ABSTRACT
OBJECTIVES: To determine whether the appearance of glucose in the fluid spontaneously obtained by the epidural catheter after its insertion during combined intradural-epidural anaesthesia with hyperbaric bupivacaine is a usual occurrence. PATIENTS AND METHODS: A prospective, observational study was conducted on 34 patients with combined intradural-epidural anaesthesia in whom an epidural catheter was introduced, after locating the epidural space with a saline solution, inserting a spinal needle and injecting hyperbaric bupivacaine. After observing whether any fluid was spontaneously dripping from it, it was determined if this contained glucose. Withdrawal of the needle and washing its lumen with saline solution, it was checked whether there was glucose in washout. The samples were analysed using a glucose meter. When the motor block disappeared a dose of local anaesthetic was administered through the epidural catheter. The relationship of the demographic parameters with the spontaneous dripping of the epidural catheter was evaluated. RESULTS: Spontaneous dripping by the epidural catheter after its insertion was observed in 22 patients. All the samples obtained contained glucose. There was glucose in 9 out of 34 epidural needle wash samples. None of the patients suffered from excessive motor-sensory block. There was a statistically significant relationship between patient age (P<.05) and spontaneous dripping by the catheter (the higher the age, more dripping). CONCLUSION: The finding of glucose in the fluid obtained by the epidural catheter is a frequent occurrence and is of no clinical significance. We propose that it could be due to a leak of cerebrospinal fluid by the dural puncture needle during or after the administering of the hyperbaric bupivacaine and the spillage of this into the epidural space.
Subject(s)
Anesthesia, Epidural , Bupivacaine/administration & dosage , Glucose/cerebrospinal fluid , Adult , Aged , Anesthesia, Epidural/instrumentation , Anesthesia, Epidural/methods , Blood Glucose/analysis , Catheters , Dura Mater/injuries , Epidural Space , Female , Humans , Male , Middle Aged , Needles , Pressure , Prospective Studies , PuncturesABSTRACT
BACKGROUND: Intraoperative monitoring of cerebral ischemia with shunting during carotid endarterectomy (CEA) remains controversial. Our objective was to evaluate the sensitivity and specificity of BIS changes during carotid clamping in relation to shunted patients in awake CEA. METHODS: Eighty CEAs under cervical block were included. There were two patient groups: with clinical signs of cerebral ischemia (shunted patients) and without signs of cerebral ischemia (nonshunted patients). Data were based on bispectral index (BIS) values and neurological monitoring at different surgery time points, with special attention paid during carotid clamping. BIS values were compared between shunted and nonshunted patients. Sensitivity and specificity, along with positive and negative predictive values of a percentage BIS value decrease during carotid clamping from baseline BIS values, were calculated in both patient groups. RESULTS: Shunting was performed in 11 patients with cerebral ischemia at carotid clamping. Mean BIS values were 82.82+/-11.98 in shunted patients and 92.31+/-5.42 in nonshunted patients at carotid clamping (p<0.001). Relative decreased BIS values in relation to basal BIS values were 13.57% in shunted patients and 3.68% in nonshunted patients (p<0.05). The percentage decrease in BIS was 14%, sensitivity was 81.8% (95% CI 49.9-96.8), and specificity was 89.7% (95% CI 79.3-95.4). CONCLUSION: BIS monitoring during carotid clamping is an easy, noninvasive method which correlates with cerebral ischemia in patients undergoing CEA. A decrease>or=14% from the basal BIS value presents a high negative predictive value, and ischemia is unlikely without a decrease. Nonetheless, a decrease may not always indicate cerebral ischemia with a low positive predictive value.
