A. K. Chhibber, S. J. Lustik
[Applied Cardiopulmonary Pathophysiology 14: 178-181, 2010]
Background and objectives: The molecular mechanism of hypotension post spinal anesthesia is unknown. This study hypothesized that the sympathectomy from spinal anesthesia would cause an increase in nitric oxide (NO) levels.
Methods: 36 ASA 1 or 2 patients undergoing extracorporeal shock wave lithotripsy were prospectively enrolled. Plasma levels of NO reaction products were measured pre and post spinal anesthesia.
Results: The mean NO metabolite level significantly decreased (15.9 +/- 10 vs. 13.9 +/- 8.7 µM, P < 0.0001) after spinal anesthesia. There was no correlation between NO and MAP.
Conclusions: Contrary to our hypothesis, plasma NO levels significantly decreased after the administration of intrathecal lidocaine. Vasodilatation produced by intrathecal lidocaine does not appear to be mediated by NO.
Key words: hypotension, nitric oxide, spinal anesthesia, sympathectomy
Ashwani K. Chhibber, M.D.
Department of Anesthesiology
University of Rochester Medical Center
601 Elmwood Avenue, Box 604
Rochester, NY 14642