Hypertonic NaCl antagonizes cardiac arrhythmia induced by bupivacaine

RESUMO

We studied the effects of pretreatment with hypertonic solutions on the conduction disturbances and cardiac arrhythmias caused by iv injection of bupivacaine in anesthetized mongrel dogs. Bupivacaine was injected in doses of 3 ms/Kg and 6.5 mg/Kg. The hypertonic solutions used were 7.5% NaCl, 5.4% LiCi, 50% Glucose (5 ml/Kg and 20% mannitol (10 ml/Kg). Bupivacaine induced severe conduction disturbances, as reflected by significant increases in QRS complex duration, HV interval and IV interval, and severe hypertension. The arrhythmias observed wereÑ sinus node dysfunction, nonustained ventricular tachycardia, sustained ventriculara tachycardia and ventricular fibrillation. These effects were dose dependent, and were more evident with the higher dose of bupivacine. Among all the hypertonic sulutions tested, only 7.5% NaCl effectivelly protected against conduction disturbances and cardiac arrhythmias. These findings suggest an important role for socium overload in these situations and provide a potentially harmless tool for the treatment of anesthetic accidents with bupivacaine during regionalo anesthesia