From the Guidelines
Patients should remain nil by mouth for at least 6 hours before a scope for solid foods and 2 hours for clear liquids. This recommendation is based on the most recent and highest quality study, which suggests that preoperative fasting from midnight is unnecessary in most patients 1. The study recommends that patients undergoing surgery, who are considered to have no specific risk of aspiration, shall drink clear fluids until 2 hours before anesthesia and solids shall be allowed until 6 hours before anesthesia.
Key Points to Consider
- The exact timing of nil by mouth may vary depending on the type of scope and the patient's medical history 1.
- Clear liquids may be allowed up until 2 hours before the procedure, but solid foods should be avoided for at least 6 hours prior 1.
- The recommendation to remain nil by mouth for at least 6 hours for solid foods and 2 hours for clear liquids is supported by multiple studies, including those published in 2021 1 and 2022 1.
- It is essential to follow the healthcare provider's specific instructions, as they may vary based on the patient's medical history, the timing of the procedure, and the type of sedation planned.
Evidence-Based Recommendations
- The ESPEN practical guideline recommends that patients undergoing surgery shall drink clear fluids until 2 hours before anesthesia and solids shall be allowed until 6 hours before anesthesia 1.
- The ERAS society recommendation suggests that patients should be encouraged to eat a light snack up until 6 hours and clear fluids up until 2 hours before surgery 1.
- A study published in 2022 found that preoperative fasting results in a prolonged period without fluids or nutrition, and that multiple meta-analyses have demonstrated that healthy adults undergoing elective surgery can safely consume clear fluids up to 2 hours and a light meal up to 6 hours before induction of anesthesia 1.
From the Research
Nil by Mouth Guidelines
- The recommended duration for nil by mouth (NBM) before a scope procedure is at least 6 hours for solids and 2-4 hours for liquids, but this can vary depending on the specific procedure and individual patient factors 2.
- A study published in the Journal of Gastroenterology and Hepatology found that a 6-hour fast for solids and a 1-hour fast for water prior to upper gastrointestinal endoscopy (UGIE) provided good endoscopic vision and resulted in minimum patient discomfort 2.
- However, there is no one-size-fits-all answer to the question of how many hours before a scope procedure a patient should be nil by mouth, as this depends on various factors, including the type of procedure, the patient's medical history, and the anesthesia protocol used 3, 4, 5, 6.
Patient Preparation and Safety
- Patient preparation and safety are critical aspects of scope procedures, and nil by mouth guidelines are an important part of this preparation 3, 6.
- Assessing the risk of gastric content aspiration is critical for determining appropriate anesthetic protocols and ensuring patient safety during endoscopic procedures 6.
- The availability of adequate monitoring devices, anesthetic drugs, and oxygenation equipment guarantees the quality of sedation and patient safety during endoscopic procedures 6.