Tests to Differentiate Cerebrospinal Fluid from Local Anesthetics during Epidural Anesthesia / 대한마취과학회지

BACKGROUND: One of the most serious risks of epidural anesthesia is total spinal blockade from unintentional dural puncture. We evaluated the glucose test and the thiopental precipitation test to differentiate cerebrospinal fluid (CSF) from local anesthetics (LA). METHODS: (1) Experiment 1: CSF from twenty patients was serially diluted with 2% lidocaine or 0.5% bupivacaine. The ratio of CSF to LA-CSF mixture (CSF/(LA+CSF)) was from 0 to 1.0 at an interval of 0.1. We measured the glucose level of each sample with blood sugar meter. (2) Experiment 2: CSF from a hydrocephalus patient was serially diluted and its glucose level of each sample was measured in the same way as Experiment 1. We performed a urine stick test with each sample. Ten anesthetists blinded to the nature of the sample were asked to identify the results of the tests. (3) Experiment 3: Two milimeters of 2.5% thiopental was respectively mixed with local anesthetics, the amount of which was from 0.1 to 1.0 ml at an interval of 0.1 ml. Sixteen anesthetists blinded to the nature of sample were asked to identify the results of the tests. RESULTS: (1) Experiment 1: We can measure glucose level at CSF/(LA +CSF) of 0.5 in 2% lidocaine group and 0.6 in 0.5% bupivacaine group. (2) Experiment 2: We can detect glucose at lower level of CSF/(LA +CSF) by glucose meter than urine stick test (p<0.05). (3) At least 0.35 ml of 2% lidocaine and 0.29 ml of 0.5% bupivacaine was needed respectively to detect precipitation. CONCLUSION: We suggest that blood glucose meter be used instead of glucose test strip. For thiopental precipitation test, we have to adjust the amount of thiopental depending on the amount of test fluid.

Tests to Differentiate Cerebrospinal Fluid from Local Anesthetics during Epidural Anesthesia / 대한마취과학회지

BACKGROUND: One of the most serious risks of epidural anesthesia is total spinal blockade from unintentional dural puncture. We evaluated the glucose test and the thiopental precipitation test to differentiate cerebrospinal fluid (CSF) from local anesthetics (LA). METHODS: (1) Experiment 1: CSF from twenty patients was serially diluted with 2% lidocaine or 0.5% bupivacaine. The ratio of CSF to LA-CSF mixture (CSF/(LA+CSF)) was from 0 to 1.0 at an interval of 0.1. We measured the glucose level of each sample with blood sugar meter. (2) Experiment 2: CSF from a hydrocephalus patient was serially diluted and its glucose level of each sample was measured in the same way as Experiment 1. We performed a urine stick test with each sample. Ten anesthetists blinded to the nature of the sample were asked to identify the results of the tests. (3) Experiment 3: Two milimeters of 2.5% thiopental was respectively mixed with local anesthetics, the amount of which was from 0.1 to 1.0 ml at an interval of 0.1 ml. Sixteen anesthetists blinded to the nature of sample were asked to identify the results of the tests. RESULTS: (1) Experiment 1: We can measure glucose level at CSF/(LA +CSF) of 0.5 in 2% lidocaine group and 0.6 in 0.5% bupivacaine group. (2) Experiment 2: We can detect glucose at lower level of CSF/(LA +CSF) by glucose meter than urine stick test (p<0.05). (3) At least 0.35 ml of 2% lidocaine and 0.29 ml of 0.5% bupivacaine was needed respectively to detect precipitation. CONCLUSION: We suggest that blood glucose meter be used instead of glucose test strip. For thiopental precipitation test, we have to adjust the amount of thiopental depending on the amount of test fluid.

The Effect of Hemodynamic Changes on the Regression of Sensory Analgesia after Epidural Block / 대한마취과학회지

BACKGROUND: The aim of this study was to compare the difference in regression of sensory analgesia on hemodynamic changes between bupivacaine and lidocaine in epidural blockade. METHODS: The thirty-six patients (ASA physical status Ior II) scheduled for elective cesarean section, we performed lumbar epidural blockade using 2% lidocaine (group I, II) or 0.5% bupivacaine (group III, IV). Eighty minutes after surgery, we divided the patients into 4 groups: The group I, III received normal saline, 20 ml, for 30 min; the group II, IV received normal saline, 20 ml, containing ephedrine, 2 mg ml, for 30 min. We compared the regression of sensory analgesia at 80 min with that at 140 min. RESULTS: The proximal extent of sensory analgesia at 140 min was significantly lower than that at 80 min in group II. However, no such significant changes occurred in group I, III, IV. CONCLUSIONS: The ephedrine-induced blood pressure increase accelerates regression of epidural blockade using lidocaine. We thought that even moderate and clinically insignificant cardiovascular activation by anxiety or pain can be a cause of reduction in the efficacy and duration of epidural blockade.

Direction of Catheter Insertion and Spread of Sensory Block during Lumbar Epidural Anesthesia / 대한마취과학회지

BACKGROUND: Endoscopic urologic surgery including transurethral resection of prostate (TURP) requires adequate sacral analgesia for insertion of resectoscope. But epidurally administered local anesthetic does not produce anesthetic effects uniformly. Failure to completely block S1 during epidural anesthesia because of the large size of nerve root has been noted. The purpose of this study to compare the relation between catheter direction and sensory anesthesia. METHODS: Thirty patients scheduled for endoscopic urologic surgery were enrolled. The epidural catheter was inserted at L3-4 using a standard 18 gauge Tuohy needle. In group A (n=15), the Tuohy needle with bevel pointed in a cephalad direction during catheter insertion. In group B (n=15), it pointed caudally. And the catheter was introduced 3 cm into the epidural space. After test dose, 2% lidocaine 5 cc, 0.5% bupivacaine 5 cc and 2% lidocaine 3 cc were administered with fractionate dose through it. The extent of the sensory anesthesia to loss of cold sensation and pin prick test was measured every 5minute for 30 minutes. RESULTS: Analgesia spread to loss of cold sensation and pin prick test was no significant statistical difference between the two groups. In 15 minutes after injection of surgical dose, complete blockade in L5, S1 dermatome was present in both groups. CONCLUSION: Our results conclude that epidural catheter direction is not significantly influence the epidural anesthetic spread including sacral area in continuous lumbar epidural anesthesia in elderly patients.