Venepuncture

Introduction:
Correct  technique is necessary to collect blood for laboratory analysis. Recently I was sick and had to go to many laboratories for various analysis of blood. I have  detected many technicians (including that of some private medical colleges) do not know how to collect blood properly.
I have therefore
decided  to write an article on this matter.
Equipments Required:
1. Syringe:Large enough for blood sample.
2. Needle:Fine one can induce haemolysis.
3. Tubes for blood: Vaccum blood collection tubes are designed to draw pre-determined volume of blood.
4. Tourniquet: Velcro fastener.
5. Mediswab or swab moisten with chlorhexidine.
6. Self sealing plastic bag: when blood is taken from a high risk patient.
7. Butter fly needle
8. Gloves: to be worn before  phlebotomy
Anatomical consideration:
Usually blood is taken from Median cubital vein, but sometimes Cephalic or Basilic vein is also used.
Cephalic vein is the pre-axial vein of upper limb like Great Saphenus vein of lower limb and Basilic vein  is the post axial vein of upper limb as Short Saphenus vein of lower limb. Cubital vein begins from Cephalic vein 2’5cm below bend of elbow and runs upwards shunting blood from Cephalic to Basilic vein. The perforator veins fix it and does not allow it to slip away making it ideal for blood collection.
Site Selection:
The Median Cubital vein is commonly used. Sometimes Basilic vein or veins on the dorsal venous arch of hand also used. However the wrist should be avoided. In case of fresh new born blood may be collected from umblical  vein. In case of infants blood may be collected from scalp vein after shaving the head and putting a rubber band around the skull by using butter fly needle.
Sites Avoided:
1.Veins under side of wrist.
2.Area of extreme scarring due to burns/surgery.
3.Upper extremity on the side that mastectomy was performed.
4.Site of haematoma.
5.Area of skin diseases e.g. eczema, infection etc.
6.Oedematous extremity
7.Drawing blood from arm with cannula, fistula, vascular graft
Procedure:    
The patient is identified first. The anxious patient is reassured that minimum amount of blood for the test will be drawn. All the tubes are properly labelled.
The patient is given a comfortable seat with a arm rest. The fist is clenched.
The path of vein is palpated and traced.It is tapped by fingers to make it more visible and stretched with index and thumb .The proper size needle is selected and attached it or a butterfly to the syringe or a vacutainer hub. Now the site is prepared with chlorhexidine wipe. The skin is drawn taut and the vein is anchored. Then holding the needle in the line of vein it is inserted with swift but gentle thrust keeping bevel  side up at 15-30 degree angle. If the patient complains of shooting or electrical pain then the needle is removed as it indicates pricking of underlying nerve.
If blood does not begin to flow, the needle is slightly moved forwards or backwards . A ‘give’ is felt when needle enters the vein. When blood flows the tourniquet is released and the patient is asked to open  the fist .Prior to withdraw the needle the site is covered with gauze and pad.
After compressing it  for sometime by flexing the elbow a piece first aid adhesive tape is applied. The blood in the syringe is gently ejected into the tube to avoid splitting. All the tubes containing  additives are gently inverted 8-10 times but not shaken vigorously.
N.B.: It must be remembered that a maximum 2 attempts may be made before someone else try.The needle is bent after the procedure. The contaminated materials, gloves, syringe and  needle should be discarded in a appropriate waste container for incineration.
Conclusion:
It is a simple procedure but if not done properly the patient will suffer and the lab. and technicians will earn a bad repute. There will be also wastage of time. The major causes of failure in blood drawing are as follows:
a)Needle inserted too deep.
b)Puncture is not done in the line of vein but from lateral side and there occurs double puncture.
c)Too much subcutaneous fat with invisible vein especially in ladies. This should be made visible by proper effort taking time before puncturing.
The lab personnel should be alerted when sample is corrected from a high risk patient. Self adhesive plastic bag is required in these cases.

 

Venepuncture

Introduction: Correct technique is necessary to collect blood for laboratory analysis. Recently I was sick and had to go to many laboratories for various analysis of blood. I have detected many technicians (including that of some private medical colleges) do not know how to collect blood properly. I have therefore decided to write an article on this matter. Equipments Required: 1. Syringe:Large enough for blood sample. 2. Needle:Fine one can induce haemolysis. 3. Tubes for blood: Vaccum blood collection tubes are designed to draw pre-determined volume of blood. 4. Tourniquet: Velcro fastener. 5. Mediswab or swab moisten with chlorhexidine. 6. Self sealing plastic bag: when blood is taken from a high risk patient. 7. Butter fly needle 8. Gloves: to be worn before phlebotomy Anatomical consideration: Usually blood is taken from Median cubital vein, but sometimes Cephalic or Basilic vein is also used. Cephalic vein is the pre-axial vein of upper limb like Great Saphenus vein of lower limb and Basilic vein is the post axial vein of upper limb as Short Saphenus vein of lower limb. Cubital vein begins from Cephalic vein 25cm below bend of elbow and runs upwards shunting blood from Cephalic to Basilic vein. The perforator veins fix it and does not allow it to slip away making it ideal for blood collection. Site Selection: The Median Cubital vein is commonly used. Sometimes Basilic vein or veins on the dorsal venous arch of hand also used. However the wrist should be avoided. In case of fresh new born blood may be collected from umblical vein. In case of infants blood may be collected from scalp vein after shaving the head and putting a rubber band around the skull by using butter fly needle. Sites Avoided: 1.Veins under side of wrist. 2.Area of extreme scarring due to burns/surgery. 3.Upper extremity on the side that mastectomy was performed. 4.Site of haematoma. 5.Area of skin diseases e.g. eczema, infection etc. 6.Oedematous extremity 7.Drawing blood from arm with cannula, fistula, vascular graft Procedure: The patient is identified first. The anxious patient is reassured that minimum amount of blood for the test will be drawn. All the tubes are properly labelled. The patient is given a comfortable seat with a arm rest. The fist is clenched. The path of vein is palpated and traced.It is tapped by fingers to make it more visible and stretched with index and thumb .The proper size needle is selected and attached it or a butterfly to the syringe or a vacutainer hub. Now the site is prepared with chlorhexidine wipe. The skin is drawn taut and the vein is anchored. Then holding the needle in the line of vein it is inserted with swift but gentle thrust keeping bevel side up at 15-30 degree angle. If the patient complains of shooting or electrical pain then the needle is removed as it indicates pricking of underlying nerve. If blood does not begin to flow, the needle is slightly moved forwards or backwards . A give is felt when needle enters the vein. When blood flows the tourniquet is released and the patient is asked to open the fist .Prior to withdraw the needle the site is covered with gauze and pad. After compressing it for sometime by flexing the elbow a piece first aid adhesive tape is applied. The blood in the syringe is gently ejected into the tube to avoid splitting. All the tubes containing additives are gently inverted 8-10 times but not shaken vigorously. N.B.: It must be remembered that a maximum 2 attempts may be made before someone else try.The needle is bent after the procedure. The contaminated materials, gloves, syringe and needle should be discarded in a appropriate waste container for incineration. Conclusion: It is a simple procedure but if not done properly the patient will suffer and the lab. and technicians will earn a bad repute. There will be also wastage of time. The major causes of failure in blood drawing are as follows: a)Needle inserted too deep. b)Puncture is not done in the line of vein but from lateral side and there occurs double puncture. c)Too much subcutaneous fat with invisible vein especially in ladies. This should be made visible by proper effort taking time before puncturing. The lab personnel should be alerted when sample is corrected from a high risk patient. Self adhesive plastic bag is required in these cases.