Effect of preoperative paracetamol on gastric volumes and pH in children

The effect preoperative paracetamol elixir has on gastric contents is unkno wn. Children presenting for elective adenotonsillectomy were randomized to receive either paracetamol elixir (40 mg.kg(-1)) 90 min before surgery or p aracetamol suppositories (40 mg.kg(-1)) intraoperatively. Following inducti on of anaesthesia a 16 Fr multiple-oriface orogastric tube was passed into the stomach and measure taken of the residual gastric volume and pH. The ch ildren had a mean age of 8.5 years (SD 3.2) with a weight of 35 kg (SD 16.5 ). Children given elixir (n=41) had a mean residual gastric volume of 0.083 ml.kg(-1) (95% CI; 0.006, 1.24) and a pH of 1.83 (95% CI; 0.75, 4.49), whi le those given suppositories (n=40) had a mean residual gastric volume of 0 .083 ml.kg(-1) (95% CI; 0.008, 0.9) and a pH of 2.07 (95% CI; 0.84, 5.12). There was no significant difference between these two groups. Paracetamol e lixir is rapidly absorbed in the gastrointestinal system of children and pr eoperative administration has no effect on gastric contents. Given paraceta mol's slow equilibration rate constant from the central to the effect compa rtment, children may be given this medication preoperatively for routine su rgical procedures.