| Effects of Epinephrine on Cardiovascular Toxicity of Bupivacaine and the Mixture of Tetracaine and Lidocaine. |
|
Hee Suk Yoon, Hoon Kang, Kwang Woo Kim |
1Department of Anesthesiology, College of Medicine, Chungbuk National University, Chungju, Korea.
2Department of Anesthesiology, College of Medicine, Seoul National University, Seoul, Korea. |
|
|
|
|
| Abstract |
BACKGROUND
Effects of epinephrine on the cardiovascular toxicity of intravenously injected bupivacaine and mixture of tetracaine and lidocaine were studied in fifty rats.
Vasoconstrictors such as epinephrine are frequently used with local anesthetics to prevent rapid vascular absorption and/or to prolong the duration of local anesthetic action.
Epinephrine is also believed to antagonize the cardiovascular depressive effects induced by local anesthetics.
METHODS
To determine whether the addition of epinephrine to local anesthetics protects from cardiovascular toxicity induced by intravenously administerd local anesthetics, bupivacaine, the mixture of tetracaine and lidocaine, and epinephrine were administerd to anesthetized rats with thiopental sodium i.p. For the injection of local anesthetics and epinephrine, a femoral vein was cannulated, and baseline blood gas analysis was measured. Fifty rats were randomly allocated to one of five group to receive commercially available bupivacaine(0.5%) at 4 mg/1kg(group 1), the mixture of tetracaine(0.2%) and lidocaine(0.8%) at 0.8 ml/Kg(group 2). Epinephrine(1 : 200,000) was added to group 1 for group 3, and to group 2 for group 4, respectively.In group 5, normal saline (0.8 ml/kg) and epinephrine (1 : 200,000) were administerd. Rats were classified as survivors and non-survivors. Rats with severe bradycardia, ventricular fibrillation and ventricular tachycardia were considered dead. And we measured the times to circulatory arrest in each group.
RESULTS
Rats given epinephrine and bupivacaine showed the larger numbers of death than those given bupivacaine alone.
Mean survival time and time to circulatory arrest were shortest in rats given bupivacaine and epinephrine. Only one rat was dead among those given normal saline and epinephrine, suggesting that epinephrine itself was not toxic.
CONCLUSIONS
This study demonstrated that concomitantly administered i.v. epinephrine doesn't protect rats from local anesthetics-induced cardiovascular toxicity in spite of its non-toxic effect as shown in rats given normal saline with epinephrine. |
| Key Words:
Anesthetics; local; bupivacaine; lidocaine; tetracaine; Heart; arrhythmia; bradycardia; fibrillation; tachycardia |
|
PDF Links
Full text via DOI
Download Citation
