Cardiovascular Alterations After Injection of 2% Lidocaine With Norepinephrine 1:50,000 (Xylestesin) in Rats

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Cardiovascular Alterations After Injection of 2% Lidocaine With Norepinephrine 1:50,000 (Xylestesin) in Rats
Anesthesia Progress
Volume 54, Issue 2 (Summer 2007)

Fatima Neves Faraco, PhD*, Paschoal Laercio Armonia, PhD‹, Stanley F. Malamed, PhD·
* Professor of Bioethics and Biosafety and Therapeutics, Faculty of Dentistry, Department of Implantology, Post-Graduate Course, Santo Amaro University, UNISA, SÑo Paulo, Brasil
‹ Coordinator of Post-Graduate Course, Faculty of Dentistry, Paulista University, UNIP, SÑo Paulo, Brasil
· Anesthesiologist, Professor of Anesthesia and Medicine, School of Dentistry, University of Southern California, Los Angeles, California

The purpose of the present study is to determine the cardiovascular effects produced by intravascular injection of 2% lidocaine with 20 μg/mL of norepinephrine on systolic, diastolic, and mean arterial pressures and heart rate of rats at the following times: control period, during the injection (first 15 seconds), during the first minute, and at the end of 1, 2, 3, 4, 5, 10, 15, 20, 25, and 30 minutes after drug administration. The study was performed on 13 male Wistar rats with weights between 200 grams and 220 grams that were awake during the recording of these parameters. The dose administered was proportional to 1 cartridge of local anesthetic (1.8 mL) in an average-size human, which is equivalent to 0.51 mg/kg of lidocaine hydrochloride and 0.51 μg/kg of norepinephrine hydrochloride. The average time of injection was 15.7 seconds. The results of this study showed significant increases in systolic, diastolic, and mean arterial pressure and a noticeable decrease in heart rate. The greatest variation occurred in the systolic blood pressure. The greatest alterations occurred during injection and within the first minute following administration of the anesthetic solution. We would anticipate these changes in the parameters analyzed to be clinically significant. Thus, dentists using 2% lidocaine with norepinephrine 20 μg/mL should be very careful to avoid intravascular injection.

Keywords: Intravascular injection, Lidocaine, Norepinephrine

Received: April 14, 2006; Accepted: December 12, 2006

DOI: 10.2344/0003-3006(2007)54[45:CAAIOL]2.0.CO;2

Address correspondence to Dr F?tima Neves Faraco, Rua Francisco LeitÑo, 469 cj. 409, CEP 05414-901, SÑo Paulo, Capital, Brasil; email: fatimafaraco@terra.com.br.

© 2007 The American Dental Society of Anesthesiology