Severe, systemic local anesthetic toxicity is arguably the most feared complication of regional anesthesia. A combination of old and new therapies is recommended to reduce the morbidity and mortality ...of symptomatic local anesthetic overdose. Prevention remains the criterion standard for improving patient safety during regional anesthesia. However, when local anesthetic toxicity occurs, considering the diagnosis is the doctor's first step to successful treatment. Preparing a plan of action ahead of time and having the necessary tools readily at hand will likewise contribute to saving the patient's life. Airway management, oxygenation, ventilation, and good basic life support are the sine qua non of successful resuscitation. Seizure suppression is key, and we recommend communicating with a perfusion team for possible cardiopulmonary bypass. Lipid infusion should be considered early, and the treating physician should be familiar with the method. We also recommend avoiding vasopressin and using epinephrine only in small doses. Vigilance, preparedness, and quick action will improve outcomes of this dreaded complication.
BACKGROUND:The objective of this narrative review of local anesthetic systemic toxicity is to provide an update on its prevention, diagnosis, and management.
METHODS:The authors used a MEDLINE search ...of human studies, animal studies, and case reports and summarize findings following the American Society of Regional Anesthesia and Pain Medicine practice advisories on local anesthetic systemic toxicity.
RESULTS:Between March of 2014 and November of 2016, there were 47 cases of systemic toxicity described. Twenty-two patients (47 percent) were treated with intravenous lipid emulsion and two patients (4.3 percent) died. Seizures were the most common presentation. The spectrum of presenting neurologic and cardiovascular symptoms and signs are broad and can be obscured by perioperative processes. Local anesthetic type, dosage, and volume; site of injection; and patient comorbidities influence the rate of absorption from the site of injection and biodegradation of local anesthetics. Consider discussing appropriate dosages as a component of the surgical “time-out.” A large-volume depot of dilute local anesthetic can take hours before reaching peak plasma levels. Oxygenation, ventilation, and advanced cardiac life support are the first priorities in treatment. Lipid emulsion therapy should be given at the first sign of serious systemic toxicity with an initial bolus dose of 100 ml for adults weighing greater than 70 kg and 1.5 ml/kg for adults weighing less than 70 kg or for children.
CONCLUSION:All physicians who administer local anesthetics should be educated regarding the nature of systemic toxicity and contemporary management algorithms that include lipid emulsion therapy.
The objective of this narrative review of local anesthetic systemic toxicity is to provide an update on its prevention, diagnosis, and management.
The authors used a MEDLINE search of human studies, ...animal studies, and case reports and summarize findings following the American Society of Regional Anesthesia and Pain Medicine practice advisories on local anesthetic systemic toxicity.
Between March of 2014 and November of 2016, there were 47 cases of systemic toxicity described. Twenty-two patients (47 percent) were treated with intravenous lipid emulsion and two patients (4.3 percent) died. Seizures were the most common presentation. The spectrum of presenting neurologic and cardiovascular symptoms and signs are broad and can be obscured by perioperative processes. Local anesthetic type, dosage, and volume; site of injection; and patient comorbidities influence the rate of absorption from the site of injection and biodegradation of local anesthetics. Consider discussing appropriate dosages as a component of the surgical "time-out." A large-volume depot of dilute local anesthetic can take hours before reaching peak plasma levels. Oxygenation, ventilation, and advanced cardiac life support are the first priorities in treatment. Lipid emulsion therapy should be given at the first sign of serious systemic toxicity with an initial bolus dose of 100 ml for adults weighing greater than 70 kg and 1.5 ml/kg for adults weighing less than 70 kg or for children.
All physicians who administer local anesthetics should be educated regarding the nature of systemic toxicity and contemporary management algorithms that include lipid emulsion therapy.
The American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Local Anesthetic Systemic Toxicity assimilates and summarizes current knowledge regarding the prevention, diagnosis, ...and treatment of this potentially fatal complication. It offers evidence-based and/or expert opinion-based recommendations for all physicians and advanced practitioners who routinely administer local anesthetics in potentially toxic doses. The advisory does not address issues related to local anesthetic-related neurotoxicity, allergy, or methemoglobinemia. Recommendations are based primarily on animal and human experimental trials, case series, and case reports. When objective evidence is lacking or incomplete, recommendations are supplemented by expert opinion from the Practice Advisory Panel plus input from other experts, medical specialty groups, and open forum. Specific recommendations are offered for the prevention, diagnosis, and treatment of local anesthetic systemic toxicity.
Lipid emulsion infusion reverses cardiovascular compromise due to local anesthetic overdose in laboratory and clinical settings. The authors compared resuscitation with lipid, epinephrine, and saline ...control in a rat model of bupivacaine-induced cardiac toxicity to determine whether lipid provides a benefit over epinephrine.
Bupivacaine, 20 mg/kg, was infused in rats anesthetized with isoflurane, producing asystole in all subjects. Ventilation with 100% oxygen and chest compressions were begun immediately, along with intravenous treatment with 30% lipid emulsion or saline (5-ml/kg bolus plus continuous infusion at 0.5 ml . kg . min) or epinephrine (30 microg/kg). Chest compressions were continued and boluses were repeated at 2.5 and 5 min until the native rate-pressure product was greater than 20% baseline. Electrocardiogram and arterial pressure were monitored continuously and at 10 min, arterial blood gas, central venous oxygen saturation, and blood lactate were measured. Effect size (Cohen d) was determined for comparisons at 10 min.
Lipid infusion resulted in higher rate-pressure product (P < 0.001, d = 3.84), pH (P < 0.01, d = 3.78), arterial oxygen tension (P < 0.05, d = 2.8), and central venous oxygen saturation (P < 0.001, d = 4.9) at 10 min than did epinephrine. Epinephrine treatment caused higher lactate (P < 0.01, d = 1.48), persistent ventricular ectopy in all subjects, pulmonary edema in four of five rats, hypoxemia, and a mixed metabolic and respiratory acidosis by 10 min.
Hemodynamic and metabolic metrics during resuscitation with lipid surpassed those with epinephrine, which were no better than those seen in the saline control group. Further studies are required to optimize the clinical management of systemic local anesthetic toxicity.
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