Sodium bicarbonate reverts electrophysiologic cardiotoxicity of ropivacaine faster than lipid emulsions in a porcine model

Ropivacaine has been described as a safer local anaesthetic (LA); however, serious cardiotoxic accidents have been reported. Intravenous-lipid-emulsion (ILE) therapy during LA intoxication seems to act as an antidote. Sodium bicarbonate is the standard treatment for sodium channel blocker drug toxicity. We compared both antidotes on the reversion of electrophysiologic toxicity induced by ropivacaine. Ropivacaine 5 mg kg^-1 was administered in 24 pigs, and 3 min later, the animals received ILE: 1.5 ml kg^-1 + 0.25 ml kg^-1 min^-1 (ILE group); sodium bicarbonate: 2 mEq kg^-1 + 1 mEq kg^-1 h^-1 (NaHCO₃ group); saline solution (CTL group). Electrophysiological parameters were evaluated for 30 min. The area under the curve (AUC) for the first 5 or 30 min was compared between groups. Ropivacaine induced a lengthening of the PR interval by 17% (P = 0.0001), His-ventricle-interval by 58% (P = 0.001), sinus QRS complex by 56% (P = 0.0001), paced QRS at 150 bpm by 257% (P = 0.0001), and at 120 bpm by 143% (P = 0.0001) in all groups. At 5 min after treatment, sinus QRS in the NaHCO₃ group was shorter than that in the CTL group (AUC_QRS5 , P = 0.003) or ILE group (AUC_QRS5 , P = 0.045). During the first minute, seven of the animals in the NaHCO₃ group vs. two in the ILE or 0 in the CTL group recovered more than 30% of the sinus QRS previously lengthened by ropivacaine (P = 0.003). Sodium bicarbonate reversed the electrophysiological toxicity of ropivacaine faster than ILE and control groups.