Blood Transfusion

by Geoffrey Keynes

Whole Blood Transfusion with Kimpton’s Tube.—The principle of this method depends upon the use of paraffin wax as a coating for the vessel into which the blood is drawn, so that clotting is prevented or greatly delayed. The form of the vessel has been modified by different workers, but the essentials are the same in each. One form of the apparatus, known as the Kimpton-Brown tube, is illustrated in the accompanying diagram. It consists of a graduated glass cylinder, of about 700 cc. capacity, the lower end of which is drawn out into a cannula point at an acute angle with the body of the cylinder; the point is of a size convenient for introducing into a vein and its bore large enough to allow of a free flow of blood through it. Near the upper end is a side tube to which a rubber tube can be attached, and an opening at the top is closed by a rubber bung. An ordinary rubber double-bulb bellows is the only other apparatus that is needed.

Fig. 8.—Kimpton-Brown Tube

The glass vessel is first sterilized in the autoclave, and then it must be coated on the inside with a thin layer of paraffin wax. The whole success of this method depends upon this wax coating being absolutely complete right up to the tip of the cannula at the bottom. If the tiniest area of glass be left exposed in the cannula, the process will fail. The production of this perfect wax coating used to be exceedingly difficult of attainment without very frequent practice. The apparatus was first raised to exactly the right temperature; sterile, melted paraffin was then put into it, and distributed evenly over the surface, excess being allowed to run out. The apparatus was then cooled down, and could be put away in a sterile towel ready for use, great care being taken that the lumen of the cannula was patent and not blocked with excess of wax. A simplification of the process was introduced by the use of a saturated solution of wax in ether. This solution is put into the vessel, which must not be heated, and is made to run all over the surface, excess as before being allowed to escape through the lower opening. The ether quickly evaporates, leaving a very thin and perfect film of wax over the surface of the glass. As before, it must be ascertained that the lumen of the cannula is patent. The apparatus is then ready for use.

The donor and recipient need not be lying close together, but they must be in the same room. A vein is exposed in the arm of each by dissection under a local anæsthetic. The operator then picks up the vein with a pair of dissecting forceps, and makes an oblique cut into the lumen as in the diagram on p. 131. A flap is thus made which is held in the dissecting forceps in the left hand or is picked up with a fine-pointed pair of artery forceps. The Kimpton’s tube is taken in the right hand, and the point of the cannula is introduced into the vein; that part of the lumen lying opposite the flap serves as a gutter which guides the cannula directly into the lumen, so that it is introduced without any fumbling or delay. The cannula is pushed on so that its widest part engages the whole circumference of the vein, forming a joint through which blood does not leak. The cannula having been pushed well up into the vein, the forceps holding the venous flap may be let go. At the same time an assistant grips the donor’s upper arm, or some form of tourniquet of the necessary degree of tightness is applied, so that the veins become congested without obliteration of the arterial pulse. Blood now flows rapidly into the tube, and the venous pressure is always sufficient to overcome the counter-pressure of the increasing head of fluid in the tube. It is unnecessary, therefore, to produce any negative pressure within the tube with a reversed Higginson’s syringe or an exhaustion pump, which has been used by some workers. Blood is allowed to flow into the tube until the requisite amount has been obtained. The venous congestion is then released, and at the same time the tube and cannula, held at the lower end with the right hand in such manner that the index finger is free, is withdrawn from the vein. At the moment of withdrawal the end of the cannula is closed with the right index finger. To prevent hæmorrhage from the donor’s vein, a ligature previously put round it is tied by an assistant, or pressure on it is maintained with a sterile swab. The operator must now, without a moment’s delay, carry the tube filled with blood over to the recipient. An opening in his vein is made by an assistant in the same manner as already described, the finger is removed from the cannula, and its point is instantly introduced into the vein. It is now necessary to produce some degree of positive pressure in the tube to ensure that the blood shall at once begin to flow steadily into the vein. This is done with a rubber bellows, attached by an assistant to the upper side tube, and the level of the blood in the tube should at once begin to fall. Great care must be taken that the positive pressure is released before the tube is completely emptied of blood in order to avoid the obvious danger of the entry of air into the patient’s vein. When the tube is nearly empty it is withdrawn, the vein is ligatured, and the wounds in donor and recipient are sutured. The most convenient pattern of Kimpton-Brown tube holds only about 500 cc. of blood, so that if more is needed, the process must be repeated.

There is virtually only one cause of failure in transfusion by this method, and that is the occurrence of clotting in the cannula or at the bottom of the tube. If it does occur at any stage of the operation, it cannot be remedied. It may happen when the tube is nearly full; if so, the blood that has been withdrawn cannot be used. Clotting may be due to an imperfection in the paraffin coating on the glass, but if there is any delay from any cause, it may take place independently of this. The method is therefore never absolutely certain of success even in the hands of an expert, and for general use it is certainly unsuitable. It was introduced into the British Army by some of the American surgeons in 1917, and was used by the writer under the guidance of Major Alton of the Harvard Medical Unit during the first battle of Cambrai with good results. Many of the English surgeons, however, soon abandoned it as a routine method in favour of anticoagulants. There are other objections to it besides its uncertainty. A vein must be exposed by dissection in both donor and recipient, so that avoidable injury is inflicted on the former. It is not a perfectly clean method, some blood necessarily escaping at each successive stage in the process, though an expert can reduce this to a minimum. In the hands of a novice it may occasion a very bloody scene. The whole operation is one of urgency, and the best interests of donor and recipient cannot always be considered.

Modifications have been introduced, such as that of Vincent, who uses an attachment with a needle instead of the glass cannula point. This obviates some of the objections, but introduces other difficulties, such as the necessity for coating the inside of the needle with paraffin wax. The technique can certainly be acquired, and the method has rendered excellent service in the past, but it has no obvious advantages except the uncertain one of avoiding chemical treatment of the blood.

Transfusion with Anticoagulants.—It will have become evident from the descriptions of the transfusion of whole blood already given, how great a difficulty is introduced into the technique of these methods by the physiological process of clotting in blood outside the body. It is clear how much the process of transfusion would be simplified if the clotting were to be prevented. Something has already been said in the historical sketch of the various means by which this problem was attacked, and it need only be stated here that the most suitable substance for this purpose has been found to be sodium citrate. This method was introduced by Lewisohn as recently as 1915, and it soon became the method of choice among most of those who tried it.

The process of the formation of a blood clot has always been one of the great problems of physiology, and numerous theories have been propounded to explain it. The theory accepted at the present time regards the process as a complicated one depending on the presence in the blood of a number of different factors. This theoretical explanation may be represented diagrammatically as follows: