The lipid sink phenomenon was observed in this study. The use of a lipid emulsion accelerated the elimination of bupivacaine.

Background:The superiority of Intralipid, a long-chain triglyceride (LCT) emulsion versus Lipovenoes, a long-and medium-chain triglyceride (LCT/MCT) emulsion, in reversing local anesthetic-induced cardiac arrest is poorly defined and needs to be determined. Methods:The study included two parts: in experiment A, bupivacaine (20 mg/kg) was injected to produce asystole. Either Intralipid 20% (LCT group, n ϭ 30) or Lipovenoes 20% (LCT/MCT group, n ϭ 30) with epinephrine was infused immediately. Return of spontaneous circulation and recurrence of asystole after resuscitation were recorded. In experiment B, 80 rats using the same model and resuscitation protocol were divided into 10 groups: LCT 0 , LCT 15 , LCT 30, LCT 60 , and LCT 120 and LCT/MCT 0 , LCT/MCT 15 , LCT/ MCT 30 , LCT/MCT 60 , and LCT/MCT 120 (n ϭ 8 each; the subscripts represent respective observation period). LCT 15 -LCT 120 and LCT/MCT 15 -LCT/MCT 120 groups received Intralipid 20% or Lipovenoes 20%, respectively. Plasma and myocardial bupivacaine and triglyceride concentrations, as well as myocardial bioenergetics, were determined.