Podcast 818: Local Anesthetics and LAST

<p><strong>Contributor: Don Stader, MD</strong></p> <p><strong>Educational Pearls:</strong></p> <ul> <li style="font-weight: 400;" aria-level="1"><span style= "font-weight: 400;">There are two major groups of local anesthetics: Amide and Esther </span></li> <ul> <li style="font-weight: 400;" aria-level="2"><span style= "font-weight: 400;">To recall what group an anesthetic belongs to, use this memory trick:  </span></li> </ul> </ul> <p><span style="font-weight: 400;">Amide has an ‘i’ in the name and Amide anesthetics have 2 ‘i’s e.g., Lidocaine.</span> <span style= "font-weight: 400;"><br /></span><span style= "font-weight: 400;">Ester has no ‘i’ and most common Ester anesthetics have only one ‘i’ e.g., Tetracaine.  </span></p> <ul> <li style="font-weight: 400;" aria-level="1"><span style= "font-weight: 400;">In a true allergy and/or contraindication to both local anesthetic groups, diphenhydramine is an acceptable alternative. </span></li> <li style="font-weight: 400;" aria-level="1"><span style= "font-weight: 400;">Epinephrine is administered with local anesthetics to decrease bleeding, increase duration of action, and minimize systemic spread of the anesthetic, thus reducing toxicity. </span></li> <li style="font-weight: 400;" aria-level="1"><span style= "font-weight: 400;">Symptoms of Local Anesthetic Systemic Toxicity (LAST) may begin with dizziness, confusion and/or slurred speech, and can progress to cardiovascular collapse and death.</span></li> <li style="font-weight: 400;" aria-level="1"><span style= "font-weight: 400;">Treat LAST with lipid emulsion therapy i.e. ‘Intralipids’ to create a lipid sink that absorbs anesthetic agent</span></li> <ul> <li style="font-weight: 400;" aria-level="2"><span style= "font-weight: 400;">Administer initial 1.5 ml/kg bolus (approximately 100 ml in 70 mg adult) followed by infusion rate of 0.25 mg/kg/hour. Do not surpass 10 mg/kg total. </span></li> </ul> </ul> <p><strong>References</strong></p> <p><span style="font-weight: 400;">Dickerson DM, Apfelbaum JL. Local anesthe