LE infusions modulate cytokine production by mononuclear white cells in response to Candida yeast, suggesting an increased risk of infection
11,12; LE infusions may produce thrombophlebitis during peripheral IV administration
13; they may lead to impaired reticuloendothelial system function and altered inflammatory responses during long-term therapy
14,15; they may induce allergic reactions, including anaphylaxis, especially if they contain soy bean oil
16,17; they may result in pulmonary, splenic, placental, and cerebral fat emboli, especially if the emulsified fat particles are greater than 5 microns in diameter
18,19; they may cause pulmonary hypertension if administered at rates larger than 100 mg · kg
−1 · h
−1 19; they may lead to warfarin resistance by facilitating warfarin binding to albumin
20; they may interfere with extracorporeal membrane oxygenation circuits
21; they may induce weakness, altered mental status, and seizures in children
22; and they may induce an increase in the intracranial pressure after a severe traumatic brain injury.
23 Because of the many possible side effects associated with LE administration, the multiple types and combinations of lipid preparations, the various free fatty acid concentrations, and the wide range of lipid globule sizes available, some experts have suggested the adoption of certain pharmaceutical requirements and standards.
24–26 Of all these reported side effects, however, only allergic reactions are likely to arise after acute, short-term administration, such as would occur with administration of LE for rescue from local anesthetic toxicity.
Based on the available evidence, therefore, it would seem imprudent to withhold LE administration in local anesthetic-induced toxicity clinical settings while awaiting scientific proof. This recommendation is not to imply, however, that administration of LE should be the first step in such a clinical setting. Clearly, CNS symptoms such as loss of responsiveness, disorientation, tremors, or seizures must be treated conventionally by ensuring oxygenation and ventilation, securing the airway to protect aspiration of gastric contents in patients at risk, administering anticonvulsants, and instituting advanced cardiac life support protocols in the case of cardiac arrest. Once these conventional treatment modalities have begun, however, immediate IV administration of LE would seem very reasonable and desirable.
