SHOCK 313 



immediately beneficial results. In shock there is no migration of fluid into 

 the blood, indeed the reverse is usually the case, and transfusion does not 

 always succeed in reestablishing normal conditions. 



Finally, with regard to the composition of the transfusion fluid, should 

 this be human blood, or can a reliable substitute be found in saline solutions 

 containing gum? There is much diversity of opinion over this question. 

 Keith sums up by stating that there does not appear to be any decided 

 advantage in blood over gum solutions, although the immediate restoration 

 of natural color to the patient, which occurs with blood but not with gum 

 solutions, may make the former appear to be the more satisfactory treat- 

 ment. 



Much painstaking work has been done by Erlanger and Gasser 41 to de- 

 termine the exact conditions for success in using gum solutions. As their 

 criterion for successful treatment, they did not merely see whether the 

 blood pressure was restored, but they allowed the animals to recover from 

 the effects of the anesthetic and then watched them to see whether they 

 became restored to normal. Many animals might appear to be recovering, 

 but nevertheless succumb within 24 hours. These workers point out that 

 strong gum solutions owe their efficacy to the fact that they slowly attract 

 water into the blood from the tissues, and once attracted the water re- 

 mains in the vessels. Hypertonic solutions of crystalloids on the other hand, 

 quickly attract water, but this is not retained long. Erlanger and Gasser, 

 therefore, devised the scheme of combining the two factors, and they found 

 that success depended on how this was attempted. In the shock produced 

 by partial clamping of the vena cava about one-half of the animals died 

 within 48 hours. Neither weak gum (6 per cent) and weak alkali (2 per 

 cent) given in large amount (12 c.c. per kg.) nor strong gum (25 per cent) 

 in strong alkali (5 per cent) given in smaller dosage (5 c.c. per kg.) de- 

 creased the above mortality; but if strong gum (25 per cent) were given 

 along with strong glucose solutions (18 per cent) at the rate of 5 c.c. per 

 kg. an hour, many more animals survived. The alkali was chosen to fur- 

 nish the crystalloid, in many of the experiments, so that it might inciden- 

 tally combat any existing acidosis. We have already seen, however, that 

 there is no reason to believe that acidosis is an important factor in shock. 

 Two precautions are necessary to success in using the gum solutions, first 

 they must be properly prepared, and second they must not be injected so 

 rapidly that their high viscidity would slow the circulation and so embar- 

 ress the heart's action. 



CIRCULATION REFERENCES 



(Monographs) 



Wiggers, C. J.: The Circulation in Health and Disease, Philadelphia, 1915. 

 Mackenzie, J. : Diseases of the Heart, Oxford Medical Publishers, ed. 2, 1910. 



