① Patients who are not awake after general anesthesia: Lie on your back, remove the pillow and turn your head to one side.

② Patients with subarachnoid block: supine or head down for 6-8h.

③ Craniocerebral surgery: If there is no shock or coma, take 15-30 heads with high feet and low slopes.

④ Cervical and thoracic surgery: supine position.