104. VASOCONSTRICTORS 



Therefore, as might be expected, pulmonary edema is- readily brought 

 about by a combination of saline and adrenaline. 



Summary. When the volume of blood has not been reduced, 

 saline infusion is generally useless to raise arterial pressure, and by 

 producing edema may cause serious consequences. If used as a 

 medium for the administration of drugs, it should be supplied in 

 small quantities and slowly introduced. 



When the Volume of Blood Is Notably Below Normal as 

 After a Severe Hemorrhage. According to Levin, 25 — 50 per 

 cent, of an animal's blood may be removed and replaced vs^ith normal 

 saline solution without serious consequences. Crile found that after 

 a moderate hemorrhage a saline infusion would increase the volume 

 of blood and maintain a normal arterial pressure for a considerable 

 time. He found also that the period of coagulation was reduced, 

 infusion evidently favoring the cessation of the hemorrhage. Conse- 

 quently salines are valuable to replace the lost blood and may be 

 used with advantage whether bleeding has stopped or not. A few 

 other observations by Crile are: The temperature of the infusion, 

 if within reasonable limits, has little if any effect upon the temper- 

 ature of the patient or the heart beat. The rate of flow makes nci 

 difference in the extent of the effect upon arterial pressure. The 

 effect upon respiration is an increase in frequency and depth, but 

 from greater than safe amounts, the breathing becomes , slowed and 

 there regularly follow edema of the lungs and death from respira- 

 tory failure. 



Therapeutics. 1. In hemorrhage to restore the volume of 

 blood to normal and thus permit the maintenance of blood pressure. 

 At the same time if the hemorrhage is still in progress, the infusion 

 may check it by increasing the coagulability of the blood (as in 

 hemorrhage from injury or operation). Oxygen may first be passed 

 through the fluid, since it is found that if the saline is saturated with 

 oxygen, it favors the transference of oxygen to the tissues at the 

 capillaries. 



2. In toxemic conditions to promote kidney activity and hasten 

 elimination of the poison. Levin does not consider bleeding followed 

 by infusion as reliable treatment in toxemias since he was unable to 

 get appreciable results in artificial toxemias. In nephritis with 

 edema, salt retention contraindicates the use of salines. 



3. In severe collapse and shock a small saline infusion combined 

 with adrenaline (of about 500 mils, in man), given slowly and re- 

 peated as necessary, may produce and maintain blood pressure. 

 Large infusions or one containing much adrenaline simply favor 

 edema. A saline may replace the blood lost in an operation and 

 prevent or favorably influence post operative collapse but care should 

 be used not to overdo it. 



Saline by Hypodermoclysis and Per Rectum. Saline may 



