Bupivacaine Toxicity Increases Transmural Dispersion of Repolarization, Developing of a Brugada-like Pattern and Ventricular Arrhythmias, Which is Reversed by Lipid Emulsion Administration. Study in an Experimental Porcine Model

Intrathecal Anesthesia Prevents Ventricular Arrhythmias in Rats with Myocardial Ischemia/Reperfusion

INTRODUCTION

Ventricular arrhythmia is commonly provoked by acute cardiac ischemia through sympathetic exaggeration and is often resistant to anti-arrhythmic therapies. Thoracic epidural anesthesia has been reported to terminate fatal ventricular arrhythmia; however, its underlying mechanism is unknown.

METHODS

Rats were randomly divided into four groups: sham, sham plus bupivacaine, ischemia/reperfusion (IR), and IR plus bupivacaine groups. Bupivacaine (1 mg/mL, 0.05 mL/100 g body weight) was injected intrathecally into the L5-L6 intervertebral space prior to establishing a myocardial IR rat model. Thereafter, cardiac arrhythmia, cardiac function, myocardial injury, and electrical activities of the heart and spinal cord were evaluated.

RESULTS

Intrathecal bupivacaine inhibited spinal neural activity, improved heart rate variability, reduced ventricular arrhythmia score, and ameliorated cardiac dysfunction in IR rats. Furthermore, intrathecal bupivacaine attenuated cardiac injury and myocardial apoptosis and regulated cardiomyocyte autophagy and connexin-43 distribution during myocardial IR.

CONCLUSION

Our results indicate that intrathecal bupivacaine blunts spinal neural activity to prevent cardiac arrhythmia and dysfunction induced by IR and that this anti-arrhythmic activity may be associated with regulation of autonomic balance, myocardial apoptosis and autophagy, and cardiac gap junction function.

Effect of lipid emulsion on neuropsychiatric drug-induced toxicity: A narrative review

Lipid emulsion has been shown to effectively relieve refractory cardiovascular collapse resulting from toxic levels of nonlocal anesthetics. The goal of this study was to examine the effect of lipid emulsions on neuropsychiatric drug-induced toxicity using relevant case reports of human patients, with a particular focus on the Glasgow Coma Scale (GCS) score and corrected QT interval, to analyze drugs that frequently require lipid emulsion treatment. The following keywords were used to retrieve relevant case reports from PubMed: "antidepressant or antipsychotic drug or amitriptyline or bupropion or citalopram or desipramine or dosulepin or dothiepin or doxepin or escitalopram or fluoxetine or haloperidol or olanzapine or phenothiazine or quetiapine or risperidone or trazodone" and "lipid emulsion or Intralipid." Lipid emulsion treatment reversed the corrected QT interval prolongation and decreases in Glasgow Coma Scale scores caused by toxic doses of neuropsychiatric drugs, especially lipid-soluble drugs such as amitriptyline, trazodone, quetiapine, lamotrigine, and citalopram. The log P (octanol/water partition coefficient) of the group which required more than 3 lipid emulsion treatments was higher than that that of the group which required less than 3 lipid emulsion treatments. The main rationale to administer lipid emulsion as an adjuvant was as follows: hemodynamic depression intractable to supportive treatment (88.3%) > lipophilic drugs (8.3%) > suspected overdose or no spontaneous breathing (1.6%). Adjuvant lipid emulsion treatment contributed to the recovery of 98.30% of patients with neuropsychiatric drug-induced toxicity. However, further analyses using many case reports are needed to clarify the effects of lipid emulsion resuscitation.

Biomedical Nanosystems for In Vivo Detoxification: From Passive Delivery Systems to Functional Nanodevices and Nanorobots

The problem of low efficiency of nanotherapeutic drugs challenges the creation of new alternative biomedical nanosystems known as robotic nanodevices. In addition to encapsulating properties, nanodevices can perform different biomedical functions, such as precision surgery, in vivo detection and imaging, biosensing, targeted delivery, and, more recently, detoxification of endogenous and xenobiotic compounds. Nanodevices for detoxification are aimed at removing toxic molecules from biological tissues, using a chemical- and/or enzyme-containing nanocarrier for the toxicant to diffuse inside the nanobody. This strategy is opposite to drug delivery systems that focus on encapsulating drugs and releasing them under the influence of external factors. The review describes various kinds of nanodevices intended for detoxification that differ by the type of poisoning treatment they provide, as well as the type of materials and toxicants. The final part of the review is devoted to enzyme nanosystems, an emerging area of research that provides fast and effective neutralization of toxins in vivo.

Mechanisms and Efficacy of Intravenous Lipid Emulsion Treatment for Systemic Toxicity From Local Anesthetics

Local anesthetics are widely used clinically for perioperative analgesia to achieve comfort in medical treatment. However, when the concentration of local anesthetics in the blood exceeds the tolerance of the body, local anesthetic systemic toxicity (LAST) will occur. With the development and popularization of positioning technology under direct ultrasound, the risks and cases of LAST associated with direct entry of the anesthetic into the blood vessel have been reduced. Clinical occurrence of LAST usually presents as a series of severe toxic reactions such as myocardial depression, which is life-threatening. In addition to basic life support (airway management, advanced cardiac life support, etc.), intravenous lipid emulsion (ILE) has been introduced as a treatment option in recent years and has gradually become the first-line treatment for LAST. This review introduces the mechanisms of LAST and identifies the clinical symptoms displayed by the central nervous system and cardiovascular system. The paper features the multimodal mechanism of LAST reversal by ILE, describes research progress in the field, and identifies other anesthetics involved in the resuscitation process of LAST. Finally, the review presents key issues in lipid therapy. Although ILE has achieved notable success in the treatment of LAST, adverse reactions and contraindications also exist; therefore, ILE requires a high degree of attention during use. More in-depth research on the treatment mechanism of ILE, the resuscitation dosage and method of ILE, and the combined use with other resuscitation measures is needed to improve the efficacy and safety of clinical resuscitation after LAST in the future.