This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
CCF is associated with increase in all of the following, except: 
Select and explain. 
A. Right atrial mean pressure, B. Serum sodium, C. Serum urea, D. Serum norepinephrine
B: Serum sodium
Answer: B: Serum sodium 
Explanation: Congestive cardiac failure (CCF) is associated with decreased sodium levels or hyponatremia. CCF is associated with increased right atrial mean pressure, increased serum urea and increased serum nor-epinephrine. Ref: Harrison's Principles of Internal Medicine, 17th Edition, Page 1447 & 1448; 16th Edition, Page 255, 1366; CMDT2006 Edition, Page 870, 389