Patient with chronic obstructive lung disease (COPD) was admitted with a febrile exacerbation of his symptoms. Laboratory investigation showed: Arterial PH 7.21, Pco2 60mmhg and Hco3 19 mEq/L. Which of the following is the underlying acid base disorder?
سؤال مجاني 3 من 10 اليوم · اشترك وكمّل بدون حد
اعرض الإجابة
الإجابة والشرح
ادخل لحسابك عشان نحفظ إجاباتك ونوريك أخطاءك.
الإجابة: C. respiratory acidosis and metabolic acidosis
pH 7.21 with PCO2 60 = respiratory acidosis (CO2 retention in COPD). With a 20 mmHg rise, HCO3 should go up (≈ +2 acutely, ≈ +8 chronically), but it is 19 (low) → a concurrent metabolic acidosis (e.g. from the febrile illness). Pure respiratory acidosis (A) cannot explain a low HCO3.
ليش كل خيار صح أو غلط
-
A
ليش غلط
A pure respiratory acidosis would raise HCO3 (about +1 per 10 mmHg PCO2 acutely, +4 chronically); here PCO2 is 60 but HCO3 is low (19), so a second disorder is present.
✓ ABG & A-a gradient.pdf · p. 2 -
B
ليش غلط
A high HCO3 suggests metabolic alkalosis (or compensation for respiratory acidosis); this patient's HCO3 is low (19), so there is no metabolic alkalosis.
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 5 -
C
ليش صح
Elevated CO2 points to respiratory acidosis, while a low HCO3 points to metabolic acidosis; together with pH 7.21 this is a mixed respiratory and metabolic acidosis.
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 5 -
D
ليش غلط
A low CO2 would suggest respiratory alkalosis (or compensation for metabolic acidosis); this patient's PCO2 is high (60), so there is no respiratory alkalosis.
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 5 -
E
ليش غلط
Metabolic acidosis alone would come with a low CO2 (respiratory compensation); this patient's PCO2 is high (60), so a respiratory acidosis is also present.
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 5
- المصدر
- ABG & A-a gradient.pdf · p. 2
Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 5 - المحاضرة
- Respiratory Failure & Acid–Base · Pulmonology · Module B
- ظهر في
- Respi bank