Local anesthetic systemic toxicity: Continuing Professional Development

Abstract

Purpose Regional anesthesia is enjoying a renaissance due in part to the advent of ultrasound guidance and the development of new techniques such as tissue plane blocks and local infiltration analgesia. The purpose of this Continuing Professional Development module is to provide practitioners with an understanding of the current state of knowledge surrounding local anesthetic systemic toxicity (LAST) in order to help them prevent and manage this complication more effectively. Principal findings The causes of LAST are multifactorial, but recognized risks include patient factors, drug doses, pharmacokinetics, and choice of regional anesthetic technique. Local anesthetic systemic toxicity produces a biphasic course of clinical events that generally begin with central nervous system excitation followed by inhibition. At the same time, it causes cardiovascular compromise due to dysrhythmias, myocardial depression, and reduced systemic vascular resistance. Clinical presentation can be highly variable, however, and atypical presentations are not uncommon. Local anesthetic systemic toxicity is prevented by careful choice and dosing of drugs, aspiration before injection, dose fractionation, use of intravascular markers and ultrasound guidance. The management of LAST includes adequate oxygenation and ventilation, seizure termination, maintenance of circulation, and intravenous lipid emulsion therapy.Conclusions Local anesthetic systemic toxicity is a potentially lethal condition with protean manifestations, and anesthesiologists must understand its risks, prevention, and safe management.

Surgical wound infiltration by local anesthetic: Wound infiltration

“…Toksičnost lokalnih anestetika može da se ispolji kao sistemska toksičnost (zbog resorpcije anestetika sa mesta primene) i direktna neurotok-sičnost (zbog njihovog lokalnog efekta kada se primene visoke koncentracije u blizini velikih nerava ili kičmene moždine) 2 . Sistemska toksičnost lokalnih anestetika (LAST) predstavlja životno ugrožavajuću komplikaciju 5 . Lokalni anestetici ometaju funkciju svih organa u koje se prenose impulsi, blokiranjem sprovođenja impulsa kroz aksone u perifernom nervnom sistemu 3 .…”

“…Povećanjem koncentracije lokalnih anestetika ispoljava se njihov efekat i na centralni nervni sistem, blokadom kortikalnih inhibitornih puteva. Kao posledica ove blokade javljaju se simptomi i znaci ekscitacije centralnog nervnog sistema, kao što su senzorni i vizuelni poremećaji, mišićni trzaji i konvulzije 5 . Sa daljim povećanjem njihove koncentracije u plazmi, dolazi do blokade ekscitatornih neurona, pa je druga faza CNS toksičnosti depresija CNS-a, praćena poremećajem svesti, komom i depresijom disanja 5 .…”

“…Kod pacijenata sa prekomernom težinom, doziranje je zasnovano na mišićnoj masi pacijenta, a ne na njegovoj apsolutnoj težini. Ukoliko se koriste kombinacije dva lokalna anestetika, rizik za nastanak LAST-a treba da se proceni kao aditivan, pa u skladu sa tim treba da se redukuju doze svakog od anestetika 5 .…”

CaMK II γ down regulation protects dorsal root ganglion neurons from ropivacaine hydrochloride neurotoxicity

“…However, high concentrations or long exposure times of local anesthetics to neurons also results in neuronal damage 5, 6 . Ropivacaine hydrochloride is commonly used in peripheral nerve block or spinal analgesia with a long exposure time, but it also causes nerve damage and abnormal sensations similar to other local anesthetics 7, 8 .…”

Local Anesthetic Lidocaine for Gastroscopy Induces Diffuse Alveolar Hemorrhage

“…[23] According to literature, lidocaine at a 5 μg/ml plasma concentration induces the toxicity of lidocaine reaction, which manifests as lethargy. [4] Lidocaine has a high safety range and clinical applications; we should pay attention to its rare toxicity. Gastroscopy is commonly used in our clinical practice.…”