UBC Theses and Dissertations
Lidocaine in experimental ventricular fibrillation : endotracheal vs intravenous use Brown, Linda Kathleen
The endotracheal (ET) route for the administration of selected drugs has been proposed as an effective alternate route of drug administration during emergency situations when an intravenous (IV) line cannot be established. Lidocaine may be beneficial in the treatment of ventricular fibrillation (VF) resulting from acute myocardial infarction, although this hypothesis has not been confirmed in the literature. The efficacy of lidocaine in the treatment of ventricular fibrillation due to acute coronary artery ligation was examined, as well as the use of the endotracheal route as an alternative to IV injection. Rabbits were anesthetized with sodium pentobarbital or halothane, intubated with an endotracheal tube, and animals receiving pentobarbital were mechanically respired. Ventricular fibrillation was produced by occlusion of the left circumflex coronary artery, or by subsequent reperfusion of ischemic myocardium. Endotracheal administration of 2mg/Kg lidocaine (2mg/ml in normal saline) resulted in lower peak plasma lidocaine concentrations initially compared with IV injection, but more sustained levels in the therapeutic range for lidocaine (p<0.05). Administration of lidocaine either IV or ET during ventricular fibrillation resulted in a significant increase (p<0.05) in plasma lidocaine concentrations during the first minute compared with controls. During ventricular fibrillation there was no significant difference between plasma lidocaine levels following IV or ET administration. Administration of lidocaine 2mg/Kg endotracheally (in normal saline) during VF resulted in a significant decrease in the duration of fibrillation compared with untreated and normal saline controls (p <0.001).
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