Lipid emulsion combined with epinephrine and vasopressin does not improve survival in a swine model of bupivacaine-induced cardiac arrest.
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.
Hicks
Shawn D
SD
Department of Anesthesiology, University of Ottawa, Ottawa, Ontario, Canada. shawn_hicks@alumni.pitt.edu
Salcido
David D
DD
Logue
Eric S
ES
Suffoletto
Brian P
BP
Empey
Philip E
PE
Poloyac
Samuel M
SM
Miller
Donald R
DR
Callaway
Clifton W
CW
Menegazzi
James J
JJ
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*
D005217:Fat Emulsions, Intravenous; D014667:Vasopressins; D002045:Bupivacaine; D004837:Epinephrine