Benefits in adults allowed to drink clear liquids before anaesthesia until called to the operating room

BACKGROUND: Liquid fasting durations often exceed current recommendations, resulting in patient discomfort. OBJECTIVE: To investigate the feasibility of three preoperative liquid fasting protocols in patients with low risk of aspiration in preparation for a future large-scale trial, with a particular focus on patient-centred benefits. DESIGN: Prospective, randomised, controlled, pilot trial. SETTING: Secondary care; single academic centre in Germany. PATIENTS: One hundred and seventy-four adult surgical patients with low risk of aspiration. INTERVENTION: Patients were randomised either to 'control group' (usual care, 2 h liquid fasting protocol), 'conservative intervention' (patients received assistance in adhering to a 2 h liquid fasting protocol) or 'liberal intervention' (patients could drink until they were called to the operating room). MAIN OUTCOME MEASURES: Piloting process endpoints and performance endpoints were assessed. The primary outcome was patient-reported thirst before anaesthesia induction categorised as none, moderate, or severe. RESULTS: No patient dropped out or was lost to follow-up. Blinding was successful in 98.3%. The conservative and liberal interventions reduced the median [interquartile range or IQR] fluid fasting time from 5.38 h [3.67 to 9.53 h] in the control group to 3.00 h [2.23 to 4.25 h], P < 0.001, and 1.97 h [1.20 to 3.02 h], P < 0.001, respectively. Both conservative and liberal intervention significantly reduced the risk of preoperative thirst compared with the control group, presented as odds ratio (OR) and 95% confidence intervals (CI); conservative intervention OR 0.41 (CI, 0.20 to 0.82), P = 0.013; liberal intervention: OR 0.21 (CI, 0.10 to 0.43), P < 0.001. In the liberal intervention group, postoperative thirst, OR 0.32 (CI, 0.13 to 0.75), P = 0.009, and preoperative headache, OR 0.24 (CI, 0.07 to 0.66), P = 0.009, were significantly reduced compared with those in the control group. No adverse events were reported. CONCLUSIONS: The trial design proved feasible. Liberal fluid intake reduced thirst and headache. The trial was not powered to provide definitive conclusions on safety. TRIAL REGISTRATION: The clinical investigation plan can be accessed at ClinicalTrials.gov identifier NCT06253052. Deidentified individual participant data, the data dictionary, and statistical code can be accessed upon reasonable request from the corresponding author.