Certified Medical-Surgical Registered Nurse (CMSRN) Practice Exam

A high HCO3 level in arterial blood gas (ABG) analysis indicates alkalosis, specifically metabolic alkalosis. Bicarbonate (HCO3) is a major component of the body's buffering system, helping to maintain acid-base balance. When the HCO3 level is elevated, it suggests that there is an increased amount of bicarbonate in circulation, which can result from factors such as excessive vomiting, loss of acids, or the use of certain diuretics.

In metabolic acidosis, the HCO3 level would typically be low because there is either an accumulation of acids or a loss of bicarbonate. In the case of respiratory acidosis, the HCO3 level may be normal or elevated as a compensatory response to account for increased carbon dioxide (CO2) levels in the blood.

Understanding these principles is crucial for proper interpretation of ABG results, as it helps healthcare professionals diagnose and treat underlying conditions effectively. Hence, a high HCO3 level clearly indicates a state of alkalosis.