Difficulty: Medium
Average Score: 76%
Simulated
Mrs. Kalen is a 70 year old female who has arrived into the ER due to persistent vomiting for two days now. She appears to be lethargic and weak and has myalgia. She is noted to have dry mucus membranes and her capillary refill takes >4 seconds. She is diagnosed as having gastroenteritis and dehydration. Measurement of arterial blood gas shows pH 7.5, PaO2 85 mm Hg, PaCO2 40 mm Hg, and HCO3 34 mmol/L. What would you interpret the acid-base disorder to be?
Correct answer
C
Rationale
Elevated pH (7.5) and HCO3 (34 mmol/L) with normal PaCO2 indicate uncompensated metabolic alkalosis due to vomiting-induced acid loss. Other options do not align with the blood gas findings.