Treatment of Acute Systemic Toxicity After the Rapid Intravenous Injection of Ropivacaine and Bupivacaine in the Conscious Dog

Abstract

Two groups of six beagle dogs received rapid intravenous (IV) injections of ropivacaine or bupivacaine on two occasions in a blinded random fashion. Initially, a dose sufficient to cause convulsions (CD) was given followed by twice the CD (2 x CD), which was administered 48 h later. The CD of bupivacaine (4.3 mg/kg) and ropivacaine (4.9 mg/kg) caused significant (P less than 0.05) increases in heart rate and mean arterial blood pressure. There was no difference between drug groups. Seizures were abolished by 10 mg/kg of intravenous thiamylal. Endotracheal intubation and controlled respiration with O2-enriched air with no other treatment resulted in rapid and complete recovery in all dogs. All dogs receiving 2 x CD of bupivacaine (8.6 mg/kg) or ropivacaine (9.8 mg/kg) were initially treated with thiamylal and mechanical ventilation. Two dogs in the bupivacaine group developed hypotension, respiratory arrest, ventricular tachycardia, and ventricular fibrillation, which were resistant to closed chest cardiac massage, treatment with epinephrine, bretylium, and atropine, and direct current cardioversion. The four remaining dogs in the infusion group were successfully resuscitated. All of the animals in the ropivacaine-treated group survived the administration of the 2 x CD dose. Mild hypotension developed in one dog and was treated with intravenous epinephrine (0.75 mg). This resulted in nodal tachycardia, which was abolished after treatment with bretylium. Another dog had two 1-s bursts of premature ventricular contractions requiring no treatment. The rapid treatment of convulsions and cardiovascular toxicity resulted in a decreased number of deaths in both groups when compared with dogs from a previously published study in which no therapy was instituted. Thus, early aggressive treatment of central nervous system and cardiovascular system toxicity is capable of reducing the incidence of mortality associated with the rapid intravenous administration of excessive doses of local anesthetics.

Relative Nerve Blocking Properties of Bupivacaine and Ropivacaine in Dogs Undergoing Brachial Plexus Block Using a Nerve Stimulator

“…The dosage of ropivacaine in the 0.75% RopiS group was 3 mg/kg in the present study. Feldman et al [6] reported that the intravenous dose required to induce twitching is 4.9 mg/kg for ropivacaine and 4.3 mg/kg for bupivacaine. They also observed increases in respiratory and heart rates with central nervous system toxicity after intravenous administration of bupivacaine and ropivacaine in conscious dogs.…”

Insulin/glucose infusion successfully resuscitates bupivacaine-induced sudden-onset circulatory collapse in dogs

“…2,3 Insulin can reverse bupivacaine-induced cardiac toxicity in animal experiments, presumably via metabolic, inotropic, and electrophysiologic mechanisms. 4,5 In the previous insulin studies, bupivacaine was infused at a rate of 0.5 mgÁkg…”

A Prospective, Randomised, Double-Blind Comparative Clinical Study of 0.5% Bupivacaine and 0.75% Ropivacaine for Sciatic Nerve Block in Patients Undergoing Elective Below Knee Surgeries

“…Resuscitation after ropivacaine toxicity is more successful than bupivacaine. 7,8,9 Hence, we selected to compare these two drugs in our study.…”

“…5,6 Resuscitation after Ropivacaine toxicity is found to be more successful than Bupivacaine. 7,8,9 The improved safety profile of Ropivacaine may allow the use of higher concentrations to try and hasten the speed of onset. Ropivacaine is found to be half as potent as Bupivacaine, the potency ratio being 1.5:1 between Ropivacaine and Bupivacaine respectively.…”