It is very common that you will be asked to not have any food or liquids for a certain amount of time before your procedure or operation. It is very important that you follow these fasting instructions. The American Society of Anesthesiologists has published fasting guidelines for healthy patients undergoing elective procedures. The goal is to prevent perioperative pulmonary aspiration.
When I give a patient anesthesia, their body becomes relaxed. Any food or liquid in their stomach can come up the esophagus and go down into the lungs. This is the definition of aspiration. It can occur while going off to sleep, during the procedure, or immediately after the procedure. Gastric contents in the lungs can lead to breathing issues, pneumonia, or worse.
By following your surgeon's or proceduralist's preoperative fasting instructions, you are reducing the likelihood that aspiration will occur. There are certain conditions that increase the likelihood of aspiration in the perioperative period. It is important to let your anesthesiologist know about all of your medical conditions. Conditions like obesity, diabetes, acid reflux, or a hiatal hernia can increase the risk of aspiration.
To read more about this topic, you can search for the ASA fasting guidelines by The American Society of Anesthesiologists in 2017.
Bobbie Freeman, M.D.