title: Lipid emulsion combined with epinephrine and vasopressin does not improve survival in a swine model of bupivacaine-induced cardiac arrest.
abstract: BACKGROUND
  This study sought to evaluate the efficacy of lipid emulsion in reversing bupivacaine-induced cardiovascular collapse when added to a resuscitation protocol that included the use of epinephrine and vasopressin.
  
  
  METHODS
  After induction of general anesthesia and instrumentation, 19 mixed-breed domestic swine had cardiovascular collapse induced by an intravenous bolus of 10 mg/kg bupivacaine. After 5 min of resuscitation including chest compressions, epinephrine (100 microg/kg) and vasopressin (1.5 U/kg), animals were randomized to receive either a bolus of 20% lipid emulsion (4 ml/kg) followed by a continuous infusion (0.5 ml x kg(-1) x min(-1)) or an equal volume of saline. Investigators were blinded to the treatment assignment. The primary endpoint was return of spontaneous circulation (mean arterial pressure of at least 60 mmHg for at least 1 min).
  
  
  RESULTS
  Treatment groups were similar with respect to baseline measurements of weight, sex, and hemodynamic and metabolic variables. The rates of return of spontaneous circulation were similar between groups: (3 of 10) in the lipid group and 4 of 9 in the saline group (P = 0.65). Total serum bupivacaine concentrations were higher in the lipid group at the 10-min timepoint (mean +/- SEM: 23.13 +/- 5.37 ng/ml vs. 15.33 +/- 4.04 ng/ml, P = 0.004). More norepinephrine was required in the lipid group compared to the saline group to maintain a mean arterial pressure above 60 mmHg during the 60-min survival period (mean +/- SEM: 738.6 +/- 94.4 vs.. 487.3 +/- 171.0 microg).
  
  
  CONCLUSIONS
  In this swine model, lipid emulsion did not improve rates of return of spontaneous circulation after bupivacaine-induced cardiovascular collapse.
authors.affiliation: Department of Anesthesiology, University of Ottawa, Ottawa, Ontario, Canada. shawn_hicks@alumni.pitt.edu
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Hicks
authors.forename: David D
authors.initials: DD
authors.lastname: Salcido
authors.forename: Eric S
authors.initials: ES
authors.lastname: Logue
authors.forename: Brian P
authors.initials: BP
authors.lastname: Suffoletto
authors.forename: Philip E
authors.initials: PE
authors.lastname: Empey
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Poloyac
authors.forename: Donald R
authors.initials: DR
authors.lastname: Miller
authors.forename: Clifton W
authors.initials: CW
authors.lastname: Callaway
authors.forename: James J
authors.initials: JJ
authors.lastname: Menegazzi
mesh_terms: D000818:Animals; D002045:Bupivacaine / Q000633:toxicity*; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination; D004837:Epinephrine / Q000008:administration & dosage*; D005217:Fat Emulsions, Intravenous / Q000008:administration & dosage*; D005260:Female; D006323:Heart Arrest / Q000139:chemically induced / Q000188:drug therapy* / Q000401:mortality; D008297:Male; D015996:Survival Rate; D013552:Swine; D014667:Vasopressins / Q000008:administration & dosage*
chemical_list: D005217:Fat Emulsions, Intravenous; D014667:Vasopressins; D002045:Bupivacaine; D004837:Epinephrine