Successful intralipid-emulsion treatment of local anesthetic systemic toxicity following ultrasound-guided brachial plexus block: case report

Cardio Protective Effects of Lipid Emulsion against Ropivacaine-Induced Local Anesthetic Systemic Toxicity—An Experimental Study

Inadvertent intravascular injection of local anesthetics (LA) during regional anesthesia causes Local Anesthetic Systemic Toxicity (LAST). Theories of lipid rescue in the case of LAST proved that the administration of lipids in LAST has beneficial effects. One possible mechanism of action is based on the lipophilic properties of LA which allow plasma-free LA to be bound by the molecules of Lipid Emulsion (LE). The association LA–LE is shuttled towards organs such as liver and the kidneys, and the half-life of LA is shortened. The main objective of this experimental study was to assess the possible cardio-prophylactic effect of LE administration before the induction of LAST by intravenous administration of Ropivacaine. This was an experimental, interventional, prospective, and non-randomized study. The subjects were divided into groups and received, under general anesthesia, LE 20% first 0.3–0.4 mL, followed by 0.1 mL Ropivacaine 2 mg/mL, or Ropivacaine alone. At the end of the experiment, the subjects were sacrificed, and tissue samples of kidney, heart and liver were harvested for histopathological examination. LE, when administered as prophylaxis in Ropivacaine-induced LAST, had protective cardiac effects in rats. The LE known side effects were not produced if the substance was administered in the low doses used for LAST prophylaxis.

Intravenous Lipid Emulsion for the Treatment of Perioperative Cocaine Intoxication

Symptomatic cocaine intoxication in the preoperative period is a potentially life-threatening condition, especially before emergent surgery. The anesthesiologist is faced with a dilemma where the patient is deemed unsafe for induction of general anesthesia but also in need of immediate surgical intervention. Cocaine is a local anesthetic and, as such, has been proposed to respond to lipid emulsion treatment as other local anesthetics would. We present a case supporting this statement and review the relevant published literature on the topic.

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.

Dexmedetomidine may decrease the bupivacaine toxicity to heart

Objective

The purpose of our study was to explore the effect of dexmedetomidine on cardiac tolerance to bupivacaine.

Method

Human coronary endothelial cells were used to establish in vitro model. They were randomly divided into control (Con) group, dexmedetomidine (Dex) group, bupivacaine (Bupi) group, dexmedetomidine + bupivacaine group (DB group), and dexmedetomidine + bupivacaine + PI3K inhibitor (DB-inhibitor) group. Cell activity was measured by Cell counting kit-8 (CCK-8). Transwell was used to detect cell permeability. Western blotting was used to detect the protein expression of related factors.

Results

There were no notable differences in cell activity among the five groups (P > 0.05). Dexmedetomidine significantly reduced the permeability of endothelial cells to bupivacaine and increased the protein expression of Zonulaoeeludens-1 (ZO-1) (P < 0.01). However, the aforementioned effects of dexmedetomidine were disappeared after the addition of PI3K inhibitors. Furthermore, Dex and DB markedly increased the protein expression of PI3K, p-Akt, and p-PTEN in comparison with Con group (P < 0.001), but there was no significant difference in p-PTEN among DB-inhibitor, Con, and Bupi groups (P > 0.05).

Conclusion

Dex reduced Bupi-induced vasopermeability through protein expression of ZO-1 and PI3K/Akt pathway, which may lead to the decrease of Bupi-induced cardiotoxicity.

Updates in our understanding of local anaesthetic systemic toxicity: a narrative review

Despite advances in clinical practice, local anaesthetic systemic toxicity continues to occur with the therapeutic use of local anaesthesia. Patterns of presentation have evolved over recent years due in part to the increasing use of ultrasound which has been demonstrated to reduce risk. Onset of toxicity is increasingly delayed, a greater proportion of clinical reports are secondary to fascial plane blocks, and cases are increasing where non-anaesthetist providers are involved. The evolving clinical context presents a challenge for diagnosis and requires education of all physicians, nurses and allied health professionals about these changing patterns and risks. This review discusses: mechanisms; prevention; diagnosis; and treatment of local anaesthetic systemic toxicity. The local anaesthetic and dose used, site of injection and block conduct and technique are all important determinants of local anaesthetic systemic toxicity, as are various patient factors. Risk mitigation is discussed including the care of at-risk groups, such as: those at the extremes of age; patients with cardiac, hepatic and specific metabolic diseases; and those who are pregnant. Advances in the changing clinical landscape with novel applications and settings for the use of local anaesthesia are also described. Finally, we signpost future directions to potentially improve the management of local anaesthetic systemic toxicity. The utility of local anaesthetics remains unquestionable in clinical practice, and thus maximising the safe and appropriate use of these drugs should translate to improvements in patient care.