P. Karaaslan

Comparison of propofol versus ketamine induced upper airway anatomic changes in children using magnetic resonance imaging: A-609

Departments of Anesthesiology and Radiology, Baskent University, School of Medicine, Ankara, Turkey Background and Goal of Study: Anesthesia associated upper airway obstruction is generally attributed to reduced genioglossus activity and consequent posterior displacement of the tongue (1). The aim of this study was to compare propofol versus ketamine induced upper airway morphologic changes in children regarding the site of the airway narrowing and the smallest cross-sectional area of the airway, using magnetic resonance imaging (MRI). Materials and Methods: Twenty-five ASA 1–2 children (aged 1–4 yrs) undergoing MRI of the head were studied. The children were randomly assigned to two groups. The propofol group (Group P, n 13) received an IV propofol bolus of 1–3 mg/kg followed by a propofol infusion of 3–6 mg/kg/hr. The patients in the ketamine group (Group K, n 12) were anesthetized with an IV ketamine bolus of 1–2 mg/kg followed by a ketamine infusion of 1.5–3.0 mg/kg/hr. All patients underwent additional MRI scans of the upper airway during deep sedation. The groups were compared with respect to demographic data, hemodynamic and respiratory parameters/complications, the site of airway narrowing and the smallest cross-sectional area of the airway. Results and Discussions: Spontaneous breathing was maintained in all patients. The groups’ demographic data, hemodynamic and respiratory parameters/complications were similar, except for the significantly higher heart rates in Group K (p 0.001). In both Group K and Group P, the most common site of the airway narrowing was the soft palate (75% and 62%, respectively). The smallest cross-sectional area of the upper airway in Group K and Group P were 88.6 46.35 mm2 and 79.3 30.51 mm2, respectively (p 0.05). Conclusion(s): This study suggests that in contrast to the generally accepted view that posterior displacement of the tongue causes airway obstruction during anesthesia, airway narrowing occurs more commonly at the level of the soft palate. This study also showed that propofol and ketamine cause similar morphologic changes in the upper airway. Reference: 1 Mathru M. Anesthesiology 1996:84;273–9.