From the Guidelines
Clear fluids are transparent liquids that you can see through when held up to light, including water, clear broths, tea or coffee without milk, clear fruit juices without pulp, clear sodas, sports drinks, and gelatin that has fully dissolved, and are recommended to be consumed up to 2 hours before anesthesia, as supported by the most recent and highest quality study 1.
Definition of Clear Fluids
Clear fluids are defined as liquids that are transparent and can be seen through when held up to light. They include:
- Water
- Clear broths
- Tea or coffee without milk
- Clear fruit juices without pulp (like apple or white grape juice)
- Clear sodas
- Sports drinks
- Gelatin that has fully dissolved
Medical Context
In medical contexts, particularly before surgery or certain diagnostic procedures, clear fluids are important because they are easily digested and leave minimal residue in the digestive tract. They are also recommended during the initial stages of recovering from gastrointestinal illnesses because they are gentle on the stomach and help prevent dehydration.
Recommendations
The most recent and highest quality study 1 recommends that patients should reach the anesthesia room in a state as close to euvolemia as possible, and that clear fluids should be allowed up to 2 hours prior to the induction of anesthesia. This is supported by other studies, including 1 and 1, which also recommend allowing clear fluids up to 2 hours before anesthesia.
Key Points
- Clear fluids are transparent liquids that can be seen through when held up to light
- They are easily digested and leave minimal residue in the digestive tract
- They are recommended before surgery or certain diagnostic procedures, and during the initial stages of recovering from gastrointestinal illnesses
- They should be consumed up to 2 hours before anesthesia, as supported by the most recent and highest quality study 1
From the Research
Definition of Clear Fluids
- Clear fluids are liquids that are transparent and free from solid particles, such as water, clear broths, and electrolyte-rich beverages like sports drinks 2.
- Examples of clear fluids include apple juice, clear electrolyte solutions, and Ensure Clear, a high-protein drink 3.
Medical Context
- In a medical setting, clear fluids are often used as a first step in the postoperative management of surgical patients, although some studies suggest that a regular diet may be tolerated just as well 4.
- Clear fluids may be recommended for patients who are at risk of dehydration, such as those with diarrheal illness or those who are undergoing vigorous exercise 2.
- In pediatric outpatients, ingestion of clear liquids until 2 hours before surgery has been shown to be a safe and effective alternative to preoperative fasting 5.
Characteristics
- Clear fluids can have different compositions, such as varying levels of electrolytes, carbohydrates, and proteins 3.
- The gastric emptying time of clear fluids can vary depending on the individual and the type of fluid consumed, but studies have shown that the stomach is essentially clear by 3-3.5 hours for most clear fluids 3.
- The use of clear fluids in postoperative management can help to maintain fluid balance and reduce the need for intravenous hydration 6.