PAEA Surgery End Of Rotation (EOR) Practice Exam

In the context of metabolic acidosis, which of the following conditions is NOT a contributing factor?

1. Diabetic ketoacidosis (DKA)

2. Lactic acidosis

3. Chronic obstructive pulmonary disease (COPD)

4. Renal failure

The correct answer is: Chronic obstructive pulmonary disease (COPD)

In metabolic acidosis, the primary issue is an accumulation of acid or a loss of bicarbonate, leading to a decrease in blood pH. Each of the other conditions listed contributes to this state in distinct ways. Diabetic ketoacidosis occurs in patients with uncontrolled diabetes when ketone bodies—acids—accumulate in high amounts due to the lack of insulin. This directly contributes to metabolic acidosis. Lactic acidosis results from the accumulation of lactic acid, often due to conditions causing hypoxia (like sepsis or shock) or certain metabolic disturbances. The increased production of lactic acid significantly decreases blood pH. Renal failure also plays a significant role in metabolic acidosis because the kidneys are unable to adequately excrete hydrogen ions and maintain bicarbonate levels. The retention of acids from metabolic processes coupled with impaired bicarbonate reabsorption leads to a net increase in acidity. Chronic obstructive pulmonary disease (COPD), while it can lead to respiratory acidosis due to impaired gas exchange and retention of carbon dioxide, does not directly contribute to metabolic acidosis. Instead, COPD primarily affects the respiratory system, influencing bicarbonate levels indirectly and can lead to a mixed acid-base disorder under severe conditions, but it is not a primary