Disfunción autonómica en pacientes con enfermedad pulmonar obstructiva crónica: efectos del entrenamiento sobre la recuperación de la frecuencia cardiaca / Autonomic dysfunction in patients with chronic obstructive pulmonary disease: Effects of training on heart rate recovery

Introducción: La recuperación de la frecuencia cardíaca (RFC) tras un esfuerzo máximo es un índice de función autonómica y se asocia con mayor mortalidad en algunas patologías. El objetivo de este estudio fue evaluar la prevalencia de disfunción autonómica en pacientes con enfermedad pulmonar obstructiva crónica (EPOC) estable y sus eventuales cambios con un programa de rehabilitación pulmonar. Pacientes y métodos: Estudio transversal de 68 pacientes con EPOC en fase estable (edad media: 71 años [DE: 8]), 65 hombres y 3 mujeres, volumen espiratorio forzado en el primer segundo (%) medio: 36,8 (DE: 11,9), incluidos en programa de entrenamiento aeróbico y de fuerza y resistencia (25 sesiones). Se realizó prueba de esfuerzo cardiopulmonar (PECP), prerrehabilitación en todos los pacientes. En un subgrupo de 12 se realizó, además, PECP posrehabilitación. Se evaluó la RFC en valores absolutos y categorizada tras claudicación en la PECP respecto a la frecuencia cardíaca pico (normalidad RFC>12). Resultados: Hubo 52 (76,5%) pacientes con alteración de la RFC (cambios<12lpm en el primer minuto de la recuperación). La RCF no se asoció con la severidad de la EPOC, la gasometría ni los valores de DLCO. En el subgrupo con PECP, el entrenamiento mejoró la RFC en 4 (80%) y la normalizó en 3 (50%). No se observaron complicaciones durante la rehabilitación en ninguno de los pacientes con disfunción autonómica. Conclusiones: La disfunción autonómica es muy prevalente en pacientes con EPOC estable independientemente de la severidad de la enfermedad, y su relevancia ha sido subestimada. La rehabilitación pulmonar es segura en estos pacientes y modifica el grado de esta disfunción autonómica con tendencia beneficiosa. Si la morbilidad y la supervivencia de los pacientes tienen relación con la disfunción autonómica también en nuestro medio merece ser evaluada (AU)

Introduction: Heart rate recovery (HRR) after maximal effort is an indicator of autonomic function and is related to mortality in different diseases. This study was aimed to estimate prevalence of autonomic dysfunction in patients with chronic obstructive pulmonary disease (COPD) and assess potential clinical effects of a pulmonary rehabilitation program (PRP). Patients and methods: Transversal study of 68 stable COPD patients (71±8 years; 65 men and 3 women; FEV1 36.8±11.9%) who received a PRP consisting of 5-week general and specific training (25 sessions). Cycle ergometry test (CET) was performed in all patients prior to the PRP. In a subset of 12 patients, CET was performed both previously and after rehabilitation. The primary end point was the prevalence of autonomic dysfunction as assessed by abnormal heart rate recovery in the first minute of recovery following a maximal symptom limited CET, and the potential changes following a normalised PRP. Results: A total of 52 (76.5%) patients showed abnormal HRR (i.e. change from peak exercise to first recovery minute <12bpm). HRR was not associated with the severity of COPD, arterial blood gases or DLCO values. The PRP induced significant changes in exercise capacity which was related to improvement of HRR in 4 (80%) and was normalised in 3 (50%). No complications or adverse effects were observed during rehabilitation. Conclusions Autonomic dysfunction is a highly prevalent impairment in COPD patients, irrespective the severity of the disease as assessed by conventional pulmonary function test. Relevance of autonomic dysfunction has been understimated in COPD. Pulmonary rehabilitation is safe and modifies the degree of autonomic dysfunction with potential benefits. The relatioship of morbidity and mortality with autonomic dysfunction in COPD in our setting remains to be evaluated (AU)

Entrenamiento de los músculos respiratorios: ¿sí o no? / Respiratory muscle training: yes or no?

Introducción Existen numerosos ensayos clínicos y experimentales que han puesto en evidencia los beneficios del entrenamiento de los músculos respiratorios (EMR) en pacientes con enfermedades crónicas respiratorias o extrapulmonares. Específicamente, estos estudios han demostrado que el entrenamiento de músculos inspiratorios y espiratorios mediante la respiración ante cargas específicas y controladas produce beneficios funcionales clínicamente relevantes, predecibles y mesurables. A pesar de esta relativa plétora de información respecto a la función y a la estructura muscular respiratoria, hay todavía algunos interrogantes pendientes de contestar que parecen justificar la controversia entre defensores y detractores del EMR. Objetivo El objetivo de este trabajo es revisar críticamente la información disponible para ofrecer un instrumento de consenso basado en la evidencia que oriente el EMR hacia decisiones clínicas y farmacoeconómicas relevantes. Conclusión Este artículo se centra en 5 grupos de cuestiones en los campos de la investigación fisiopatológica, básica, clínica, traslacional y farmacoeconómica del EMR en pacientes con enfermedades respiratorias y en atletas de élite(AU)

Introduction It is clear that circumstantial, experimental and clinical trial evidences support respiratory muscle training as a beneficial strategy in patients with chronic respiratory disease. In recent years, a number of studies have demonstrated that, when training loads are controlled, inspiratory and expiratory muscle training result in important functional benefits. Nevertheless, despite this relative plethora of information regarding not only respiratory muscle function but also structure, there are critical and valuable questions that still remain to be answered and appear to stimulate controversies around the rationale for respiratory muscle training. These controversies translate into the fact that respiratory muscle training has both detractors and defenders in the context of rehabilitation. Objective One critical point is how detractors and defenders can reach an evidence-based consensus to orientate respiratory muscle training towards clinically and pharmaco-economically relevant decisions. Conclusion This article focuses in five groups of questions on the fields of physiopathological, basic, clinical, and pharmaco-economic research regarding respiratory muscle training in patients with respiratory diseases and elite sport athletes(AU)

Cambios en la función muscular respiratoria y periférica en niños asmáticos: efectos de los corticoides inhalados / Changes in respiratory and peripheral muscle function in asthmatic children: effects of inhaled corticoids

Introducción: El asma es la enfermedad crónica más común en los niños y los adolescentes. Las sobrecargas mecánicas intermitentes durante las crisis pueden inducir cambios funcionales en los músculos respiratorios, que experimentan fenómenos de adaptación. Este trabajo pretende evaluar el estado funcional muscular respiratorio y periférico en niños asmáticos que reciben corticoides inhalados y conocer la correlación entre la función muscular y la función respiratoria. Pacientes y métodos: Se seleccionó a 12 niños con asma mayores de 7 años de edad y tratados durante al menos 2 años con corticoides inhalados a dosis intermedias (budesonida ≥400μg o fluticasona ≥200μg) y a 7 niños controles sanos emparejados por edad. Se determinaron espirometría forzada, volúmenes pulmonares estáticos, resistencia de las vías aéreas, presiones inspiratoria y espiratoria máximas, función muscular esquelética periférica y composición corporal mediante bioimpedanciometría. Resultados: Las variables antropométricas, nutricionales y de función muscular periférica fueron equivalentes en ambos grupos. Los niños asmáticos presentaban signos de atrapamiento aéreo e hiperinsuflación pulmonar y valores de presión inspiratoria máxima más elevados. Conclusiones: No se encuentra evidencia de que los esteroides inhalados a dosis altas y de forma crónica deterioren la función muscular respiratoria o periférica en los niños asmáticos. En cambio, se encuentran signos de adaptación muscular respiratoria frente a la sobrecarga a largo plazo que supone el asma persistente. El llamado "efecto entrenamiento" aparenta estar limitado únicamente a los músculos de la inspiración (AU)

Introduction: Asthma is the most common chronic disease in children and adolescents. The intermittent mechanical overloads during crises can lead to functional changes in the respiratory muscles, which experience adaptation phenomena. This article attempts to evaluate the respiratory and peripheral muscle state in asthmatic children who receive inhaled corticoids, and to find out if there is an association between muscle function and respiratory function. Patients and methods: The study involved 12 children over 7-years old with asthma and treated with inhaled corticoids for at least 2 years at intermediate doses (budesonide ≥400ug, or fluticasone ≥200ug) and 7 healthy control children paired by age. The following were determined: forced spirometry, static lung volumes, airway resistance, maximum inspiratory and expiratory pressures, peripheral musculo-skeletal function, and body composition using bioimpedance measurements. Results: The anthropometric, nutritional variables and peripheral muscle function were similar in both groups. The asthmatic children showed signs of air trapping, lung hyperinflation, and higher maximum inspiratory pressure values. Conclusions: No evidence was found that continuous high doses of inhaled steroids lead to a deterioration in respiratory or peripheral muscle function in asthmatic children. On the other hand, signs were found of respiratory muscle adaptation to the long-term overload of persistent asthma. The so-called "training effect" seems to be limited only to the inspiratory muscles (AU)

[Changes in respiratory and peripheral muscle function in asthmatic children: effects of inhaled corticoids]. / Cambios en la función muscular respiratoria y periférica en niños asmáticos: efectos de los corticoides inhalados.

INTRODUCTION: Asthma is the most common chronic disease in children and adolescents. The intermittent mechanical overloads during crises can lead to functional changes in the respiratory muscles, which experience adaptation phenomena. This article attempts to evaluate the respiratory and peripheral muscle state in asthmatic children who receive inhaled corticoids, and to find out if there is an association between muscle function and respiratory function. PATIENTS AND METHODS: The study involved 12 children over 7-years old with asthma and treated with inhaled corticoids for at least 2 years at intermediate doses (budesonide >or=400 microg, or fluticasone >or=200 microg) and 7 healthy control children paired by age. The following were determined: forced spirometry, static lung volumes, airway resistance, maximum inspiratory and expiratory pressures, peripheral musculo-skeletal function, and body composition using bioimpedance measurements. RESULTS: The anthropometric, nutritional variables and peripheral muscle function were similar in both groups. The asthmatic children showed signs of air trapping, lung hyperinflation, and higher maximum inspiratory pressure values. CONCLUSIONS: No evidence was found that continuous high doses of inhaled steroids lead to a deterioration in respiratory or peripheral muscle function in asthmatic children. On the other hand, signs were found of respiratory muscle adaptation to the long-term overload of persistent asthma. The so-called "training effect" seems to be limited only to the inspiratory muscles.

Mortality of COPD patients infected with multi-resistant Pseudomonas aeruginosa: a case and control study.

BACKGROUND: The incidence of infections caused by multiresistant Pseudomonas aeruginosa (MDRP) is increasing, especially in critically ill patients. The relevance of MDRP in the prognosis of chronic obstructive pulmonary disease (COPD) acute exacerbation in patients admitted to the hospital's general ward is not well known. PATIENTS AND METHODS: Case and control study. Cases were patients admitted for COPD acute exacerbation in which a MDRP was isolated from spontaneous sputum. MDRP was defined as the absence of susceptibility to three or more antibiotic families (betalactams, quinolones, carbapenems and aminoglycosides). Patients currently or previously admitted to the intensive care unit (ICU), who had a recent surgery, neoplasia or immunosuppressive treatment were excluded from the study. Patients from the control group were admitted for COPD acute exacerbation and matched 1:1 with each case-patient in terms of age, sex, date of admission and degree of airway obstruction. Pseudomonas aeruginosa susceptible to all antimicrobials or other microorganisms was isolated from sputum. RESULTS: During the study period (2000-2005), 50 case-patients and 50 controls were included. Crude mortality at 2 years was 60% for the case-patients and 28% for the control group. In the logistic regression analysis adjusted for age, FEV(1) and number of previous hospital admissions, MDRP infection was associated to an increased mortality in comparison to patients without MDRP (OR = 6.2; IC 95%: 1.7-22.1; p < 0.01). CONCLUSIONS: In COPD patients admitted to the general ward, acute exacerbation with MDRP in sputum was associated with higher mortality.

Upregulation of pro-inflammatory cytokines in the intercostal muscles of COPD patients.

Muscle dysfunction is a characteristic feature of chronic obstructive pulmonary disease (COPD). Recent studies suggest that cytokines may operate as local regulators of both muscle function and regeneration. The aim of the present study was to characterise the expression of different cytokines in the external intercostal muscle of COPD. Muscle biopsies were obtained from 25 stable COPD patients and eight healthy controls. Local tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, -6 and -10 expressions (real-time PCR and ELISA), sarcolemmal damage (immunohistochemistry), and the transcript levels of CD18 were assessed. Muscle TNF-alpha and IL-6 transcripts were significantly higher in COPD patients compared with controls, and IL-1beta and sarcolemmal damage showed a strong tendency in the same direction. Similar results were observed at protein level. The CD18 panleukocyte marker was similar in COPD and controls. Respiratory muscle function was impaired in COPD patients and it correlated to both the severity of lung function impairment and TNF-alpha muscle expression. Chronic obstructive pulmonary disease is associated with the upregulation of pro-inflammatory cytokines in the intercostal muscles. This phenomenon might be involved in respiratory muscle dysfunction.

Mitochondrial dysfunction in COPD patients with low body mass index.

Patients with chronic obstructive pulmonary disease (COPD) show abnormal adaptations of skeletal muscle redox status after exercise training. Increased skeletal muscle oxidative stress in COPD patients may prompt mitochondrial dysfunction. The present study explores the association between body composition and mitochondrial respiration in seven COPD patients with low body mass index (BMI(L)), eight COPD patients with normal body mass index (BMI(N)) and seven healthy controls. All of them underwent a vastus lateralis biopsy in which muscle structure, in vitro mitochondrial respiratory function, uncoupling protein 3 (UCP3) mRNA expression and glutathione levels in both isolated mitochondria and the whole muscle were determined. Mitochondrial respiratory function (assessed by acceptor control ratio (ACR)) was impaired in BMI(L) (2.2+/-0.6) compared with both BMI(N) (5.3+/-1.3) and controls (8.2+/-1.3). ACR significantly correlated with arterial oxygen tension and with muscle endurance but it showed a negative association with exercise-induced increase in blood lactate levels. UCP3 mRNA expression was reduced in BMI(L) patients. In conclusion, chronic obstructive pulmonary disease patients with low body mass index show electron transport chain dysfunction, which may contribute to low muscle endurance in the current subgroup of patients.

[Physiologic particularities of muscle impairments in the patient with COPD]. / Particularidades fisiopatológicas de las alteraciones musculares en el paciente con EPOC.

Patients with chronic obstructive pulmonary disease (COPD) frequently have skeletal muscle dysfunction, of either respiratory muscles or those located of the limbs. This dysfunction may appear even at relatively early stages and it conditions symptoms and patient's quality of life. In the case of respiratory muscles, factors that seem to determine muscle dysfunction are, particularly, changes in thorax configuration and an unbalance between decreased energy availability and increased energy demands by the muscle. However, respiratory muscles show signs of structural and metabolic adaptation to this situation, partially compensating the above-mentioned deleterious effects. However, at muscles of the limbs, particularly of the lower limbs, dysfunction seems to be essentially due to deconditioning by physical activity reduction. Structural changes in these muscles are involutional in nature. At both respiratory and peripheral muscles, other factors such as nutritional impairments, inflammation, oxidative stress, some drugs, and the presence of comorbidity seem to play a relevant role. All of them will condition both dysfunction and structural changes, which will be heterogeneous for the different muscle groups in each patient.

Wood smoke exposure and risk of chronic obstructive pulmonary disease.

It was hypothesised that wood smoke exposure could be a risk factor for chronic obstructive pulmonary disease (COPD) in Spain. The present study was designed as a case-control study of 120 females requiring hospitalisation during 2001-2003 at Hospital del Mar (Barcelona, Spain). Cases were recruited from hospital records as females who had been admitted for an exacerbation of COPD. Controls were obtained from pulmonary function test laboratory consultations prior to a surgical intervention. All patients answered a standardised questionnaire. Exposure to wood or charcoal smoke was strongly associated with COPD after adjusting for age and smoking. The association between length of exposure and COPD suggested a dose-response pattern. Intensity of exposure in both summer and winter was also related to COPD. Wood or charcoal alone independently increased risk of COPD (odds ratio (OR) 1.8 and 1.5, respectively), but only the combination of both was statistically significant (OR 4.5). In conclusion, the present study shows a strong association between wood or charcoal smoke exposure and chronic obstructive pulmonary disease, supporting its existence not only in developing countries, but also in European countries, such as Spain. Further studies assessing whether this association also exists in other European societies are warranted.

Particularidades fisiopatológicas de las alteraciones musculares en el paciente con EPOC / Physiologic particularities of muscle impairments in the patient with copd

Los pacientes con enfermedad pulmonar obstructiva crónica (EPOC) presentan con frecuencia disfunción de sus músculos esqueléticos, sean respiratorios o localizados en las extremidades. Esta disfunción puede aparecer incluso en fases relativamente precoces y condiciona los síntomas y calidad de vida del paciente. En el caso de los músculos respiratorios, los factores que parecen determinar la disfunción muscular son sobre todo los cambios en la configuración torácica y el desequilibrio entre ofertas energéticas al músculo disminuidas y demandas elevadas. Sin embargo, los músculos respiratorios muestran signos de adaptación estructural y metabólica a dicha situación, compensando parcialmente los efectos deletéreos de los factores antes mencionados. Por su parte, en los músculos de las extremidades, sobre todo de las inferiores, la disfunción parece debida fundamentalmente al decondicionamiento por reducción en la actividad física. Los cambios estructurales en estos músculos son de tipo involutivo. Tanto en los músculos respiratorios como en los periféricos, otros factores como las alteraciones nutricionales, inflamación, estrés oxidativo, determinados fármacos y la presencia de comorbilidad parecen jugar también un papel relevante. Todos ellos condicionarán tanto disfunción como cambios estructurales, que serán heterogéneos para los diferentes grupos musculares en cada paciente (AU)

Patients with chronic obstructive pulmonary disease (COPD) frequently have skeletal muscle dysfunction, of either respiratory muscles or those located of the limbs.This dysfunction may appear even at relatively early stages and it conditions symptoms and patient's quality of life. In the case of respiratory muscles, factors that seem to determine muscle dysfunction are, particularly, changes in thorax configuration and an unbalance between decreased energy availability and increased energy demands by the muscle. However, respiratory muscles how signs of structural and metabolic adaptation to this situation, partially compensating the above-mentioned deleterious effects. However, at muscles of the limbs, particularly of the lower limbs, dysfunction seems to be essentially due to deconditioning by physical activity reduction. Structural changes in these muscles are involutional in nature. At both respiratory and peripheral muscles, other factors such as nutritional impairments, inflammation, oxidative stress, some drugs, and the presence of comorbidity seem to play a relevant role. All of them will condition both dysfunction and structural changes, which will be heterogeneous for the different muscle groups in each patient (AU)

Relevance of assessing quadriceps endurance in patients with COPD.

The aims of this study were to investigate whether the impairment in endurance of limb muscles is a general finding in chronic obstructive pulmonary disease (COPD) patients, affecting even those with mild-to-moderate disease or relatively normal physical activity. In addition, this study aimed to determine the physiopathology of exhaustion in local endurance tests and whether the reduction in quadriceps endurance can be predicted from muscle strength measurements. A total of 75 volunteers were assigned to one of two groups according to pulmonary function tests: COPD patients or healthy age-matched controls. Functional assessment included both quadriceps strength (maximum voluntary contraction (QMVC)), and quadriceps endurance (contractions against a load equivalent to 10% QMVC until task failure or for up to a limiting time of 30 min (QTlim)). COPD patients showed a decrease of approximately 43%, in QMVC and approximately 77% in QTlim compared with controls. Task failure occurred only in COPD patients and was due to muscle fatigue, since limiting symptoms were associated with a decrease in the median frequency of quadriceps electromyographical signal and a reversible decrease in QMVC. The impairment in skeletal muscle endurance was present even in patients with mild-to-moderate airflow obstruction and individuals with relatively normal physical activity, and was irrespective of lung function variables, anthropometrical data or quadriceps strength. Peripheral muscle endurance was impaired in chronic obstructive pulmonary disease patients, even in those with relatively normal physical activity and mild-to-moderate airflow obstruction. This impairment associated with an early onset of muscle fatigue and could not be predicted from the severity of the disease or the reduction in quadriceps strength.

[Analysis of respiratory muscle structure and tumor necrosis and insulin-like growth factor expression in chronic obstructive pulmonary disease: are samples valid if obtained during thoracotomy performed because of localized pulmonary neoplasia?]. / Análisis estructual y expresión de los factores de necrosis tumoral y crecimiento insulina-like en los músculos respiratorios de pacientes con EPOS. Son válidas las muestras obtenidas en el curso de una toracotomía por neoplasia pulmonar localizada?

OBJECTIVE: Various methods have been used to obtain samples to study the structure of human respiratory muscles and the expression of diverse substances in them. Samples are most often obtained from autopsies, from muscle biopsies during thoracotomy performed because of a localized pulmonary lesion (TLL), and from ambulatory thoracoscopic biopsy in patients free of comorbidity (AT). The disadvantage of the first 2 of these methods lies in the possibility of interference from factors related to the patient's death in the first case or from the disease that necessitated surgery in the second. Although AT is free from the disadvantages of the other 2 methods, it is impossible to obtain samples of the diaphragm the principal respiratory muscle with this procedure. The objective of this study was to analyze the fibrous structure of the external intercostal muscle of patients with chronic obstructive pulmonary disease and to quantify the expression of the principal inflammatory cytokine tumor necrosis factor alpha (TNF-alpha)- and of insulin-like growth factor (IGF-1) in the same muscle, comparing the results obtained with TLL and AT samples. METHODS: Prospective and consecutive samples were taken of the external intercostal muscle (fifth space, anterior axillary line) in 15 patients with chronic obstructive pulmonary disease (mean [SD] age 66 [6] years; forced expiratory volume in 1 second 49% [9%] of predicted; PaO2 75 [9] mm Hg). Samples were taken during TLL (8 patients, all with pulmonary neoplasms but carefully selected in order to rule out systemic effects) or TA (7 patients). Patients with serious comorbidity were excluded from the second group. Samples were processed for structural analysis of fibers (immunohistochemical and enzymatic histochemical) and genetic expression of TNF-alpha and IGF-1 (real-time polymerase chain reaction). RESULTS: No differences in the structure of fibers were found between the 2 groups. No differences were observed in the expression of TNF-alpha or IGF-1. CONCLUSIONS: Using rigorous criteria, the TLL method appears to be suitable for studying the structural characteristics and expression of inflammatory cytokines and growth factors in the external intercostal muscle. Moreover, it can also be inferred that TLL is probably also useful for obtaining samples of the diaphragm, a muscle which cannot currently be sampled by any alternative method.

Glutathione and glutamate levels in the diaphragm of patients with chronic obstructive pulmonary disease.

Recently, decreased glutamate (Glu) and reduced glutathione (GSH) levels were reported in the quadriceps femoris of patients with chronic obstructive pulmonary disease (COPD). The aim of the present study was to investigate whether Glu and GSH levels are also modified in the diaphragm of these patients. Nine male COPD patients (forced expiratory volume in one second (FEV1) range 28-68% of the predicted value) and seven male patients with normal pulmonary function (mean +/- SD FEV1 86 +/- 3% pred) submitted to thoracotomy were included. Biopsy specimens were taken from the diaphragm (both groups) and the quadriceps femoris (COPD group alone) in order to assess fibre size, myosin heavy chain expression, GSH levels and amino acid profile. The COPD group was characterised by preserved fibre size, a higher proportion of type I fibres (mean +/- SEM 70 +/- 3 versus 26 +/- 4%), and higher Glu and GSH content in the diaphragm compared to the quadriceps muscle. However, Glu and GSH levels were similar in diaphragm from the COPD and control groups. Glu level correlated with GSH level in both muscles. No significant correlation was found between Glu or GSH level and fibre size or proportions. This study shows that glutamate and reduced glutathione levels are preserved in the diaphragm of chronic obstructive pulmonary disease patients. Alterations in glutamate and reduced glutathione metabolism are muscle-specific in chronic obstructive pulmonary disease, affecting the quadriceps femoris but not the diaphragm. Glutamate and reduced glutathione levels are strongly interrelated in both muscles, independent of fibre type distribution and fibre size.

Structure and function of the respiratory muscles in patients with COPD: impairment or adaptation?

Respiratory muscles are essential to alveolar ventilation. These muscles work against increased mechanical loads due to airflow limitation and geometrical changes of the thorax derived from pulmonary hyperinflation. Respiratory muscle fibres show several degrees of impairment in cellular and subcellular structures which, in many cases, are proportional to the severity of the disease and accompanying conditions (ageing, deconditioning, starvation, comorbidity). This structural impairment translates, from the functional point of view, to a loss of strength (capacity to generate tension) and an increased susceptibility to failure in the face of a particular load (early onset of fatigue). On the other hand, there is accumulating evidence that the diaphragm and other respiratory muscles are also able to express adaptive changes in response to the chronic mechanical load imposed by the disease. In most cases, impairment and adaptation of the respiratory muscles reaches a balance that permits enough ventilation for patients' survival. However, this balance can be altered for additional increments of the mechanical or metabolic load on the muscles (e.g. abdominal or thoracic surgeries, pneumonia, pulmonary embolism, etc.). Moreover, loss of balance is not always associated with extreme situations. Many patients develop ventilatory failure and require hospital admission even if the cause of the exacerbation is less dramatic (bronchial infections, pain of any nature, electrolyte disturbances, etc.). Although the physiopathology of chronic obstructive pulmonary disease exacerbations is multifactorial, the above-mentioned fragility suggests the existence of a "fragile balance" between respiratory muscle overload and respiratory muscle adaptations. Assessment of respiratory muscle function through specific tests evaluating the strength and endurance could offer valuable information about this particular susceptibility to muscle imbalance. Identification of patients possessing a fragile respiratory muscle balance could have important implications for the application of specific strategies such as respiratory muscle training, nutrition, or anabolic treatment.

Gastro-oesophageal reflux in mechanically ventilated patients: effects of an oesophageal balloon.

Gastro-oesophageal reflux (GOR) and bronchoaspiration of gastric content are risk factors linked with ventilator-associated pneumonia. This study was aimed at evaluating the effect of a nasogastric tube (NGT) incorporating a low-pressure oesophageal balloon on GOR and bronchoaspiration in patients receiving mechanical ventilation. Fourteen patients were studied in a semi-recumbent position for 2 consecutive days. Inflation or deflation of the oesophageal balloon was randomised. Samples of blood, gastric content, and oropharyngeal and bronchial secretions were taken every 2 h over a period of 8 h. A radioactively labelled nutritional solution was continuously administered through the NGT. The magnitude of both the GOR and bronchoaspiration was measured by radioactivity counting of oropharyngeal and bronchial secretion samples, respectively. Inflation of the oesophageal balloon resulted in a significant decrease of both GOR and bronchoaspiration of gastric content. This protective effect was statistically significant from 4 h following inflation throughout the duration of the study. This study demonstrates that an inflated oesophageal balloon delays and decreases gastro-oesophageal and bronchial aspiration of gastric content in patients carrying a nasogastric tube and receiving enteral nutrition during mechanical ventilation. Although the method was found to be safe when applied for 8 h, longer times should be considered with caution.

Síndrome de bajo peso asociado a la EPOC en nuestro medio / Low-weight syndrome associated with COPD in our setting

INTRODUCCIÓN: La enfermedad pulmonar obstructiva crónica (EPOC) es una entidad de elevada prevalencia, con importantes consecuencias económicas y sanitarias, que derivan en gran parte de la limitación que la enfermedad comporta en la actividad y expectativas vitales del paciente. Uno de los factores recientemente implicados en las citadas limitaciones es la presencia de bajo peso asociada con la enfermedad. Aunque la causa no está clara, esta alteración parece afectar a un número importante de pacientes (entre el 25 y el 35 per cent según las series), al menos en el norte de Europa y los EE.UU. Sin embargo, existe la percepción de que la situación podría ser diferente en el área mediterránea. OBJETIVO: Aproximar la prevalencia del síndrome de bajo peso en pacientes con EPOC de nuestro entorno. MÉTODOS: Se revisaron las características antropométricas básicas de los pacientes con EPOC filiados funcionalmente en nuestro laboratorio a lo largo de los dos últimos años (2000-2001).RESULTADOS: De los 3.126 sujetos analizados, la prevalencia de un índice de masa corporal (IMC) por debajo de 20 kg/m2 fue de tan sólo el 6,6 per cent, cifra que se reducía al 3,1 per cent si el dintel escogido era el de 18 kg/m2. Este dato es aún más llamativo si se tiene en cuenta que casi la mitad de los pacientes evidenciaban enfermedad grave (volumen espiratorio forzado en el primer segundo [FEV1] inferior al 50 per cent ref). El IMC se correlacionó directamente con FEV1/FVC y transferencia del CO.CONCLUSIONES: Estos resultados sugieren que los pacientes con EPOC de nuestra área geográfica presentan características fenotípicas diferenciadas de las previamente descritas en otras latitudes. En concreto, una menor prevalencia del síndrome de bajo peso. Sin embargo, esta observación debe ser confirmada en estudios más amplios (AU)

[Fiber-optic bronchoscopic biopsy of bronchial smooth muscle. Efficacy of the technique in individuals with normal lung function and patients with COPD]. / Biopsia de músculo liso bronquial mediante fibrobroncoscopia. Eficacia de la técnica en individuos con función pulmonar normal y en pacientes con EPOC.

BACKGROUND AND OBJECTIVES: The epithelium and airway smooth muscles of patients with chronic obstructive pulmonary disease (COPD) or bronchial asthma undergo certain structural changes that are probably related to increased expression of inflammatory molecules and cell growth factors. Studying the relation between disease and changes in bronchial smooth muscle is difficult if investigation is restricted to samples from autopsies or thoracotomies. This study was designed to evaluate the probability of obtaining bronchial smooth muscle by endoscopic bronchial biopsy in patients with COPD and from individuals with normal lung function, the relation of disease to bronchial epithelial histology, and the potential usefulness of studying airway muscle remodeling events. METHODS: Forty-two patients undergoing diagnostic fiberoptic bronchoscopy were enrolled. Bronchial biopsies were taken systematically from the lobar and segmental dividing ridges. The epithelial structure was analyzed by conventional histology. The smooth muscle was identified by immunohistochemistry (anti-desmin antibody assay) and Western-blot analysis (anti-desmin, actin and myosin antibodies). RESULTS: Sixty-nine percent of the biopsies contained bronchial smooth muscle. The probability of obtaining smooth muscle was higher in segmental than in lobar biopsies (72 vs 30%, p < 0.05). This probability was unrelated to the presence of COPD or to signs of epithelial inflammation. The fragments allowed us to use electrophoresis to identify protein structures (myosin, actin, desmin) involved in muscle remodeling processes. CONCLUSIONS: Endoscopic biopsy of the bronchi allows us to obtain bronchial smooth muscle samples in a large percentage of patients, particularly when performed on segmental bronchi. The technique may be useful for future studies examining the processes of airway smooth muscle remodeling.

Biopsia de músculo liso bronquial mediante fibrobroncoscopia. Eficacia de la técnica en individuos con función pulmonar normal y en pacientes con EPOC / Fiber-optic bronchoscopic biopsy of bronchial smooth muscle. Efficacy of the technique in individuals with normal lung function and patients with COPD

FUNDAMENTO Y OBJETIVOS: El epitelio y el músculo liso de las vías aéreas de pacientes con enfermedad pulmonar obstructiva crónica (EPOC) o asma bronquial evidencian cambios estructurales asociados probablemente con un aumento de la expresión de moléculas inflamatorias y con factores de crecimiento celular. El estudio de la relación entre enfermedad y cambios en el músculo liso bronquial es difícil si se restringe a muestras necrópsicas o de toracotomía. El presente estudio fue diseñado para evaluar la probabilidad de obtener músculo liso bronquial mediante biopsia bronquial endoscópica, tanto en pacientes con EPOC como en individuos con función pulmonar normal, su relación con la histología del epitelio bronquial, y la potencial utilidad para estudiar episodios de remodelado del músculo de la vías aéreas. MÉTODOS: Se incluyó a 42 pacientes a quienes se realizó una fibrobroncoscopia con finalidad diagnóstica. Se tomaron sistemáticamente biopsias bronquiales de los espolones de división lobares y segmentarios. La estructura epitelial se analizó mediante histología convencional. El músculo liso fue identificado mediante immunohistoquímica (anticuerpo antidesmina) y análisis por Western-blot (anticuerpos contra desmina, actina y miosina). RESULTADOS: El 69 per cent de las biopsias contenía músculo liso bronquial. La probabilidad de obtener músculo liso fue mayor en biopsias de bronquios segmentarios que lobares (el 72 frente al 30 per cent; p < 0,05), y no evidenció relación con la presencia de EPOC ni con los signos de inflamación epitelial. Los fragmentos permitieron la identificación electroforética de proteínas estructurales implicadas en los procesos de remodelado muscular (miosina, actina, desmina). CONCLUSIONES: La biopsia bronquial endoscópica permite obtener muestras de músculo liso bronquial, especialmente cuando se realiza en los bronquios segmentarios, en un elevado porcentaje de pacientes. Es posible que esta técnica sea útil en futuros estudios que evalúen los procesos de remodelado del músculo liso de la vía aérea (AU)