Venesection is performed to treat polycythaemia vera, a condition that causes an elevated red blood cell volume (haematocrit). Venesection is also prescribed for patients with disorders that increase the amount of iron in their blood to dangerous levels, such as haemochromatosis, hepatitis B, and hepatitis C. Patients with pulmonary oedema may undergo phlebotomy procedures to decrease their total blood volume.
Venesection is performed by a nurse or a technician known as a phlebotomist. Blood is usually taken from a vein on the back of the hand or inside of the elbow. The skin over the area is wiped with an antiseptic, and an elastic band (Tourniquet) is tied around the arm.
The band acts as a tourniquet, slowing the blood flow in the arm and making the veins more visible. The technician feels the veins in order to select an appropriate one. When a vein is selected, a needle is inserted into the vein and the elastic band is released.
The appropriate amount of blood is drawn and the needle is withdrawn from the vein.
The client’s pulse and blood pressure will be monitored before and after the procedure. This is the simplest and quickest way of reducing the number of red cells in your blood. It will reduce the amount of blood in your body by removing about one pint (half a litre) of blood at a time. It is similar to the procedure used for donating blood.