Question

Kelsey, a 9-year-old with a history of asthma, is brought to the pediatric clinic by her parent because she has had audible wheezing for one week and has not slept in two nights. She presents sitting up, using accessory muscles to breathe, and with audible wheezes. The results of her arterial blood gas drawn on room air are pH: 7.51, pCO2: 25 mmHg, pO2: 35 mmHg, HCO3: 22 mEq/L. The best analysis is:

A. Compensated metabolic acidosis
B. Compensated metabolic alkalosis
C. Uncompensated respiratory alkalosis
D. Uncompensated respiratory acidosis

Answer 1

C. Uncompensated respiratory alkalosis

Step-by-step explanation:

When the partial pressure of CO2 in systemic arteries falls below 35 mmHg, the condition is called respiratory alkalosis. Since pCO2 levels are below 35 mmHg (25 mmHg given), Kelsey is suffering from respiratory alkalosis. Alkalosis is also confirmed by higher pH levels (pH = 7.51).

The ratio of CO2 and HCO3 is around 1:1 (pCO2= 25 mmHg : HCO3= 22 mmEq/L) and confirms the "Uncompensated respiratory alkalosis". The compensated respiratory alkalosis reduces the HCO3 levels far below and exhibits the CO2: HCO3 ratio in the range of 10:2 to 10:4.