Surgery – Truss – Pad
Patent
1989-08-16
1991-10-08
Hindenburg, Max
Surgery
Truss
Pad
128770, A61B 500
Patent
active
050544985
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns a device for taking and storing blood for gasometric analysis. The present invention is more particularly concerned with a device which reduces contamination of the blood by ambient air, the stresses that can break down the internal gas equilibrium of the blood and the tendency of the blood to coagulate in situ.
DESCRIPTION OF PRIOR ART
Numerous prior art methods raise problems. These include methods which use the conventional form of syringe with a main body serving as a reservoir and a piston controlling the quantity sampled. This system, apart from the fact that it uses a large quantity of blood, has a large surface area of exchange with the air leading to contamination of the sampled blood. However, the major disadvantage of a system of this kind lies in the possibility, consequent upon the presence and function of the piston, of the operator reinjecting hazardous products such as the anticoagulating agents usually contained in the syringe.
Other prior art systems use a capillary device which makes it possible to collect a smaller quantity of blood. Also, the air/blood exchange surface area is reduced because of the small diameter of the capillary tube. However, these systems have the disadvantage of using glass capillary tubes which by their very nature activate coagulability of the blood (as a result of the `glass-effect` phenomenon), are difficult to transport and store and sometimes sample too little blood to enable a number of analyses to be carried out afterwards.
SUMMARY OF THE INVENTION
The object of the invention is to overcome the defects and problems of the systems previously described. The sampling device in accordance with the invention is characterised in that it comprises an inert piston that is not accessible to the operator reducing gaseous exchange between the air and the blood and a blood-tight filter that is porous to air guaranteeing minimal contamination of the sample taken.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the present invention with its main elements. FIG. 2A shows the present invention with its main elements aligned to be placed together. FIG. 2B shows the present invention with its elements in their initial places. FIG. 3 shows the present invention in the artery of a patient. FIG. 4 shows the stages of using the present invention with collected blood.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The system of the invention comprises a main body (1 FIG. 1) serving as a blood container, an inert cylindrical piston (2 FIG. 1), a blood-tight cylindrical plug porous to air (3 FIG. 1), and a plastics material plug (4 FIG. 1). In the following description of the invention the term anterior part (A FIG. 2) is arbitrarily applied to the part connecting to the sampling needle (5 FIG. 3) or the part in which the blood enters the system and the term posterior part (T FIG. 2) is arbitrarily applied to the opposite part of the system.
The main body (1) is formed of five characteristic parts. An anterior part (A) to which the sampling needle is connected, a central part (C) forming a chamber accommodating the piston and the collected blood, a narrower part (F) against which the piston abuts at the end of sampling, a posterior part (T) accommodating the filter (3) and a final part at the level of the hole (G FIG. 2) into which a plug may be fitted. The anterior part (A FIG. 2) is coaxial with the system and has an outside diameter enabling a sampling needle to be fitted and an inside diameter of at least 1.5 mm. This minimum inside diameter is necessary for the use of the invention with INSTRUMENTATION LABORATORY and RADIOMETTER brand gasometric analysers, for example.
The inert piston (2) is formed of two characteristic parts: a main part and an anterior part (P) coaxial to the main part (0 FIG. 2). The anterior part (P FIG. 2) of the piston (2) has a smaller diameter than its main part (O) which is also slightly smaller than the inside diameter of the anterior part (A) of the main body (1). Before sampling this cylindrical part (P) mates
REFERENCES:
patent: 3920002 (1975-11-01), Dye et al.
patent: 4215702 (1980-08-01), Ayer
patent: 4361155 (1982-11-01), Anastasio
patent: 4385637 (1983-05-01), Akhavi
patent: 4492634 (1985-01-01), Villa-Real
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