The Efficacy of Dexmedetomedine as an Indicator for Intravascular Epidural Catheter in Adult During General Anesthesia

Background: No perfect method exists for identifying intravascular catheters all methods described in the literature have incidence of false positive and false negative results. Aim: To evaluate the efficacy of dexmedetomedine as an Indicator for Intravascular Epidural Catheter in adult during General Anesthesia. Methods: Forty patients scheduled for elective general surgery under propofol-fentanyl isoflurane anesthesia were randomized to receive either 3mL of lidocaine 15mg/mL with dexmedetomedine 1m/kg or 3mL of saline IV (n=20 each). HR, SBP, was monitored for 5min. after injection. Results: After IV injection of the test dose, mean values of HR and SBP in the dexmedetomedine group were significantly lower than those in the saline group between 40-300 and 60-300s, respectively (p 0.05). Mean maximum decrements in HR and SBP in the dexmedetomedine group were 11.65±2.89bpm and 18.5±6.18mmHg and occurred at 140 and 240s after injection, respectively. All patients in the dexmedetomedine group, and none in the saline group, developed HR decrease to 10 bpm. Therefore, sensitivity, specificity, +PV, and –PV according to the HR criterion were all 100%. On the other hand, 18 patients in the dexmedetomedine group, and none in the saline group, exhibited SBP decrements to 15mm Hg, resulting in 90% sensitivity, 100% Specificity, 90, 9% –PV and 100% +PV. Two patients missed using SBP criterion. Conclusion: Dexmedetomedine is a reliable indicator for detection of an intravascular injection of epidural test dose in adult patients under propofol-fentanyl isoflurane anesthesia.