COMPARISON OF ATRACURIUM AND PANCURONIUM IN MECHANICALLY VENTILATED NEONATES

Objective: To compare haemodynamic and gas exchange effects after eith er atracurium or pancuronium given to ventilated neonates with respira tory failure. Design: In this prospective study neonates were alternat ely assigned to receive either atracurium or pancuronium, intravenousl y. Setting: Paediatric and neonatal ICU in a teaching hospital. Patien ts: 21 ventilated neonates with mean birth weight of 2293 g, suffering from respiratory distress syndrome, meconium aspiration syndrome or p neumonia were included in the study. Patients were entered if they wer e breathing out of phase with the ventilator and required FIO2 > 0.4 a nd peak inspiratory pressure (PIP) > 15 cm H2O. Exclusion criteria wer e unstable haemodynamics or a pneumothorax. Interventions: Heart rate, respiratory rate, invasive blood pressure and transcutaneous oxygen t ension were monitored continuously. IV atracurium (0.3 mg/kg) or pancu ronium (0. 1 mg/kg) were administered. Arterial blood gas analysis was performed before and 10 min after injection of muscle relaxant. Measu rements and results: Atracurium caused a significant decrease in heart rate (p < 0.05), systolic and mean blood pressure (p < 0.01). There w as also a slight decrease in PaO2 and PaCO2 (n.s.). Administration of pancuronium resulted in an increase in heart rate (p < 0.01) and a sli ght decrease of blood pressure (n.s.). PaCO2 remained unchanged, where as PaO2 increased slightly (n.s.). The PtcO2 index (PtCO2/PaO2) decrea sed after atracurium and did not change after pancuronium (both n.s.). With both drugs a slight increase in alveolar to arterial oxygen tens ion difference was observed (n.s.). There was one episode of hypotensi on and one of hypoxaemia - both after pancuronium. Conclusion: Both dr ugs may be used for muscle relaxation in neonates with respiratory fai lure. Atracurium however causes more cardiovascular depression, wherea s the effect of pancuronium may be difficult to predict.