Lidocaine levels during CPR: differences after peripheral venous, central venous, and intracardiac injections.

Drug administration via peripheral vein, central vein, and intracardiac routes is generally assumed to be equally effective during cardiopulmonary resuscitation (CPR). Experiments were performed in an animal model to evaluate this assumption. Twelve mongrel dogs weighing greater than 20 kg were studied. Arterial blood pressure and electrocardiogram were monitored continuously. Cardiac outputs were evaluated before CPR to determine control. After thoracotomy and fibrillation of the heart, cardiac massage was started and the rate of compression adjusted to give 30% of control cardiac output. A lidocaine bolus of 1.5 mg/kg was given via peripheral vein in four dogs, central vein in four dogs, and intracardiac (left ventricle) in four dogs. Drug levels were sampled through an aortic catheter at the level of the coronary artery ostia every 20 sec for five min, every 30 sec for 10 min, and every 60 sec for 15 min. There was no significant difference in the appearance of effective levels or time of peak levels in the three groups. The peak levels were highest in the central venous group, while peripheral venous and intracardiac peak levels were 63% and 31%, respectively, of the central venous peak. Duration of effective levels was 20 min in the intracardiac group, 14.5 min in the central venous group, and 9.6 min in the peripheral venous group. Further studies are needed to determine whether changes are needed in drug administration during CPR in man.