Local anesthetic systemic toxicity: Difference between revisions
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==Background== | ==Background== | ||
*Life-threatening adverse reaction to local anesthetic toxicity. | *Life-threatening adverse reaction to local anesthetic toxicity. | ||
* | *Causes<ref name="Fencl">Fencl JL. Local anesthetic systemic toxicity: perioperative implications. AORN J. 2015 Jun;101(6):697-700.</ref> | ||
**Injection of local anesthetic into systemic circulation | **Injection of local anesthetic into systemic circulation | ||
**Exceeding the maximum dose of local anesthetic (see table below) | **Exceeding the maximum dose of local anesthetic (see table below) |
Revision as of 07:55, 16 July 2015
Background
- Life-threatening adverse reaction to local anesthetic toxicity.
- Causes[1]
- Injection of local anesthetic into systemic circulation
- Exceeding the maximum dose of local anesthetic (see table below)
- Absorption of anesthetic into systemic circulation by injection into extremely vascular area.
- Incidence = ~0.2% of nerve blocks
- Generally occurs within minutes of injection
Maximum Doses of Anesthetic Agents
Agent | Without Epinephrine | With Epinephrine | Duration | Notes |
Lidocaine | 5 mg/kg (max 300mg) | 7 mg/kg (max 500mg) | 30-90 min |
|
Mepivicaine | 7 mg/kg | 8 mg/kg | ||
Bupivicaine | 2.5 mg/kg (max 175mg) | 3 mg/kg (max 225mg) | 6-8 hr |
|
Ropivacaine | 3 mg/kg | |||
Prilocaine | 6 mg/kg | |||
Tetracaine | 1 mg/kg | 1.5 mg/kg | 3hrs (10hrs with epi) | |
Procaine | 7 mg/kg | 10 mg/kg | 30min (90min with epi) |
Clinical Features
- CNS symptoms (typically occur before CVS symptoms[1])
- Agitation
- Auditory changes
- Metallic taste
- Seizures or drowsiness
- Coma
- Respiratory arrest
- Cardiovascular[1]
- Early signs
- Tachycardia
- Ventricular dysrhythmia
- Hypertension
- Late signs
- Bradycardia
- Conduction block
- Cardiovascular collapse
- Asystole
- Early signs
Differential Diagnosis
- Anaphylaxis
- Anxiety
Diagnosis
- Clinical diagnosis
Workup
- Directed by clinical picture
- Blood levels of anesthetic are available, but not clinically useful.
Management
- Lipid emulsion, 20% solution
- 1.5 mL/kg bolus over 1 minute
- Then, 15 mL/kg per hour x 20-minute infusion (0.25 mL/kg/min for 20 min or until hemodynamic stability)
- Manage seizures with benzodiazepines; propofol is an option but may worsen CV toxicity
- ACLS modifications per ASRA (Am Soc of Regional Anesthesia):
- Small initial doses of 100 μg boluses in adults
- No vasopressin
- Avoid CCBs and BBs
- Amiodarone preferred in ventricular dysrhythmias
See Also
External Links
Medscape:Local Anesthetic Toxicity