A nurse is caring for a 59-year-old male client in the intermediate care unit. Exhibits Which of the following findings requires the nurse's immediate attention?

Choice A rationale: Oxygen saturation of 56% is critically low and indicates severe hypoxemia, which requires immediate intervention to improve oxygenation and prevent life-threatening complications. Choice D rationale: Tracheal deviation to the right suggests a possible tension pneumothorax, which is a medical emergency. It requires immediate attention to relieve the pressure on the affected lung and restore normal breathing. Choice B rationale: Crackles heard in the right lung indicate fluid or atelectasis but are not immediately life-threatening compared to the other findings. Choice C rationale: A pH of 7.21 indicates acidemia and respiratory acidosis but is a secondary concern compared to the immediate need to address the client's hypoxemia and potential tension pneumothorax.