Aquiles Camelier

Guía de práctica clínica de la enfermedad pulmonar obstructiva crónica (EPOC) ALAT-2014: Preguntas y respuestas

ALAT-2014 COPD Clinical Practice Guidelines used clinical questions in PICO format to compile evidence related to risk factors, COPD screening, disease prognosis, treatment and exacerbations. Evidence reveals the existence of risk factors for COPD other than tobacco, as well as gender differences in disease presentation. It shows the benefit of screening in an at-risk population, and the predictive value use of multidimensional prognostic indexes. In stable COPD, similar benefits in dyspnea, pulmonary function and quality of life are achieved with LAMA or LABA long-acting bronchodilators, whereas LAMA is more effective in preventing exacerbations. Dual bronchodilator therapy has more benefits than monotherapy. LAMA and combination LABA/IC are similarly effective, but there is an increased risk of pneumonia with LABA/IC. Data on the efficacy and safety of triple therapy are scarce. Evidence supports influenza vaccination in all patients and anti-pneumococcal vaccination in patients <65years of age and/or with severe airflow limitation. Antibiotic prophylaxis may decrease exacerbation frequency in patients at risk. The use of systemic corticosteroids and antibiotics are justified in exacerbations requiring hospitalization and in some patients managed in an outpatient setting.

Chronic obstructive pulmonary disease is underdiagnosed and undertreated in São Paulo (Brazil): results of the PLATINO study

Chronic obstructive pulmonary disease (COPD) is a common disease in adults over 40 years of age and has a great social and economic impact. It remains little recognized and undertreated even in developed countries. However, there are no data about its diagnosis and treatment in Brazil. The objectives of the present study were to evaluate the proportion of COPD patients who had never been diagnosed and to determine if the COPD patients who had been identified were receiving appropriate treatment. The Latin American Project for the Investigation of Obstructive Lung Disease (PLATINO) was a randomized epidemiological study of adults over 40 years living in five metropolitan areas, including São Paulo. The studied sample was randomly selected from the population after a division of the metropolitan area of São Paulo in clusters according to social characteristics. All subjects answered a standardized questionnaire on respiratory symptoms, history of smoking, previous diagnosis of lung disease, and treatments. All subjects performed spirometry. The criterion for the diagnosis of COPD was defined by a post-bronchodilator FEV1/FVC ratio lower than 0.7. A total of 918 subjects were evaluated and 144 (15.8%) met the diagnostic criterion for COPD. However, 126 individuals (87.5%) had never been diagnosed. This undiagnosed group of COPD patients had a lower proportion of subjects with respiratory symptoms than the previously diagnosed patients (88.9 vs 54.8%) and showed better lung function with greater FEV1 (86.8 +/- 20.8 vs 68.5 +/- 23.6% predicted) and FVC (106.6 +/- 22.4 vs 92.0 +/- 24.1% predicted). Among the COPD patients, only 57.3% were advised to stop smoking and 30.6% received the influenza vaccine. In addition, 82.3% did not receive any pharmacological treatment. In conclusion, COPD is underdiagnosed and a large number of COPD patients are not treated appropriately.

Deficiência de alfa-1 antitripsina: diagnóstico e tratamento

Alpha-1 antitrypsin deficiency is a recently identified genetic disease that occurs almost as frequently as cystic fibrosis. It is caused by various mutations in the SERPINA1 gene, and has numerous clinical implications. Alpha-1 antitrypsin is mainly produced in the liver and acts as an antiprotease. Its principal function is to inactivate neutrophil elastase, preventing tissue damage. The mutation most commonly associated with the clinical disease is the Z allele, which causes polymerization and accumulation within hepatocytes. The accumulation of and the consequent reduction in the serum levels of alpha-1 antitrypsin cause, respectively, liver and lung disease, the latter occurring mainly as early emphysema, predominantly in the lung bases. Diagnosis involves detection of low serum levels of alpha-1 antitrypsin as well as phenotypic confirmation. In addition to the standard treatment of chronic obstructive pulmonary disease, specific therapy consisting of infusion of purified alpha-1 antitrypsin is currently available. The clinical efficacy of this therapy, which appears to be safe, has yet to be definitively established, and its cost-effectiveness is also a controversial issue that is rarely addressed. Despite its importance, in Brazil, there are no epidemiological data on the prevalence of the disease or the frequency of occurrence of deficiency alleles. Underdiagnosis has also been a significant limitation to the study of the disease as well as to appropriate treatment of patients. It is hoped that the creation of the Alpha One International Registry will resolve these and other important issues.

Músculos respiratorios y rehabilitación pulmonar en asmáticos

El movimiento normal de la pared torácica durante la respiración tranquila comprende la proyección hacia fuera de los dos compartimientos: el torácico y el abdominal. Sentado o de pie predomina el movimiento del tórax sobre el abdomen, y en posición supina ocurre lo contrario, es decir, predomina el movimiento del compartimiento abdominal. Al contrario de lo que se afirmaba en el pasado, hoy día está claro que varones y mujeres tienen el mismo comportamiento toracicoabdominal1. El diafragma es el músculo predominante en la respiración, pero actualmente se sabe que también los paraesternales y los escalenos son músculos que participan en el acto respiratorio. La acción del diafragma depende de su unión en las seis últimas costillas, haciendo que su contracción las eleve en sentido cefálico, y también del área de aposición que comprende el área en que el diafragma se yuxtapone a la zona interna del gradeado costal; la contracción del diafragma eleva la presión abdominal y ejerce una acción sobre el área de aposición, proyectándola hacia fuera. A medida que el volumen pulmonar aumenta, el área de aposición disminuye progresivamente y la acción conjunta de los dos compartimientos se vuelve ineficiente, hasta el punto de que la región costal basal se disloca hacia adentro (señal de Hoover). Este fenómeno puede ser observado fácilmente en individuos normales que voluntariamente pasan a respirar con un alto volumen pulmonar. Pacientes asmáticos, al inhalar histamina, muestran broncoconstricción, aumentan su volumen pulmonar y alteran el comportamiento toracicoabdominal normal2. En esta situación hay un aumento de las cargas resistiva y elástica, principalmente esta última, como consecuencia del aumento del volumen pulmonar3. En esta situación de broncoconstricción, la insuflación pulmonar es proporcional al aumento de la resistencia de las vías aéreas dislocando el volumen corriente hacia una parte más lineal de la curva de presión-volumen, haciendo que el sistema respiratorio genere una presión más negativa a costa de un mayor reclutamiento de las fibras de músculos intercostales y diafragma, elevando el gasto energético de esos músculos. El mayor aumento del producto presión-tiempo en los músculos intercostales demuestra que éstos son más reclutados que el diafragma durante la inducción de la broncoconstricción por histamina. En la espiración ocurre un aumento de la presión gástrica, lo que refleja reclutamiento de los músculos abdominales, haciendo que el inicio de la próxima inspiración se realice sin aumento de la presión abdominal. La persistencia del tono de los músculos inspiratorios durante la espiración3 impide que la presión abdominal tenga un aumento exagerado durante el final de la expiración, lo que hace que la acción del diafragma sea más eficiente, tanto por la preservación del área de aposición como por el hecho de dejar la fibra en una longitud más adecuada para su acción. Por el contrario, ya se ha demostrado que adolescentes asmáticos durante la fase de sueño REM, al tener broncospasmo, disminuyen la actividad electromiográfica de sus músculos intercostales, con un consecuente aumento de la actividad del diafragma. Esta alteración en la actividad muscular de los dos compartimientos lleva al movimiento paradójico de la parrilla costal, haciendo que ésta se mueva hacia dentro durante la inspiración, lo que tiene como consecuencia una mayor expansión del abdomen. Este comportamiento del conjunto toracicoabdominal es semejante al que ocurre en el recién nacido debido a la alta distensibilidad de su pared costal. Durante el asma nocturna, y como consecuencia de la mayor actividad del diafragma, el volumen corriente disminuye, lo que lleva a creer que parte de esta actividad se disipa modificando la pared costal. Es normal que durante el sueño tranquilo haya una pérdida de tono de los músculos centrales, incluyendo intercostales y accesorios, colocando una carga extra sobre el diafragma4, lo que provoca que haya poca expansión de la parrilla costal.

Modelo de cámara inhaladora para los estudios controlados sobre la toxicidad del humo del tabaco en los roedores

INTRODUCTION Smoking is a serious worldwide public health problem. Animal models act as a bridge between laboratory and human studies. The models applied are difficult to reproduce because of the use of different types of inhalation chambers and mainly because of the lack of continuous monitoring of smoke concentration. OBJECTIVE To develop an inhalation chamber for rats (with only the nose exposed) in which the amount of carbon monoxide (CO) can be maintained and monitored constantly. MATERIAL AND METHODS Male Wistar rats weighing 250g were exposed to 50ppm CO produced by the smoke from a filter-free cigarette. The animals were submitted to a single 2-h exposure and then sacrificed at 0, 4, 24 and 48h. The control group was left restrained inside the small perpendicular chambers, receiving only 5L/min of compressed air. RESULTS The model was able to increase HbCO levels immediately after the end of exposure (p<0.001), with a decrease being observed from 2h onwards when compared to the levels of the control group. Plasma cotinine increased immediately after exposure, and showed still detectable levels at 2 and 4h (p<0.05). CONCLUSION We conclude that the presented inhalation chamber system is able to maintain a controlled CO concentration in a model in which small animals are exposed to the inhalation of cigarette smoke, permitting well-controlled studies, as well as investigations involving other toxic gases and air pollutants.

Discriminative Properties and Validity of a Health Status Questionnaire in Obstructive Airway Disease Patients: The Airways Questionnaire 20

OBJECTIVE To evaluate the discriminative properties and validity of the Airways Questionnaire 20 (AQ20) in a sample of patients with airway obstruction and to compare its properties with those of the St Georges Respiratory Questionnaire (SGRQ) and the Short Form 36 (SF-36). PATIENTS AND METHODS A convenience sample of 47 subjects was recruited from among 61 consecutive patients referred to an outpatient clinic specialized in obstructive airway diseases. All subjects completed the AQ20, SGRQ, and SF-36. Other measures were the baseline dyspnea index (BDI), 6-minute walk test (6MWT) distance, spirometry, results of arterial blood gas analysis, and body mass index. RESULTS The AQ20 showed very good correlation with the SGRQ total score (rho=0.84, P< .001) and moderate correlation with all SF-36 domains (physical capacity, rho=-0.53; physical functioning, rho=-0.61; bodily pain, rho=-0.55; general health, rho=-0.59; vitality, rho=-0.55; social functioning, rho=-0.57; emotional role functioning, rho=-0.51; mental health, rho=-0.61; all P< .001). The BDI and the 6MWT distance were the best predictors of AQ20 score (r2=0.31) in the regression model. An area under the receiver operating characteristic curve of 0.91 (P< .001) indicated a high level of accuracy for the AQ20, using the SGRQ as the gold standard. CONCLUSION This study shows that the AQ20 is an accurate health status questionnaire in patients with moderate-to-severe airway obstruction. It could be an alternative to longer, traditional questionnaires such as the SGRQ.