使用病人自控式止痛劑（Patient-controlled analgesia, PCA）時，若病人需要由morphine 轉換為hydromorphone，應如何轉換？
Morphine 10 mg/hour＝hydromorphone 1 mg/hour
Morphine 20 mg/hour＝hydromorphone 1 mg/hour
Morphine 10 mg/hour＝hydromorphone 2 mg/hour
Morphine 1 mg/hour＝hydromorphone 10 mg/hour
