The following calculations can be used to estimate sodium balance in a patient with ascites and advanced cirrhosis |
Mean serum sodium concentration = ascitic fluid sodium concentration = 130 meq/L |
Daily net positive balance is 78 meq if intake is 88 meq, excretion is close to zero, and nonurinary losses are 10 meq |
Total sodium accumulation over 14 days is 1092 meq (78 x 14) |
Increase in extracellular fluid volume (most of which will accumulate as ascites) is 8.4 liters (1092 meq รท 130 meq/L) |
Thus, if a patient is complying with dietary sodium
excretion, an 8.4 liter paracentesis will remove 14 days of accumulated
sodium. Paracentesis can be performed less often in compliant patients
who still have some urinary sodium excretion. |