Usually, before having a general anaesthetic, you will not be allowed anything to eat or drink. This is because when the anaesthetic is used, your body's reflexes are temporarily stopped. If your stomach has food and drink in it, there's a risk of vomiting or bringing up food into your throat.
You are encouraged to drink clear liquids — NOT milk or dairy products — until 2 hours before the time you are scheduled to arrive at the hospital or surgery center. Staying hydrated is good for you, and it's especially important in hot weather! Clear, see-through liquids include: Water.
While food, especially fat- or protein-rich food, can take up to 8 hours to leave your stomach, studies have shown that clear fluids like coffee, water or pulp-free orange juice are clear of your stomach within two hours or faster. Therefore, clear fluids can be safely consumed up until two hours before surgery.
In 1999, 2011, and again in 2017, the American Society of Anesthesiologists issued NPO guidelines that permitted the consumption of clear liquids until two hours before surgery for all healthy patients undergoing elective procedures requiring general anesthesia, regional anesthesia, sedation, or analgesia.
Liquids leave the stomach faster because there is less to break down: Plain water: 10 to 20 minutes. Simple liquids (clear juices, tea, sodas): 20 to 40 minutes. Complex liquids (smoothies, protein shakes, bone broths): 40 to 60 minutes.
After you drink water, it doesn't take long at all for your body to absorb it. Unlike foods, water can be “digested” in as little as 5 minutes. Excess water leaves your body through urination and feces but is also excreted by sweating.
In general speaking, people in good health will absorb water and produce urine within 2 hours.
Answer and Explanation: It takes a healthy human body about 3 hours to process through a liter of fluid. The reason it takes so long for fluid to reach the bladder is because fluid consumed by mouth must go through the digestive tract first and into blood circulation.
After surgery, anesthesia stays in the body for a short period. Drinking plenty of water can help flush the anesthesia from the system. During recovery, many people also take pain medications that can cause constipation. Water helps the digestive system work more efficiently, reducing this uncomfortable side effect.
Traditionally, postoperative oral hydration after general anesthesia (non-gastrointestinal surgery) has been withheld for about 4-6 hours for safety, in order to avoid vomiting, nausea because of residual anesthetics and incomplete emergence [2,3].
For example, American Society of Anesthesiologists guidelines generally permit clear liquids until two hours before surgery. A ban on eating and drinking too close to the time of general anesthesia has a practical reason: to prevent aspiration of stomach contents, resulting in pneumonia.