A previously healthy 27-year-old man was involved in a motorcycle accident. He sustained a ruptured spleen, bilateral haemopneumothoraces, compound tibial fractures, and multiple lacerations, abrasions and contusions. He arrived in the ER comatose and was taken immediately to the OR. Blood chemistries: BUN 25 mg/dL, Cr 1.4 mg/dL, Na 145 mEq/L, K 5.9 mEq/L, HCO3 15 mEq/L, Cl 105 mEq/L, CK 2500 U/L. Arterial blood gases: pH 7.25, pCO2 35 mmHg, pO2 49 mmHg. Urinalysis: pH 5.0, protein 2+, RBC 20–30/HPF, WBC 5–10/HPF, specific gravity 1.018, many hyaline, granular and broad coarsely granular casts with epithelial cells. Urine Na 48 mEq/L, Cr 18 mg/dL, K 28 mEq/L. Which of the following best describes the acid–base status of this patient?
سؤال مجاني 6 من 10 اليوم · اشترك وكمّل بدون حد
اعرض الإجابة
الإجابة والشرح
ادخل لحسابك عشان نحفظ إجاباتك ونوريك أخطاءك.
الإجابة: A. He has a mixed metabolic and respiratory acidosis
HCO3 15, pH 7.25 → metabolic acidosis (AG = 145 − 120 = 25, high: shock, crush injury, AKI). Winter: expected pCO2 = 1.5 × 15 + 8 = 30.5 ± 2 (28.5–32.5); actual 35 is higher → additional respiratory acidosis (chest trauma with haemopneumothoraces, coma) → mixed disorder. The bank's later change to B (uncomplicated metabolic acidosis) is not supported by Winter's formula.
ليش كل خيار صح أو غلط
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A
ليش صح
Winter's expected pCO2 is 1.5 × 15 + 8 = 30.5 ± 2; his pCO2 of 35 is higher, so a respiratory acidosis is added to the metabolic acidosis (mixed disorder).
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 6 -
B
ليش غلط
A simple metabolic acidosis needs PaCO2 within the predicted range; his pCO2 of 35 is above the expected 28.5 to 32.5, so it is not uncomplicated.
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 6 -
C
ليش غلط
Respiratory acidosis alone would give an elevated (compensatory) HCO3; his HCO3 is low (15), so a metabolic acidosis is present.
✓ Step Up To Medicine 6th Edition 2024 (Acid-base imbalance).pdf · p. 5 -
D
ليش غلط
Respiratory alkalosis needs an actual PaCO2 lower than the Winter-predicted value; his pCO2 of 35 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. 6
ABG⭐️⭐️.pdf · p. 7 - المحاضرة
- Respiratory Failure & Acid–Base · Pulmonology · Module B
- ظهر في
- Respi bank