A 22-year-old woman with a history of type 1 diabetes mellitus presents to the emergency department with a 1-day history of nausea, vomiting, and diffuse abdominal pain. She missed several doses of her insulin because she was not feeling well. Her temperature is (), blood pressure is mmHg, heart rate is , and respiratory rate is . Physical examination reveals dry mucous membranes and diffuse abdominal tenderness without rebound or guarding.
Laboratory studies show:
| Laboratory Study | Result |
|---|---|
| Serum sodium | mEq/L |
| Serum potassium | mEq/L |
| Serum chloride | mEq/L |
| Serum bicarbonate | mEq/L |
| Blood glucose | mg/dL |
| Serum creatinine | mg/dL |
Which of the following is the expected arterial partial pressure of carbon dioxide () if appropriate respiratory compensation has occurred in this patient?
- AmmHg
- BmmHg
- mmHgCevap
- DmmHg
- EmmHg
Cevap
The expected arterial is mmHg.
The correct expected arterial is mmHg. This patient presents with diabetic ketoacidosis, which causes a primary anion gap metabolic acidosis. In the presence of a metabolic acidosis, the physiological response is hyperventilation to decrease arterial and normalize the blood pH (respiratory compensation). The appropriate degree of respiratory compensation is calculated using Winter's formula: Expected . Using the patient's serum bicarbonate of mEq/L, the expected mmHg. A measured within the range of to mmHg indicates a simple metabolic acidosis with appropriate compensation.
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Anahtar Kavram
Winter's formula for predicting appropriate respiratory compensation in primary metabolic acidosis