Evaluation of the ‘Sip Til Send’ regimen before elective caesarean delivery using bedside gastric ultrasound

Abstract

BACKGROUND Pre-operative fasting is routinely advocated to avoid pulmonary aspiration. The European Society of Anaesthesiology and Intensive Care (ESAIC) recommends a fasting period of 2 h for liquids before surgery. Liberal drinking policies such as the ‘Sip Til Send’ are a suggested alternative to maintain hydration before surgery. OBJECTIVES To compare residual gastric volumes in fully fasted nonlabouring parturients before elective caesarean delivery with the ‘Sip Til Send’ with water liberal drinking protocol. Our hypothesis was the ‘Sip Til Send’ would be noninferior to standard fasting at minimising the residual gastric volume immediately before surgery. DESIGN A paired cohort prospective observational pragmatic study using gastric ultrasound, analysed by an operator blinded to the fasting status of each scan. SETTING A tertiary maternity hospital in Dublin, Ireland. The study was conducted between January and June 2023. PARTICIPANTS Pregnant women about to undergo elective caesarean delivery who had followed ESAIC fasting guidelines before admission. INTERVENTIONS Each participant underwent two pairs (semi-recumbent and the semi-recumbent right lateral positions) of standardised ultrasound examinations of the gastric antrum: the order of these scans was randomised. The first pair of scans occurred on admission before the ‘Sip Til Send’ protocol commenced, the other pair just before spinal anaesthesia for caesarean delivery, after a variable time following the ‘Sip Til Send’ protocol. MAIN OUTCOME MEASURE The primary outcome was the difference in antral cross-sectional area (CSA) between the fully fasted women on admission and the same women after following the ‘Sip Til Send’ protocol until just before spinal anaesthesia. RESULTS Fifty-eight women were randomised for the study: 55 and 54 scans in the semi-recumbent position on admission, and 55 and 54 scans in the right lateral position just before spinal anaesthesia. The mean differences (95% CI) in CSA in the semi-recumbent and RL positions were 0.07 (-0.39 to 0.53) cm2 and 0.04 (-0.60 to 0.68) cm2, respectively. Since the of 95% CIs did not cross the predefined noninferiority margin of 0.88 cm2, ‘Sip Til Send’ was noninferior to fully fasting in in terms of the antral CSA. CONCLUSION The ‘Sip Til Send’ protocol of liberal hydration with water was noninferior to standard fasting prior to elective caesarean delivery. TRIAL REGISTRY NUMBER NCT05783427 ClinicalTrials.gov