Retrievals of aerosol optical and microphysical properties from Imaging Polar Nephelometer scattering measurements.

A method for the retrieval of aerosol optical and microphysical properties from in situ light-scattering measurements is presented and the results are compared with existing measurement techniques. The Generalized Retrieval of Aerosol and Surface Properties (GRASP) is applied to airborne and laboratory measurements made by a novel polar nephelometer. This instrument, the Polarized Imaging Nephelometer (PI-Neph), is capable of making high-accuracy field measurements of phase function and degree of linear polarization, at three visible wavelengths, over a wide angular range of 3 to 177°. The resulting retrieval produces particle size distributions (PSDs) that agree, within experimental error, with measurements made by commercial optical particle counters (OPCs). Additionally, the retrieved real part of the refractive index is generally found to be within the predicted error of 0.02 from the expected values for three species of humidified salt particles, with a refractive index that is well established. The airborne measurements used in this work were made aboard the NASA DC-8 aircraft during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field campaign, and the inversion of this data represents the first aerosol retrievals of airborne polar nephelometer data. The results provide confidence in the real refractive index product, as well as in the retrieval's ability to accurately determine PSD, without assumptions about refractive index that are required by the majority of OPCs.

Anestesia espinal y cirugía ambulatoria / Spinal anesthesia in Ambulatory Surgery

En los últimos años hemos asistido a un abandono de la anestesia espinal como técnica habitual en pacientes ambulatorios por el auge de la anestesia general. Esto se debe a los efectos adversos clásicamente asociados a su empleo y al retraso en el alta domiciliaria. Sin embargo, la irrupción en el mercado de los nuevos anestésicos locales de corta duración y la utilización de la anestesia subaracnoidea selectiva en procedimientos ortopédicos ha suscitado un interés creciente por esta técnica anestésica. Con este artículo pretendemos hacer una revisión de la anestesia espinal, de las indicaciones, contraindicaciones y de los efectos adversos asociados a la técnica. Finalmente, proponemos un resumen breve de los nuevos anestésicos locales de acción corta y unas recomendaciones para la cirugía proctológica y del miembro inferior (AU)

Recently, we have witnessed a drop of spinal anesthesia as a routine technique in outpatients by the rise of general anesthesia. This is due to the adverse effects typically associated with its employment and delayed discharge home. However, the introduction of new local anesthetics of short duration and the use of selective spinal anesthesia in orthopedic procedures has led to a growing interest in the anesthetic technique. We intend with this article to make a review of spinal anesthesia, including indications and contraindications and associated technical side effects. Finally, we provide a brief summary of the new short-acting local anesthetics and recommendations for the proctologic and lower limb surgery (AU)

Inducción inhalatoria con sevoflurano versus inducción inhalatoria con sevoflurano y remifentanilo en anestesia ambulatoria / Inhalatory induction whit sevoflurane versus inhalatory induction with sevoflurane and remifentanilo in ambulatory surgery

Objetivos: Determinar las condiciones de intubación orotraqueal, efectos secundarios y características hemodinámicas de la inducción anestésica inhalatoria con sevoflurano con o sin remifentanilo en pacientes sometidos a cirugía mayor ambulatoria sin relajantes neuromusculares. Material y métodos: Se realizó un estudio prospectivo, comparativo, aleatorizado y doble ciego en una muestra de 85 pacientes programados para timpanoplastia y septorinoplastia en régimen ambulatorio. La inducción anestésica se realizó por vía inhalatoria mediante dos técnicas: Grupo S (sevoflurano) y Grupo SR (sevoflurano y remifentanilo). Se evaluó el tiempo de pérdida del reflejo palpebral, el tiempo para alcanzar un valor de BIS menor o igual a 50, la aparición de eventos adversos durante la laringoscopia e intubación, las condiciones de intubación, variables hemodinámicas y respiratorias. Asimismo, se valoró el grado de satisfacción y confort de los pacientes con estas técnicas anestésicas. Resultados: De los pacientes incluidos inicialmente en el estudio se excluyó del análisis estadístico uno de cada grupo. Los tiempos de pérdida del reflejo palpebral fueron de 1,30 minutos en el grupo S vs. 1,24 minutos en el grupo SR y para alcanzar un valor de BIS menor o igual a 50 fue significativamente menor (p < 0,05) en el grupo SR (4,51 minutos) vs. grupo S (5,64 minutos). En el grupo S, las (..) (AU)

Objectives: To determine the intubation conditions, side effects and hemodynamic characteristics of inhalational anesthetic induction with sevoflurane with or without remifentanil in patients undergoing outpatient surgery without using neuromuscular relaxants. Materials and Methods: We performed a prospective, comparative, randomized, double-blind in a sample of 85 patients scheduled for tympanoplasty and septorhinoplasty on an outpatient basis. Anesthetic induction was performed by inhalation using two techniques: Group S (sevoflurane) and group SR (sevoflurane and remifentanil). We evaluated the time to loss of eyelid reflex, time to reach a BIS value less than or equal to 50, the occurrence of adverse events during laryngoscopy and intubation, intubation conditions and hemodynamic and respiratory variables. Also assessed the degree of satisfaction and comfort of patients with these anesthetic techniques. Results: Of the patients initially included in the study, one from each group was excluded from statistical analysis. Time to loss of eyelid reflex was 1.30 minutes in S group vs. 1.24 minutes in the SR group. The time to achieve a BIS value less than or equal to 50 was significantly lower (p <0.05) in the SR group (4.51 minutes) vs. the S group (5.64 minutes). In S group, hemodynamic variables remained significantly more stable and 30% of patients had good intubation conditions, 49% excellent and 21% were classified as poor. In the SR group, 42.5% of patients had good intubation conditions, 47.5% excellent and 10% poor. Regarding respiratory variables in S group, 2.3% of patients lost spontaneous breathing compared with 80% of patients in the SR group. Differences between groups in the incidence of complications during induction were observed; the occurrence of cough (..) (AU)

[Anesthetic treatment of patients with osteogenesis imperfecta]. / Experiencia en el tratamiento anestésico de los pacientes afectos de osteogénesis imperfecta.

BACKGROUND AND OBJECTIVE: Although the prevalence of osteogenesis imperfecta is low, the effect of this hereditary disease on patients' quality of life is considerable. We report our experience in the perioperative management of patients with this condition in our hospital. PATIENTS AND METHODS: Retrospective study describing the interventions on patients with this disease in our hospital from 1991 to 2009. We analyzed demographic data, disease variants, concomitant disorders, surgical procedures, type of anesthesia, and intraoperative and postoperative complications. RESULTS: From 1991 to 2009, 105 procedures were performed on 29 patients (ages 1 to 25 years) with osteogenesis imperfecta (37.9% women and 62.1% men). The most common type of osteogenesis imperfecta was type III (65.5%). Most patients (93%) had no associated diseases. Two patients were allergic to latex. No complications occurred in 62% of interventions. Reported complications during surgery were 1 case of non-malignant hyperthermia and 1 contralateral femur fracture. CONCLUSIONS: The prevalence of osteogenesis imperfecta is low. Treatment requires a multidisciplinary approach, in which appropriate perioperative management must be based on a proper understanding of the skeletal and extraskeletal abnormalities associated with this disease.

Experiencia en el tratamiento anestésico de los pacientes afectos de osteogénesis imperfecta / Anesthetic treatment of patients with osteogenesis imperfecta

Objetivos: La osteogénesis imperfecta es una enfermedad hereditaria con una baja prevalencia, pero gran impacto en la calidad de vida de los pacientes. Se presenta la experiencia en el manejo perioperatorio de estos pacientes en nuestro hospital. Pacientes y métodos: Estudio descriptivo retrospectivo de las intervenciones realizadas en nuestro centro durante los años 1991 a 2009, en los pacientes con esta enfermedad. Se analizan los datos demográficos, variante de la enfermedad, alteraciones asociadas, procedimientos quirúrgicos, tipo de anestesia y complicaciones intraoperatorias y postoperatorias. Resultados: Desde el año 1991 hasta el 2009 se han realizado un total de 105 intervenciones en 29 pacientes con osteogénesis imperfecta (37,9% mujeres, 62,1% varones), con una edad que oscila entre 1 a 25 años. El tipo más frecuente de osteogénesis imperfecta fue el tipo III (65,5%). El 93% de los pacientes no presentaron enfermedades asociadas. Dos pacientes eran alérgicos al látex. El 62% de las intervenciones transcurrieron sin complicaciones. Se registró un caso de hipertermia no maligna y una fractura de fémur contralateral en el quirófano. Conclusiones: La osteogénesis imperfecta es una enfermedad de baja prevalencia que precisa un tratamiento multidisciplinar. Es necesario un adecuado conocimiento de las alteraciones tanto esqueléticas como extraesqueléticas de esta enfermedad para un correcto tratamiento perioperatorio(AU)

Background and objective: Although the prevalence of osteogenesis imperfecta is low, the effect of this hereditary disease on patients’ quality of life is considerable. We report our experience in the perioperative management of patients with this condition in our hospital. Patients and methods: Retrospective study describing the interventions on patients with this disease in our hospital from 1991 to 2009. We analyzed demographic data, disease variants, concomitant disorders, surgical procedures, type of anesthesia, and intraoperative and postoperative complications. Results: From 1991 to 2009, 105 procedures were performed on 29 patients (ages 1 to 25 years) with osteogenesis imperfecta (37.9% women and 62.1% men). The most common type of osteogenesis imperfecta was type III (65.5%). Most patients (93%) had no associated diseases. Two patients were allergic to latex. No complications occurred in 62% of interventions. Reported complications during surgery were 1 case of non-malignant hyperthermia and 1 contralateral femur fracture. Conclusions: The prevalence of osteogenesis imperfecta is low. Treatment requires a multidisciplinary approach, in which appropriate perioperative management must be based on a proper understanding of the skeletal and extraskeletal abnormalities associated with this disease(AU)

Infraclavicular brachial plexus block: variation in approach and results in 360 cases.

BACKGROUND AND OBJECTIVES: Brachial plexus block is clinically useful. Although the infraclavicular approach to brachial block is the less commonly used form it may offer advantages. We describe the results with three local anesthetic mixtures used during this observational study. METHODS: Three hundred and sixty patients, ASA physical status I and II, scheduled for upper extremity orthopedic surgery, were anesthetized with an infraclavicular brachial plexus block. They were divided into three groups (120 patients each) by type of 40-mL anesthetic mixture: group I had even parts of 2% plain lidocaine and 0.5% bupivacaine with epinephrine 1:200,000; group II had even parts of 1% plain lidocaine and 0.25% bupivacaine with epinephrine 1:200,000; and group III had even parts of 1.5% plain lidocaine and 0.37% bupivacaine with epinephrine 1:200,000. Plexus identification was made by nerve stimulator. The observational assessments were: adequacy and latency time of the block, tourniquet tolerance, postoperative analgesia, local anesthetics doses, sedative doses, complications, and side effects. RESULTS: In groups I, II, and III, adequacy of the block was 95, 75, and 96%, latency time was 10.4, 12.9, and 10.9 minutes, tourniquet tolerance was 99, 84, and 98%, postoperative analgesia time was 663, 331, and 502 minutes, anesthetic doses of lidocaine/bupivacaine were 5.2/1.3, 2.9/0.7 and 4.1/1.1 mg/kg, respectively. Differences were noted between group II and groups I and III (P range: .01-.0001). Sedatives in adequate blocks were midazolam with/without fentanyl (2-3 mg/50-100 microg) in all groups. There were two complication cases with no consequences: two vascular punctures that did not hold up or delay the anesthetic or surgical procedure. There were no clinical manifestations or side effects. CONCLUSIONS: The infraclavicular approach described is effective. It produced reliable anesthesia and is associated with minimal complications and side effects. The mixture of local anesthetics used in group II is not adequate for producing reliable anesthesia.

Mathematical analysis of epidural space location.

BACKGROUND: The location of epidural space for local anaesthetic injection can be difficult. The aim of this study was to define the mathematical function of the pressure changes in the syringe during puncture of the epidural space. Knowledge of pressure changes might be of help to the anesthetist who attempts to ascertain the location of the needle, and it is essential to the design of a device with which to locate epidural space. METHODS: Epidural punctures were performed in 20 patients, using an 18-Tuohy needle connected to a 10 ml syringe. The epidural space was located by the loss of resistance technique. Pressure variations within the injection system during epidural puncture were measured and digitized at 250 Hz. Pressure curves were analyzed for amplitude and rate of a decay after entry of the needle into the epidural space. RESULTS: Pressure increased as the needle passed through skin, subcutaneous fat and muscle. The maximal pressure was observed when the needle perforated the ligamentum flavum (689 +/- 124 cm H2O). When the needle entered the epidural space, an exponential decrease in pressure was observed in all patients (R2 = 0.99; tau = 2.1 +/- 0.9 seconds). End-residual pressure was 22 +/- 12 cm H2O. The change in pressure observed when the needle entered the epidural space fitted a negative exponential function (y = e-x/2.08). CONCLUSIONS: Pressures within the injection system for epidural puncture can reach 1100 cm H2O. Location of the epidural space is characterized by an exponential decay to and end-residual pressure below 50 cm H2O, with a constant time of approximately 2 seconds.

[Etomidate perfusion in neurosurgery]. / Perfusión de etomidato en neurocirugía.

In this prospective study, 20 patients undergoing mean duration (2-3 h) neurosurgical operations on fossa cranii posterior, and cervical and dorsolumbar rachis, were induced with 0.3 mg/kg etomidate bolus dose. To maintain anesthesia, etomidate perfusions at 10 micrograms/kg/min (group I) and 20 microg/kg/min (group II) were administered. Fentanyl at fractionated doses was used as analgesic without association to nitrous oxide and relaxation was achieved with pancuronium bromide. Quality of hypnosis, changes in serum concentration of cortisol as well as hemodynamic and electrolyte changes were evaluated. Serum concentrations of cortisol, glucose, sodium and potassium were measured in basal state, and during perioperative and postoperative period. Hemodynamic status was monitored and side effects were recorded. Patients of group I presented signs of deficient hypnosis consisting of marked sympathetic response. When etomidate perfusion ceased, both groups presented serum concentrations of cortisol under the lower normal limit. Six hours after operation, mean serum concentration of cortisol in group 2 patients was significantly lower than in group I patients; in their samples, a dose-dependent recovery was detected. Serum glucose concentration increased during anesthesia and operation and serum electrolyte concentration remained within normal range during perioperative and postoperative periods. Our results demonstrate that a 20 micrograms/kg/min etomidate infusion is adequate to achieve neuroanesthesia when nitrous oxide administration is contraindicated.

[Chemonucleolysis. Peridural anesthesia versus general anesthesia]. / Quimionucleólisis. Anestesia peridural versus anestesia general.

A prospective comparative study was carried out between two anesthetic techniques for chemonucleolysis. Patients were divided into 2 groups of 50 patients each. Group A were submitted to general anesthesia and group B to epidural anesthesia with 0.5% bupivacaine, 2% mepivacaine and buprenorphine. Group B was divided into 2 subgroups: in B1, buprenorphine was administered with the local anesthetics, while in B2 buprenorphine was administered postoperatively when pain appeared. Postoperative pain and side effects like anaphylaxis were evaluated. No anaphylactic reactions occurred. Severe lumbar pain appeared in 22% of patients in group A in spite of systematic analgesics, while group B lumbalgia was not severe in any case. Patients in subgroup B1 did not have pain during the 24 first hours and 47.8% of patients in subgroup B2 needed in most of the cases only a dose of buprenorphine. We conclude that epidural anesthesia is a good technique in chemonucleolysis and that the association bupivacaine, mepivacaine and buprenorphine provides a good postoperative pain relief.