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)

[Comparison of 2 devices to measure spinal fluid glucose concentration in hyperbaric spinal anesthesia]. / Comparación de dos sistemas de medida de las concentraciones de glucosa en líquido cefalorraquídeo en la anestesia intradural hiperbara.

OBJECTIVES: To compare spinal fluid glucose measurements recorded by the laboratory analyzer Synchron LX20 Pro and the glucometer Ascensia Elite XL during continuous spinal anesthesia after injection of 10 mg of hyperbaric bupivacaine, in order to assess the reliability and speed of the 2 devices for monitoring changes in glucose concentration. PATIENTS AND METHODS: Prospective study of 34 patients under continuous spinal anesthesia administered through a 22-gauge catheter; 9 samples of spinal fluid were extracted from each patient for glucose level measurement. The first extraction was before administration of the anesthetic and the remaining ones were during spinal anesthesia until the end of complete motor block. Correlation was assessed with the Pearson test and agreement with the Bland-Altman method. RESULTS: A total of 241 pairs of measurements were obtained. The correlation was r = 0.96 (P < .01). The mean (SD) difference in measurements from the 2 devices was -1.06 (34.82 mg x dL(-1)). The percentage of variation (systematic error) was -1.9% (11.8%), placing the 95% confidence interval between -25% and 21.2%. CONCLUSIONS: Measurements from the 2 devices are highly correlated. The absolute and percentage systematic error (bias) is negligible. Finding that 95% of measurements are within 23% of the mean seems a fair percentage of error to us. We therefore believe the percentage variation, or systematic error, is clinically acceptable and that either device can be used.

Comparación de dos sistemas de medida de las concentraciones de glucosa en líquido cefalorraquídeo en la anestesia intradural hiperbara / Comparison of 2 devices to measure spinal fluid glucose concentration in hyperbaric spinal anesthesia

OBJETIVOS: Comparar las mediciones de glucorraquia realizadas en el Laboratorio con el autoanalizador Synchron LX20 PRO(R) (Beckman Coulter) con las realizadas con un glucómetro Ascensia EliteXL&Elite(R) durante la anestesia espinal, después de administrar 10 mg de bupivacaína hiperbara para así disponer de un método rápido y fiable al medir las cifras de glucorraquia durante una anestesia espinal continua y seguir su evolución. PACIENTES Y MÉTODOS: Estudio prospectivo de 34 pacientes bajo anestesia espinal continua con un catéter 22 G a través del cual se extrajeron 9 muestras por paciente de líquido cefalorraquídeo para determinar la glucorraquia, la primera antes de la administración del anestésico y los siguientes durante la anestesia espinal hasta el final del bloqueo motor completo. La correlación se midió con el test de Pearson y el grado de concordancia con el método de Bland-Altman. RESULTADOS: Se obtuvieron 241 pares de medidas. El coeficiente de correlación fue de r = 0,96 (p < 0,01). La diferencia media entre los dos métodos fue de –1,06 ± 34,82 mg dL–1. El porcentaje de variación (error sistemático) fue de –1,9 ± 11,8%, situándose el intervalo de confianza del 95% entre el –25% y el 21,2%. CONCLUSIONES: Se obtiene una buena correlación entre ambos métodos. El error sistemático absoluto y porcentual (bias), es despreciable. Encontrar el 95% de los valores con un margen de un 23% sobre la media del error porcentual nos parece razonable, por lo que consideramos la variación porcentual del error sistemático clínicamente aceptable para poder intercambiar ambos métodos de medida

OBJECTIVES: To compare spinal fluid glucose measurements recorded by the laboratory analyzer Synchron LX20 Pro and the glucometer Ascensia Elite XL during continuous spinal anesthesia after injection of 10 mg of hyperbaric bupivacaine, in order to assess the reliability and speed of the 2 devices for monitoring changes in glucose concentration. PATIENTS AND METHODS: Prospective study of 34 patients under continuous spinal anesthesia administered through a 22-gauge catheter; 9 samples of spinal fluid were extracted from each patient for glucose level measurement. The first extraction was before administration of the anesthetic and the remaining ones were during spinal anesthesia until the end of complete motor block. Correlation was assessed with the Pearson test and agreement with the Bland-Altman method. RESULTS: A total of 241 pairs of measurements were obtained. The correlation was r=0.96 (P<.01). The mean (SD) difference in measurements from the 2 devices was –1.06 (34.82 mg·dL-1). The percentage of variation (systematic error) was –1.9% (11.8%), placing the 95% confidence interval between -25% and 21.2%. CONCLUSIONS: Measurements from the 2 devices are highly correlated. The absolute and percentage systematic error (bias) is negligible. Finding that 95% of measurements are within 23% of the mean seems a fair percentage of error to us. We therefore believe the percentage variation, or systematic error, is clinically acceptable and that either device can be used

[Relation between glucose concentrations in cerebrospinal fluid and sensory and motor block during spinal anesthesia with hyperbaric bupivacaine]. / Relación de los niveles de la glucorraquia con el bloqueo sensitivo y motor durante la anestesia raquídea con bupivacaína hiperbara.

OBJECTIVE: To study the relation between cerebrospinal fluid (CSF) glucose levels, the highest level of sensory block, and the duration of motor block after intrathecal injection of 2 mL of hyperbaric bupivacaine. To determine CSF glucose levels upon recovery from motor block. PATIENTS AND METHODS: A prospective study of 34 patients administered a spinal anesthetic in continuous infusion through a 22-gauge catheter. CSF samples were extracted through the catheter 5, 10, 15, 20, 30, 45, and 60 minutes after start of infusion and upon motor recovery. After each extraction the intensity of the motor block was assessed; the intensity of the sensory block was assessed after each extraction up to 20 minutes. RESULTS: Glucose concentrations in CSF tended to decrease from 5 minutes (1027.07 [SD 349.04] mg dL(-1)) until full motor recovery (247.50 [20.39] mg dL(-1)). The probability of finding a motor block at a CSF glucose concentration of 287.5 mg dL(-1) or higher was less than 5%. We identified a positive correlation between the highest level of sensory block and the duration of full motor block (r=0.62, P<0.01) and between CSF glucose levels at the moment of greatest sensory block and upon full motor recovery (r=0.50, P<0.01). CONCLUSIONS: After continuous spinal anesthesia with hyperbaric bupivacaine, glucose concentrations in CSF are directly related to the highest level of sensory block, the course of the blockade, and its reversal.

Relación de los niveles de la glucorraquia con el bloqueo sensitivo y motor durante la anestesia raquídea con bupivacaína hiperbara / Relation between glucose concentrations in cerebrospinal fluid and sensory and motor block during spinal anesthesia with hyperbaric bupivacaine

OBJETIVO: Estudiar la relación de la glucorraquia conel nivel más alto del bloqueo sensitivo y con la duracióndel bloqueo motor después de la administración intratecalde 2 mL de bupivacaína hiperbara. Averiguar lascifras de glucorraquia al finalizar el bloqueo motor.PACIENTES Y MÉTODOS: Estudio prospectivo de 34pacientes bajo anestesia espinal continua con un catéter22 G, a través del cual se extraen muestras de líquidocefalorraquídeo para determinar la glucorraquia a los 5,10, 15, 20, 30, 45, 60 minutos y al final del bloqueomotor. Después de cada extracción se valora el grado delbloqueo motor y durante los primeros 20 minutos elnivel del bloqueo sensitivo.RESULTADOS: Se observa una tendencia descendente delos niveles de glucorraquia desde los 5 minutos (1027,07 ±349,04 mg dL-1), hasta el final del bloqueo motor completo(247,50 ± 20,39 mg dL-1). La probabilidad de no encontrarbloqueo motor con cifras de glucorraquia de 287,5 mgdL-1 o superiores es menor del 5%. Identificamos unacorrelación positiva entre el nivel más alto de bloqueo sensitivoy la duración del bloqueo motor completo (r = 0,62,p < 0,01) y entre las glucorraquias obtenidas en el momentodel nivel más alto de bloqueo sensitivo y al final del bloqueomotor completo (r = 0,50, p <0,01).CONCLUSIÓN: Después de una anestesia espinal continuacon bupivacaína hiperbara, la glucorraquia guardauna relación directa con el nivel más alto de bloqueosensitivo, la evolución y el final del bloqueo motor

OBJECTIVE: To study the relation between cerebrospinalfluid (CSF) glucose levels, the highest level of sensoryblock, and the duration of motor block after intrathecalinjection of 2 mL of hyperbaric bupivacaine. Todetermine CSF glucose levels upon recovery from motorblock.PATIENTS AND METHODS: A prospective study of 34patients administered a spinal anesthetic in continuousinfusion through a 22-gauge catheter. CSF samples wereextracted through the catheter 5, 10, 15, 20, 30, 45, and60 minutes after start of infusion and upon motor recovery.After each extraction the intensity of the motorblock was assessed; the intensity of the sensory blockwas assessed after each extraction up to 20 minutes.RESULTS: Glucose concentrations in CSF tended todecrease from 5 minutes (1027.07 [SD 349.04] mg dL-1)until full motor recovery (247.50 [20.39] mg dL-1). Theprobability not to find a motor block at a CSF glucoseconcentration of 287.5 mg dL-1 or higher was less than5%. We identified a positive correlation between the highestlevel of sensory block and the duration of full motorblock (r=0.62, P<0.01) and between CSF glucose levels atthe moment of greatest sensory block and upon fullmotor recovery (r=0.50, P<0.01).CONCLUSIONS: After continuous spinal anesthesia withhyperbaric bupivacaine, glucose concentrations in CSFare directly related to the highest level of sensory block,the course of the blockade, and its reversal