Anesthesiology
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Comparative Study
Comparative effects of bupivacaine and ropivacaine on intracellular calcium transients and tension in ferret ventricular muscle.
Recent evidence suggests that ropivacaine exerts markedly less cardiotoxicity compared with bupivacaine; however, the mechanisms are not fully understood at the molecular level. ⋯ The cardiodepressant effect of bupivacaine is approximately twofold greater than that of ropivacaine. Bupivacaine suppresses Ca transients more markedly than does ropivacaine and reduces myofibrillar activation, which may at least in part underlie the greater inhibitory effect of bupivacaine on cardiac contractions. These results suggest that ropivacaine has a more favorable profile as a local anesthetic in the clinical settings.
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Opioid receptors mediate cardiac ischemic preconditioning. Remifentanil is a new, potent ultra-short-acting phenylpiperidine opioid used in high doses for anesthesia. The authors hypothesize that pretreatment with this drug confers cardioprotection. ⋯ Remifentanil mimics cardioprotection via all three opioid receptors. This differs from ischemic preconditioning, which confers cardioprotection via kappa- and Delta-, but not mu-opioid receptors. Part of the protective effect of remifentanil may be produced by mu-agonist activity outside the heart.
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Mortality from sepsis frequently results from multiple organ injury and dysfunction. Cecal ligation and puncture is an established murine model of septic peritonitis that produces septic shock characterized by an initial hyperinflammatory response. In addition to their anesthetic properties, local anesthetics have been shown to attenuate inflammatory responses both in vivo and in vitro. In the current study, the ability of local anesthetic infusions to protect against sepsis-induced mortality, as well as renal and hepatic dysfunction after cecal ligation and puncture, was investigated. ⋯ The current data demonstrate that local anesthetic infusions confer a protective effect in mice from septic peritonitis by attenuating the hyperacute inflammatory response. This suppression resulted in improved mortality and less progression to acute kidney and liver injury and dysfunction.
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Comment Letter
Three arguments regarding a paradigm of general anesthesia.