Correct Answer: B

Rationale: The correct answer is B: Ensuring the tracheostomy ties are secure. This is the nurse's first priority because it is critical to prevent accidental decannulation, which could compromise the patient's airway. Providing humidified oxygen, suctioning the tracheostomy tube, and monitoring for signs of infection are important aspects of care but ensuring the tracheostomy ties' security takes precedence to maintain the patient's airway.

Correct Answer: C

Rationale: Darbepoetin alfa is used to stimulate red blood cell production in clients with CKD. Monitoring hemoglobin levels is essential to assess the effectiveness of the treatment and to adjust the dosage to avoid complications such as hypertension or thrombosis. Monitoring calcium (Choice A), phosphorus (Choice B), or white blood cell count (Choice D) is not directly related to the effectiveness of darbepoetin alfa in treating anemia associated with CKD.

Correct Answer: A

Rationale: The olfactory nerve (Cranial Nerve I) is indeed responsible for the sense of smell. It is located in the nasal cavity and transmits olfactory information to the brain. The optic nerve (Choice B) is responsible for vision, the trigeminal nerve (Choice C) is responsible for sensation in the face, and the vagus nerve (Choice D) is responsible for various functions such as heart rate, digestion, and speech. Therefore, the correct answer is the olfactory nerve (Choice A).

Correct Answer: D

Rationale: The correct answer is D. TENS works by delivering a mild electrical stimulus to the skin, which can help close the 'gates' in the nervous system to block pain signals from reaching the brain, thus reducing pain perception. Choice A is incorrect because TENS does not distract from pain but rather helps manage it. Choice B is incorrect as it describes a different pain management technique involving medication in the spinal canal. Choice C is incorrect because TENS acts peripherally on nerve conduction rather than dulling pain perception in the cerebral cortex.

Correct Answer: B

Rationale: Checking the pH of the aspirate is the most reliable method to confirm nasogastric tube placement as it provides direct evidence of the tube's location in the stomach. When the pH is acidic (pH < 5), it indicates that the tube is correctly placed in the stomach. Auscultating over the stomach while injecting air may not always be accurate, as the sound can be misleading due to various factors. Observing the patient's response during feeding is not a definitive method for confirming tube placement, as it can be influenced by other factors. Measuring the external length of the tube does not ensure correct placement within the GI tract and can be affected by external factors like patient anatomy.