The Changes of Neurologic Injury and Cytokine mRNA Expression according to Spinal Ischemia Time in the Rat / 대한마취과학회지

BACKGROUND: Spinal cord ischemia initiates a deleterious cascade of biochemical events that ultimately result in an increased intracellular calcium concentration. Many papers have been published on this topic but without a clear consensus on the best way of minimizing the problem. For the further study of preventing neurological injury after spinal ischemia, the proper animal model is necessary. In this study we compared spinal ischemia time on neurologic and histopathologic outcome, and inflammatory gene expression in transient spinal ischemia. METHODS: Rats were anesthetized with halothane, and divided into 4 groups:12.5 minutes of spinal ischemia (Group 1), 15 minutes of spinal ischemia (Group 2), 17.5 minutes of spinal ischemia (Group 3), and 20 minutes of spinal ischemia (Group 4). Spinal ischemia was produced by both induced hypotension and thoracic aortic cross clamping. After spinal ischemia neurologic scores were assessed after 1, 3, 6, and 24 hours. After 24 hours, rats were euthanized and spinal cords were removed for histopathologic assessment and an assay of TNF-alpha and IL-1 mRNA. RESULTS: The neurologic scores worsened according to the ischemia time. The histopathologic scores correlated well with the neurologic scores. The TNF-alpha and IL-1 mRNA expression results of group 2 were larger than those of group 1. There were no significant differences between group 2, group 3, and group 4. CONCLUSIONS: Inflammatory gene expressions are increased during transient spinal ischemia. After 15 minutes of ischemia, no further increase of mRNA expression was shown. The 15 minutes of spinal ischemia was sufficient for the spinal ischemic study in rats.

The Assessment of Midazolam Effect as Premedication by Bispectral Index System / 대한마취과학회지

BACKGROUND: Midazolam is often used as an anxiolytic premedication before surgery, but it is difficult and complex to assess its effect. This study evaluated the bispectral index as an objective indicator of midazolam premedication and the relation of cardiovascular response to anesthetic induction. METHODS: Forty patients (aged 20 to 60 and in ASA class I or II) to undergo simple elective surgery under general anesthesia entered the study. The patients were divided into the midazolam group (n = 20) that received midazolam (0.08 mg/kg IM) and glycopyrrolate (0.2 mg IM) premedication, and the control group (n = 20) that received glycopyrrolate (0.2 mg IM) only. Then, anesthetic induction (fentanyl 1 microgram/kg, propofol 2 mg/kg, succinylcholine 1 mg/kg) was done. The bispectral index of the electroencephalogram, blood pressure, and heart rate were measured under unanesthetized conditions, after fentanyl, propofol injection, and intubation. RESULTS: The bispectral index was significantly lower in the midazolam group as compared with the control group before anesthetic induction, after fentanyl injection, and intubation. Blood pressure was not significantly different in the two groups. Heart rate was significantly lower in the midazolam group compared with the control group before anesthetic induction and after fentanyl injection. CONCLUSIONS: Midazolam-premedicated patients appear to maintain stable hemodynamics during anesthetic induction and intubation. The bispectral index can be objectively used in midazolam-premedicated patients when evaluating the degree of sedation. (Korean J Anesthesiol 2000; 38: 947~953)