Correct Answer: A

Rationale: The correct answer is A: Use tweezers to remove any remaining ticks. The first step is to remove the tick to prevent further transmission of any potential pathogens. This is crucial in preventing tick-borne illnesses. Checking vital signs (B) can be done after the tick is removed. Administering doxycycline (C) should be based on guidelines and individual factors. Obtaining information about recent outdoor activities (D) is important but not the immediate priority.

Correct Answer: D

Rationale: The correct answer is D: Thrombolytics. Thrombolytics are medications that can dissolve blood clots, making them effective in treating a thrombus lodged in the pulmonary artery. They work by activating the body's natural clot-dissolving system. Aspirin (A) is an antiplatelet drug and may prevent further clot formation but cannot dissolve an existing thrombus. Embolectomy (B) is a surgical procedure to remove a clot and is invasive, usually reserved for cases where thrombolytics are contraindicated. Heparin (C) is an anticoagulant that prevents clot formation but does not dissolve existing clots like thrombolytics do.

Correct Answer: C

Rationale: The correct answer is C: “The fistula will be usable in about 4 to 6 weeks.” The rationale for this is that an arteriovenous fistula typically requires 4 to 6 weeks to mature and be ready for use. During this time, the fistula develops the necessary blood flow for efficient dialysis. Choice A is incorrect because immediate use of the fistula is not recommended as it needs time to mature. Choice B is incorrect as it underestimates the time needed for the fistula to heal and mature. Choice D is incorrect as the usability of the fistula is not dependent on the manufacturer but rather on the patient's individual healing process.

Correct Answer: A

Rationale: The correct answer is A: Medical futility. In this scenario, the patient's condition is terminal with no treatment options left. Continuing chemotherapy offers no benefit and may even harm the patient. Medical futility refers to interventions that are unlikely to achieve the desired outcome. B: Palliative care focuses on improving quality of life for patients with serious illnesses, which is not being addressed in this case. C: Terminal weaning involves gradually removing life-support measures, which is not happening here. D: Withdrawal of treatment would be appropriate if the treatments were no longer beneficial, but the issue here is the continued provision of futile treatment.

Correct Answer: B

Rationale: The correct answer is B: Central nervous system depression. This factor can lead to respiratory acidosis by depressing the respiratory drive, causing hypoventilation and retention of carbon dioxide. Anxiety and fear (A) may lead to hyperventilation, reducing carbon dioxide levels. Diabetic ketoacidosis (C) results in metabolic acidosis, not respiratory acidosis. Nasogastric suctioning (D) may cause respiratory alkalosis from excessive removal of carbon dioxide. Thus, central nervous system depression is the most likely factor predisposing a patient to respiratory acidosis.