Eco-doppler transcraneal. Utilización en anestesiología / Transcranial doppler ultrasonography. Use in anesthesilogy

El efecto Doppler ha sido utilizado en numerosas parcelas científicas, incluida la anestesiología. La información que muestra la ecografía Doppler transcraneal relativa a los índices de pulsatilidad y resistencia, derivadas del estudio de la velocidad de flujo sanguíneo intracerebral, supone un avance en el estudio del comportamiento de los distintos fármacos y técnicas anestésicas. Se muestra aquí una breve descripción de los fundamentos de uso en anestesiología y la utilidad que puede presentar como sistema de monitorización compleja aunque no invasiva, en el conocimiento de los patrones específicos de comportamiento que presentan los fármacos más utilizados actualmente respecto de la velocidad de flujo intracranial (AU)

The Doppler effect is used in many scientific fields, even anaesthesiology. The inform data showed by the transcranial Doppler ultrasound, regarding to pulsatility or resistance index, derived from the study of the behaviour of the different drugs and anaesthetic techniques. We present here a brief description of the use basis in anaesthesiology and the utility that can present like a complex although non-invasive monitoring system in knowledge of the specific pattern behaviour that the more actually utilized drugs present respect to the cerebral blood flow velocity(AU)

Monitorización intratraqueal de gases en anestesia / Intratracheal gases monitoring in anaesthesia

Los avances tecnológicos en el análisis de gases y su incorporación a todas las máquinas actuales de anestesia han permitido la monitorización de los agentes halogenados en la anestesia inhalatoria. El primer descubrimiento de la monitorización intratraqueal encontró que el ETCO2 intratraqueal era muy similar a los valores alveolares de ETCO2 porque sus valores eran casi los mismos que los valores arteriales. Además estos eran diferentes a los valores extratraqueales aunque existía una buena correlación. Sin embargo, las diferencias intra- y extratraqueales de los gases halogenados y el N2O no fueron estudiados. Recientemente se han descubierto diferencias significativas en la monitorización intratraqueal de gases. Este tipo de monitorización puede ser muy útil en el futuro en pacientes críticos, pediátricos y ofrecer un buen control del Et de los vapores halogenados cuando no se dispone de sistemas de monitorización de hipnosis. Son analizadas las ventajas e inconvenientes de este tipo novedoso de monitorización intratraqueal con un prometedor futuro (AU)

Technology advantages in gases analyse and their supply inmost anaesthesia machines have improved halogenated agents monitoring in inhaled anaesthesia. The first discovering about endotracheal monitoring found intratracheal ETCO2 were very similar to alveolar ETCO2 because their values were almost the same to arterial values. Moreover these ones are different to extratracheal values but there were good correlation level. However, intra and extratracheal differences of halogenated gases and N2O were not studied. Lately, it has discovered significant differences in intratracheal gases monitoring during paediatric anaesthesia. This kind of monitoring can be very useful in the future in critical, paediatric patients and offers a good control of Et halogenated vapors when we don’t have hypnosis monitoring. Advantages and disadvantages are studied of this new intratracheal monitoring system with a promised future (AU)

[Monitoring airway gas in pediatric anesthesia: an experimental model for endotracheal gas measurement]. / Monitorización de los gases de la vía aérea en anestesia pediátrica. Presentación de un modelo experimental de medición endotraqueal de gases.

BACKGROUND: We designed an endotracheal probe for measuring inspired and expired gas fractions during pediatric general anesthesia. OBJECTIVE: To compare the gas fractions measured by means of intratracheal and extratracheal monitoring. MATERIAL AND METHODS: The study included ASA 1 patients between the ages of 7 and 12 years under inhaled anesthesia with mechanical ventilation. The following parameters were recorded inside and outside the trachea: inspired and expired oxygen, nitric oxide (N2O) and sevoflurane fractions; the expired and inspired fraction gradients; PaCO2; and end-tidal carbon dioxide (ETCO2). Measurements were taken by an airflow sensor (Pedi-Lite) in the circuit before the point of connection to the endotracheal tube and by an intratracheal probe placed between the tube and the carina. Both sensors were connected to the same monitor. Measurements were taken on intubation and 5, 10, 15, 20, 30, 40, 50, and 60 minutes thereafter. PaCO2 was recorded at the same time. The recorded values were analyzed using the t test and the Pearson product moment correlation coefficient (r), and regression models were constructed using analysis of variance. RESULTS: Seventy-one patients were enrolled in the study. The mean difference (SD) ETCO2 was 5 (3) mm Hg higher according to endotracheal measurement (P < .005), and that measurement was almost identical (+/-13 mm Hg) to the PaCO2 (P < or = .5). The inspired/expired gradients of endotracheal measurement of oxygen and N2O were 3 (2) points higher (P < .05) than the gradients of extratracheal measurements. In the case of sevoflurane gradients, however, the extratracheal values were higher (mean difference, 0.6 [0.2] points, P < .05). The inspired/expired oxygen and N2O gradients became equal after 18 (3) minutes; the sevoflurane gradients became equal after 8 (2) minutes. CONCLUSIONS: Intratracheal and extratracheal measurements of the inspired and expired fractions of mixed gases provide different results.

Monitorización de las presiones intratraqueales en anestesia / No disponible

Durante la monitorización anestésica, la presión de la vía aérea se obtiene en el respirador o en la conexión más proximal al tubo endotraqueal. La diferencia de las mediciones de las presiones dentro y fuera de la tráquea se debe a la resistencia del tubo, de manera que los valores de la presión pico extratraqueal son mayores que los valores de la presión máxima traqueal. Existen diferentes métodos de medición de presiones intratraqueales. Los más utilizados son las sondas rellenas de gas o suero, de luz terminal o lateral. Otros métodos con sensores distales y sondas de fibra óptica o electrodos también han sido utilizados. A pesar de la dificultad para interpretar los bucles de presión volumen y el trabajo respiratorio, estos sistemas tienen un futuro prometedor en la monitorización de pacientes críticos, pediátricos y de distrés respiratorio (AU)

During anaesthesia monitoring, airway pressure is obtained inside the anaesthesia machine or in the connecting more proximal to endotracheal tube. The difference in the measurement of pressure inside or outside of trachea is due to the tube resistance, so the pick pressure extratracheal values are higher than pick pressure intratracheal values. There are different methods of intratracheal pressure measurement. The most used to gas or liquid full cannulas, with lateral or end tip. Other methods with distal sensor and optic fibber or electrodes have been used too. In spite of the difficulty for interpretation of pressure-volume loops and work breathing, these systems have a promising future in critical, paediatric and distress patients monitoring (AU)

Monitorización de los gases de la vía aérea en anestesia pediátrica. Presentación de un modelo experimental de medición endotraqueal de gases / Monitoring airway gas in pediatric anesthesia: an experimental model for endotracheal gas measurement

INTRODUCCIÓN: Diseñamos una sonda endotraqueal para medir fracciones inspiradas y espiradas de los gases de la mezcla durante anestesia general pediátrica. OBJETIVOS: Comparar los gases analizados en el circuito, mediante monitorización intra y extratraqueal, y comprobar sus posibles diferencias. MATERIAL Y MÉTODOS: Pacientes de 7 a 12 años; ASA I; bajo anestesia inhalatoria en ventilación mecánica. Se analizan dentro y fuera de la tráquea, fracciones inspiradas (Fi) y espiradas (Fe) de O2/N2O/Sevoflurano; la relación Fe/Fi; presión arterial de CO2 (PaCO2); y end tidal CO2 (ETCO2); mediante medición previa al tubo endotraqueal (TET) desde pedi-lite, y mediante sonda en tráquea, anterior a la carinay posterior al TET. Ambos dispositivos fueron conectadosal mismo monitor. Se realizaron mediciones en inicio, 5’,10’, 15’, 20’, 30’, 40’, 50’ y 60 minutos tras ntubación, y de PaCO2 en los mismos tiempos. Se compararon valoresmedios (T Student), coeficiente correlación de Pearson (r), y se determinaron modelos de regresión (ANOVA).RESULTADOS: Incluimos 71 pacientes. La diferencia media (DE) de ETCO2 fue 5(±3) mmHg superior para la medición endotraqueal (p < 0,005), casi coincidente (±1,3 mmHg) con la PaCO2 (p ≤ 0,5). Los gradientes (DE) de Fi-Fe O2/N2O fueron 3 (±2) puntos superiores en la mediciónendotraqueal (p < 0,05). Sin embargo, sevoflurano presentódiferencia media extratraqueal superior 0,6 (±0,2) puntos(p < 0,05). Conforme avanza el tiempo anestésico, losgradientes Fi-Fe O2/N2O, se equiparan transcurridos 18(±3) minutos, para sevoflurano esto sucede en 8 (±2) minutos. CONCLUSIONES: Las fracciones inspiradas y espiradas de los gases de la mezcla son distintos, según se realice la medición intra o extratraqueal (AU)

BACKGROUND: We designed an endotracheal probe for measuring inspired and expired gas fractions during pediatric general anesthesia. OBJECTIVE: To compare the gas fractions measured by means of intratracheal and extratracheal monitoring. MATERIAL AND METHODS: The study included ASA 1 patients between the ages of 7 and 12 years under inhaled anesthesia with mechanical ventilation. The following parameters were recorded inside and outside the trachea: inspired and expired oxygen, nitric oxide (N2O) and sevoflurane fractions;the expired and inspired fraction gradients; PaCO2; andend-tidal carbon dioxide (ETCO2). Measurements were takenby an airflow sensor (Pedi-Lite) in the circuit before the point of connection to the endotracheal tube and by an intratracheal probe placed between the tube and the carina. Both sensors were connected to the same monitor. Measurements were taken on intubation and 5, 10, 15, 20, 30, 40, 50, and 60 minutes thereafter. PaCO2 was recorded at the same time. The recorded values were analyzed using the t test and the Pearson product moment correlation coefficient (r), and regression models were constructed using analysis of variance. RESULTS: Seventy-one patients were enrolled in the study. The mean difference (SD) ETCO2 was 5 (3) mm Hg higher according to endotracheal measurement (P < .005), and that measurement was almost identical (±1.3 mm Hg) to the PaCO2 (P ≤ .5). Theinspired/expired gradients of endotracheal measurement of oxygen and N2O were 3 (2) points higher (P< .05) than the gradients of extratracheal measurements. In the case of sevoflurane gradients, however, the extratracheal values were higher (mean difference, 0.6 [0.2] points, P < .05). The inspired/expired oxygen and N2O gradients became equal after 18 (3) minutes; the sevoflurane gradients became equal after 8 (2) minutes. CONCLUSIONS: Intratracheal and extratracheal measurements of the inspired and expired fractions of mixed gases provide different results (AU)