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Category: Critical Care Medicine-Renal, Electrolyte and Acid Base Disorders--->Acid Base Disorders
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Question 11# Print Question

A 74-year-old man presents to his primary care physician for worsening lower extremity edema. He has advanced chronic obstructive pulmonary disease and benign prostatic hyperplasia and is a former alcoholic. He is prescribed a diuretic and returns to the office 1 week after. His swelling has improved, but he is complaining about worsening shortness of breath. Given that, an ABG on room air is obtained and shows the following:

  • pH 7.47
  • PaO2 82 mm Hg
  • PCO2 53 mm Hg
  • HCO3 38 mEq/L

What is the MOST likely acid-base disturbance?

A. Chronic respiratory alkalosis
B. Acute respiratory alkalosis with metabolic compensation
C. Acute metabolic alkalosis with respiratory compensation
D. Mixed acid-base disorder
E. Chronic metabolic alkalosis

Question 12# Print Question

A previously healthy 23-year-old woman is taken to the hospital by her boyfriend for weakness since 2 weeks. They recently returned from a trip to Caribbean after which she developed an upper respiratory infection. She was given Levofloxacin by the urgent care provider. While her cough improved, she noticed weakness in her feet that subsequently traveled up to her arms. On physical examination, vital signs are unremarkable except for a respiratory rate of 8 breaths/min. Deep tendon reflexes are diminished bilaterally. 

Lab results:

  • Sodium 137 mEq/L (mmol/L)
  • Potassium 3.9 mEq/L (mmol/L)
  • Chloride 109 mEq/L (mmol/L)
  • Bicarbonate 32 mEq/L (mmol/L)
  • Glucose 121 mg/dL
  • BUN 16 mg/dL
  • Creatinine 0.8 mg/dL

Arterial blood gas:

  • pH 7.26
  • PCO2 72 mm Hg

What is the MOST likely acid-base disturbance in this patient?

A. Acute on chronic respiratory acidosis
B. Respiratory alkalosis with increased anion gap metabolic acidosis
C. Mixed disorder
D. Respiratory acidosis with metabolic alkalosis
E. Uncompensated acute respiratory acidosis

Question 13# Print Question

A 78-year-old man presents from his skilled nursing facility for generalized weakness and a “funny feeling in his ears.” He recently sustained a fall complicated by a left femur fracture. He underwent open reduction and internal fixation a week ago and has been undergoing physical rehabilitation. He has medical history of hypertension, coronary artery disease, and chronic obstructive pulmonary disease (COPD).

On physical examination:

  • his blood pressure is 152/86 mm Hg
  • pulse rate is 64 beats/min
  • respiratory rate is 22 breaths/min

He is confused to time and place. Laboratory data show the following:

  • Sodium 140 mEq/L (mmol/L)
  • Potassium 3.8 mEq/L (mmol/L)
  • Chloride 111 mEq/L (mmol/L)
  • Bicarbonate 10 mEq/L (mmol/L)
  • Glucose 95 mg/dL
  • BUN 22 mg/dL
  • Creatinine 1.4 mg/dL (baseline 1.0 mg/dL)
  • Albumin 3.7 g/L
  • Lactate 1.0 mmol/L

An arterial blood gas (ABG) is also obtained which shows:

  • pH 7.21
  • pCO2 38 mm Hg
  • plasma osmolality 288 mOsm/kg H2O

What is the MOST likely acid-base disturbance in this patient?

A. Anion gap metabolic acidosis and metabolic alkalosis
B. Anion gap metabolic acidosis and respiratory acidosis
C. Respiratory acidosis and metabolic alkalosis
D. Normal anion gap metabolic acidosis
E. Respiratory acidosis

Question 14# Print Question

A 67-year-old man is brought to the local hospital for severe onset of acute abdominal pain. He has chronic obstructive pulmonary disease and hypertension and is an active smoker. On physical examination, his vital signs are unremarkable except for a blood pressure of 188/94 mm Hg and pulse rate of 118 beats/min. He is tender to abdominal palpation and unable to lie still due to pain. A CT angiogram reveals an aortic dissection for which he is taken to the operating room emergently. He receives a total of 12 units of packed red blood cells during the case. He remains intubated postoperatively, and laboratory data obtained after surgery reveal the following:

  • Sodium 147 mEq/L (mmol/L)
  • Potassium 3.2 mEq/L (mmol/L)
  • Chloride 100 mEq/L (mmol/L)
  • Bicarbonate 37 mEq/L (mmol/L)
  • BUN 18 mg/dL
  • Creatinine 1.2 mg/dL
  • Calcium 7.8 mg/dL
  • Urine pH 5.8


  • pH 7.52
  • pCO2 48 mm Hg

What is the MOST appropriate treatment for his acid-base disturbance?

A. Furosemide
B. Bicarbonate infusion
C. Lactated Ringer
D. Normal saline
E. Acetazolamide

Question 15# Print Question

A 43-year-old woman is brought to the emergency department by her neighbor by ambulance after being found unresponsive. She has a known past medical history of bipolar disease, seizures, and previous suicide attempts. Her medications include lithium and levetiracetam. She was in her usual state of health prior to this; however, he recalls she was recently treated with “some antibiotic” for acute bronchitis. On physical examination, her temperature is 37.2°C, blood pressure is 110/72 mm Hg, pulse rate is 98 beats/min, and respiratory rate is 8 breaths/min. She is lethargic and unable to follow commands or answer questions. A tongue bite mark and a soiled underwear are also noted. Laboratory data obtained after 6 days are shown below:

  • Sodium 134 mEq/L (mmol/L)
  • Potassium 4.2 mEq/L (mmol/L)
  • Chloride 102 mEq/L (mmol/L)
  • Bicarbonate 12 mEq/L (mmol/L)
  • Glucose 99 mg/dL
  • BUN 24 mg/dL
  • Creatinine 1.6 mg/dL
  • Lactate 4.4 mmol/L
  • Plasma osmolality 289 mOsm/kg H2


  • pH 7.48
  • pCO2 45 mm Hg

What is the MOST likely cause of her acid-base disturbance?

A. Methanol overdose
B. Acute kidney injury
C. Rhabdomyolysis
D. Aspirin-induced
E. Isopropyl poisoning

Category: Critical Care Medicine-Renal, Electrolyte and Acid Base Disorders--->Acid Base Disorders
Page: 3 of 3