A 32 year old woman develops severe vomiting due to viral gastroenteritis. This problem persist
for 2 days, with the patient able to eat only small amounts of hot soup. Physical examination in the
Doctor’s office reveals a blood pressure of 110/70 mmHg supine position and 95/60 mmHg upright
position, the estimated jugular venous pressure is below 5 cmH2O and skin turgor is moderately
reduced. The patient’s weight is 2.1 kg below the previous baseline.
Initial blood and urine test reveal the following:
BUN = 31 mg/dL (9-25)
Creatinine = 1.2 mg/dL (0.8-1.4)
Na+
= 141 mEq/L (136-142)
K
+
= 3.2 mEq/L (3.5-5)
Cl+
= 90 mEq/L (98-108)
Aterial pH = 7.50 (7.37-7.43)
HCO-
3 = 36 mEq/L (21-30)
PCO2 = 48 mmHg (36-44)
Question
1. What acid-base disorder after vomiting for 2 days? How does vomiting cause this acid-base
disorder?
2. Why was patient‘sblood pressure decrease? What effect would her decreased blood pressure
be expected to have the Renin angiotensin aldosterone system?
3. What effect did patient’s extracellular fluid (ECF) volume contraction have on her acid-base
status?
4. Why was patient’ blood K+
concentration so low? (identify three mechanisms that might have
contributed to her hypokalemia)