Toxicité systémique à la mépivacaïne après un bloc axillaire chez un patient insuffisant rénal chronique

Mepivacaine reduces calcium transients in isolated murine ventricular cardiomyocytes

Background

The potential mechanism of mepivacaine’s myocardial depressant effect observed in papillary muscle has not yet been investigated at cellular level. Therefore, we evaluated mepivacaine’s effects on Ca²⁺ transient in isolated adult mouse cardiomyocytes.

Methods

Single ventricular myocytes were enzymatically isolated from wild-type C57Bl/6 mice and loaded with 10 μM fluorescent Ca²⁺ indicator Fluo-4-AM to record intracellular Ca²⁺ transients upon electrical stimulation. The mepivacaine effects at half-maximal inhibitory concentration (IC₅₀) was determined on calibrated cardiomyocytes’ Ca²⁺ transients by non-parametric statistical analyses on biophysical parameters. Combination of mepivacaine with NCX blockers ORM-10103 or NiCl₂ were used to test a possible mechanism to explain mepivacaine-induced Ca²⁺ transients’ reduction.

Results

A significant inhibition at mepivacaine’s IC₅₀ (50 μM) on Ca²⁺ transients was measured in biophysical parameters such as peak (control: 528.6 ± 73.61 nM vs mepivacaine: 130.9 ± 15.63 nM; p < 0.05), peak area (control: 401.7 ± 63.09 nM*s vs mepivacaine: 72.14 ± 10.46 nM*s; p < 0.05), slope (control: 7699 ± 1110 nM/s vs mepivacaine: 1686 ± 226.6 nM/s; p < 0.05), time to peak (control: 107.9 ± 8.967 ms vs mepivacaine: 83.61 ± 7.650 ms; p < 0.05) and D₅₀ (control: 457.1 ± 47.16 ms vs mepivacaine: 284.5 ± 22.71 ms; p < 0.05). Combination of mepivacaine with NCX blockers ORM-10103 or NiCl₂ showed a significant increase in the baseline of [Ca²⁺] and arrhythmic activity upon electrical stimulation.

Conclusion

At cellular level, mepivacaine blocks Na⁺ channels, enhancing the reverse mode activity of NCX, leading to a significant reduction of Ca²⁺ transients. These results suggest a new mechanism for the mepivacaine-reduction contractility effect.

Evaluation of the plasmatic level of mepivacaine in different anatomical regions

Background

To evaluate the serum level of the local anesthetic mepivacaine 3% without vasoconstrictor in patients who underwent procedures performed in the anterior and posterior maxilla, through a method of possible extraction to quantify it in human plasma by high performance liquid chromatography (HPLC).

Material and Methods

This was a hybrid study consisting of 18 patients (7 females and 11 males) classified as ASA I, adults and with normal body mass index, submitted to procedures in the anterior region (group I) and posterior region of the maxilla (group II). For 40 minutes, five 6 ml blood samples were collected every 10 minutes after infiltrative injection in each region of the maxilla. Serum levels of the drug were obtained through HPLC. Blood pressure (BP) and heart rate (HR) were measured throughout the procedure.

Results

When compared to the general average of the concentrations of each group, significant values (p<0.05) with greater absorption were observed for the anterior region of the maxilla (group I). There was no significant difference when comparing blood pressure (BP) and heart rate (HR) values.

Conclusions

The concentrations found are safe for infiltrative anesthesia in the analyzed patients, there was a higher plasma level of the local anesthetic in the anterior region of the maxilla and there was no change in HR and BP in relation to the anesthetized area.

Key words:Local anesthetic. toxicity. mepivacaine. chromatography. chromatography, high pressure liquid.

Linoleic Acid Attenuates the Toxic Dose of Bupivacaine-Mediated Reduction of Vasodilation Evoked by the Activation of Adenosine Triphosphate-Sensitive Potassium Channels

The goal of this study was to investigate the effect of lipid emulsion on a toxic dose of local anesthetic-mediated reduction of vasodilation evoked by the ATP-sensitive potassium (K_ATP) channel agonist levcromakalim. The effect of lipid emulsion (LE) and linoleic acid on the local anesthetic-mediated reduction of vasodilation and membrane hyperpolarization evoked by levcromakalim was assessed in isolated endothelium-denuded vessels (rat aorta and mesenteric artery) and aortic vascular smooth muscle cells. The effect of LE and linoleic acid on K_ATP channel activity in transfected HEK-293 cells was investigated, as was the effect of LE on bupivacaine concentration. The efficacy of LE in attenuating the local anesthetic-mediated reduction of vasodilation evoked by levcromakalim was correlated with the lipid solubility of the local anesthetic. Linoleic acid attenuated the bupivacaine-mediated reduction of vasodilation evoked by levcromakalim. LE decreased the bupivacaine-mediated reduction of membrane hyperpolarization evoked by levcromakalim but did not significantly alter the mepivacaine-mediated reduction. LE and linoleic acid both reversed the bupivacaine-mediated decrease of K_ATP activity and enhanced K_ATP activity. LE decreased the bupivacaine concentration. Linoleic acid may be the major contributor to LE-induced attenuation of bupivacaine-mediated reduction of vasodilation evoked by levcromakalim via the direct activation of K_ATP channels and indirect effects.

Lipid emulsions enhance the norepinephrine-mediated reversal of local anesthetic-induced vasodilation at toxic doses

PURPOSE

Intravenous lipid emulsions have been used to treat the systemic toxicity of local anesthetics. The goal of this in vitro study was to examine the effects of lipid emulsions on the norepinephrine-mediated reversal of vasodilation induced by high doses of levobupivacaine, ropivacaine, and mepivacaine in isolated endothelium-denuded rat aorta, and to determine whether such effects are associated with the lipid solubility of local anesthetics.

MATERIALS AND METHODS

The effects of lipid emulsions (0.30, 0.49, 1.40, and 2.61%) on norepinephrine concentration-responses in high-dose local anesthetic (6×10(-4) M levobupivacaine, 2×10(-3) M ropivacaine, and 7×10(-3) M mepivacaine)-induced vasodilation of isolated aorta precontracted with 60 mM KCl were assessed. The effects of lipid emulsions on local anesthetic- and diltiazem-induced vasodilation in isolated aorta precontracted with phenylephrine were also assessed.

RESULTS

Lipid emulsions (0.30%) enhanced norepinephrine-induced contraction in levobupivacaine-induced vasodilation, whereas 1.40 and 2.61% lipid emulsions enhanced norepinephrine-induced contraction in both ropivacaine- and mepivacaine-induced vasodilation, respectively. Lipid emulsions (0.20, 0.49 and 1.40%) inhibited vasodilation induced by levobupivacaine and ropivacaine, whereas 1.40 and 2.61% lipid emulsions slightly attenuated mepivacaine (3×10(-3) M)-induced vasodilation. In addition, lipid emulsions attenuated diltiazem-induced vasodilation. Lipid emulsions enhanced norepinephrine-induced contraction in endothelium-denuded aorta without pretreatment with local anesthetics.

CONCLUSION

Taken together, these results suggest that lipid emulsions enhance the norepinephrine-mediated reversal of local anesthetic-induced vasodilation at toxic anesthetic doses and inhibit local anesthetic-induced vasodilation in a manner correlated with the lipid solubility of a particular local anesthetic.

ECMO for Cardiac Rescue after Accidental Intravenous Mepivacaine Application

Mepivacaine is a potent local anaesthetic and used for infiltration and regional anaesthesia in adults and pediatric patients. Intoxications with mepivacaine affect mainly the CNS and the cardiovascular system. We present a case of accidental intravenous mepivacaine application and intoxication of an infant resulting in seizure, broad complex bradyarrhythmia, arterial hypotension and finally cardiac arrest. The patient could be rescued by prolonged resuscitations and a rapid initiation of ECMO and survived without neurological damage. The management strategies of this rare complication including promising other treatment options with lipid emulsions are discussed.

[Cardiac arrest after axillary plexic anaesthesia with ropivacaine in a chronic kidney failure dialysis patient]

The local anaesthetics are responsible for an important part of morbidity and mortality during conduction anaesthesia. We describe fatal accident plexic anaesthesia with ropivacaine in spite of a classical reanimation measure in a dialysis patient.

Reversal of central nervous system and cardiac toxicity after local anesthetic intoxication by lipid emulsion injection

A 91-yr-old man (57 kg, 156 cm, ASA III) received an infraclavicular brachial plexus block for surgery of bursitis of the olecranon. Twenty minutes after infraclavicular injection of 30 mL of mepivacaine 1% (Scandicain) and 5 min after supplementation of 10 mL of prilocaine 1% (Xylonest) using an axillary approach, the patient complained of agitation and dizziness and became unresponsive to verbal commands. In addition, supraventricular extrasystole with bigeminy occurred. Local anesthetic toxicity was suspected and a dose of 200 mL of a 20% lipid emulsion was infused. Symptoms of central nervous system and cardiac toxicity disappeared within 5 and 15 min after the first lipid injection, respectively. Plasma concentrations of local anesthetics were determined before, 20, and 40 min after lipid infusion and were 4.08, 2.30, and 1.73 microg/mL for mepivacaine and 0.92, 0.35, and 0.24 microg/mL for prilocaine. These concentrations are below previously reported thresholds of toxicity above 5 microg/mL for both local anesthetics. Signs of toxicity resolved and the patient underwent the scheduled surgical procedure uneventfully under brachial plexus blockade.