Influence of Temperature and Injection Speed of a 0.5% Bupivacaine Solution on the Distribution in a Spinal Canal Model Filledwith Human Cerebrospinal Fluid / 대한마취과학회지

BACKGROUND: The density of 0.5% bupivacaine solution at 37degreesC is known to be slightly hypobaric. However, its clinical character in spinal anesthesia appears to be nearly isobaric. We tried to find evidence on how the hypobaric 0.5% bupivacaine solution could show the pattern of isobaric distribution in the subarachnoid space. METHODS: The distribution of 0.5% bupivacaine solution containing 0.029 mg methylene blue per milliliter of bupivacaine solution (BMB) was examined in a vertically mounted spinal canal model filled with human cerebrospinal fluid (CSF) at 37degreesC. The CSF was collected from natural drainage bags of 5 brain tumor patients. Three milliliters of the BMB solution at 22degreesC or 37degreesC was injected into the middle of the spinal canal four times with a high speed of injection (0.6 ml/sec) and four times with a slow speed (0.05 ml/sec). Nine 1-ml samples were drawn simultaneously from the 9 sampling sites in the longitudinal direction, each 5 cm apart, then those samples were analyzed for the spectrophotometric absorbance of methylene blue concentration. RESULTS: The concentrations of methylene blue were decreased toward the upper and lower parts of our spinal model with the highest concentrations at the central 5th sampling site, regardless of the temperature and injection speed of the BMB solution. However, the high temperature (37degreesC) and low injection speed respectively contributed to a little more distribution of the BMB solution toward the upper part of the spinal model, and the low temperature (22degreesC) contributed to a little more distribution of the BMB solution toward the lower part of the spinal model. CONCLUSIONS: Our study shows that the distribution of plain 0.5% bupivacaine solution in the subarachnoid space is similar to that of isobaric solutions.

Effect of Speed of Injection on Spinal Anesthesia with 0.5% Plain Bupivacaine / 대한마취과학회지

To observe the anesthetic characteristics of two different speeds of injection using 0.5% plain bupivacaine during spinal anesthesia, 40 patients undergoing lower extremity surgery were allocated randomly into two groups. In one group, 3 ml of 0.596 plain bupivacaine was administered into the subarachnoid space using 25 gauge Quincke spinal needle to the patients with a lateral horizontal position at duration of 10 seconds. In the other group, the duration was 180 seconds. There were no statistically significant differences between two groups in maximal level and its onset time of sensory blockade, hemodynamic changes, onset time to grade 3 Bromage motor blockade. We concluded that the speed of injection does not affect the anesthetic characteristics of spinal anesthesia using 0.5% plain bupivacaine.

Hemodynamic Changes by Speed of Injection of d-Tubocurarine under General Anesthesia / 대한마취과학회지

d-Tubocurarine(d-TC) causes hypotension, probably as a result of the liberation of histamine; in larger doses, it produces ganglionic blockade. An increase of histamine levels in plasma to 200 to 300 percent of baseline causes a brief decrease in arterial blood pressure(1 to 5 minutes) and the increase in heart rate. The amount of histamine released by d- TC is dose related and is also related to speed of injection. Therefore histamine release can be minimized by the slow administration, light level of surgical anesthesia, and the use of smaller doses. Thus, the purpose of this study was to prevent the cardiovascular effect of d-TC by the slow administration undergoing general anesthesia. The study population was from 40 patients scheduled for elective surgery at Yeungnam University Hospital, who belonged to physical status I or II of ASA classification. Patients were divided into 4 groups by speed of injection of 10, 30, 60 and 120 seconds(group 1, 2, 3 and 4, respectively). All patients were premedicated with hydroxyzine 1mg/kg, glycopyrrolate 0.2mg, and fentanyl 1 ug/kg IM 30 minutes before anesthesia. Patients were induced with thiopental sodium 4-5 mg/kg until the disappearance of lid-reflex. Succinylcholine 1.0 mg/kg IV was used to facilitate endotracheal intubation. As soon as relaxafion was complete, laryngoscopy was initiated. After the completion of intubation, nitrous oxide and 50% oxygen with 0.6% halothane was administrated. The blood pressure and heart rate were measured using noninvasive automatic blood pressure manometer for 60 minutes per 1 minute. Data were analyzed with one-way ANOVA test within the groups. p<0.05 was considered significant. The results were as follows, The changes of blood pressure was decreased in rapid injection groups(Group 1 & 2) compared with slowly injection groups(Group 3 & 4) at 2 min, 5 min after d-TC administration. The changes of heart rate was significantly increased(p<0.05) at 1min, 2 min after d-TC administration in rapid injection groups compared with slow injection groups. These results show that the cardiovascular effect of d-TC might be prevented by slowly administration undergoing general anesthesia.