Lipid emulsion is superior to vasopressin in a rodent model of resuscitation from toxin-induced cardiac arrest.
OBJECTIVE
Lipid emulsion infusion is an emerging antidotal therapy for toxin-induced cardiac arrest. To compare the efficacy of resuscitation from bupivacaine-induced asystole using lipid emulsion infusion vs. vasopressin, alone and with epinephrine.


METHODS
Prospective, randomized, animal study.


METHODS
University research laboratory.


METHODS
Adult, male Sprague-Dawley rats.


METHODS
Instrumented rats were given an intravenous bolus of 20 mg/kg bupivacaine to induce asystole (zero time). Rats (n = 6 for all groups) were ventilated with 100% oxygen, given chest compressions, and randomized to receive 30% lipid emulsion (L, 5 mL/kg bolus then 1.0 mL/kg/min infusion) and vasopressin 0.4 U/kg bolus alone (V) or combined with epinephrine, 30 microg/kg (V + E); boluses (L, V, or V + E) were repeated at 2.5 and 5 minutes for a rate-pressure product (RPP) less than 20% baseline.


RESULTS
The arterial blood pressure and electrocardiogram were measured continuously for 10 minutes when blood was drawn for arterial blood gas analysis, lactate content, and central venous oxygen saturation (ScvpO2). Hemodynamic parameters of the L group at 10 minutes (30,615 +/- 4782 mm Hg/min; 151 +/- 19.1 mm Hg; 197 +/- 8.6 min; RPP, systolic blood pressure and heart rate, respectively) exceeded those of the V group (5395 +/- 1310 mm Hg/min; 85.8 +/- 12 mm Hg; 61 +/- 10.8 min) and the V + E group (11,183 +/- 1857 mm Hg/min; 75.5 +/- 12.9 min, RPP and heart rate, respectively; systolic blood pressure was not different). Metrics indicated better tissue perfusion in the L group (7.24 +/- 0.02; 83% +/- 3.5%; 2.2 +/- 0.36 mmol/L; pH, ScvpO2, lactate, respectively) than V (7.13 +/- 0.02; 29.9% +/- 4.4%; 7.5 +/- 0.6 mmol/L) and V + E groups (7.07 +/- 0.03; 26.2% +/- 8.9%; 7.7 +/- 1 mmol/L). Wet-to-dry lung ratios in V (8.3 +/- 0.6) and V + E (8.7 +/- 0.2) were greater than that in the L group (6.2 +/- 05) (mean +/- sem; p < 0.05 for all shown results).


CONCLUSIONS
Lipid emulsion in this rat model provides superior hemodynamic and metabolic recovery from bupivacaine-induced cardiac arrest than do vasopressors. Systolic pressure was not a useful metric in the vasopressor groups. Vasopressin was associated with adverse outcomes.
Di Gregorio
Guido
G
Department of Anesthesiology, University of Illinois College of Medicine at Chicago, USA.
Schwartz
David
D
Ripper
Richard
R
Kelly
Kemba
K
Feinstein
Douglas L
DL
Minshall
Richard D
RD
Massad
Malek
M
Ori
Carlo
C
Weinberg
Guy L
GL
D000818:Animals; D002045:Bupivacaine / Q000008:administration & dosage; D004195:Disease Models, Animal; D004837:Epinephrine / Q000627:therapeutic use*; D005217:Fat Emulsions, Intravenous / Q000627:therapeutic use*; D006323:Heart Arrest / Q000139:chemically induced / Q000628:therapy*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012151:Resuscitation; D014662:Vasoconstrictor Agents / Q000627:therapeutic use*; D014667:Vasopressins / Q000627:therapeutic use*
D005217:Fat Emulsions, Intravenous; D014662:Vasoconstrictor Agents; D014667:Vasopressins; D002045:Bupivacaine; D004837:Epinephrine