Intralipid

Definition & Use

Intravenous lipid emulsion (‘Intralipid’ / lipid rescue) is the specific treatment for severe local anaesthetic systemic toxicity (last), particularly the cardiovascular collapse caused by lipophilic agents such as bupivacaine. It is a sterile fat emulsion given intravenously as a bolus followed by an infusion once last causes seizures or cardiovascular compromise.

Mechanism & Points

It is thought to act as a ‘lipid sink’ — the emulsion droplets absorb the lipophilic local anaesthetic from the plasma and heart, lowering the free drug concentration at the sodium channels — and to improve cardiac energy metabolism. It is given alongside standard resuscitation (airway, oxygen, seizure control, CPR), which may need to be prolonged. Lipid emulsion should be immediately available wherever large doses of local anaesthetic are used.

Availability & Protocol

Because severe local anaesthetic toxicity is rare but rapidly life-threatening, the key to using lipid emulsion effectively is that it is immediately available and its regimen known in advance wherever large doses of local anaesthetic are given, so that it can be started without delay when seizures or cardiovascular compromise appear. National guidelines set out the bolus and infusion doses and a maximum cumulative dose, and stress that lipid rescue is given in addition to, not instead of, meticulous standard resuscitation, which may need to continue for a prolonged period because bupivacaine-induced arrest is notoriously refractory.

Note

The guideline dose is a weight-based bolus repeated as needed with an infusion, up to a stated maximum, and it is kept physically with the resuscitation equipment in areas where large blocks are done.

Continue resuscitation for over an hour — recovery can be delayed.

• Intralipid (lipid emulsion) = specific treatment for severe last (esp. Bupivacaine cardiovascular collapse).
• Given as IV bolus + infusion when last causes seizures/cardiovascular compromise.
• Acts as a ‘lipid sink’ that absorbs lipophilic LA from plasma/heart.
• Use with standard (often prolonged) resuscitation; keep it available where large LA doses are used.