METHODS OF BLOOD TRANSFUSION

Intravenous blood transfusion is the main method of blood transfusion. Most often, puncturing the cubital or subclavian veins is used. A venesection is only rarely used. To puncture the cubital vein, a tourniquet is applied to the lower third of the upper arm, the puncture site is cleansed with alcohol or iodine and isolated with a sterile material. The tourniquet should compress only the veins leaving the arteries patent. With several fist clenching and contracting the forearm muscles the veins engorge and can be easily identified.

Using a wide lumen needle (with or without a syringe) the skin is punctured, through the subcutaneous tissue, the needle is inserted further (about 1 cm) over the subcutaneous vein and then the anterior wall of the vein is punctured. The needle is then inserted into the vein. The appearance of blood from the needle or in the syringe suggests successful venipuncture. Three to five millilitres of blood are taken from the vein for group and Rh typing and compatibility test. Further, the tourniquet is removed and a blood giving or infusion set is attached to an infusion solution (e.g. normal saline) to prevent blood from clotting in the needle. The needle is fixed to the skin with some adhesive plaster. Subsequently, the blood giving set is attached and transfusion started.

In case the superficial veins cannot be punctured (e.g. collapsed veins in shock, marked obesity) transfusion is done through a venesection. The puncture site is cleansed with alcohol or iodine and isolated with a sterile material. The site of incision is infiltrated with 0, 25% novocain. A tourniquet is applied to compress only the veins leaving the arteries patent. The skin and subcutaneous tissues are incised and a forceps is used to expose the vein. Two ligatures are passed beneath the vein, the peripheral one serving as the retractor. Pulling the vein by the retractor, it is punctured directing towards the centre, a pair of scissors can also be used to slit open the anterior wall and the needle or vein catheter is inserted through. The central ligature is used to fix the needle. The blood giving set is then attached to the needle and the skin is closed with two or three sutures.

At the end of transfusion, when about 20 ml of blood is left in the system, it is closed and the needle removed. The place of puncture or venesection is cleaned with iodine tincture and pressing bandage applied.

In cases when long-term (i.e. for several days) infusion of solutions, blood and its components is anticipated, venipuncture of either the subclavian or external jugular is preferred, a special catheter, which can stay for long periods (up to a month) is placed in the vein and blood or infusion sets can be attached for transfusion, when needed.

Intra-arterial blood transfusion is indicated for:

• clinical death (respiratory and cardiac arrests) caused by massive blood loss

• severe traumatic shock with persistently low systolic arterial blood pressure of less than 60 mm Hg

• ineffective intravenous blood transfusion.

Therapeutic effects of intra-arterial transfusion are assessed based on the reflective stimulation of cardiovascular functions and restoration of coronary blood circulation. To achieve this, blood has to be given at a rate of 200-250 ml for 1¹/₂-2 minutes and under the pressure of 200 mm Hg; on restoration of cardiac functions the pressure is reduced to 120 mm Hg. When the pulse is clearly felt, intravenous infusion is started; when the systolic pressure is stabilised at 90-100 mm Hg, the needle is removed from the artery.

The system for intra-arterial blood transfusion (fig. 36) is similar to the intravenous one, with the exception being that the long needle in the bottle is attached to Richardson's tube used to pump in air, which, in turn, is connected to a manometer. The artery is punctured through the skin or arteriosection is done.

The femoral and brachial arteries are used for transfusion. Arteriosection is often necessary, using the radial and posterior tibial arteries. The manipulation is done using local infiltration anaesthesia.

Pumping blood under pressure can be associated with a great risk of air embolism. It is therefore recommended that the blood flow in the system be monitored to be able to promptly close it, if necessary.

Fig. 36. The system for intra-arterial blood transfusion.

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