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Aim
To determine the bleeding time of a patient.
Materials :
Sterilized needle, filter paper, cotton, spirit, and stop watch.
Theory
The time required for complete stopping of blood flow from the punctured blood vessels called the bleeding time. Normally it is 1-3 minutes for a normal human's blood. Normal clotting time and bleeding time values differ because bleeding time is the time for stopping bleeding by the formation of fibrin network on the surface of punctured skin; that is it is the surface phenomenon.
But the clotting time is the time for clotting the whole blood, collected in the capillary tube; therefore it is a volume phenomenon. For this reason clotting time is more than the bleeding time, when determining by conventional methods.
Clinical significance:
It plays a significant role
i) to study the haemorrhagic disorders.
ii) to study the coagulation defects
iii)to have an idea about the platelets count of the patient. Bleeding time is prolonged in few
disorders like: vascular lesions, platelet defect, severe liver disease, uremia and anti-coagulant drug administration.
Procedure (Duke's method)
Finger of a subject is sterilized with spirit and pricked with sterilized needle. Time of pricking is
noted. Take the stain of the punctured point on a filter paper on 30 second and keep taking stain
of blood in 20 second intervals until the bleeding stops. The time of no stain has come is noted
properly; it is the bleeding time of the subject.
Precaution:
Following precautions should be enforced
i) Needle should be sterilized.
ii) A fain stain of blood should not be avoided.
iii) Time should be noted properly.
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