Acid-base disorders in surgical patients — MCQs

A 65-year-old man is brought to the emergency department from his home. He is unresponsive. His son requested a wellness check because he had not heard from his father in 2 weeks. He reports that his father was sounding depressed during a telephone call. The paramedics found a suicide note and a half-empty bottle of antifreeze near the patient. The medical history includes hypertension and hyperlipidemia. The vital signs include: blood pressure 120/80 mm Hg, respiratory rate 25/min, heart rate 95/min, and temperature 37.0°C (98.5°F). He is admitted to the hospital. What do you expect the blood gas analysis to show?

A 24-year-old woman presents to the emergency department after she was found agitated and screaming for help in the middle of the street. She says she also has dizziness and tingling in the lips and hands. Her past medical history is relevant for general anxiety disorder, managed medically with paroxetine. At admission, her pulse is 125/min, respiratory rate is 25/min, and body temperature is 36.5°C (97.7°F). Physical examination is unremarkable. An arterial blood gas sample is taken. Which of the following results would you most likely expect to see in this patient?

A 27-year-old man presents to the emergency department with his family because of abdominal pain, excessive urination, and drowsiness since the day before. He has had type 1 diabetes mellitus for 2 years. He ran out of insulin 2 days ago. The vital signs at admission include: temperature 36.8°C (98.2°F), blood pressure 102/69 mm Hg, and pulse 121/min. On physical examination, he is lethargic and his breathing is rapid and deep. There is a mild generalized abdominal tenderness without rebound tenderness or guarding. His serum glucose is 480 mg/dL. Arterial blood gas of this patient will most likely show which of the following?

What is the primary mechanism for maintaining acid-base balance during prolonged vomiting?

A 37-year-old G1P0 woman presents to her primary care physician for a routine checkup. She has a history of diabetes and hypertension but has otherwise been healthy with no change in her health status since the last visit. She is expecting her first child 8 weeks from now. She also enrolled in a study about pregnancy where serial metabolic panels and arterial blood gases are obtained. Partial results from these studies are shown below: Serum: Na+: 141 mEq/L Cl-: 108 mEq/L pH: 7.47 pCO2: 30 mmHg HCO3-: 21 mEq/L Which of the following disease processes would most likely present with a similar panel of metabolic results?

A 29-year-old woman presents to the emergency department with a broken arm after she tripped and fell at work. She says that she has no history of broken bones but that she has been having bone pain in her back and hips for several months. In addition, she says that she has been waking up several times in the middle of the night to use the restroom and has been drinking a lot more water. Her symptoms started after she fell ill during an international mission trip with her church and was treated by a local doctor with unknown antibiotics. Since then she has been experiencing weight loss and muscle pain in addition to the symptoms listed above. Urine studies are obtained showing amino acids in her urine. The pH of her urine is also found to be < 5.5. Which of the following would most likely also be seen in this patient?

Three days after undergoing an open cholecystectomy, a 73-year-old man has fever and abdominal pain. He has hypertension, type 2 diabetes mellitus, chronic obstructive pulmonary disease, and benign prostatic hyperplasia. He had smoked one pack of cigarettes daily for 40 years but quit 1 year ago. He does not drink alcohol. Prior to admission to the hospital, his medications included lisinopril, metformin, ipratropium, and tamsulosin. He appears acutely ill and lethargic. His temperature is 39.5°C (103.1°F), pulse is 108/min, respirations are 18/min, and blood pressure is 110/84 mm Hg. He is oriented only to person. Examination shows a 10-cm subcostal incision that appears dry and non-erythematous. Scattered expiratory wheezing is heard throughout both lung fields. His abdomen is distended with tenderness to palpation over the lower quadrants. Laboratory studies show: Hemoglobin 10.1 g/dl Leukocyte count 19,000/mm3 Serum Glucose 180 mg/dl Urea Nitrogen 25 mg/dl Creatinine 1.2 mg/dl Lactic acid 2.5 mEq/L (N = 0.5 - 2.2 mEq/L) Urine Protein 1+ RBC 1–2/hpf WBC 32–38/hpf Which of the following is the most likely underlying mechanism of this patient's current condition?

A 58-year-old cirrhotic man with ascites undergoes large volume paracentesis (6 liters removed). Four hours later, he becomes hypotensive (BP 80/50 mmHg) and tachycardic (HR 115/min). Labs show: Cr 2.1 mg/dL (baseline 1.0), Na+ 128 mEq/L, Hct 38%. What is the most appropriate immediate management?

A 42-year-old woman with prolonged vomiting from gastroparesis is admitted with weakness. Labs show: K+ 2.1 mEq/L, pH 7.51, HCO3- 42 mEq/L, Mg2+ 1.4 mg/dL. She receives 80 mEq of IV potassium chloride over 24 hours, but repeat K+ is 2.3 mEq/L. What explains the refractory hypokalemia?

A 65-year-old diabetic man with TURP syndrome presents with confusion, nausea, and seizures 2 hours post-operatively. Labs show: Na+ 115 mEq/L, serum osmolality 240 mOsm/kg. He weighs 70 kg. What is the target sodium correction rate and fluid management strategy?