A DOUBLE LUMEN CANNULA FOR BLOOD SAMPLING
First Claim
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1. In a blood sampling apparatus, a double lumen cannula instrument comprising:
- a. a body portion molded from silastic;
b. said body portion including a integral neck portion of silastic and of smaller cross-sectional area than said body portion;
c. a first bore of a first diameter extending for a first distance towards said neck portion from the opposite end of said body and opening into a second bore;
d. said second bore being of a second greater diameter than said first bore and extending from its junction with the first bore towards and through said neck portion to form an orifice to the exterior of said neck portion;
e. an inner-lumen-forming cannula extending through said first and second bores;
f. said first diameter being substantially equal to the external diameter of the inner-lumen-forming cannula so as to provide a fluidtight seal between said body portion and the inner-lumenforming cannula;
g. a third bore extending through said body portion from the exterior thereof and opening into said second bore substantially in the region of said junction of said first bore and a tubular member in said third bore having one end emerging into said region and the other end extending to said exterior of the body portion;
h. a plastic cannula sheath concentric with said inner cannula and having one end fitting over said neck portion whereby an outer lumen is formed between the external surface of said inner-lumen-forming cannula and the inner surface of said plastic cannula sheath;
g. whereby, in use during the sampling of a patient'"'"''"'"'s blood an anticoagulant diluent can be passed along said outer lumen to the outer tip of the inner lumen and blood plus anticoagulant diluent can be with drawn along said inner lumen.
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Abstract
A double lumen cannula instrument for use in withdrawing blood from a patient and having an outer lumen for providing an anticoagulant diluent and an inner lumen for withdrawing blood plus diluent, the body portion of the instrument being approximately one inch long and made of a silastic material. A method and apparatus for separating red cells from plasma in whole blood is also provided in which a diluent is added to whole blood to produce separation of the red cells.
113 Citations
4 Claims
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1. In a blood sampling apparatus, a double lumen cannula instrument comprising:
- a. a body portion molded from silastic;
b. said body portion including a integral neck portion of silastic and of smaller cross-sectional area than said body portion;
c. a first bore of a first diameter extending for a first distance towards said neck portion from the opposite end of said body and opening into a second bore;
d. said second bore being of a second greater diameter than said first bore and extending from its junction with the first bore towards and through said neck portion to form an orifice to the exterior of said neck portion;
e. an inner-lumen-forming cannula extending through said first and second bores;
f. said first diameter being substantially equal to the external diameter of the inner-lumen-forming cannula so as to provide a fluidtight seal between said body portion and the inner-lumenforming cannula;
g. a third bore extending through said body portion from the exterior thereof and opening into said second bore substantially in the region of said junction of said first bore and a tubular member in said third bore having one end emerging into said region and the other end extending to said exterior of the body portion;
h. a plastic cannula sheath concentric with said inner cannula and having one end fitting over said neck portion whereby an outer lumen is formed between the external surface of said inner-lumen-forming cannula and the inner surface of said plastic cannula sheath;
g. whereby, in use during the sampling of a patient'"'"''"'"'s blood an anticoagulant diluent can be passed along said outer lumen to the outer tip of the inner lumen and blood plus anticoagulant diluent can be with drawn along said inner lumen.
- a. a body portion molded from silastic;
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2. A cannula according to claim 1 wherein the oval length of the body portion of the double lumen cannula instrument is approximately 1 inch.
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3. A double lumen cannula instrument according to claim 1 wherein said third bore is at right angles to said first bore.
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4. A double lumen cannula instrument according to claim 3 wherein said tubular member is a stainless steel tube inserted in said third bore.
Specification