200 TRANSFUSION OF BLOOD. 



(2.) In cases of poisoning, where the blood has been rendered use- 

 less by being mixed with a poisonous substance, and hence is unable 

 to support life. In such cases, remove a considerable quantity of the 

 blood, and replace it by fresh blood. Carbonic oxide is a poison of 

 this kind (Kuhne), and its effects on the body have already been 

 described (compare p. 32). The indication is also obtained for a 

 similar practice in poisoning with ether, chloral, chloroform, opium, 

 morphia, strychnine, cobra poison. 



(3.) Under certain pathological conditions, the blood may become so 

 altered in quality as to be unable to support life. The morphological 

 elements of the blood may be altered, and so may the relative propor- 

 tion of its other constituents. Amongst these conditions, may be cited 

 the pathological condition of uraemia, due, it may be, to the accumula- 

 tion of urea or the products of its decomposition within the blood [or 

 to the retention of the potash and other urinary salts Feltz and 

 Ritter] ; accumulation of the biliary constituents in the blood (Cholaemia), 

 and great increase of the carbonic acid. All these three conditions, when 

 very pronounced, may cause death. In these cases part of the impure 

 blood may be replaced by normal human blood (Landois). 



Amongst conditions where the morphological constituents of the blood 

 are altered qualitatively or quantitatively are: hydrsemia (excessive 

 amount of water in the blood 41, 1) ; oligocythsemia (abnormal dimi- 

 nution of red blood-corpuscles). When these conditions are highly 

 developed, more especially in pernicious anaemia ( 10, 2), healthy 

 blood may be substituted. Transfusion is not suited for persons suffer- 

 ing from leukaemia (compare p. 23). 



After-Effects. A quarter or half an hour after normal blood has been 

 injected into the blood-vessels of a man, there is a greater or less febrile 

 reaction, according to the amount of blood transfused (compare Fever). 



Operation. The operative procedure to be adopted in the process of trans- 

 fusion varies according as defibrinated or non-defibrinated blood is used. In order 

 to defibrinate blood, some blood is withdrawn from a vein of a healthy man in the 

 ordinary way, it is collected in an open vessel and whipped or beaten with a glass 

 rod until all the fibrin is completely removed from it. It is then filtered through 

 an atlas filter, heated to the temperature of the body (by placing it in warm water) 

 and injected by means of a syringe into an artery opened for the purpose. A vein 

 (e.g., basilic or great saphenous) may be selected for the transfusion, in which case 

 the blood is driven in, in the direction of the heart; if an artery is selected (radial 

 or posterior tibial) the blood is injected towards the periphery (Huter), or towards 

 the heart (Landois, Unger, Schafer). 



Dangers. It is most important not to permit the entrance of air into the circu- 

 lation, for if it be introduced in sufficient quantity, it may cause death. When air 

 enters the circulation it reaches the right side of the heart where, owing to the 

 movement of the blood, it forms air-bubbles and makes a froth. The air-bubbles 

 are pumped into the branches of the pulmonary artery, in which they become 

 impacted, arrest the pulmonary circulation, and rapidly cause death. 



