The reason why you can’t drink or eat before surgery is to prevent nausea and vomiting after anesthesia, which may cause choking.
In order to reduce the patient’s pain or ensure smooth operation, anesthesia is needed for the patient before the operation, because after anesthesia the human body is in the state of muscle relaxation, so the corresponding lower esophageal sphincter is also relaxed, and some of the anesthetics will cause the patient nausea, vomiting phenomenon, and the patient’s chest muscles are also relaxed, so the swallowing reflex and cough reflex are gone.
After vomiting, it is very easy for the vomitus to enter the trachea, and the obstruction of the trachea will lead to asphyxiation and then threaten the patient’s life.
In addition, for gastric surgery patients, abstaining from drinking and fasting can be beneficial to the operation and avoid postoperative infections. In general, it is necessary to prohibit drinking for more than 4 hours and fasting for 8 to 12 hours.
If hypoglycemia or dehydration occurs during the period of abstinence from drinking and fasting, moderate rehydration is required under the guidance of the doctor.