A 42-year-old man with a history of seizure disorder experiences a grand mal seizure. His laboratory tests, taken shortly afterwards, reveal the following: Serum Sodium 140 mEq/L Serum Potassium 4.1 mEq/L Chloride 97 mEq/L Plasma bicarbonate concentration (HCO3) 16 mEq/L Arterial pH 7.15 PCO2 46 mmHg Which of the following best characterizes the acid-base disturbance?
سؤال مجاني 2 من 10 اليوم · اشترك وكمّل بدون حد
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الإجابة: C. Metabolic acidosis plus respiratory acidosis
After a grand mal seizure: HCO3 16 with AG = 140 − (97 + 16) = 27 → lactic acidosis (seizure energy expenditure). Winter: expected PCO2 = 1.5 × 16 + 8 = 32 ± 2, but actual is 46 → patient is underbreathing (post-ictal) → concurrent respiratory acidosis. D would need a PCO2 below 30.
ليش كل خيار صح أو غلط
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A
ليش غلط
Respiratory acidosis alone would give an elevated (compensatory) HCO3; his HCO3 is low (16), so a metabolic acidosis is present too.
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 5 -
B
ليش غلط
A simple metabolic acidosis needs PaCO2 within the Winter range (1.5 × 16 + 8 = 32 ± 2); his PaCO2 of 46 is outside it, so a second disorder is present.
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 6 -
C
ليش صح
Low HCO3 means metabolic acidosis, and a PaCO2 (46) higher than the Winter-predicted 32 ± 2 adds a respiratory acidosis (underbreathing).
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 6 -
D
ليش غلط
Respiratory alkalosis needs an actual PaCO2 lower than the Winter-predicted value; his PaCO2 of 46 is higher.
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 6
- المصدر
- Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 3
Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 6 - المحاضرة
- Respiratory Failure & Acid–Base · Pulmonology · Module B
- ظهر في
- Respi bank