The Effects of Intrathecal Adenosine A1 Receptor Agonists (R-PIA) on the Morphine Tolerance in a Rat Model of Postoperative Pain / 대한마취과학회지

BACKGROUND: Analgesic tolerance to opioids has been described in both experimental and clinical conditions, which may limit their clinical utility. This study investigated the effects of intrathecal adenosine A1 receptor agonist (R-PIA) on spinal morphine tolerance. METHODS: SD rats were given intrathecal injections of saline 10microliter, R-PIA 10microgram, morphine 10microgram, or R-PIA plus morphine combinations for 7 days (R-PIA given for days 1-7; days 1-3; or days 5-7). Antiallodynic testing using von Frey filaments was carried out before and 30 minutes after the drug injection. On day 8, an antiallodynic dose-response curve was constructed and the 50% effective dose (ED(50)) for morphine (given alone) was calculated for each study group. RESULTS: The coinjection group of R-PIA with morphine blocked the development of tolerance, as shown by the preservation of morphine antiallodynia over 7 days the concomitant decrease in the ED(50) values on day 8, compared with the morphine-alone group. Although additive analgesia over days 1-7 cannot be ruled out, the reductions of the ED(50) in the R-PIA and morphine combination group suggest some suppression of tolerance. CONCLUSIONS: These results suggest that intrathecal R-PIA prevents the development of spinal opioid tolerance. Future studies will be needed to examine the respective roles of supraspinal and peripheral sites of R-PIA and morphine interaction, and to investigate the mechanisms underlying the action of R-PIA on opioid tolerance.

Changes in Jugular Venous Oxygen Saturation during Liver Transplantation / 대한마취과학회지

BACKGROUND: Marked changes in systemic hemodynamics during liver transplantation may lead to changes in cerebral hemodynamics and metabolism. Therefore, continuous monitoring of the jugular venous oxygen saturation (SjvO2) may help the anesthetic management of liver transplantation. METHODS: We observed changes in SjvO2 using a double lumen oximetry catheter for continuous monitoring and analyzed the correlation between SjvO2 and hemodynamic measurements in thirty patients undergoing liver transplantation. RESULTS: There were no significant changes in SjvO2 compared to initial SjvO2 during liver transplantation. SjvO2, however, increased from 72.5 to 79.6 % (P < 0.05), before and after reperfusion. There was a weak correlation between changes in SjvO2 and cardiac output (r = 0.38, P < 0.05), whereas no correlation was found among changes in SjvO2 and arterial carbon dioxide tension, mean arterial pressure, central venous pressure, or mixed venous oxygen saturation before and after reperfusion. CONCLUSIONS: SjvO2 that reflects changes in cerebral oxygen demand-supply balance was well maintained during liver transplantation except the reperfusion period. Continuous monitoring of changes in SjvO2 at this period may provide further insight to understand physiology of cerebral oxygenation during liver transplantation and merits further studies.

Abnormal BIS and Cerebral Oxygen Saturation during Mitral Valvuloplasty following Reversible Visual Loss in Postoperative Period: A case report / 대한마취과학회지

Cerebral complication after cardiac surgery with cardiopulmonary bypass varies widely focal neurologic deficit, stupor, coma, dementia, memory deficit, or seizures. The incidence of visual loss from ischemic optic neuropathy is from 0.06% to 0.113%. Visual loss is a rare but devastating complication of cardiac surgery. This report describes a patient who had reversible visual loss in postoperative period. She had undergone the decrease of bispectral index, cerebral oxygen saturation and the increase of suppression ratio during mitral valvuloplasty.