Neonatal Nurse Practitioner Practice Exam

If a term neonate shows a pH of 7.51 with a bicarbonate level of 36 mEq/L, what does this blood gas suggest?

1. PO₂ is inadequate

2. The primary problem is metabolic

3. The primary problem is respiratory

4. There is no significant issue

The correct answer is: The primary problem is metabolic

A pH of 7.51 along with a bicarbonate level of 36 mEq/L indicates a state of metabolic alkalosis. In metabolic alkalosis, the primary disturbance is an elevated bicarbonate level, which can occur due to various causes such as loss of gastric acid (e.g., from vomiting) or increased bicarbonate intake. The elevated pH indicates alkalinity in the blood, and in this case, the bicarbonate level is above the normal range, which reinforces the diagnosis of a metabolic issue rather than a respiratory one. In a healthy individual, the body's primary regulators of pH are the lungs and kidneys. In cases of respiratory problems, you would typically find altered carbon dioxide levels affecting pH but in this scenario, the bicarbonate is the dominant player and suggests a primary metabolic process rather than a respiratory cause. Therefore, the combination of the high pH and high bicarbonate level clearly points to a primary metabolic problem, confirming that the correct interpretation of this arterial blood gas result is that there is a metabolic alkalosis present in the neonate.