Effects of i.v. metoclopramide, atropine and their combination on gastric insufflation in children anaesthetized with sevoflurane and nitrous oxide

Methods: To determine effects of i.v. metoclopramide, atropine and their co mbination on the airway pressures at which gastric insufflation occurs in c hildren, 45 healthy infants and children (ASA I) received an inhalational i nduction of anaesthesia with sevoflurane, N2O and O-2 A blinded observer us ed a stethoscope to auscultate over the upper abdomen for any air entry. Fi rst, proximal airway pressure was slowly increased by closing the pop-off v alve of the anaesthesia machine until gas was heard entering the stomach (p op-off point, control measurement). If the peak inspiratory pressure reache d 40 cm H2O, the patient was to be excluded from the study. Then, all subje cts randomly received i.v. atropine 0.01 mg.kg(-1), metoclopramide 0.2 mg.k g(-1), or atropine 0.01 mg.kg(-1) plus metoclopramide 0.2 mg.kg(-1) (n = 15 each), and determination of the pop-off point was repeated 5 min later. Th e stomach was evacuated before each measurement. Results: Atropine significantly decreased the pop-off point [from 21 +/- 3 to 19 +/- 2 cm H2O (mean +/- SD), P < 0.05], while metoclopramide significa ntly increased the pop-off point (from 20 <plus/minus> 3 to 26 +/- 6 cm H(2 )0\O, P < 0.05). The combination of metoclopramide and atropine did not alt er the pop-off point (from 20 <plus/minus> 2 to 19 +/- 5 cm H2O). Conclusions: Since metoclopramide exerts only mild effect on the pop-off po int, cricoid pressure still remains the standard anaesthetic practice to pr event gastric insufflation in children. Prophylactic i.v. metoclopramide ma y be restricted to, and its clinical usefulness should be determined in, sy mptomatic patients with gastro-oesophageal reflux.