Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/15—Devices for taking samples of blood
  • A61B5/153—Devices specially adapted for taking samples of venous or arterial blood, e.g. with syringes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/15—Devices for taking samples of blood
  • A61B5/150007—Details
  • A61B5/150015—Source of blood
  • A61B5/15003—Source of blood for venous or arterial blood
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/15—Devices for taking samples of blood
  • A61B5/150007—Details
  • A61B5/150206—Construction or design features not otherwise provided for; manufacturing or production; packages; sterilisation of piercing element, piercing device or sampling device
  • A61B5/150213—Venting means
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/15—Devices for taking samples of blood
  • A61B5/150007—Details
  • A61B5/150206—Construction or design features not otherwise provided for; manufacturing or production; packages; sterilisation of piercing element, piercing device or sampling device
  • A61B5/150236—Pistons, i.e. cylindrical bodies that sit inside the syringe barrel, typically with an air tight seal, and slide in the barrel to create a vacuum or to expel blood
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/15—Devices for taking samples of blood
  • A61B5/150007—Details
  • A61B5/150206—Construction or design features not otherwise provided for; manufacturing or production; packages; sterilisation of piercing element, piercing device or sampling device
  • A61B5/150244—Rods for actuating or driving the piston, i.e. the cylindrical body that sits inside the syringe barrel, typically with an air tight seal, and slides in the barrel to create a vacuum or to expel blood
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/15—Devices for taking samples of blood
  • A61B5/150007—Details
  • A61B5/150206—Construction or design features not otherwise provided for; manufacturing or production; packages; sterilisation of piercing element, piercing device or sampling device
  • A61B5/150259—Improved gripping, e.g. with high friction pattern or projections on the housing surface or an ergonometric shape
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/15—Devices for taking samples of blood
  • A61B5/150007—Details
  • A61B5/150351—Caps, stoppers or lids for sealing or closing a blood collection vessel or container, e.g. a test-tube or syringe barrel
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/15—Devices for taking samples of blood
  • A61B5/150007—Details
  • A61B5/150374—Details of piercing elements or protective means for preventing accidental injuries by such piercing elements
  • A61B5/150381—Design of piercing elements
  • A61B5/150389—Hollow piercing elements, e.g. canulas, needles, for piercing the skin
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/15—Devices for taking samples of blood
  • A61B5/150007—Details
  • A61B5/150374—Details of piercing elements or protective means for preventing accidental injuries by such piercing elements
  • A61B5/150381—Design of piercing elements
  • A61B5/150503—Single-ended needles
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/15—Devices for taking samples of blood
  • A61B5/150007—Details
  • A61B5/150732—Needle holders, for instance for holding the needle by the hub, used for example with double-ended needle and pre-evacuated tube

Definitions

• This invention relates to the field of blood sampling in general and, specifically, to arterial blood gas analysis.
• the invention also relates to the manufacture of disposable syringes and the apparatus associated therewith.
• Basic information obtained by blood gas analysis is the amount of oxygen (pO 2 ), carbon dioxide (pCO 2 ) and the acidity (pH) of arterial blood.
• pO 2 oxygen
• pCO 2 carbon dioxide
• pH acidity
• Clinically, arterial blood provides very useful information since it directly reflects the ability of the human lung to transport oxygen from the inspired air into the bloodstream in order to make oxygen available to the tissues.
• the measure of carbon dioxide in arterial blood is an indicator of the ability of the lung to eliminate this metabolic waste product.
• Arterial blood should reflect the body's lowest CO 2 levels and any increases in arterial pCO 2 levels. Increases in arterial PCO 2 not only indicate a possible respiratory problem, but also cause the acidity of the blood to increase, which could have serious metabolic implications, since the body can function normally only in a carefully controlled pH range.
• the measure of pO 2 , pCO 2 , and pH are important diagnostic indicators of respiratory and metabolic disorders.
• a sample is analyzed twice to minimize analyzed air. Normally, turnaround time for the results is fifteen minutes to three hours, although some operating rooms and respiratory therapy departments of modern hospitals have blood gas analyzers on site.
• the usual frequencies for arterial sampling are every ten minutes for cardiopulmonary resusitation, every twenty minutes for initiating or leading a patient on a ventilator, every thirty minutes for a patient undergoing cardiovascular surgery, and every one to two hours for patients in an intensive care unit.
• blood gas analysis and acid-base analysis is critical to the evaluation of patient status and response to therapy, as many as thirty-five analyses per patient in an intensive care unit are considered normal. It is estimated that in the United States, eighteen to twenty million blood gas samples are taken annually from approximately one and one-half to two million patients; indeed, blood gas analysis is one of the most frequently performed of all hospital procedures.
• blood gas determinations rank in importance with blood pressure and ECG measurements.
• a blood sample should always be taken slowly to minimize the effect of temporary stimulation of ventilation resulting from insertion of the needle.
• Local anesthetics are sometimes employed to reduce the patient's response to the pain and trauma of arterial puncture. Changes in respiration rate, heart rate, etc, can introduce significant errors in pO 2 , pCO 2 , and pH measurements.
• the eannula employed should be large enough to allow free entry of blood to the syringe with minimal traction on the plunger. In most cases, the arterial pressure is utilized to fill the syringe to prevent contamination of the sample by air, which can leak between the syringe plunger and barrel if aspiration is applied.
• Non-disposable glass syringes capillary tubes, disposable glass syringes, disposable plastic syringes, and devices such as the VACUTAINER TM (Beeton-Dickinson & Co., Rutherford, New Jersey).
• VACUTAINER TM Beeton-Dickinson & Co., Rutherford, New Jersey.
• a 5 ml. glass or special plastic syringe with a 20 gauge x 1 1/2" needle is utilized. This combination can be handled easily by most individuals because of its good balance. It fills quickly and has good visible pulsations to observe filling of the syringe.
• kits containing disposable arterial syringes have been introduced into the U.S. market.
• the advantages of the kits are many, especially for hospitals drawing sizable number of arterial bloods: they (1) provide surety of the avoidance of potential cross-contamination, (2) provide greater protection for patients and personnel, (3) take up less time in gathering components and are seemingly always available when needed, (4) provide in a convenient fashion everything necessary to obtain quickly blood samples for blood gas analysis, (5) provide easy storage capabilities and ease of storing supplies, (6) avoid the necessity of hospital sterilization, (7) in many instances, cost less than reusable apparatus of the traditional practice, and (8) offer the hospital standardized blood gas testing procedure from department to department.
• kits containing these disposable syringes are the (Concord Laboratories of Keene, New Hampshire) PULSATOR R 3 cc syringe (prefilled with heparin); the (Medical Products Inc. of Englewood, California) OMNIS ⁇ K TM /MINISTIK TM 5cc syringe (precoated with crystalline sodium heparin); the (Bard-Parker division of Becton-Dickinson & Co. of Rutherford, New Jersey) U-MID TM 3cc or 5cc syringe (prefilled with sodium heparin solution); and the Becton-Dickinson "B-D" (logo) 3cc blood gas syringe.
• the housing member 14 of '304 may be an elongated tubular construction such as that of a conventional syringelike device.
• the housing member 14 comprises an elongated center chamber 20 having a cylindrical configuration and a circular cross section.
• the chamber 20 extends axially from an open end 22 of the housing member, and typical wing portions 23 extend from the open end 22 to facilitate handling and use of the syringe-like housing member 14.
• the opposite end of chamber 20 is terminated with a barrel portion end member 24.
• An axially extending and cylindrieally shaped outside surface serves as one form of means for connecting the hypodermic needle 12 to the barrel portion end member 24.
• a bore extends axially through the barrel portion end member 24 and serves as one form of means adapted for providing fluid communication between the center chamber 20 and the connected hypodermic needle 12.
• the resilient member 38 expands to receive at least one length or piece of fluid conductive fibrous material such as string or thread 40 which projects through the resilient member 38 to allow a small amount of fluid communication from the repository 33 of the capillary tube through the thread 40.
• U.S. Pat. 4,133,304 indicates at Col. 2, lines 11-13 that the fibrous material 40 can be removed so that the resilient member seals the cap member 34 of the capillary tube 16.
• Cap 34 is constructed of plastic material and scaled on capillary tube 16 by heat shrinking it to the end of the capillary tube at the cap hinge 35.
• the resilient member 38 may be constructed of silicone, rubber or other similar material and serves as one form of means for expanding to receive a portion of the thread 40 or other fibrous material extending through the resilient member 38 and as means for sealing the fluid outlet means 32 of the capillary tube upon removal of the fibrous material.
• the resilient characteristics of the member 38 close the opening through which the thread 40 was inserted upon removal of the thread. As repository 33 fills with blood, gas and air escapes through the fluid conductive fibrous material or thread 40.
• the fluid outlet means 32 serves to release or outlet fluid from the interior or repository 33 of the capillary tube.
• the scaling means or resilient sleeve member 18 shown in Figure 2 connects the fluid inlet nozzle 30 of the capillary tube 16 into the bore of the barrel portion end member 24, and establishes an air-tight and fluid conductive path through the connected hypodermic needle and into the capillary tube 16.
• the sleeve member 18 is received within the bore and comprises an opening (not shown) extending through the sleeve member coaxially with the bore.
• the sleeve member 18 also comprises a flange portion (not shown) adjacent the outer axial end of barrel portion end member 24.
• the nozzle end 30 of the capillary tube 16 is partially inserted into one end of the opening and compresses the resilient material of the sleeve member 18 against the interior wall of the bore, thus causing a fluid tight seal between the fluid inlet nozzle 30 and end portion of the opening of the sleeve member.
• the compressive forces of the resilient material of the sleeve member firmly holds the fluid inlet nozzle 30 of the capillary tube thus causing the sleeve member 18 to also serve as one form of means for positioning the capillary tube generally in an axially extending manner within the chamber 2 0 of the housing member 14 with the fluid inlet means or nozzle 30 oriented toward the bore.
• the hypodermic needle 12 shown in Figure 2 is of a construction having an axially extending elongated hollow shaft (cannula) 50 terminated with a flesh piercing point 52.
• the hollow shaft 50 is received within a hub member 54, and a center tubular projection member 56 is sealed to and extends from the shaft 50 within the hub member 54.
• An axially extending opening 58 of the hub 54 receives the barrel portion of the end member 24 to attach the hypodermic needle 12 to the syringe-like housing member 14 with the surface of barrel portion serving as means for frictionally connecting the hypodermic needle 12 to the housing member 14.
• a reduced diameter end portion (not shown) of the tubular projection 56 extends into and mates with the opening in the sleeve member 18 adjacent the flange.
• Crystalline heparin 59 or other suitable anticoagulant is said to be deposited on the interior of the capillary tube 16 prior to use.
• the crystalline heparin 59 may be deposited by placing a drop of a solution of heparin into the interior of the capillary tube, and then allowing the dilutent to evaporate, thereby leaving only the solid heparin deposited on the walls of the repository 33. This process can be expedited by heating the capillary tube to hasten the evaporation.
• the crystalline heparin 59 or other suitable anticoagulant prevents the blood sample from coagulating in the capillary tube after it has been collected.
• the capillary tube 16 of '304 is received within the housing member 14 with the nozzle 30 being sealed within the bore of the end member barrel portion 24 by the sleeve member 18.
• the user attaches the hypodermic needle 12 causing the end portion of the tubular projection 56 to be received within the opening through the sleeve member 18.
• the flesh piercing point is inserted in an artery of a person from whom the blood sample is collected.
• the blood pressure within the artery forces blood upward through the hollow shaft 50 and tubular projection 56, through the opening in the sleeve member 18 and into the fluid inlet nozzle 30 of the capillary tube 16.
• the hollow interior or repository 33 gradually fills because of the blood pressure in the artery and because the fibrous material or thread 40 of the fluid outlet means 32 expels air and other gases to allow the repository 33 to fill with blood.
• a small amount of the blood sample is conducted by the thread 40 through the resilient member 38 forming a drop on the top of the resilient member 38.
• the drop of blood signals the operator to remove the hypodermic needle from the artery, thereby terminating the blood sample collection.
• a cork or stopper (not shown) is immediately placed over the flesh piercing point 52 of the hypodermic needle to seal the hollow opening through the needle shaft 50.
• the syringe of U.S. Pat. 4,133,304 is a state-of-the-art practical disposable arterial blood gas syringe and, because of its capillary construction, it permits one to avoid (1) taking large samples and use of liquid heparin, (2) employing large needles required to obtain the large samples, and (3) CO 2 dilution (a problem generally occurring because of the presence of aqueous heparin).
• Syringes made under U.S. Pat. 4,133,304 come in at least three sizes - to sample 0.3 cc, 0.6 cc, and 1.2 cc.
• Figure 4 discloses a plastic disposable single-use syringe now also commonly used in hospitals.
• the apparatus comprises an apparatus 10 comprising a tube 14 having wing or flange portions 23 for use with the hypodermic needle 80.
• the apparatus 10 is equipped with a plunger 17 that is adapted to slidably engage tube 10 by pressing or pulling plunger top 17a which is affixed by a shaft 17b narrower than that of tube 14.
• the shaft is affixed to a resilient rubber plug means 92 by balljoint 17c; the plug means that traverses and closes tube 10 to form a center chamber 95.
• a good example of such a state of the art device is the "B-D 1.Oce Sterile Single Use Tuberculin Syringe", Recorder No. 5602 by Becton-Dickinson & Co., Rutherford, New Jersey.
• a new and useful apparatus for use with a hypodermic means to collect an animal fluid material (generally a blood or urine sample) having one or more predetermined gases or other clinically significant substances, consisting essentially of:
• (a) means for storably receiving and housing a fluid material comprising an elongated center chamber means open at a first end, and second member means terminating the center chamber means at a second end, the second end member means adapted to connectably and sealably receive hypodermic needle means thereto, and said second end member means further having bore means extending through the second member means, which bore means are adapted to communicate said fluid material between said center chamber means and said connectably received hypodermic needle means;
• closure means adapted to fit the elongated center chamber means (for example, at the open end) to form a center chamber and for providing (1) low resistance escape means for air (which includes for our purposes all gases not entrained in the liquid) while the center chamber is filling with hquid, and (2) high resistance escape means to the flow of liquid.
• Low resistance escape means are to allow air to escape (without allowing liquid to escape) at pressure equal to or less than the pressure of the fluid material to be collected;
• high resistance escape means are to prevent liquid from escaping at pressures less than or equal to a predetermined pressure which is greater than or equal to the pressure of the fluid material to be collected.
• the new and useful apparatus comprises the following:
• Another suitable membrane is the ACCUREL R microporous polymer membrane by Armak Co., Chicago, Illinois.
• the means (a) for all three embodiments are preferably made of plastic, most preferably polypropylene, which is coated with a suitable anticoagulant, such as solid heparin.
• the opening of the capillary tube extending through the plug means is flush with the surface of the plug means bordering the center chamber to minimize entrapment of air.
• the plug means is preferably made of resilient rubber.
• the type of plug is selected and constructed so that it can be moved to any predetermined position along the center chamber with an application of a predetermined force which is greater than the surface area of the plug times the pressure of the incoming fluid material.
• the capillary tube means is preferably comprised of one or more flexible plastic hollow fibers, most preferably cuprophane (most preferably having an internal diameter of about 200 to about 250 microns and a wall thickness of from 9 to about 16 microns). We prefer the use of one fiber, possibly coaxial with the plug and tube.
• the one-way valve means comprise two or more overlapping membranes or impermeable film layers, each of which substantially traverse the center chamber means, so that the layers form a tortuous path for the air to escape in the event of a positive pressure in the center chamber.
• the one-way valve means comprises two or more sheets of plastic film impermeable to the fluid material to be collected.
• An excellent plastic film where blood is the fluid to be collected is polyethylene terephthalate.
• a heavy, solid sphere such as metal, be employed to mix the liquid material in the center chamber.
• the membrane materials should be non-water wettable, non-antigenic, inert and impermeable to the blood sample. Accordingly, it is an object of the invention to provide an arterial blood gas syringe which need take only a small sample, in order to minimize chances of CO 2 /O 2 contamination and the use of large needles.
• Figure 1 is a perspective view of one embodiment of the state of the art syringe of U.S. Pat. 4,133,304 in use with an attached hypodermic needle.
• Figure 3 is an enlarged fragmentary section view taken along line 3-3 of Figure 2 also illustrating a layer of anticoagulant deposited in the interior of one of the elements of the apparatus of the '304 patent.
• the plug is then inserted at and moved to a predetermined position in the tube 14.
• the center chamber 95 fills up with fluid, air escaping through opening 102 of the fiber 90; afterwards, blood can be seen to commence rising in the fiber 90.
• the fiber is removed by pulling and the plug 92 seals completely the upper end of the outer chamber 95.
• the string 40 of Bailey is unacceptable for our use because it is not guaranteed to be (1) non-antigenic and (2) inert to the blood to be sampled.
• the use of a hollow fiber for the resilient member is truly synergistic in that (a) it provides a movable assembly for the plug (eliminates the necessity of different size syringes for different volumes), (b) is non-antigenic and inert for safety and efficacy, and (c) is removed easily.
• one primary result of the closure in each of the embodiments of Figures 5, 6, 6a, 7 and 10 is providing low resistance air escape means while the means for storably receiving and housing the fluid is filling with fluid.
• Another primary result is providing a very high resistance to the flow of fluids, such as blood. This allows the tubular means to fill with fluid freely while expelling the air originally in the tube and stopping the flow of sample when the liquid reaches the closure. In the case of the embodiment of Figure 6, the stopping function is accomplished by removing the venting means from the resilient plug.
• Another function of the closure is to prevent contamination of the sample by O 2 and CO 2 .
• this is accomplished by applying a layer of pressure-sensitive adhesive coated barrier film over the end of the device once the tubular means, i.e., the center chamber 95, is filled.
• the volume of sample taken by the device is generally dependent upon the volume of the tubular means 14.
• the resilient plug may be positioned at suitable locations along the length of the tubular means 14 to obtain varying sample size volumes. This, of course, will require that the venting means be provided with sufficient length so that it extends beyond the open end of the tubular means 14 in all cases.
• the operation of the device of the invention is as follows for blood sampling. An appropriately sized syringe needle 80 is placed on the tapered bore 24 of the tubular means 14.
• the blood sample can be ejected from the sampling device as follows.
• the closure membrane or film is peeled away and an appropriately sized syringe plunger is inserted into the tubular means. After removing the resilient plug from the syringe needle, or the syringe needle itself, the sample can be expelled.
• the membrane 78 can be peeled away or punctured and the sample aspirated by a blood gas analysis machine, or by forcibly discharging the sample with air pressure, as with a pressure bulb pump.
• a shaft or rod is inserted into the open end of the tube 14.
• Glass tube 137a was affixed to 1/4 inch (I.D.) rubber tube 131 to a common aspirator bulb 130. In the center of the length of the tube, a three-way stop cock 132 was employed (3-way stopcock of borosilieate glass by Corning Glass Co. - Stock 'No. 7380 having stopper bore 4mm, side arms 10mm) to release pressure in bottle 120 if desired.
• Glass tube 137b was affixed to a 100cm U- tube manometer (provided by SCA Scientific Supply Inc., Bloomfield, N.J.) 135 by 3/8 inch rubber tube 136 through clamp 129, the manometer containing mercury 134. The manometer was provided with stand 133.
• EXAMPLE II 350mg of sodium heparin are ground with a mortar and pestal and are dispersed in a non-solvent such as CH 2 Cl 2 which wets the polypropylene tube 14 of the invention. 140 ml CH 2 Cl 2 was employed. The polypropylene tube is wet by the dispersed solution and the CH 2 Cl 2 is allowed to evaporate, leaving a fine white powdered dust coating of sodium heparin on the tube.
• Sodium heparin is available from:
• Heparinic acid is dissolved in a 140ml organic solvent (chloroform) which wets polypropylene. Proceed in the same manner to coat tube 14 as in Example II.
• EXAMPLE IV To a concentrated solution of sodium heparin in water was added dropwide a volumn of aqueous solution of dodecyltrim ethyl ammonium chloride to form a precipitate of a heparin dodecyltrimethyl ammonium chloride. This was collected and washed with excess water and dried at ambient temperature under 1mm Hg vacuum.
• heparin/quarternary ammonium complex 160mg of the heparin/quarternary ammonium complex, to-wit, dodecyltrimethyl ammonium chloride is dissolved in sufficient isopropyl alcohol solvent to form a concentration of 2.5 mg/ec of heparin/quarternary ammonium complex.
• the solution is loaded into a 1.0cc plastic syringe. After evaporation, a film coating of heparin/quarternary complex was left on the tube.
• a new approach is disclosed in which a concentrated aqueous solution of sodium heparin is prepared to which an alcohol, e.g., methanol, ethanol or 2-propanol, is added at a 1:1 or 2:1 ratio to the volume of the aqueous heparin solution.
• the sodium heparin will form a colloid and the alcohol will aid in wetting the hydrophobic polypropylene surface.
• An evaluation of the suitability of this approach was undertaken, and it was found that with an isopropanol to water ratio of about 30:1 to about 50:1, a stable dispersion was possible and good wetting of polypropylene was also achieved.
• a concentrated aqueous solution of sodium heparin was formed by mixing 250mg sodium heparin in lcc water. 20cc of isopropanol was added to the volume, after which the solution was again diluted with isopropanol to 100cc A tube 14 was wetted with the solution and the solution allowed to evaporate. Small particles of heparin could be seen on the tube.
• the colloid may be dried by shaking with a sufficient quantity of 3A or 4A molecular sieve (Linde Division of Union Carbide Co., Terrytown, New York). The removal of substantially all water from the coUoid will aid in wetting the tube and will make the coating smoother and more uniform for coating after evaporation.
• EXAMPLE VI Sample devices using the CELGARD R 2400 membrane were prepared using the heparin powder dispersion approach of Example I, the quart ernary heparin complex of Example IV, and the heparin alcohol colloid of Example V.
• the heparin alcohol colloid was used to dose syringe barrels at the concentration of 2.5 mg per cc of alcohol and 1.25 mg per cc of alcohol.
• the other two heparin forms were both dosed at 2.5 mg per cc.
• the dosing procedure involved filling the syringe barrel and allowing the solution to drain from the inside through the luer taper end. The samples were dried under vacuum after complete draining of the contents.
• Half of the devices of each type of heparin dose form were prepared with a small steel mixing ball inside the syringe barrel Results indicated all of the devices had adequate anti-thrombogenic capacity.

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• 1981
  • 1981-06-01 WO PCT/US1981/000735 patent/WO1981003426A1/en not_active Ceased
  • 1981-06-01 EP EP81901851A patent/EP0052656A1/de not_active Withdrawn

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