A nurse is caring for a client in the emergency department (ED) who has high anxiety and shallow respirations at a rate of 30/min. Which of the following acid-base disturbances is the client most likely experiencing?

A. Respiratory acidosis occurs due to hypoventilation, resulting in carbon dioxide retention. This condition is characterized by slow, shallow breathing and confusion, which is not consistent with the client's rapid respiratory rate of 30/min.
B. Respiratory alkalosis is typically caused by hyperventilation, where excessive breathing leads to a decrease in carbon dioxide levels. The client's symptoms of high anxiety and rapid, shallow respirations are indicative of hyperventilation, making respiratory alkalosis the most likely diagnosis.
C. Metabolic acidosis is characterized by deep, rapid breathing (Kussmaul respirations) as the body attempts to expel excess acid. The client's shallow respirations are inconsistent with the breathing pattern seen in metabolic acidosis.
D. Metabolic alkalosis usually presents with symptoms such as dizziness and tingling, often with compensatory slow respirations. The rapid respiratory rate in this case does not suggest metabolic alkalosis, making this option unlikely.

A. Impaired carbon dioxide elimination due to shunting: In ARDS, shunting can impair oxygenation but not directly carbon dioxide elimination. Shunting refers to blood flow through areas of the lung that are not ventilated properly, primarily affecting oxygenation.

B. Decreased pulmonary arterial pressure due to ventilation-perfusion (V/Q) mismatch: ARDS is typically associated with increased, not decreased, pulmonary arterial pressure due to the inflammatory process and reduced lung compliance. V/Q mismatch in ARDS usually results in elevated pulmonary arterial pressure.

C. Hypoxemia due to dead space: ARDS hypoxemia results from impaired gas exchange in damaged alveoli rather than dead space, which is more related to ventilation without perfusion.

D. Decreased pulmonary compliance due to stiffness: ARDS is characterized by decreased pulmonary compliance, which is due to the stiffening of lung tissue from inflammation and edema. This stiffness makes lung expansion more difficult and is a key feature of ARDS.