Correct Answer: B

Rationale: In this scenario, with no DNR order in place and the client not breathing, the nurse should initiate CPR and call for emergency assistance. Option A is incorrect as immediate action is required in the absence of breathing. Option C is incorrect as the nurse should act promptly to provide life-saving measures. Option D is incorrect because the nurse's primary duty is to provide care in the absence of a directive preventing intervention.

Correct Answer: D

Rationale: In a postoperative patient, an oxygen saturation level of 88% on room air indicates a significant drop below the normal range, suggesting potential respiratory distress. This finding requires immediate intervention by the nurse to ensure the patient receives adequate oxygenation. A heart rate of 88 beats per minute is within the normal range, making it a less concerning finding. A blood pressure of 130/80 mmHg falls within the normal range for blood pressure and does not require immediate intervention. Crackles heard in the lung bases may indicate fluid accumulation but may not always require immediate intervention unless accompanied by other concerning signs or symptoms.

Correct Answer: B

Rationale: Providing the immobile patient with a special mattress is an effective way to prevent pressure ulcers. Special mattresses help distribute pressure evenly and reduce the risk of developing pressure ulcers by relieving pressure on sensitive areas. Turning the patient every 4 hours (Choice A) is a standard practice to prevent pressure ulcers but may not be as effective as using a special mattress. Elevating the patient's legs (Choice C) can help with circulation but may not directly prevent pressure ulcers. Limiting the patient's movement (Choice D) can lead to other complications and is not a recommended method for preventing pressure ulcers.

Correct Answer: C

Rationale: When a surgical mask becomes moist, it loses its effectiveness as a barrier against microorganisms. Therefore, the perioperative nurse should apply a new mask. Choice A is incorrect because a moist mask should not be continued to be worn even if the nurse is comfortable. Choice B is not the best course of action as the mask should be changed immediately when it becomes moist. Choice D is also incorrect as waiting for the mask to air-dry is not recommended due to the loss of barrier effectiveness.

Correct Answer: B

Rationale: The most appropriate method for assessing a patient's pain level is to use a standardized pain scale, such as a 0-10 scale. This method provides an objective and consistent way to measure and communicate the intensity of pain experienced by the patient. Choice A, observing facial expressions, can be subjective and may not always accurately reflect the level of pain. Choice C, asking the patient to rate their pain based on their mood, may be influenced by various factors unrelated to pain. Choice D, involving the patient's family members in assessing the pain, is not ideal as pain is a subjective experience that should be reported by the patient themselves.