Should clear liquid fasting time be shortened to less than two hours?
I am a big believer in questioning everything. One reason I started writing about anesthesia was that I too often found long-held ideas to be misleading or incorrect. Until recently, I had not questioned fasting guidelines. I was pleasantly surprised when I read a paper suggesting clear liquids could be consumed right up until going to the operating room, at least in pediatrics.
In 2025, a group of researchers conducted a prospective, multi-center, international study comparing three different fasting times in pediatric patients aged < 16 years. The guidelines at each participating center dictated whether patients were in one of three groups: clear liquids allowed until the patient was taken to the operating room (called the sip-til-send group), clear liquids allowed and encouraged ≥ 1 hour before induction, and clear liquids allowed ≥ 2 hours before induction of anesthesia (the control). The primary outcome was pulmonary aspiration defined as regurgitation or vomiting leading to respiratory symptoms requiring “high-dependency unit or ICU admission,” gastric contents seen in the trachea, or radiologic evidence of aspiration pneumonia.
In total, 306,900 anesthetics were included with 34,028 in the sip-til-send group, 251,021 in the ≥ 1 hour group, and 21,851 in the control group. There were 420 aspiration events categorized as either transient (n = 286, 68%), requiring escalation of care (n = 94, 22%), or requiring intensive care (n = 40, 9.5%).1 Aspiration incidence in the sip-til-send (1.18:10,000) and the ≥ 1 hour (0.96:10,000) groups was non-inferior to the control group (1.83:10,000) with 95% CIs of -1.48 to 3.63 and -0.34 to 3.76, respectively. When looking only at aspirations leading to ICU admission, the sip-til-send and ≥ 1 hour groups were again non-inferior to the control group.
Most of the aspiration events occurred in children fasting ≥ 2 hours (76%) compared to 5.9% in the sip-til-send group and 18% in the ≥ 1 hour group. The most common complications related to aspiration were hypoxemia (33%), laryngospasm (15%), aspiration pneumonia (5.4%), and bronchospasm (4.4%).
The main limitation of this study is that it was not randomized, as groups were allocated based on entire centers. It is possible that centers with more liberal fasting policies differed in other meaningful ways. Actual fasting times were analyzed for each aspiration event, but data were unavailable for 114 of the 420 cases. Lastly, because patients aged ≥ 16 years were excluded, we are unable to know if these results would be similar in adults.
The European Society of Anesthesia and Intensive Care (ESAIC) currently recommends that children be encouraged to drink clear liquids until 1 hour before anesthesia. The results of this study, and the authors’ own conclusion, support liberalizing pediatric fasting guidelines to ≤ 1 hour. If a sip-til-send policy were universally adopted, it could likely lead to fewer cancelled and delayed surgeries and higher patient satisfaction. I hope this new evidence can support meaningful change at your institution.
One center reported a disproportionately high number of transient symptom aspiration events, but a sensitivity analysis excluding this site did not alter the results.