RESUMEN
Tsunamis are rare, extreme events and cause significant damage to coastal infrastructure, which is often exacerbated by soil instability surrounding the structures. Simulating tsunamis in a laboratory setting is important to further understand soil instability induced by tsunami inundation processes. Laboratory simulations are difficult because the scale of such processes is very large, hence dynamic similitude cannot be achieved for small-scale models in traditional water-wave-tank facilities. The ability to control the body force in a centrifuge environment considerably reduces the mismatch in dynamic similitude. We review dynamic similitudes under a centrifuge condition for a fluid domain and a soil domain. A novel centrifuge apparatus specifically designed for exploring the physics of a tsunami-like flow on a soil bed is used to perform experiments. The present 1:40 model represents the equivalent geometric scale of a prototype soil field of 9.6 m deep, 21 m long, and 14.6 m wide. A laboratory facility capable of creating such conditions under the normal gravitational condition does not exist. With the use of a centrifuge, we are now able to simulate and measure tsunami-like loading with sufficiently high water pressure and flow velocities. The pressures and flow velocities in the model are identical to those of the prototype yielding realistic conditions of flow-soil interaction.
RESUMEN
BACKGROUND: Dural puncture, paraesthesia and vascular puncture are the most common complications of epidural catheter insertion. Their association with variation in midline needle insertion depth is unknown. OBJECTIVE: This study evaluated the risk of dural and vascular punctures and the unwanted events paraesthesia and multiple skin punctures related to midline needle insertion depth. MATERIAL AND METHODS: A total of 14,503 epidural catheter insertions including lumbar (L1-L5; nâ¯= 5367), low thoracic (T7-T12, nâ¯= 8234) and upper thoracic (T1-T6, nâ¯= 902) insertions, were extracted from the German Network for Regional Anaesthesia registry between 2007 and 2015. The primary outcomes were compared with logistic regression and adjusted (adj) for confounders to determine the risk of complications/events. Results are presented as odds ratios (OR, [95% confidence interval]). MAIN RESULTS: Midline insertion depth depended on body mass index, sex, and spinal level. After adjusting for confounders increased puncture depth (cm) remained an independent risk factor for vascular puncture (adjOR 1.27 [1.09-1.47], pâ¯= 0.002) and multiple skin punctures (adjOR 1.25 [1.21-1.29], pâ¯< 0.001). In contrast, dural punctures occurred at significantly shallower depths (adjOR 0.73 [0.60-0.89], pâ¯= 0.002). Paraesthesia was unrelated to insertion depth. Body mass index and sex had no influence on paraesthesia, dural and vascular punctures. Thoracic epidural insertion was associated with a lower risk of vascular puncture than at lumbar sites (adjOR 0.39 [0.18-0.84], pâ¯= 0.02). CONCLUSION: Variation in midline insertion depth is an independent risk factor for epidural complications; however, variability precludes use of depth as a reliable guide to insertion in individual patients.
Asunto(s)
Anestesia Epidural/efectos adversos , Adulto , Anciano , Anestesia Epidural/instrumentación , Anestesia Epidural/estadística & datos numéricos , Anestesia Obstétrica , Cateterismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Agujas , Punciones/estadística & datos numéricos , Factores de RiesgoRESUMEN
BACKGROUND: To analyze safety issues of regional anaesthesia and analgesia in Germany only a few single center studies are available. Therefore, the German Society for Anaesthesiology and Intensive Care Medicine (Deutschen Gesellschaft für Anästhesiologie und Intensivmedizin, DGAI) and the Professional Association of German Anaesthetists (Berufsverband Deutscher Anästhesisten, BDA) initiated a network for safety in regional anaesthesia. From this the first results on infectious complications will be reported. MATERIALS AND METHODS: In a Delphi process the documentation of the setup and maintenance of regional anaesthesia and analgesia was agreed with the participants in a working group from the DGAI. After approval by the officially authorized representative for patient data privacy protection a registry was programmed to collect anonymous data. Up to October 2008 data from 6 centers could be analyzed. RESULTS: After testing for plausibility 8,781 regional anaesthesia procedures (22,112 catheter days) could be analyzed. The 5,057 neuraxial and 3,724 peripheral catheter-based procedures were in place for a median of 2.48 days (range 1.0-3.0 days) and 4 severe, 15 moderate and 128 mild infections were recorded. Diabetics were not found to show a statistically significant increase in risk (2.6% compared to 1.9% for non-diabetics: n.s.). Neuraxial procedures seem to have a higher rate of infections than peripheral procedures (2.7% vs. 1.3%, p<0.0001). Multiple punctures of the skin also seem to be associated with a higher infection rate than single skin punctures (4.1% vs. 1.6%, p<0.0001). CONCLUSIONS: Infectious complications of catheter-based regional anaesthesia are common. Strict hygienic standards must therefore be complied with. More data are necessary to calculate risk factors. The registry provided can also be used as a benchmark to reduce these rates further.
Asunto(s)
Anestesia de Conducción/efectos adversos , Infecciones Relacionadas con Catéteres/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Analgesia/efectos adversos , Anestesia Epidural/efectos adversos , Anestesia Raquidea/efectos adversos , Infecciones Relacionadas con Catéteres/prevención & control , Niño , Preescolar , Técnica Delphi , Complicaciones de la Diabetes/epidemiología , Documentación , Femenino , Alemania/epidemiología , Humanos , Higiene , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Bloqueo Nervioso/efectos adversos , Sistema de Registros , Riesgo , Seguridad , Adulto JovenRESUMEN
Portable digital assistants (PDAs) may be of value to the anaesthesiologist as development in medical care is moving towards "bedside computing". Many different portable computers are currently available and it is now possible for the physician to carry a mobile computer with him all the time. It is data base, reference book, patient tracking help, date planner, computer, book, magazine, calculator and much more in one mobile device. With the help of a PDA, information that is required for our work may be available at all times and everywhere at the point of care within seconds. In this overview the possibilities for the use of PDAs in anaesthesia and intensive care medicine are discussed. Developments in other countries, possibilities in use but also problems such as data security and network technology are evaluated.