# Two minutes after an ultrasound-guided interscalene nerve block with bupivacaine for shoulder surgery, a client reports ringing in the ears and numbness around the mouth, becomes agitated, and then has a generalized tonic-clonic seizure. The ECG shows a widening QRS complex and heart rate 48/min; blood pressure is 70/38 mm Hg. There is no rash, wheezing, or facial swelling. No antibiotic has been given yet, and no neuraxial injection was performed. Complete the diagram by selecting the condition the client is most likely experiencing, 2 actions the nurse should take to address that condition, and 2 parameters the nurse should monitor to assess the client's progress.

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=617365&lang=en  
> language: en  
> subject: Parenteral/IV Therapies  
> category: PPT

## Question

Two minutes after an ultrasound-guided interscalene nerve block with bupivacaine for shoulder surgery, a client reports ringing in the ears and numbness around the mouth, becomes agitated, and then has a generalized tonic-clonic seizure. The ECG shows a widening QRS complex and heart rate 48/min; blood pressure is 70/38 mm Hg. There is no rash, wheezing, or facial swelling. No antibiotic has been given yet, and no neuraxial injection was performed. Complete the diagram by selecting the condition the client is most likely experiencing, 2 actions the nurse should take to address that condition, and 2 parameters the nurse should monitor to assess the client's progress.

Condition

Select 1
High spinal anesthesia
Perioperative anaphylaxis
Local anesthetic systemic toxicity
Phrenic nerve blockade from the block

Actions to take

Select 2
Administer the prescribed 20% lipid emulsion bolus
Administer the prescribed propofol bolus for seizure
Administer prescribed IM epinephrine 0.5 mg
Administer the prescribed IV vasopressin dose
Administer the prescribed IV benzodiazepine dose

Parameters to monitor

Select 2
Serum tryptase level
Blood pressure
Dermatomal sensory level
QRS duration on the ECG
Serum bupivacaine level

## Explanation

A neurologic prodrome followed by seizure and then cardiac conduction widening and hypotension minutes after bupivacaine is local anesthetic systemic toxicity. The nurse gives prescribed 20% lipid emulsion early and a benzodiazepine for the seizure. Blood pressure and QRS duration show whether cardiotoxicity is reversing.

## In-depth explanation

Quick answer
Local anesthetic systemic toxicity; give the prescribed 20% lipid emulsion and an IV benzodiazepine; monitor blood pressure and QRS duration.

Why this is correct
Bupivacaine blocks sodium channels in the brain first (tinnitus, perioral numbness, agitation, seizure) and then in the heart (QRS widening, bradycardia, hypotension). The ASRA checklist calls for early lipid emulsion and benzodiazepines as the preferred seizure drug. Blood pressure and a narrowing QRS show that lipid therapy is binding the drug and reversing sodium-channel blockade.

Easy analogy or mental picture
Lipid emulsion works like a sponge dropped into the bloodstream, soaking up the fat-soluble anesthetic and pulling it away from the heart.

Memory hook
Ears ring, lips tingle, seizure, wide QRS = LAST; treat with Lipid And Seizure control (benzo).

NCLEX decision rule
When CNS excitation is followed by cardiovascular toxicity within minutes of a local anesthetic injection, give lipid emulsion early and modify resuscitation (benzodiazepine first-line, no vasopressin, reduced epinephrine).

Why the other choices are wrong
High spinal anesthesia follows a neuraxial injection and causes ascending block and apnea, not tinnitus and seizure; dermatomal level tracks that. Anaphylaxis would bring rash, wheezing, or swelling after an antigen such as an antibiotic, so IM epinephrine and tryptase are off target. Phrenic nerve blockade is an expected interscalene effect that causes dyspnea, not seizures or QRS widening. Propofol stops seizures but worsens hypotension in LAST. Vasopressin is not recommended in the LAST algorithm. A serum bupivacaine level is not available in time to guide treatment.

References
1ASRA Checklist for Treatment of Local Anesthetic Systemic ToxicityLipid emulsion, benzodiazepine for seizures, avoid propofol with instability and avoid vasopressin
2NCSBN 2026 NCLEX-RN Test PlanClient Needs category and clinical judgment framework

## Clinical scenario

Scenario
Minutes after a bupivacaine interscalene block, a client develops tinnitus and perioral numbness, a seizure, QRS widening, bradycardia, and hypotension.

## Key concepts

- **Local anesthetic systemic toxicity** — Toxic plasma levels of a local anesthetic causing CNS and cardiac sodium-channel blockade.
- **Lipid emulsion therapy** — IV 20% lipid given as an antidote that sequesters lipophilic anesthetic.
- **QRS widening** — Slowed ventricular conduction from sodium-channel blockade.

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