Comparative systemic toxicity and a mechanism for lethality of intravenously infused cocaine, lidocaine and bupivacaine in spontaneously and mechanically breathing unconscious pigs

FRANÇAIS :
Les animaux anesthésiés au thiopental respirent soit naturellement (groupes 1, 2, 3) soit à l'aide d'un respirateur (groupes 4, 5, 6). Les paramètres cardiaques et respiratoires sont mesurés après injection de cocaïne (groupes 1 et 4), lidocaïne (groupes 3 et 6) ou bupivacaïne (groupes 2 et 5). L'arrêt respiratoire est la première cause de mort chez les animaux respirant spontannément. Ou relève une diminution de la vitesse du coeur et de la pression centrale et une augmentation de la résistance vasculaire pulmonaire, de la pression périphérique veineuse et du niveau de potassium sanguin chez les animaux ventilés artificiellement. Les trois anesthésiques locaux entrainent les mêmes effets.
ENGLISH :
Pigs were given sodium thiopental and ventilated with 70% nitrous oxide in 30% oxygen. Pigs in groups 1, 2, and 3 pigs were allowed to breathe spontaneously and groups 4, 5, and 6 were mechanically ventilated. The animals in groups 1 and 4 were infused iv with C (0.8 mg/kg/min), groups 2 and 5 were infused with B (0.8 mg/kg/min), and groups 3 and 6 were infused with L (3.2 mg/kg/min). Our results showed that RA is the primary cause of death in spontaneously breathing pigs and that mechanical ventilation significantly delayed the occurrence of CA (p<0.05). Significant decreases in cardiac output, mean blood pressure, and heart rate and significant increases in systemic and pulmonary vascular resistances, central venous and pulmonary wedge pressures, and blood K+ levels were noticed in mechanically ventilated pigs (p<0.05). Our experiments demonstrated that all three local anesthetic drugs produced similar systemic effects with continuous iv administration of lethal doses.