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Questions and Answers
What is the primary function of hemostasis?
What is the primary function of hemostasis?
What is the normal range for bleeding time?
What is the normal range for bleeding time?
Which of the following is NOT a cause of prolonged bleeding time?
Which of the following is NOT a cause of prolonged bleeding time?
What is the purpose of the bleeding time test?
What is the purpose of the bleeding time test?
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What is the name of the method used to estimate bleeding time?
What is the name of the method used to estimate bleeding time?
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What is the normal range of bleeding time in Ivy's method?
What is the normal range of bleeding time in Ivy's method?
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What is the normal range of clotting time?
What is the normal range of clotting time?
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What is the purpose of using a sphygmomanometer in Ivy's method?
What is the purpose of using a sphygmomanometer in Ivy's method?
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Which of the following is a method to estimate clotting time?
Which of the following is a method to estimate clotting time?
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What is the purpose of cleaning the finger with alcohol in the Capillary tube method?
What is the purpose of cleaning the finger with alcohol in the Capillary tube method?
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Study Notes
Bleeding and Hemostasis
- Bleeding is the loss of blood from damaged or injured blood vessels.
- Hemostasis is the process of preventing blood loss through the injured vessel, involving a series of events leading to clot formation and prevention of further blood loss.
- Steps of blood clot formation:
- Vasoconstriction (contraction of injured blood vessels)
- Platelet plug formation
- Formation of a blood clot
Bleeding Time (BT)
- Bleeding time is a test of hemostasis, indicating how well platelets interact with blood vessel walls to form blood clots.
- Measured from the onset of the wound until the bleeding stops.
- Purpose: detecting platelet defects and evaluating their function.
- Normal value: 1-5 minutes
- Prolonged bleeding time can occur in:
- Hemophilia
- Thrombocytopenia
- Platelet functional disorders
- Aspirin use
- Vessel wall defects
Experimental Methods of Bleeding Time
- Two main methods:
- Duke's method
- Ivy's method
Duke's Method
- Materials required:
- Disposable lancet
- Clean filter papers
- Stop watch
- 70% alcohol
- Cotton
- Procedure:
- Clean the tip of a finger with alcohol
- Puncture the finger using a sterile lancet
- Start the stopwatch
- Blot the blood with filter paper every 30 seconds
- Record the time when the filter paper no longer shows signs of blood
- Normal range: 2-5 minutes
Ivy's Method
- Materials required:
- Disposable lancet
- Filter paper
- Sphygmomanometer
- Stop watch
- 70% alcohol
- Procedure:
- Clean the front surface of the forearm with 70% alcohol
- Place a sphygmomanometer cuff around the patient's upper arm and raise the pressure to 40 mmHg
- Make one, two, or three punctures in the front surface of the forearm
- Start the stopwatch
- Remove the drops of blood with filter paper every 30 seconds
- Record the time when the bleeding stops
- Normal range: 1.5-4 minutes
Clotting Time
- Clotting time is the time required for blood to clot under certain conditions.
- When the blood vessels rupture, the blood loses its fluidity and sets into a semisolid mass called the "clot".
- Normal clotting time range: 3-10 minutes
- Clotting time prolonged in:
- Hemophilia
- Vitamin K deficiency
Experimental Methods of Clotting Time
- Two main methods:
- Capillary tube method (Wright's method)
- Slide method
Capillary Tube Method (Wright's Method)
- Materials required:
- Disposable lancet or needle
- Stop watch
- Capillary tube (non-heparinized)
- Cotton
- 70% alcohol
- Procedure:
- Clean the finger with alcohol
- Puncture the finger by lancet and record the time immediately
- Squeeze the finger to obtain a large drop of blood and fill the capillary tube with blood
- Record the time when the clot forms
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Description
Learn about the process of bleeding, hemostasis, and blood clot formation. Understand the steps involved in preventing blood loss from injured vessels.
