From the Research
The patient is experiencing metabolic alkalosis with respiratory compensation, as evidenced by the elevated pH, increased bicarbonate (HCO3-), and elevated PCO2. This condition is likely caused by the loss of hydrogen ions through vomiting, resulting in a relative excess of bicarbonate in the bloodstream 1. The elevated PCO2 represents a compensatory respiratory response, where the body retains carbon dioxide to partially offset the alkalemia. Dehydration worsens this condition by causing volume contraction, which enhances bicarbonate reabsorption in the kidneys. Key characteristics of this condition include:
- Elevated pH (7.5)
- Elevated bicarbonate (HCO3-: 32)
- Elevated PCO2 (40)
- Normal PO2 Treatment should focus on addressing the underlying cause of vomiting, rehydration with isotonic saline (0.9% NaCl) to correct volume depletion and dilute bicarbonate, and potassium replacement if hypokalemia is present (common in this scenario) 1, 2. Antiemitics such as ondansetron 4-8 mg IV/PO every 8 hours may be needed to control vomiting. Severe cases might require acetazolamide 250-500 mg to enhance bicarbonate excretion, but this is rarely necessary once fluid resuscitation is achieved. Given the patient's presentation, the most appropriate diagnosis is metabolic alkalosis with respiratory compensation, and treatment should prioritize correction of the underlying cause and replenishment of lost fluids and electrolytes.