This paper examines the ethical, legal, and governance challenges posed by sentient artificial intelligence (SAI) in the healthcare sector. Examining the evolution of AI from the Dartmouth Conference to the present contextualizes the renewed fascination with "thinking machines" capable of subjective experiences, self-awareness, and autonomy. Even though people have been talking about the ethics of AI for a long time, SAI brings up current issues about how it affects decision-making, data ownership, transparency, and responsibility. The research says that strong governance mechanisms and working together across fields are important for solving these difficulties. By raising awareness of critical issues, it aims to facilitate the development of healthcare AI ethics and establish a foundation for future research and policy-making.