The objective of this clinical trial is to assess the feasibility of the remimazolam combined with esketamine OFA (opioid-free anesthesia) protocol for painless gastroscopy and colonoscopy in elderly patients and to determine if it is non-inferior to the traditional OA (opioid-containing anesthesia) protocol. The main questions it aims to answer are: * Is the remimazolam combined with esketamine protocol feasible for painless gastroscopy and colonoscopy in elderly patients? * Is the OFA protocol superior to the OA protocol? Participants will: * During anesthesia induction, the experimental group will receive remimazolam combined with esketamine for anesthesia, while the control group will receive remimazolam combined with remifentanil. * Record respiratory and circulatory indicators and adverse reaction times.