[The finding of glucose in the fluid obtained by epidural catheter after its insertion during combined intradural-epidural anaesthesia with hyperbaric bupivacaine is a usual occurrence]. / El hallazgo de glucosa en el fluido obtenido por el catéter epidural después de su inserción durante la anestesia combinada intradural-epidural realizada con bupivacaína hiperbara es un suceso habitual.

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.

Bispectral index changes in carotid surgery.

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.

Utilización del BIS como predictor de la amnesia anterógradaproducida por el midazolam intranasal administradocomo premedicación / The bispectral index as a predictor of anterograde amnesia caused by premedication with intranasal midazolam

OBJETIVOS: Determinar la capacidad del índice biespectral(BIS) como predictor de amnesia anterógrada para loseventos que ocurren desde la llegada a quirófano de lospacientes hasta la inducción anestésica, después de premedicarloscon 10 mg de midazolam intranasal.PACIENTES Y MÉTODOS: Pacientes intervenidos paracualquier intervención quirúrgica programada con anestesiageneral, después de monitorizarlos con el índice biespectraly administrarles 10 mg de midazolam por víaintranasal. Se observó el BIS hasta que empezó a bajar demanera continua y mantenida por debajo del valor de 90,se anotó el tiempo transcurrido y se les trasladó a quirófano.Todos los pacientes fueron sometidos a seis maniobrasrutinarias antes de la inducción. Finalizada la intervenciónse les interrogó sobre los recuerdos de las maniobras realizadas.Se estudiaron los valores de sensibilidad, especificidady valores predictivos; para obtener la cifra de BISque presenta una mejor combinación de sensibilidad yespecificidad, se trazó una curva ROC.RESULTADOS: Incluímos 55 pacientes, el tiempo mediotranscurrido en descender el valor de BIS fue 5,93 ± 2,93minutos. La sensibilidad total de la prueba es de 0,96 y laespecificidad de 0,60, el valor predictivo positivo de 0,91 yel valor predictivo negativo de 0,75. El valor global de laprueba es del 89,1%. El mejor valor de corte de la curvaROC es 83.CONCLUSIONES: La disminución del BIS por debajo delvalor de 90 se puede usar como predictor de amnesia anterógradatras la administración de 10 mg de midazolamintranasal (AU)

OBJETIVE: To determine the ability of the bispectralindex (BIS) to predict anterograde amnesia for eventsoccurring between the arrival of patients in the operatingtheater and anesthetic induction, following premedicationwith 10 mg of intranasal midazolam.PATIENTS AND METHODS: We enrolled patients scheduledfor any type of surgery under general anesthesia. Patientswere first monitored using the BIS and administered 10mg of intranasal midazolam. The BIS was monitored untilit began to fall steadily and remained below a value of 90;the elapsed time was recorded and the patient was takento the theater. All patients underwent 6 routine maneuversbefore induction. After surgery, patients were asked abouttheir memory of the maneuvers performed. Sensitivity,specificity, and predictive values were studied to obtain theBIS value that provided the best combination of sensitivityand specificity, and a receiver operating characteristic(ROC) curve was drawn.RESULTS: We enrolled 55 patients. The mean (SD) timetaken for the BIS value to fall was 5.93 (2.93) minutes. Thesensitivity of the test was 0.96 and specificity was 0.60. Thepositive predictive value was 0.91 and the negativepredictive value was 0.75. The test classified 89.1% of thepatients correctly. The ROC curve showed the best cutoffto be 83.CONCLUSIONS: A fall in the BIS to below 90 can be usedas a predictor for anterograde amnesia followingadministration of 10 mg of intranasal midazolam (AU)