NEET PG / USMLE – MCQ 56
An 18-year-old woman has gastroenteritis with nausea and vomiting and is able to ingest only small amounts of water. After 3 days, she develops light-headedness, especially when sitting or standing. Arterial blood gas analysis is most likely to show which of the following sets of values?
| pH | PCO2 (mm Hg) | HCO3- (mEq/L) | |
| A | 7.3 | 28 | 15 |
| B | 7.3 | 55 | 27 |
| C | 7.4 | 40 | 24 |
| D | 7.5 | 30 | 22 |
| E | 7.5 | 47 | 35 |
Correct answer : E
Vomiting causes acid loss. Hence it results in metabollic alkalosis. Respiratory compensation mechanism is activated – CO2 retention is produced (respiratory acidosis).
2 Comments
e
ans b. Metabolic alkalosis with compensatory resp. Acidosis
HCO3- increase 3 meq more so compensatory pco2 rise 3*6=18mmhg.. So total pco2 58mmhg so proble ans B..
Can anyone give correct ans.. Plz pgblazer post ryt ans.