A carbohydrate loading fasting protocol versus 'Sip til Send': a randomised trial of two different fasting protocols...

Pulmonary aspiration under general anaesthesia is a rare but serious risk in obstetric populations, leading to conservative fasting protocols prior to elective caesarean delivery (CD). However, prolonged fasting may negatively impact maternal comfort and metabolic status. 'Sip til Send' (STS), a liberal fasting protocol permitting clear fluids until theatre admission, has been shown to improve the perioperative patient experience. Pre-operative carbohydrate loading (CHO), as part of Enhanced Recovery After Surgery (ERAS) pathways, may offer additional benefits, yet its role in obstetrics is underexplored. This study aimed to compare CHO with STS in women undergoing elective CD, focusing on patient-reported comfort measures.

In this single-blinded, randomised controlled trial, 100 eligible women scheduled for elective CD under spinal anaesthesia were randomised to either STS or CHO groups. Women in the CHO group consumed two 200 ml carbohydrate drinks (Nutricia preOp™) pre-operatively. Primary outcomes included self-reported pre-operative thirst, hunger, nausea, dizziness, anxiety, and comfort using a 0-10 visual analogue scale (VAS). Secondary outcomes included ketonuria, blood glucose, lactate levels, intra-operative nausea, post-operative temperature, and recovery scores at 24 h.

Mean [SD] anxiety scores were significantly lower in the CHO group compared with STS (CHO 4.1 [2.9] vs STS 5.5 [2.6], p = 0.01. No other primary patient-reported outcomes differed significantly. Ketonuria was less prevalent in the CHO group (CHO 2/50 [4%] vs. STS 10/50 [20%], p = 0.002), and mean [SD] blood glucose was higher (CHO 5.0 [1.5] mmol.L^-1 vs. STS 4.5 [0.6] mmol.L^-1, p = 0.046). Intra-operative nausea was more common in the CHO group (CHO 22/50 [44%] vs. STS 8/50 [16%], p = 0.002). No differences were observed in lactate, post-operative temperature, or quality of recovery scores (OBS QOR-11, global health score) at 24 h.

Pre-operative carbohydrate loading before elective CD significantly reduces maternal anxiety and ketonuria compared to a liberal clear fluid protocol. However, it was associated with increased intra-operative nausea and no improvement in other patient-centred outcomes or recovery quality. These findings suggest limited additional benefit of CHO over STS in this population. Further multicentre trials are warranted to refine carbohydrate loading protocols and assess their role in obstetric ERAS pathways.

Clinicaltrials.gov NCT06505915, 30th June 2024. Retrospectively registered.