ACIDOSIS 87 



of sodium bicarbonate, introduced by Magnus-Levy (e) (1899), appears 

 justified both by logic and practice. 



In the administration of bicarbonate the following precautions are 

 indicated : 



(1) Bicarbonate is to be given only when a genuine alkali deficit exists 

 in the bodv, as shown by a blood condition indicated by Areas 6 or 9, 

 Fig. II. 



(2) Only sufficient bicarbonate is to be given to restore the normal 

 blood alkali content. Even this amount may result in edema, from the 

 increase in the amount of dissolved salts (chlorid and bicarbonate) in the 

 body fluids. If unnecessarily great amounts of bicarbonate are given, the 

 probability of edema is increased. 



Another result of overdosage with bicarbonate is tetany, which ap- 

 parently is caused by abnormally high pH, the condition of "uncompen- 

 sated alkali excess" indicated by Area 1, Fig. II. 



The amount of sodium bicarbonate required to restore the normal 

 alkaline reserve may be estimated by the formula of Palmer and Van 

 Slyke (1918) from the plasma bicarbonate CO 2 content. Grams 



Weight in Kilos 



NaHCO 3 = (60 plasma CO 2 ) X - -, the plasma CO 2 



08 



being expressed in terms of volumes per cent. 



The formula is derived as follows: 1 gm. of NaHCO 3 contains 267 c.c. of 

 CO,,, measured at 0, 760 mm. If the body fluids are estimated at 700 c.c. for 

 each kilo of body weight then the distribution of 1 gram of bicarbonate among 



267 S8 



them would raise the CO 2 content, in c.c. per 100 c.c. of fluid, by -^^ -= c.c.. 



7 W W 



W representing the body weight in kilos. Conversely, the amount of bicarbonate 



1) W 

 necessary to raise the CO 2 by Z> volumes per cent would be . If b 60 



OO 



plasma CO 2 , the amount by which the bicarbonate CO 2 in the plasma has fallen 

 below 60 volumes per cent, then the bicarbonate required to raise it back to 60 



W 



would be - X (60 plasma CO 2 ). The approximate accuracy of this equa- 

 08 



tioii has been demonstrated by Palmer and Van Slyke (1918), and by Palmer, 

 Salvesen, and Jackson (1921). 



Overdosage with alkali may be avoided by estimating the amount re- 

 quired from the plasma bicarbonate CO 2 in the above manner, and giving 

 gradually somewhat less than the amount calculated. The result can then 

 be checked by another plasma bicarbonate determination. Or the bicar- 

 bonate can be given at the rate of 3 or 4 grams per hour, and stopped as 

 soon as the urinary pH shows a rise when tested as described above in 

 connection with the bicarbonate retention test. 



(3) In avoiding the production of over-alkalinity in the sense of a 

 high pH, it is essential to consider not onlv the amount of bicarbonate ad- 



