Cardiorespiratory and behavioral reactions to the lidocaine-induced convulsions in the dog.
Central nervous system (CNS) reactions to intermittently infused lidocaine HCl (i.v.) were evaluated from cardiorespiratory and behavioral responses in 33 mongrel dogs. Threshold convulsive doses were established for each of three distinct and predictable seizure patterns. The first seizure activity observed was tonic extension (TE) which occurred at an infused lidocaine dose of 12.2+/-0.6 mg/kg followed by running activity after 22.7+/-0.9 mg/kg lidocaine was given. The threshold for intermittent tonic-clonic seizures (ICS) occurred at an infused lidocaine dose of 33.3+/-1.5 mg/kg. Mean blood pressure and pulse pressure increased at the onset of TE and ICS, with a decline in arterial pH and PCO2 during the ICS. No relationship was found between the animals' acid-base status and the ICS threshold. Toxicity to lidocaine in the dog is expressed by distinct behavioral responses suggesting lidocaine may affect various parts of the CNS. The mongrel dog appears to be a satisfactory and simple model system to evaluate lidocaine toxicity from behavioral and cardiorespiratory responses.
Cardiorespiratory and behavioral reactions to the lidocaine-induced convulsions in the dog. Central nervous system (CNS) reactions to intermittently infused lidocaine HCl (i.v.) were evaluated from cardiorespiratory and behavioral responses in 33 mongrel dogs. Threshold convulsive doses were established for each of three distinct and predictable seizure patterns. The first seizure activity observed was tonic extension (TE) which occurred at an infused lidocaine dose of 12.2+/-0.6 mg/kg followed by running activity after 22.7+/-0.9 mg/kg lidocaine was given. The threshold for intermittent tonic-clonic seizures (ICS) occurred at an infused lidocaine dose of 33.3+/-1.5 mg/kg. Mean blood pressure and pulse pressure increased at the onset of TE and ICS, with a decline in arterial pH and PCO2 during the ICS. No relationship was found between the animals' acid-base status and the ICS threshold. Toxicity to lidocaine in the dog is expressed by distinct behavioral responses suggesting lidocaine may affect various parts of the CNS. The mongrel dog appears to be a satisfactory and simple model system to evaluate lidocaine toxicity from behavioral and cardiorespiratory responses.