Continuous mixed venous oxygen saturation, not mean blood pressure, is associated with early bupivacaine cardiotoxicity in dogs.
OBJECTIVE
To investigate changes of continuous mixed venous oxygen saturation (cSvO(2)) and mean arterial blood pressure (MBP) in dogs with bupivacaine-induced cardiac depression.


METHODS
Bupivacaine was infused into pentobarbital-anesthetized mongrel dogs (n = 8) at a rate of 0.5 mg.kg(-1).min(-1) until the MBP was 40 mmHg or less (end of bupivacaine infusion; BIE). The infusion time was divided into the early period, first 30 min of bupivacaine infusion and the late period, which was from 30 min of bupivacaine infusion until BIE. cSvO(2) was monitored using a fibreoptic pulmonary artery catheter, and MBP and cardiac output (CO) were measured every ten minutes after the initiation of bupivacaine infusion. Arterial blood gas, serum electrolyte and bupivacaine concentration were measured simultaneously. The relationships between CO and cSvO(2), and of CO vs MBP were compared by regression analysis in the early and late periods.


RESULTS
The Pearson's correlation coefficients between CO and cSvO(2) were 0.782 (P = 2.1 x 10(-7)) in the early period and 0.824 (P = 1.3 x 10(-6)) in the late period. The correlation coefficients between CO and MBP were 0.019 (P = 0.921) in the early period and 0.799 (P = 4.8 x 10(-6)) in the late period.


CONCLUSIONS
cSvO(2), but not MBP, is associated with CO changes in bupivacaine-induced cardiac depression during the early period of bupivacaine intoxication. Decrease of MBP with low cSvO(2) observed during the late period might imply severe cardiac depression induced by bupivacaine infusion.
Kim
Jin-Tae
JT
Department of Anesthesiology and Pain Medicine, College of Medicine, Seoul National University, 28 Yongon-Dong, Chongno-Gu, Seoul, Korea 110-774.
Rhee
Ka-Young
KY
Bahk
Jae-Hyon
JH
Do
Sang-Hwan
SH
Lim
Young-Jin
YJ
Ko
Hong
H
Lee
Kook-Hyun
KH
D000779:Anesthetics, Local / Q000633:toxicity*; D000818:Animals; D001784:Blood Gas Analysis / Q000706:statistics & numerical data; D001794:Blood Pressure / Q000187:drug effects*; D002045:Bupivacaine / Q000633:toxicity*; D002303:Cardiac Output, Low / Q000097:blood / Q000139:chemically induced*; D004285:Dogs; D004562:Electrocardiography; D004573:Electrolytes / Q000097:blood; D006321:Heart / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000187:drug effects; D013997:Time Factors
D000779:Anesthetics, Local; D004573:Electrolytes; D010100:Oxygen; D002045:Bupivacaine