What is a characteristic of a patient with metabolic alkalosis?

A characteristic of a patient with metabolic alkalosis is the retention of base by the kidneys. Metabolic alkalosis occurs when there is an excess of bicarbonate in the body or a loss of hydrogen ions. This condition can be caused by factors such as prolonged vomiting, diuretic use, or hormonal disorders that promote the retention of bicarbonate.

In this context, the kidneys play a crucial role in maintaining acid-base balance. When the body is in a state of metabolic alkalosis, the kidneys may retain more bicarbonate (a base) to counteract the acidosis, attempting to restore balance. This retention of base by the kidneys leads to increased serum bicarbonate levels, which is a hallmark of metabolic alkalosis.

The other potential choices do not accurately describe the mechanisms involved in metabolic alkalosis. For example, excess excretion of base through the kidneys would lead to decreased bicarbonate levels, contradicting the definition of metabolic alkalosis. Similarly, retention of base by the lungs or excretion of base by the lungs does not occur since the lungs primarily regulate carbon dioxide levels rather than directly manipulating bicarbonate levels in this scenario.