A nurse observes a patient presenting with shallow breathing, cyanosis, and confusion after undergoing surgery. What critical thinking process should the nurse prioritize to determine the next step?

Postoperative respiratory compromise is a life-threatening condition characterized by impaired alveolar ventilation, reduced oxygen diffusion, and possible hypoxemia leading to tissue hypoxia, cyanosis, and altered mental status. Causes include opioid-induced respiratory depression, atelectasis, airway obstruction, or residual anesthesia effects. Rationale: A. Assessing respiratory rate and oxygen saturation is the priority critical thinking step because it rapidly evaluates ventilation and oxygenation status. Cyanosis and confusion indicate potential hypoxemia requiring immediate assessment to guide intervention. This directly identifies respiratory failure risk. B. Administering pain medication may worsen respiratory depression, especially after surgery. Opioids can further suppress respiratory drive. This intervention does not address the immediate concern of oxygen deprivation and may exacerbate the condition. C. Reassuring the patient provides psychological support but does not address physiological instability. In the presence of cyanosis and confusion, immediate assessment is required. This does not correct impaired oxygenation or prevent deterioration. D. Focusing on discharge planning is inappropriate in an acute deterioration situation. The patient shows signs of possible respiratory failure requiring urgent evaluation. This does not prioritize the critical issue of gas exchange impairment.