Ricky’s grandmother has been suffering from 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 acid-base disorder is shown?
A. Respiratory Alkalosis, Uncompensated
B. Respiratory Acidosis, Partially Compensated
C. Metabolic Alkalosis, Uncompensated
D. Metabolic Alkalosis, Partially Compensated
Correct Answer: C. Metabolic Alkalosis, Uncompensated
The primary disorder is uncompensated metabolic alkalosis (high HCO3 -). As CO2 is the strongest driver of respiration, it generally will not allow hypoventilation as compensation for metabolic alkalosis.