A nurse enters an adult client's room and finds him unresponsive. After determining that the client is not breathing and does not have a pulse, which of the following actions should the nurse take first?

A. Respiratory acidosis is characterized by a low pH (below 7.35) and an elevated PaCO₂ (above 45 mm Hg), both of which are present in the client's ABG results. A respiratory rate of 7/min indicates hypoventilation, causing CO₂ retention and leading directly to respiratory acidosis. The normal bicarbonate level further confirms that the primary problem is respiratory, not metabolic.
B. Metabolic alkalosis is marked by a high pH and elevated bicarbonate levels, neither of which is present here. The client's pH is low, and the bicarbonate is within the normal range, ruling out a metabolic origin for the acid-base imbalance.
C. Respiratory alkalosis would present with a high pH and a low PaCO₂, usually caused by hyperventilation. In this case, the client is hypoventilating, with high CO₂ and low pH values, which is the opposite pattern seen in respiratory alkalosis.
D. Metabolic acidosis involves a low pH accompanied by a decreased bicarbonate level, typically less than 22 mEq/L. Since the client's bicarbonate is normal at 26 mEq/L and the PaCO₂ is elevated, the acid-base disturbance is respiratory rather than metabolic.

Thoracentesis is non-essential for a client with pneumothorax because it is primarily used to drain fluid accumulation, not air. Unless there is a suspicion of a hemothorax or fluid build-up, thoracentesis would not address the cause of the client's respiratory distress and would not be the initial intervention.

Prepare for insertion of a chest tube is anticipated because it is the standard treatment for pneumothorax. A chest tube allows continuous evacuation of air from the pleural space, promoting lung re-expansion and stabilizing breathing, which is urgently needed for clients who report severe dyspnea and shallow respirations.

Pulmonary Function Tests (PFTs) are contraindicated because they involve deep inhalation and forceful exhalation maneuvers, which could cause further lung collapse or exacerbate the pneumothorax. These tests are inappropriate during acute respiratory distress and must be deferred until the pneumothorax resolves.

Obtaining intravenous access is anticipated because having a reliable IV line ensures immediate access for emergency medications, fluids, sedation, and possible analgesia, particularly when preparing for procedures such as chest tube insertion or stabilizing hemodynamic status in case of deterioration.

Obtain ABGs is anticipated because arterial blood gases provide critical information about the client's respiratory efficiency, including oxygenation, ventilation, and acid-base balance. These results help guide the need for supplemental oxygen therapy, ventilatory support, or further interventions.