Technical communication: the effect of the double mask on anesthetic waste gas levels during pediatric mask inductions in dental offices.

A significant portion of office-based general anesthesia for pediatric patients is performed in dental offices and involves mask inductions with inhaled drugs. This can lead to significant pollution with waste gases. We assessed occupational exposure to anesthetic drugs during pediatric general anesthesia in dental offices and assessed the effectiveness of the "double mask." Nine freestanding dental offices had measurements of anesthetic waste gas levels taken before and immediately after implementation of a double-mask system. Levels of nitrous oxide decreased from a median of 40.0 parts per million (ppm; interquartile range [IQR] = 23.0-46.0 ppm, n = 9) to 3.0 ppm, (IQR = 2.3-4.7 ppm, n = 9, P = 0.0055) and exceeded 25 ppm in 0% of the 9 offices (upper 95% confidence limit 34%) when using the double mask. Levels of sevoflurane decreased from a median of 4.60 ppm (IQR = 3.10-7.00 ppm, n = 9) to 0 ppm (IQR = 0-0.39 ppm, n = 9, P = 0.0024) and exceeded 2 ppm in 0% of the 9 offices (upper 95% confidence limit 34%) when using the double mask. We demonstrated in our study that the double-mask system, when used with dental "high-volumes" suctions (high-volume evacuators producing approximately 12 m(3)/h) in freestanding dental offices, was sufficient to decrease the exposure to anesthetic waste gas during pediatric mask induction in at least two thirds of offices when compared with the traditional mask.

[Spanish Society of Anaesthesia (SEDAR) guidelines for pre-anaesthesia checking procedures]. / Directrices de procedimientos de comprobación y validación («chequeo¼) previos a la anestesia de la Sociedad Española de Anestesiología.

We present this document as a guide to preparing a specific institutional pre-anaesthesia checklist, as recommended in the Helsinki declaration on patient safety in anaesthesiology. Also, the recently recommended WHO "safe surgery check-list" includes a check-list for anaesthesia. A working group was established in accordance with the charter of the Spanish Society of Anaesthesiology and Resuscitation (Sociedad Española de Anestesiología y Reanimación [SEDAR]). The new patient safety culture introduced into medicine, and the recommendations of European anaesthesia societies has led us to design and update protocols in order to improve results in this important part of our speciality. We have prepared these recommendations or guidelines using, as examples, updates of pre-anaesthesia check-lists by other American (ASA), British, or Canadian societies of anaesthesia. With that aim, we enlisted the help of anaesthesia ventilator experts and the participation and advice of experienced anaesthesiologists from all parts of Spain. After various corrections and modifications, the document was available at www.sedar.es, so that any anaesthesiologist could propose any correction, or give their opinion. Finally, these guidelines have been approved by the SEDAR Board of Directors, before it was sent for publication in this journal. The aims of this document are to provide: a guideline applicable to all anaesthesia machines, a descriptive pre-anaesthesia check-list that include everything necessary for the anaesthesia procedure, and a resumed check-list to be available in all the anaesthesia machines or other equivalent, but prepared for each institution, which should include anaesthetic equipment and drugs. So, in order to ensure the aims and requirements of the European Board of Anaesthesiology, the European Society of Anaesthesiology, and the WHO are met, each institution should have a protocol for checking equipment and drugs. These guidelines are applicable to any anaesthesia equipment, enabling every institution to develop their own checking protocols, adapted to their anaesthesia machines and their procedures. With the consent of the SEDAR, this group will collaborate with anaesthesia machines providers in order to develop specific checklists for each of their models that will be available at www.sedar.es.

Centrales de gases medicinales tipo descritos en la norma EN-737-3 / Medical gas systems described in standard EN-737-3

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Análisis físico-matemático de la influencia de las condiciones ambientales locales en las prestaciones del vacío medico / Physical-mathematical analysis of the influence of local weather conditions on the performance of the medical vacuum

Para elaborar este trabajo se ha partido de una central de referencia: a nivel del mar (760 mm Hg) y 20 ºC, y la cruzamos con los datos de 90 observatorios meteorológicos de España viendo cómo se alteran sus prestaciones. Influencia de la presión atmosférica local Influencia en la toma La potencia disminuye al disminuir la presión atmosférica ambiente. Por ejemplo en Soria (668 mm Hg) la potencia se reduce un 12,11 por ciento respecto a si la misma toma estuviese a nivel del mar. Influencia en la capacidad de las centrales Se ha realizado un análisis bajo dos criterios: 1. Conseguir un vacío de -500 mm Hg sobre la presión atmosférica local sin corregir el caudal ambiente (consideramos el caudal ambiente como geométrico). Si el nominal de dos hospitales gemelos (uno al nivel del mar y otro en Soria) fuera de 200 m3/h según norma HTM-22, pero en Soria deberían ser 270 m3 /h. Una proporción importante de observatorios necesitaría un incremento entre el 10 y el 20 por ciento. Hay casos extremos, variaciones mayores del 50 por ciento, como Izaña con un factor de corrección máximo de 2,62 (con respecto al caso anterior en lugar de 200 seria 524 m 3/ h).2. Dimensionar la central necesaria para suministrar la misma potencia que si estuviera al nivel del mar, pero corrigiendo los diferentes caudales ambientes. Siguiendo con el ejemplo de Soria obtenemos bajo este nuevo criterio un factor de corrección es de 1,5 veces. En el mismo caso de los hospitales gemelos (uno a nivel del mar y el otro en Soria) el de Soria se necesitarla 300 m3 /h en lugar de los 200 m3 /h mencionados. Como antes Izaña es el lugar con el máximo factor de corrección: 3,25 (lo que implicaría una central de 650 m3/h).Uno de cada cinco observatorios precisaría un incremento de capacidad entre el 20 y el 30 por ciento y uno de cada 20 precisaría un incremento mayor del 50 por ciento. Influencia de la temperatura local Aunque el hospital esté climatizado, las salas de máquinas no lo están y el gas circulante por la red de vacío tenderá a tomar la temperatura ambiente de la central. Por ejemplo, si la temperatura de la sala de máquinas es de 40ºC implica que el caudal de la bomba tendrá que ser un 6,8 por ciento más grande para compensar el aumento de temperatura con respecto a la referencia de 20°C.Sevilla es el lugar con una variación máxima: 1,09. Como estadística, utilizando sólo las temperaturas máximas registradas, hay que decir que la mayoría de observatorios, precisarían un incremento de capacidad mayor del 7 por ciento, en los casos más extremos, se necesitarían incrementos del 9 por ciento. Conclusiones Las condiciones climatológicas son factores a tener en cuenta en el diseño de centrales de vacío medico (AU)

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A long-term study of the development of N2O controls at a pediatric dental facility.

A review is given of National Institute for Occupational Safety and Health (NIOSH) efforts to control N2O at a pediatric dental operatory from 1978 to the present. Measurements of N2O concentrations were made on four occasions before and after installation of different controls, using an infrared analyzer. Air velocity and volumetric flow measurements also were taken, Video imaging was done in some cases simultaneously with real-time N2O measurements to correlate work practices with exposure data. An infrared imaging system was used to identify sources of N2O. Critical components of resulting recommendations for control include monitoring of N2O concentrations; use of engineering controls, such as a scavenging mask, an effective dilution ventilation system, and auxiliary exhaust; good work practices; maintenance of the equipment; and worker education. Data presented strongly supports the hypothesis that better implementation of controls leads to reduction of N2O exposures. N2O concentrations were reduced by a factor of 61 from their initial levels. The current NIOSH recommended exposure limit of 25 ppm TWA during the time of N2O administration appears to be achievable.

Evaluation of a double-enclosure double-vacuum unit scavenging system for ribavirin administration.

BACKGROUND: Because of our concern for the safety of bedside caregivers who care for infants receiving ribavirin for long periods of time each day for many days, we evaluated the effectiveness of a double-tent enclosure with vacuum scavengers during simulated and actual patient administration. MATERIALS & METHODS: Part 1--We sought to determine whether two or three scavenging pumps were necessary, by 3 8-h trials with 2 pumps and 3 8-h trials with 3 pumps. Entry into and replacement of mannequin occurred according to protocol. Continuous samples were obtained from three locations in the room. Part 2--The double-tent, double-pump scavenger system was evaluated with patient simulation for a 16-h period. Part 3--The double-tent, double-pump system was evaluated during actual patient use. Air samples were also collected during ribavirin administration via mechanical ventilator circuit with filters in the expiratory limb. Coded environmental samples were analyzed by liquid chromatography. RESULTS: Environmental levels were effectively decreased below published maximal acceptable levels. CONCLUSIONS: Use of a double-enclosure, double-pump scavenging system and implementation of entry protocols ensure reduction of environmental ribavirin levels below recommended maximum levels during administration to spontaneously breathing patients. Use of expiratory filters adequately controls environmental ribavirin levels during mechanical ventilation.

Determination of contamination of a chemical warfare-proof operating theatre with volatile anaesthetic agents and assessment of anaesthetic gas scavenging systems.

Three types of anaesthetic waste scavenging systems (active antipollution system, Papworth Block passive system and activated charcoal absorber system) were compared with a non-scavenging control to assess their effectiveness in reducing waste halothane concentrations in a chemical warfare-proof operating theatre. All three systems were found to reduce the level of pollution significantly.

Assessment of a scavenging device for use in paediatric anaesthesia.

We describe a scavenging device, primarily for use during inhalation induction of anaesthesia in children; it was designed to optimize the often conflicting requirements of clinical acceptability and adequate gas collection. The performance was assessed in three ways. The device reduced the nitrous oxide concentration in the breathing zone of the anaesthetist during inhalation induction to about 100 p.p.m. We also describe a method to measure the direct catchment of nitrous oxide expressed as a percentage of the total nitrous oxide used. In 46 patients the mean percentage collection was 82%. Using personal sampling devices, we found that comprehensive scavenging in paediatric anaesthesia can reduce the average exposure of anaesthetists to about 130 p.p.m. of nitrous oxide.