Correct Answer: B

Rationale: The correct answer is B: Cyclosporine. Cyclosporine is an immunosuppressant medication commonly used post-bone marrow transplant to prevent graft-versus-host disease. It works by inhibiting T-cell activation and proliferation, reducing the risk of the donor's immune cells attacking the recipient's tissues. Immune globulin (A) is used for passive immunization, not prevention of graft-versus-host reaction. Prophylactic antibiotics (C) are used to prevent infections post-transplant, not graft-versus-host disease. Systemic corticosteroids (D) may be used to treat graft-versus-host disease but are not the first-line prophylactic medication.

Correct Answer: C

Rationale: The correct answer is C: Improve fetal oxygenation. Oxygen at 4 liters/minute is given to increase oxygen levels which can help improve oxygenation to the fetus during a cord prolapse scenario. This can be crucial in preventing fetal distress and hypoxia. Explanation for Incorrect Choices: A: Relieve maternal distress - Oxygen is primarily given in this scenario to benefit the fetus, not to relieve maternal distress. B: Promote her relative rest - Oxygen is not administered to promote rest, but to address the immediate concern of fetal oxygenation. D: Achieve the effect of tocolysis - Oxygen does not have a role in tocolysis, which is the inhibition of uterine contractions.

Correct Answer: D

Rationale: The correct answer is D (>90%). Mr. Mettenberger had a reexpansion of his second spontaneous pneumothorax this year, indicating a high recurrence risk. Spontaneous pneumothorax recurrence rates are high, especially in young males. Factors such as smoking history, gender, and prior occurrences contribute to increased risk. Mr. Mettenberger's cessation of smoking reduces but does not eliminate the risk. Choices A, B, and C are too low, given his history and current situation. Choice D is the most appropriate due to the high likelihood of recurrence based on his medical history and risk factors.

Correct Answer: B

Rationale: The correct answer is B: Hyperbaric oxygen. Hyperbaric oxygen therapy involves breathing pure oxygen in a pressurized room, which can help reduce gas cysts in the gastrointestinal tract by increasing oxygen delivery to tissues. This promotes healing and reduces symptoms associated with pneumatosis. A: Several days of oxygen by face mask is not as effective as hyperbaric oxygen therapy in treating pneumatosis, as it does not provide the same level of pressurized oxygen delivery to tissues. C: Surgical resection may be considered in severe cases of pneumatosis where conservative treatments have failed, but it is not the first-line treatment option. D: Treatment of underlying disease is important in managing pneumatosis, but it may not directly address the gas cysts themselves. Hyperbaric oxygen therapy specifically targets the gas cysts to alleviate symptoms.

Correct Answer: C

Rationale: The correct answer is C: Puerperal pyrexia. Maternal febrile condition within the first three weeks postpartum is suggestive of puerperal pyrexia, which is defined as a fever of 38°C or higher occurring after the first 24 hours post-delivery. This condition is commonly caused by endometritis, a uterine infection following childbirth. Puerperal sepsis (choice A) is a more severe form of infection involving systemic symptoms, while puerperal thrombosis (choice B) refers to blood clot formation. Puerperal shock (choice D) is a life-threatening condition resulting from severe infection or hemorrhage, which may present with fever but is not the primary symptom.