THE INTRAVENOUS INJECTION OF FLUIDS 797 



more concentrated than it was before the injection. Nevertheless, normal 

 saline may often be used to tide a patient over a critical emergency period, 

 and its usefulness in building up a tissue fluid reserve is established. The 

 work of Bogert, Underbill 'and Mendel may be referred to in this 

 connection. 



Hypertonic solutions of saline tend to produce hydremia, but diffusion 

 processes quickly reduce the level of salt in the blood to the normal, and 

 the excess of water is likewise returned to the tissues, a small amount 

 being eliminated by the kidneys. There is no indication for the intra- 

 venous use of hypotonic salt solution. 



Sodium chlorid has been shown by Loeb(a), Joseph and Meltzer, and 

 others, to possess toxic properties, and clinical experience has also demon- 

 strated this fact. According to Hort and Penfold, undesirable symptoms 

 include fever, rigors, subnormal temperature, diarrhea, intestinal hemor- 

 rhages and Cheyne-Stokes respiration. A. S. and H. G. Griinbaum 

 have reported several deaths due to edema of the lungs following the 

 injection of saline solutions in postoperative cases, in which ether was 

 used as the anesthetic, and in which nephritis was also present. On the 

 other hand, Joseph and Meltzer, in experimental work on dogs, rarely 

 encountered edema of the lungs which could be attributed to sodium 

 chlorid. The relation of salt to the edema associated with nephritis, as 

 suggested by Widal and Javal and others, also indicates that an excess of 

 salt may be a source of injury to the patient. Certain histological changes 

 such as vacuolation of liver cells, alteration of red corpuscles, and degen- 

 erative changes in heart muscle and capillary walls have been described 

 as due to salt. To the former idea that salt possesses only osmotic prop- 

 erties must therefore be added that of its chemical activity. 



When normal saline is injected attention should be given to the 

 amount of fluid used. This, should be approximately 1 per cent of the 

 body weight, if rapidly injected into the circulation, but of course may 

 far exceed this amount if sufficient time is allowed for the infusion period. 

 There is almost no danger from embarrassment of the circulation unless 

 very large amounts of fluid are injected rapidly, or unless an injection 

 is undertaken when a patient is suffering from edema of the lungs. It 

 is to be remembered that the capacity of the vascular system is normally 

 much greater than the volume of the blood. The ability of the vascular 

 bed to contract and expand constitutes a valuable compensatory feature 

 of the circulation, as Meltzer has suggested, and it is usually adequate to 

 prevent embarrassment to heart action from intravenous injection of fluid. 

 However, as noted above, salt infusions immediately after anesthesia, in 

 cases having damaged kidneys, should be avoided, as well as giving ex- 

 cessive amounts of sodium chlorid as shown by a fatal case reported by 

 Brooks. 



