3 Steps to Protect Your Patient from Local Anesthetic Systemic Toxicity (LAST)

Local anesthetics are a vital part of safe, effective surgical care. Most of the time, the block does exactly what it’s meant to do—block pain and nothing more.

But in rare cases, a reaction called local anesthetic systemic toxicity (LAST) can occur, and its effects can be life-threatening, including seizures, loss of consciousness, and even death.

That’s why AORN Senior Perioperative Practice Specialist Emily Jones, PhD, RN, CNOR, EBP-C, wants perioperative nurses involved in care for patients receiving local-only anesthesia to keep LAST awareness and treatment on their radar. She said, “while this type of reaction is rare, it requires a keen eye for early signs and team preparedness for rapid response.”

Jones just finished a major update to AORN’s Guideline for Care of the Patient Receiving Local-Only Anesthesia, which is now up for public comment. The new evidence-based recommendations highlight the latest research on LAST and outline practical steps for how perioperative teams can prepare, starting with awareness.

Understand Why Systemic Toxicity Reaction to Local Anesthesia Can Develop

LAST can happen within minutes of receiving a local anesthetic. It can happen if the medication is:

• Accidentally injected directly into the bloodstream
• Rapidly absorbed into a highly vascular area
• Administered at a higher dose than recommended
• Not tolerated by a patient with liver or kidney impairment

Know What Local Anesthesia Toxicity Signs to Looks For

LAST may present in a patient’s central nervous system or cardiovascular system, or both, and there is no typical clinical presentation. Jones said that “some patients can experience prodromes [early signals] ahead of more serious LAST complications.” And these early signs of LAST can include:

• Confusion
• Slurred speech
• Dizziness
• Metallic taste
• Perioral numbness
• Tinnitus

Seizure and cardiovascular signs signal more advanced toxicity and could lead to death if not treated promptly.

Be Ready to Protect Patients When LAST Develops

When LAST occurs, every second matters. Three evidence-based steps can help perioperative teams respond quickly and reduce the risk of serious or lasting harm.

Step 1: Review Preoperative History for Red Flags

During the preoperative assessment and review of patient history, the perioperative team should identify patients who might be at higher risk for LAST. Risk factors include:

• Extremes of age
• Cardiovascular, metabolic, hepatic, or central nervous system disease
• Low muscle mass

Example: An older adult with congestive heart failure could be at increased risk of developing LAST. In these situations, the perioperative RN should discuss the patient’s risk factors with the surgeon before surgery.

Step 2: Respond Immediately When Toxicity Reaction Occurs

“Pay close attention as the surgeon injects the local anesthetic to numb the operative area. If the patient tells you that something doesn’t feel right or if they become agitated or confused, notify the physician right away,” Jones said.

If LAST is suspected, the team should call for help to assist with managing treatment and:

• Stop administering the local anesthetic
• Maintain the patient’s airway
• Administer IV lipid emulsion 20%

Step 3: Follow-up to Ensure Patient Recovery

Because LAST can recur after treatment, the perioperative care team should continue to monitor the patient closely, guided by the type of reaction and the interventions provided.

Make Evidence-Based LAST Response Easy

In her guideline literature search, Jones found this 2024 quality improvement project from a high-volume outpatient surgery center. She encourages teams to review the project for practical ideas on strengthening their own LAST education and response plans.

Key strategies from the project included:

• Surveying staff to identify knowledge gaps about LAST (keep it brief)
• Developing a clinical practice guideline for evidence-based response
• Creating and sharing a LAST Response Checklist for prevention, assessment, and treatment
• Using simulation training to practice team response
• Stocking LAST treatment kits in designated perioperative areas

Get the latest on AORN Guidelines to keep up with evidence for your practice.

Support Safe Administration of Local Anesthesia with Evidence-Based Resources

• Periop 101: A Core Curriculum™ establishes foundational perioperative knowledge and skills in three Learning Plans: OR, ASC, and Cesarean Section. Each learning plan includes 23+ learning modules, one of which is on the topic of Anesthesia. The module covers the role of the periop RN in relation to anesthesia across the perioperative care continuum. This includes general, regional, local anesthesia, and moderate sedation. The learner will receive critical knowledge about anesthesia care to better assist the anesthesia provider in delivering safe patient care. See what the Periop 101 Program Package has to offer for both your novice and experienced RNs.
• eGuidelines+ is a facility-wide clinical decision support tool for the entire perioperative team. Provide access to the most current AORN Guidelines for Perioperative Practice including the Local-Only Anesthesia Guideline. Solidify best practices with more than 300 quick guides to best practices including a comprehensive guide on Local Anesthesia.