Barriers and facilitators for healthcare professionals to the implementation of Multidisciplinary Timely Undertaken Advance Care Planning conversations at the outpatient clinic (the MUTUAL intervention): a sequential exploratory mixed-methods study

门诊医护人员实施多学科及时开展的预立医疗照护计划对话（MUTUAL干预）的障碍和促进因素：一项序贯探索性混合方法研究