›Approximately 18 mL/min in a 70 kg adult
›Double the infusion rate to 0.5 mL/kg/min if blood pressure remains inadequate
›Continue infusion until hemodynamic stability achieved
›Continue for at least 10 minutes beyond attainment of circulatory stability
›Maximum cumulative dose
›Do not exceed approximately 12 mL/kg of lipid emulsion over the first 30 minutes
›Recognized upper limit to reduce risk of hypertriglyceridemia, pancreatitis, and fat overload syndrome
›Escalate to mechanical circulatory support rather than exceeding this ceiling
›Lean body weight dosing rationale
›Lipid emulsion is itself a fat load
›Dosing to total body weight in an obese patient can substantially over-deliver lipid
›Use lean body weight (ideal body weight plus a correction factor, or a lean body weight calculator) for all lipid emulsion dose calculations
›Indications for initiation
›Any sign of cardiovascular instability attributable to LAST: arrhythmia, hypotension, or arrest
›Seizure refractory to benzodiazepines is a relative indication even without cardiovascular signs
›Do not delay lipid emulsion pending confirmatory testing; LAST is a clinical diagnosis
›Pediatric lipid emulsion dosing
›Same weight-based protocol as adult: 1.5 mL/kg bolus, 0.25 mL/kg/min infusion
›Verify against current pediatric guideline before use
Modified cardiac arrest management
›Reduced epinephrine dosing
›Epinephrine 1 mcg/kg or less IV per bolus
›Avoid standard ACLS 1 mg boluses; higher doses impair resuscitation and worsen outcomes in LAST models
›Repeat per usual ACLS interval if arrest persists, maintaining the reduced per-dose ceiling
›Pediatric reduced-dose epinephrine
›Scale down proportionally from the standard pediatric arrest dose
›Verify against current pediatric guideline before use
›Agents to avoid entirely during LAST arrest
›Vasopressin
›Associated with pulmonary hemorrhage and worse hemodynamic outcomes in animal LAST models
›Calcium channel blockers and beta blockers
›Further depress an already sodium-channel-blocked, hypocontractile myocardium
›No role even if a coexisting supraventricular tachyarrhythmia is present
›Additional local anesthetic (lidocaine, procainamide) as an antiarrhythmic
›Both are sodium channel blockers and directly worsen the underlying toxicity
›Amiodarone is the preferred antiarrhythmic if one is required
›Sodium bicarbonate as an adjunct for refractory wide-complex arrhythmia
›Sodium bicarbonate 1 to 2 mmol/kg IV bolus
›Consider if QRS widening or ventricular arrhythmia persists despite lipid emulsion and modified ACLS
›Mechanism: increases extracellular sodium to partially overcome sodium channel blockade, similar rationale to other sodium-channel-blocker toxicities
›Monitor arterial pH, not to exceed 7.55, and serum sodium, not to exceed 155 mmol/l
›Correct hypokalemia aggressively, potassium falls with alkalinization
›Prolonged resuscitation and troubleshooting
›If circulation is not restored after lipid emulsion and modified ACLS
›Confirm epinephrine dose reduction was actually followed and vasopressin was not given
›Repeat lipid bolus and escalate infusion to 0.5 mL/kg/min if not already done
›Reconsider an unrecognized confounder: total spinal, pneumothorax, or a co-ingested cardiodepressant
›Continue high-quality CPR for a substantially longer duration than typical ACLS termination points
›Local anesthetic cardiotoxicity is potentially reversible as the drug redistributes and is cleared
›Do not terminate resuscitation on usual timelines for a LAST-attributed arrest
Mechanical circulatory support
›Venoarterial ECMO or cardiopulmonary bypass
›Indications
›Refractory cardiac arrest or refractory hemodynamic instability despite lipid emulsion and modified ACLS
›Activate the team early, at first sign of a refractory trajectory rather than after failed conventional resuscitation
›Rationale
›Provides circulatory support while local anesthetic redistributes and is metabolized
›Myocardial recovery is expected once the drug burden clears, making prolonged mechanical support worthwhile
›Intra-aortic balloon pump is not an adequate substitute
›Does not provide the flow support needed in profound LAST-induced cardiogenic shock or arrest
›ECMO or bypass is the preferred mechanical support modality
Hemodynamic and fluid support
›Fluid administration
›Isotonic crystalloid bolus 10 to 20 mL/kg IV for hypotension
›Reassess after each bolus; avoid volume overload if a cardiogenic component dominates
›Not a substitute for lipid emulsion or modified ACLS
›Vasopressor use outside cardiac arrest
›Norepinephrine 0.05 to 0.5 mcg/kg/min IV for hypotension without arrest
›Titrate to MAP >= 65 mmHg
›Reasonable outside the specific cardiac-arrest restrictions on vasopressin and standard-dose epinephrine
›Reassess continuously for evolution toward frank cardiac arrest, at which point the modified arrest protocol above applies
Antipyretic and analgesic considerations
›Analgesia after a LAST event
›Opioids preferred for pain control once the airway and hemodynamics are secure
›Morphine 0.05 to 0.1 mg/kg IV, titrate to effect
›Fentanyl 0.5 to 1 mcg/kg IV as an alternative
›Do not re-administer local anesthetic to the affected block site to manage pain during the acute event
›Adds further sodium channel blockade on top of an already toxic burden
›Antipyretic therapy if fever develops
›Acetaminophen 650 to 1000 mg oral or IV every 6 hours, maximum 4 g/day
›Fever is not a typical feature of LAST itself; evaluate for aspiration or another cause if present