space for the spring block 228 when the plunger is displaced within the barrel. A needle retainer 250 releasably holds the needle in the projection position against the tilt of the spring 260. In this example, the needle retainer is epoxy 252 that connects the needle to the nose 222. Referring to the figures from 7A-7B, the apparatus is as indicated below. In Figure 7A, the apparatus is illustrated before being used. The plunger 230 is removed to provide a fluid chamber between the diver 234 and the reseal seal 224 that is positioned in the nose of the barrel, and provides an antifluid seal with the outside of the needle 240. Referring to FIG. Figure 7B, needle 240 is inserted into an artery of the patient, and blood flows through a lateral port 242 that is located in needle 240 and made into the fluid chamber. Once the sample is collected, the needle is removed from the patient. Referring to Figure 7C, later the plunger 230 is displaced backwards. The backward movement brings the diver 234 into a gear with an annular base projecting inwardly from the inside wall of the barrel. The continuous backward displacement of the plunger separates the diver 234 from the stem 232 of the plunger. In addition, the backward movement causes the annular base 238 to engage with the needle block 244. Referring to Figure 7D, further backward displacement of the plunger breaks the junction between the nose 222 and the needle, releasing the needle from the needle. needle retainer 250. The needle is then pushed back into the needle chamber. The nose seal 224 is resealed to prevent the sample from seeping through the nose 222 of the barrel. In addition, the front end of the diver 234 is resealed to prevent the sample from leaking into the plunger. In this form, the nose seal 224 and the diver 234 seal the sample within the fluid chamber to prevent the sample from contacting the air. Once the needle is retracted, the sample can be expelled from the barrel into a piece of equipment to make sample tests, leading the plunger forward.

Referring now to FIGS. 8 through 11, a fourth embodiment of a fluid sampling apparatus 310 is shown. The apparatus includes a barrel 320, a retractable needle 340, and a plunger 330 that slides in and out of the body. from the barrel.

This third mode allows the operator to actuate the retraction of the needle, regardless of the axial position of the plunger. The barrel 320 is generally cylindrical. The front end of the barrel is generally closed, forming an opening of reduced diameter. A female Luer fitting 322 projects from the forward end of the barrel 320. An elastomeric seal threadedly engages the Luer fitting 322. The seal 322 includes a membrane that can be inserted through which the needle 340 projects. The membrane forms a fluid seal with the outside of the needle 340. The plunger 330 includes a diver 332 that forms a fluid-tight seal with the inner wall of the barrel. In addition, the diver 332 includes a membrane that can be inserted with the projecting needle. The diver's membrane forms a fluid-proof seal with the outside of the needle. In addition, the diver includes a hydrophobic plug 336 that allows the vessel to vent from the fluid chamber between the diver and the nose seal 224. Referring to FIGS. 10 and 11 the plunger 330 is a channel generally formed as U, having a chamber for the needle 334, for receiving the retracted needle 340. An elongated, longitudinally-extending rib 335 projects upward into the chamber for the needle 334. Referring now to figures 8 to 10, a manually operated needle retainer 350, retains the needle releasably in the projection position next to the inclination of the spring 360, tilting the needle back toward the retracted position. The needle retainer 350 comprises an actuator lever 354 and a latch that engages a block 344 attached to the needle. As shown in Figure 9, latch 364 engages needle block 344 to releasably retain the needle. By operating the lever of the actuator 352 the bolt 354 oscillates radially out of the gear as a block of the needle 344. Subsequently the spring 360 drives the needle back towards the retracted position.

The bolt 357 is inclined in the gear with the needle block 344. In this example, a spring tab 359 tilts the bolt in the gear with the needle block. The spring tongue 359 is integrated with the bolt and projects backwards from the bolt. The tongue of the spring 359 flexes elastically and engages the inner wall of the barrel 320. When the actuating lever 354 is operated, the bolt moves radially forwardly, thereby elastically deforming the tongue of the spring 359. .

Referring to Figure 10, needle retainer 350 is attached to barrel 320 by mounting brackets 352. Mounting brackets 352 mesh a groove 326 formed in the upper part of the barrel. Mounting brackets 352 fix the needle retainer relative to plunger 330. A transverse spring block 351 is connected to the needle retainer assembly. The spring block forms a front bearing surface for the spring 360. The actuator lever 354 is attached to the spring block 351 by a flexible core or holding hinge 355. The web 355 forms a balance point for the actuator lever. 354. The device operates as indicated below. The plunger 330 is removed to provide a fluid chamber for receiving a sample of blood from a patient the needle 340 is inserted into an artery of the patient. Blood flows through a side port 342 that is located in the needle and made into the fluid chamber. Once a sufficient amount of blood is removed, the needle is removed from the patient. The actuating lever is pressed to pivot the bolt 357, thereby releasing the needle retainer needle 350. Subsequently spring 360 urges the needle back into the needle chamber. Once the needle is retracted, the nose seal 324 is resealed to prevent blood from leaking out of the fluid chamber. The fluid sample can then be expelled from the apparatus in a separate apparatus to test the sample. The sample is ejected, leading the plunger forward into the barrel. Referring now to Figures 12A-12C, an apparatus for collecting a fluid sample such as blood, is designated generally with the number 410. The apparatus 410 comprises a sign 420 and a needle assembly that can be connected in removable form 430. The needle assembly 430 comprises a retractable insertion needle 460 for insertion into a patient's skin. When the assembly of the needle 430 is connected to Figure 420, the insertion needle 460 is in fluid communication with the interior of the syringe. Once the fluid sample has been collected in the syringe 420, the insertion needle 460 can be retracted into the cover of the needle assembly 430 to avoid accidental contact with the contaminated insertion needle. The assembly of the needle 430 can also be removed from the syringe 420 after the fluid sample has been collected. Subsequently the fluid sample can be transferred to where the sample will be tested. Subsequently the sample can be expelled by syringe 410 and tested.

The syringe 420 is similar to a normal syringe, having a barrel 422, a plunger 424 with a diver 425 sliding in the barrel and a Luer 428 fitting on the nose of the barrel. The diver 425 forms a fluid-proof seal with the inner wall of the barrel 422, and by driving the plunger forward it expels the fluid from the syringe 420.

The needle assembly 430 is adapted to be connected to the Luer fitting 428 of the syringe, so that the needle assembly can be used with standard syringes which are already widely used in the field of medicine. Therefore, the cover 440 of the needle assembly 430 includes an opening at the rear end, forming a socket 442 for engaging the Luer accessory 428 of the syringe. A seal having a releasable membrane that can be inserted, is placed inside the socket 442. The seal 445 is externally screwed having debris that contributes with the Luer accessory 428. The assembly of the needle 430 comprises two needles, a needle of front insert 460 projecting forward of the front end of the cover 440, and a fixed needle 450 positioned within the cover 440. The fixed needle 450 projects to the socket 442, entering the Luer seal 445. The fixed needle 450 it is attached to a needle tube 452 which is fixedly attached to the cover 440. The rear end of the fixed needle tube is generally closed, having a reduced diameter through which the fixed needle 450 projects. The fixed needle is fixedly connected to the tube of the fixed needle 452, to form a fluid-proof connection between the outer surface of the fixed needle and the generally closed rear end of the tube. the fixed needle. The insertion needle 460 is fixedly connected to a needle tube of telescope 462 which telescopically engages with the interior of the fixed needle tube 452. A needle seal 456 placed within the forward end of the needle tube Fixed 452 provides a fluid-tight seal between the fixed needle tube and the telescope needle tube. The insertion needle projects forward from the front end of the needle tube of the telescope 462. An annular base 464 projects outwardly from the needle tube of the telescope 462. A spring surrounding the telescope needle tube 462, is positioned between the base 464 and the interior of the front end of the cover. The spring 480 rests against the base 464 by tilting the tube of the telescope needle 462 on the insertion needle attached backwards. A needle retainer 470 releasably retains the insertion needle 460 against the tilt of the spring 480. The needle retainer 470 comprises an actuator button 472 and a latch 474. The latch 474 has an aperture through which the latch 474 is opened. projects the tube of the telescope needle 462. In the closed position, the lock 474 is positioned so that the edge of the aperture engages the base 464 to hold the tube of the telescope needle against the inclination of the spring. Upon pressing the actuator button 472, the latch 474 moves downwardly so that the latch opening is aligned with the annular base 464. Subsequently the spring 480 pushes back the tube of the telescope needle towards the fixed needle tube. , so that the insertion needle is stored inside the cover 440.

Therefore, the apparatus 410 operates as indicated below. The plunger 424 is positioned such that the diver 425 is located at the front end of the barrel of the syringe 422. The needle assembly 430 is connected to the front end of the syringe 420. The rear fixed needle 450 projects through the Luer seal 445 and made the barrel. Subsequently, insertion needle 460 is inserted into an artery of the patient and blood flows from the patient into the syringe. The pressure of the blood flow leads back to the diver and the plunger 424 as the blood enters the syringe 420. Once a sufficient amount of blood has been collected, the insertion needle is extracted from the patient. The actuator button 472 is depressed to drive the retraction of the insertion needle. Subsequently, the insertion needle retracts into the cover. Subsequently the assembly of the needle 430 is separated from the syringe 420. The Luer 445 seal remains in the Luer accessory 428 of the syringe, sealing the front end of the syringe to prevent fluid from leaking out of the nose of the syringe 420 The diver 425 forms a fluid-tight seal with the barrel to prevent fluid from leaking out of the rear end of the syringe. The sealed fluid sample can be transported later, to an area to test the sample later it can be expelled from the syringe by driving the plunger forward inside the barrel. Referring now to Figures 13A and 13B, a second embodiment of a needle assembly that is operable together with a syringe is generally designated 510. The needle assembly includes a cover 520 and a projecting needle 540. I made forward the cover. The rear end of the cover forms a socket 522 for connecting the needle assembly to a similar syringe for the manner described above, in connection with the apparatus designated with the number 410 and illustrated in the figures of 12 a-12c. however, in the present example, the socket 522 configured as a female raised Luer-type accessory, contributes with a male Luer fitting found in a syringe.

The needle assembly 510 includes a generally cylindrical nose piece 530 attached to the front end of the cover 520. And a nose seal 532 forms a fluid-tight seal on the exterior of the needle 540. A needle tube generally cylindrical 545 is placed inside the cover 520 and projects at the rear end of the nose piece 545. The front end wall of the socket 522 has a reduced diameter opening so that the needle tube 545 is in communication with fluids with the socket. An annular retainer 542 projects inwardly into the needle tube adjacent the leading end of the needle tube 545. An elastomeric valve 550 seals the leading end of the needle tube 545. The valve 550 has an outer circumferential groove 552 The annular retainer 542 engages with the circumferential groove to retain the valve 550 releasably.

The rear end of needle 540 projects into the valve 550. The forward end of needle 540 projects forward from the nose piece. A spring 560 attached to the needle leans the spring back to a retracted position within the cover 520. A needle retainer 570 releasably holds the needle in the projection position against the spring inclination. The needle retainer 570 is configured in a manner similar to the needle retainer described above in connection with the above apparatus 410. The retainer 570 comprises an actuator button 572 and a latch 574. The latch has an aperture. In the closed position, the edge of the bolt opening engages with the end of the spring 560. When the actuator button 572 is depressed, the bolt is displaced backward, aligning the bolt opening with the spring, thereby allowing the bolt to open. spring pushed back the needle as shown in Figure 13B. Therefore, the apparatus operates as indicated below.

The assembly of the needle 510 is attached to a syringe. Subsequently the needle is inserted into the artery of a patient. Blood flows through needle 540 and through valve 550 into needle tube 545. From the needle tube blood flows to the syringe, where the sample is collected. Once enough blood has been removed, the 540 needle is removed from the patient. The actuator button 572 is pressed to release the needle 540. The spring 560 drives the needle backwards. The needle is additionally driven into the valve, sealing the back end of the needle. In addition, the spring tilts the valve against the opening in the socket to seal the opening of the socket. In this way the needle assembly operates as a seal, sealing the front end of the syringe. The needle assembly can be separated if desired. The syringe can then be sealed with a cover and transported to an area where the sample will be tested. Subsequently the sample can be expelled from the syringe, leading the plunger forward. Although the particular embodiments of the present invention have been illustrated and described above, it is not intended to limit the present invention to said description. It will be recognized that changes and modifications may be made within the scope of the claims set forth below.

Claims

CLAIMS. Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property:

1 .- A method for extracting a sample of fluid from a patient, comprising the steps of: (a) Providing a sampling apparatus having a cover and a needle having a sharp tip to enter the patient's skin. (b) Extract patient fluid in the cover; (c) Retract the needle so that the sharp point of the needle is stored inside the cover; Y (d) Expel the fluid from the cover once the needle is retracted.

2. The method as described in claim 1, further characterized in that the apparatus comprises a displaceable plunger within the cover and the step of expelling the fluid comprises the displacement step of the plunger within the cover.

3. - The method as described in Claim 1, further characterized in that it comprises the step of sealing the fluid inside the cover. SUMMARY A method for extracting a fluid sample from a patient is described, comprising the steps of: a) providing a sampling apparatus (10) having a cover (20) and a needle (40), having a tip sharp to enter the patient's skin; b) removal of patient fluid in the cover; c) retraction of the needle, so that the sharp point of the needle is stored inside the cover; and d) expulsion of fluid from the cover, after the needle is retracted.