Final answer:
Respect the patient's prior refusal of chemotherapy; administering treatment without consent is unethical, and seeking legal authorization should only be considered if the patient is no longer competent.
Step-by-step explanation:
In the scenario where a 42-year-old man with leukemia has repeatedly refused chemotherapy and loses consciousness, it is crucial to respect the patient's autonomy and previously expressed wishes regarding their healthcare. Therefore, the appropriate response would be to respect the patient's prior refusal of chemotherapy. Administering chemotherapy without consent would be unethical and illegal. Seeking legal authorization may only be considered if there is evidence that the patient is no longer capable of making an informed decision, which is not clearly the case here given his prior refusal while conscious. Delaying treatment until the patient regains consciousness may also respect his autonomy but does not address the urgent nature of his condition. It is important to consider existing advanced directives, healthcare proxies, or legal documents that may guide healthcare decisions in this situation.