Effect of pre-operative oral paracetamol on gastric residual volume and pH in young children in the context of a 1-hour clear fluid fast: a randomised controlled trial.

High gastric residual volume and low pH are associated with increased mortality following pulmonary aspiration in animal studies. The use of pre-operative oral paracetamol has not been investigated in younger children and infants in the context of a prescriptive 1-h clear fluid fast aimed at reducing the risk of pulmonary aspiration while improving patient experience. Children aged 1 month up to a weight of 25 kg and scheduled for elective surgery were randomly allocated to receive a prescribed 3.6 ml.kg drink of water alone (water group) or 3 ml.kg water and oral Infant Calpol® syrup (24 mg.ml concentration, equivalent volume 0.6 ml.kg , paracetamol group) 1 h before the induction of anaesthesia. Following induction, a nasogastric tube was used to aspirate gastric contents and the volume and pH were recorded. Ninety-seven children, median (IQR [range]) age 24 (12-45 [1-96]) months and weight 12.4 (9.7-16.0 [2.9-27.0]) kg, were analysed. Median time from drink to induction was 54 (45-60 [21-113]) min. There was no significant difference in gastric residual volume (p = 1) or pH (p = 0.99) between the water and the paracetamol groups. Sub-group analysis revealed no significant difference in gastric residual volume or pH for 29 children who weighed < 10 kg compared with > 10 kg. Using a prescriptive fluid regime of 3 ml.kg of water, the addition of oral paracetamol syrup did not significantly alter gastric residual volume or pH in the context of a 1-h fast in infants and young children.