The Efficacy of Epinephrine-Containing Test Dose during Propofol-Nitrous Oxide Anesthesia with High Dose Fentanyl / 대한마취과학회지

BACKGROUND: The aim of this study is to determine the effect of high dose fentanyl on the test dose containing 15microgram epinephrine during propofol anesthesia. METHODS: One hundred patients with ASA physical status 1 were randomized to receive 2 mg/kg propofol with or without 10microgram/kg fentanyl at the induction of anesthesia (n = 50 each). Anesthesia was maintained with propofol 8 mg/kg/h and 67% nitrous oxide in oxygen. Each group of patients were further divided into a test dose group receiving 1.5% lidocaine 3 ml plus epinephrine 15microgram or a saline group receiving 3 ml of isotonic saline (n = 25 each). Heart rate (HR) and systolic blood pressure (SBP) were monitored for 4 min after intravenous injection of the study drugs. RESULTS: In the propofol and the propofol-fentanyl group, the intravenous injection of the test dose produced a HR increase > or = 20 bpm (conventional HR criterion) in 25 and 23 out of the total 25 patients, respectively. Therefore, in the propofol-fentanyl group, sensitivity, specificity, positive predictive value, and negative predictive value were 82%, 100%, 100%, and 92.6%. According to the modified HR criterion (HR increase > or = 10 bpm), all the values were 100%. All patients receiving test dose developed SBP increase > or = 15 mmHg. CONCLUSIONS: Our results indicate that both HR increase > or = 10 bpm or SBP increase > or = 15 mmHg are clinically applicable during propofol-nitrous oxide anesthesia with 10microgram/kg fentanyl.

The Effects of Spinal Cord Stimulation on the Spinal Nociceptive Process Evaluated by Cord Dorsum Potential in Cats / 대한마취과학회지

BACKGROUND: The pain-inhibitory effects of spinal cord stimulation (SCS) may be exerted at two alternative or complementary levels, segmentally or supraspinally. However the actual pathways, site of action, and synaptic relays are poorly understood. No data is available which concerns the changes in cord dorsum potential (CDP) associated with a single neuronal level, after SCS. METHODS: SCS was performed in normal and spinalized cats. At the lumbosacral enlargement, CDP and extracellular single cell activity in response to electrical stimulation of Asigma- or C-fiber of the dorsal root or sciatic nerve were recorded. RESULTS: The resulting CDP consisted of characteristic waves of Asigma- and C-fiber with a different time latency. CDP sno significant differences in the amplitude of Asigma- and C-fiber wave between the normal and spinalized cats. In both groups, CDP showed decrease in the amplitude of C-fiber wave. Single cell responses were either increased or decreased after SCS. The C- response changed more marKedly than the A-response in both the normal and spinalized cats. In the bicuculline administered cats, single cell responses increased after SCS, but no change was found in the amplitude of CDP. CONCLUSIONS: The above results might indicate that SCS suppresses C-fiber transmission of nociceptive electrical stimuli via a segmental inhibitory mechanism, and that SCS is more effective in blocKing the transmission of nociceptive electrical stimuli via the C-fiber than Asigma-fiber.