A nurse is admitting a client who has gastroenteritis and is reporting numbness and tingling of the toes and fingers. The nurse should recognize the client is experiencing which of the following acid-base imbalances?

A. Metabolic acidosis is characterized by a decrease in bicarbonate or an increase in acids, which can be caused by conditions like kidney failure or diabetic ketoacidosis, but it is not typically associated with numbness and tingling.
B. Respiratory alkalosis is characterized by a high pH (>7.45) and a decreased PaCO2 (<35 mm Hg). It typically results from hyperventilation, which leads to excessive elimination of CO2 and subsequent alkalosis. This condition is less likely to occur in gastroenteritis unless there are other complicating factors such as anxiety or pain causing increased respiratory rate.
C. In the context of gastroenteritis, where there may be a loss of stomach acids through vomiting or diarrhea, the most likely acid-base imbalance would be metabolic alkalosis.
D. Respiratory acidosis is characterized by a low pH and an elevated PaCO2 (>45 mm Hg). It results from hypoventilation, leading to retention of CO2 and subsequent acidosis. Respiratory acidosis would not typically present with numbness and tingling in the extremities in the context of gastroenteritis.

A. PaCO2 (partial pressure of carbon dioxide) reflects the respiratory component of acid-base balance. In metabolic acidosis, the respiratory system compensates by increasing ventilation to decrease PaCO2 (hyperventilation). Therefore, PaCO2 is typically below normal (less than 35-45 mm Hg) in metabolic acidosis, not above 45 mm Hg.
B. HCO3 (bicarbonate) is a buffer that helps regulate pH in the body. In metabolic acidosis, there is a primary decrease in HCO3 due to either increased acid production (e.g., lactic acidosis, ketoacidosis) or decreased acid elimination (e.g., renal failure). Therefore, HCO3 is typically below normal (< 22-26 mEq/L) in metabolic acidosis, not above 26 mEq/L.
C. PaO2 (partial pressure of oxygen) measures the oxygen level in the blood. It is not directly related to the diagnosis of metabolic acidosis. Low PaO2 levels may indicate respiratory dysfunction or impaired gas exchange but are not specific to metabolic acidosis.
D. pH below 7.35 indicates acidosis. In metabolic acidosis, the primary defect is a decrease in blood pH due to an excess of acids or a loss of bases. The pH typically decreases below the normal range of 7.35-7.45 in metabolic acidosis.