Antidysrhythmic of choice for ventricular ectopy, V-Fib and V-Tac In pre-hospital care, the most common cause of life-threatening ventricular dysrhythmias is AMI. After AMI the ventricular fibrillation threshold is significantly reduced. Lidocaine suppresses ventriculr ectopic activity. A person successfully defibrillated should be treated with Lidocaine. Because PVC's may lead to life threatening dysrhythmia, treat with Lidocaine for the following: more than 6 unifocal PVC's per minute; PVC's that appear to be multifocal; couplet PVC's runs of more than 2 PVC's or V-Tach; PVC's falling in the vulnerable period of the preceding normal complex (R on T Phenomena); V-Tach and V-Fib should be aggressively treated with Lidocaine.
Mechanisim of Action
Suppresses the automaticity of ventricular ectopic pacemakers; Suppresses ventricular dysrhythmia only when blood levels are between 1.5 and 6.0mcg/ml of blood; A 1mg/kg bolus of Lidocaine will maintain adequate blood levels for only 20 minutes. Therefore, a Lidocaine bolus should be followed by a 2-4 mg/min infusion
Malignant premature ventricular contractions; Ventricular Tachycardia; Ventricular Fibrillation (after the initial steps of resuscitative precedures, including defibrillation)
Second-degree Type II and Third-degree blocks (May further slow conduction of the electrical impulses); Whenever PVC's or PJC's are present with Bradycardia; Treat Bradycardia frist.
Central nervous System depression may occur when dosage exceeds 3mg/kg. Look for: decreased LOC, Irritabilty, Confusion, Muscle-twitching, Seizures, Excessive doses can result in coma and death.
Doasge and Administration
Initial Bolus is 1.0-1.5mg/kg (generally 50-100mg); followd by susequent boluses of 0.5-0.75mg/kg every 5-10 minutes until dysrhythmia is resolved or until 3.0mg/kg is achieved;
Intial dose should be decreases by 50% in pts 70 y/o or older or who have impaired liver function;
Maintenance infusion of 2-4mg/min should be initated, 2 grams of Lidocaine mixed in 500 ml of D5W