From the Guidelines
Patients can typically have clear liquids up to 2 hours before surgery, as recommended by the most recent and highest quality study 1. This guideline applies to water, clear juices without pulp, clear tea, black coffee (without milk or cream), clear broths, and sports drinks. The traditional NPO (nothing by mouth) after midnight rule has been replaced with these more liberal guidelines for most healthy patients undergoing elective procedures.
Key Considerations
- The shorter fasting period helps prevent dehydration, hunger, and discomfort while still ensuring stomach emptying to reduce aspiration risk during anesthesia.
- Specific medications may be taken with a small sip of water even during the fasting period, but this should be discussed with the anesthesiologist beforehand.
- Patients with certain conditions like diabetes, gastroesophageal reflux disease, or obesity may require modified fasting guidelines.
- Always follow the specific instructions provided by your surgical team, as they may adjust these recommendations based on your individual health status and the type of procedure you're undergoing.
Evidence Summary
The ESPEN practical guideline: clinical nutrition in surgery 1 provides a strong consensus (97% agreement) that preoperative fasting from midnight is unnecessary in most patients, and clear fluids can be consumed until 2 hours before anesthesia. This is supported by the fact that clear fluids empty the stomach within 60-90 minutes, and there is no evidence of increased risk of aspiration or regurgitation with this approach 1.
From the Research
Clear Liquid Diet Duration Before Surgery
- The duration of a clear liquid diet before surgery is not explicitly stated in the provided studies.
- However, a study published in 1996 2 suggests that the routine use of clear liquids as the initial postoperative diet may be unnecessary and nutritionally suboptimal when compared with a regular diet.
- This study found that patients who received a regular diet as their first postoperative meal did not have a statistically significant increase in dietary intolerance compared to those who received clear liquids.
- Another study published in 2017 3 discusses the use of oral electrolyte solutions for rehydration in diarrheal illness and maintaining hydration during exercise, but does not provide information on the duration of a clear liquid diet before surgery.
- Studies published in 2016 4 and 1999 5 discuss fluid and electrolyte imbalances, and dehydration and electrolyte disturbance, respectively, but do not provide information on the duration of a clear liquid diet before surgery.
- A study published in 2015 6 discusses the use of intravenous solutions in the care of patients with volume depletion and electrolyte abnormalities, but does not provide information on the duration of a clear liquid diet before surgery.