Respiratory muscles: structure, function and relationship with the ACE gene: a brief morphofunctional communication / Músculos respiratorios: estructura, función y relación con el gen de la ECA: una breve comunicación morfofuncional

SUMMARY: Pulmonary ventilation is a mechanical process in which the respiratory muscles act in coordination to maintain the oxygenation of the organism. Any alteration in the performance of these muscles may reduce the effectiveness of the process. The respiratory muscles differ from the other skeletal muscles in the vital support that they provide through rhythmiccontractions. The structure and energy system of the muscles are specially adapted to perform this function. The composition of the respiratory muscles is exceptional; they are small, and present an abundant capillary network, endowing them with a high aerobic level and resistance to fatigue. Coordinated regulation of the local renin-angiotensin system provides proper blood flow and energy supply in the myofibrils of the skeletal muscle tissue. Specifically, this performance will depend to a large extent on blood flow and glucose consumption, regulated by the renin-angiotensin system. The angiotensin converting enzyme is responsible for degrading kinins, which finally regulate muscle bioenergy and glucose between the blood vessel and the skeletal muscle. The objective of this review is to describe the structure of the respiratory muscles and their association with the angiotensin converting enzyme gene.

La ventilación pulmonar es un proceso mecánico en el que los músculos respiratorios actúan coordinadamente para mantener la oxigenación en el organismo. Así, cualquier alteración en el desempeño de estos músculos puede reducir la efectividad del proceso. Los músculos respiratorios se diferencian de otros músculos esqueléticos, debido al apoyo vital que brindan a través de sus contracciones rítmicas. La estructura y el sistema energético de estos músculos están especialmente adaptados para realizar esta función. La composición de los músculos respiratorios es especial; son pequeñas y presentan una abundante red capilar, lo que les otorga un alto nivel aeróbico y resistencia a la fatiga. La regulación coordinada del sistema renina-angiotensina local, proporciona un adecuado flujo sanguíneo y suministro de energía a las miofibrillas del músculo esquelético. En concreto, este rendimiento dependerá en gran medida del flujo sanguíneo y del consumo de glucosa, regulado por el sistema renina-angiotensina. Aquí, la enzima convertidora de angiotensina es responsable de degradar las kininas, que finalmente regulan la bioenergía muscular y la glucosa entre el vaso sanguíneo y el músculo esquelético. El objetivo de esta breve comunicación es describir la estructura de los músculos respiratorios y su asociación con el gen de la enzima convertidora de angiotensina.

Changes in Respiratory Muscle Thickness during Mechanical Ventilation: Focus on Expiratory Muscles.

BACKGROUND: The lateral abdominal wall muscles are recruited with active expiration, as may occur with high breathing effort, inspiratory muscle weakness, or pulmonary hyperinflation. The effects of critical illness and mechanical ventilation on these muscles are unknown. This study aimed to assess the reproducibility of expiratory muscle (i.e., lateral abdominal wall muscles and rectus abdominis muscle) ultrasound and the impact of tidal volume on expiratory muscle thickness, to evaluate changes in expiratory muscle thickness during mechanical ventilation, and to compare this to changes in diaphragm thickness. METHODS: Two raters assessed the interrater and intrarater reproducibility of expiratory muscle ultrasound (n = 30) and the effect of delivered tidal volume on expiratory muscle thickness (n = 10). Changes in the thickness of the expiratory muscles and the diaphragm were assessed in 77 patients with at least two serial ultrasound measurements in the first week of mechanical ventilation. RESULTS: The reproducibility of the measurements was excellent (interrater intraclass correlation coefficient: 0.994 [95% CI, 0.987 to 0.997]; intrarater intraclass correlation coefficient: 0.992 [95% CI, 0.957 to 0.998]). Expiratory muscle thickness decreased by 3.0 ± 1.7% (mean ± SD) with tidal volumes of 481 ± 64 ml (P < 0.001). The thickness of the expiratory muscles remained stable in 51 of 77 (66%), decreased in 17 of 77 (22%), and increased in 9 of 77 (12%) patients. Reduced thickness resulted from loss of muscular tissue, whereas increased thickness mainly resulted from increased interparietal fasciae thickness. Changes in thickness of the expiratory muscles were not associated with changes in the thickness of the diaphragm (R2 = 0.013; P = 0.332). CONCLUSIONS: Thickness measurement of the expiratory muscles by ultrasound has excellent reproducibility. Changes in the thickness of the expiratory muscles occurred in 34% of patients and were unrelated to changes in diaphragm thickness. Increased expiratory muscle thickness resulted from increased thickness of the fasciae.

Low diaphragm muscle mass predicts adverse outcome in patients hospitalized for COVID-19 pneumonia: an exploratory pilot study.

BACKGROUND: The aim of this study was to evaluate whether measurement of diaphragm thickness (DT) by ultrasonography may be a clinically useful noninvasive method for identifying patients at risk of adverse outcomes defined as need of invasive mechanical ventilation or death. METHODS: We prospectively enrolled 77 patients with laboratory-confirmed COVID-19 infection admitted to our intermediate care unit in Pisa between March 5 and March 30, 2020, with follow-up until hospital discharge or death. Logistic regression was used identify variables potentially associated with adverse outcomes and those P<0.10 were entered into a multivariate logistic regression model. Cumulative probability for lack of adverse outcomes in patients with or without low baseline diaphragm muscle mass was calculated with the Kaplan-Meier product-limit estimator. RESULTS: The main findings of this study are that: 1) patients who developed adverse outcomes had thinner diaphragm than those who did not (2.0 vs. 2.2 mm, P=0.001); and 2) DT and lymphocyte count were independent significant predictors of adverse outcomes, with end-expiratory DT being the strongest (ß=-708; OR=0.492; P=0.018). CONCLUSIONS: Diaphragmatic ultrasound may be a valid tool to evaluate the risk of respiratory failure. Evaluating the need of mechanical ventilation treatment should be based not only on PaO2/FiO2, but on a more comprehensive assessment including DT because if the lungs become less compliant a thinner diaphragm, albeit free of intrinsic abnormality, may become exhausted, thus contributing to severe respiratory failure.

Muscles of Breathing: Development, Function, and Patterns of Activation.

This review is a comprehensive description of all muscles that assist lung inflation or deflation in any way. The developmental origin, anatomical orientation, mechanical action, innervation, and pattern of activation are described for each respiratory muscle fulfilling this broad definition. In addition, the circumstances in which each muscle is called upon to assist ventilation are discussed. The number of "respiratory" muscles is large, and the coordination of respiratory muscles with "nonrespiratory" muscles and in nonrespiratory activities is complex-commensurate with the diversity of activities that humans pursue, including sleep (8.27). The capacity for speech and adoption of the bipedal posture in human evolution has resulted in patterns of respiratory muscle activation that differ significantly from most other animals. A disproportionate number of respiratory muscles affect the nose, mouth, pharynx, and larynx, reflecting the vital importance of coordinated muscle activity to control upper airway patency during both wakefulness and sleep. The upright posture has freed the hands from locomotor functions, but the evolutionary history and ontogeny of forelimb muscles pervades the patterns of activation and the forces generated by these muscles during breathing. The distinction between respiratory and nonrespiratory muscles is artificial, as many "nonrespiratory" muscles can augment breathing under conditions of high ventilator demand. Understanding the ontogeny, innervation, activation patterns, and functions of respiratory muscles is clinically useful, particularly in sleep medicine. Detailed explorations of how the nervous system controls the multiple muscles required for successful completion of respiratory behaviors will continue to be a fruitful area of investigation. © 2019 American Physiological Society. Compr Physiol 9:1025-1080, 2019.

ERS statement on respiratory muscle testing at rest and during exercise.

Assessing respiratory mechanics and muscle function is critical for both clinical practice and research purposes. Several methodological developments over the past two decades have enhanced our understanding of respiratory muscle function and responses to interventions across the spectrum of health and disease. They are especially useful in diagnosing, phenotyping and assessing treatment efficacy in patients with respiratory symptoms and neuromuscular diseases. Considerable research has been undertaken over the past 17 years, since the publication of the previous American Thoracic Society (ATS)/European Respiratory Society (ERS) statement on respiratory muscle testing in 2002. Key advances have been made in the field of mechanics of breathing, respiratory muscle neurophysiology (electromyography, electroencephalography and transcranial magnetic stimulation) and on respiratory muscle imaging (ultrasound, optoelectronic plethysmography and structured light plethysmography). Accordingly, this ERS task force reviewed the field of respiratory muscle testing in health and disease, with particular reference to data obtained since the previous ATS/ERS statement. It summarises the most recent scientific and methodological developments regarding respiratory mechanics and respiratory muscle assessment by addressing the validity, precision, reproducibility, prognostic value and responsiveness to interventions of various methods. A particular emphasis is placed on assessment during exercise, which is a useful condition to stress the respiratory system.

Blunted blood pressure response during hyperpnoea in endurance runners.

UNLABELLED: The purpose of this study was to elucidate the cardiovascular response during hyperpnoea in endurance-trained runners compared to sedentary controls. Twelve runners and ten sedentary individuals participated in this study. A maximal respiratory endurance test (MRET) was performed as follows: target minute ventilation was initially set at 30% of maximal voluntary ventilation (MVV12) and was increased by 10% MVV12 every 3min. The test was terminated when the subject could no longer maintain the target ventilation. Heart rate and mean arterial blood pressure (MBP) were continuously measured. Respiratory endurance time during the MRET was longer in the runners than the controls. The change in MBP during the MRET was lower in the runners compared to the sedentary controls (runners: 100.2±2.4mmHg vs. CONTROLS: 109.1±3.0mmHg at 6min of hyperpnoea). Therefore, the blood pressure response during hyperpnoea is blunted in endurance runners, suggesting that whole-body endurance exercise training attenuates the respiratory muscle-induced metaboreflex.

Origin of the unique ventilatory apparatus of turtles.

The turtle body plan differs markedly from that of other vertebrates and serves as a model system for studying structural and developmental evolution. Incorporation of the ribs into the turtle shell negates the costal movements that effect lung ventilation in other air-breathing amniotes. Instead, turtles have a unique abdominal-muscle-based ventilatory apparatus whose evolutionary origins have remained mysterious. Here we show through broadly comparative anatomical and histological analyses that an early member of the turtle stem lineage has several turtle-specific ventilation characters: rigid ribcage, inferred loss of intercostal muscles and osteological correlates of the primary expiratory muscle. Our results suggest that the ventilation mechanism of turtles evolved through a division of labour between the ribs and muscles of the trunk in which the abdominal muscles took on the primary ventilatory function, whereas the broadened ribs became the primary means of stabilizing the trunk. These changes occurred approximately 50 million years before the evolution of the fully ossified shell.

Orangutan (Pongo spp.) whistling and implications for the emergence of an open-ended call repertoire: a replication and extension.

One of the most apparent discontinuities between non-human primate (primate) call communication and human speech concerns repertoire size. The former is essentially fixed to a limited number of innate calls, while the latter essentially consists of numerous learned components. Consequently, primates are thought to lack laryngeal control required to produce learned voiced calls. However, whether they may produce learned voiceless calls awaits investigation. Here, a case of voiceless call learning in primates is investigated--orangutan (Pongo spp.) whistling. In this study, all known whistling orangutans are inventoried, whistling-matching tests (previously conducted with one individual) are replicated with another individual using original test paradigms, and articulatory and acoustic whistle characteristics are compared between three orangutans. Results show that whistling has been reported for ten captive orangutans. The test orangutan correctly matched human whistles with significantly high levels of performance. Whistle variation between individuals indicated voluntary control over the upper lip, lower lip, and respiratory musculature, allowing individuals to produce learned voiceless calls. Results are consistent with inter- and intra-specific social transmission in whistling orangutans. Voiceless call learning in orangutans implies that some important components of human speech learning and control were in place before the homininae-ponginae evolutionary split.

Neuromuscular ultrasound for evaluation of the diaphragm.

Neuromuscular clinicians are often asked to evaluate the diaphragm for diagnostic and prognostic purposes. Traditionally, this evaluation is accomplished through history, physical exam, fluoroscopic sniff test, nerve conduction studies, and electromyography (EMG). Nerve conduction studies and EMG in this setting are challenging, uncomfortable, and can cause serious complications, such as pneumothorax. Neuromuscular ultrasound has emerged as a non-invasive technique that can be used in the structural and functional assessment of the diaphragm. In this study we review different techniques for assessing the diaphragm using neuromuscular ultrasound and the application of these techniques to enhance diagnosis and prognosis by neuromuscular clinicians.

Difference in lateral abdominal muscle thickness during forceful exhalation in healthy smokers and non-smokers.

BACKGROUND AND OBJECTIVES: The present study aims to determine whether the internal oblique (IO) and transversus abdominis (TrA) muscles, which are major lumbar stabilisers and also expiratory muscles, are affected by smoking. METHODS: A total of 31 healthy individuals in their 20s (smokers: 15; non-smokers: 16) voluntarily participated in the study. They were made to maintain an upright standing posture with their scapulars on the wall. Then measurement was taken on the thickness of their right IO and TrA while they were at rest and in a state of forced expiration using a 7.5 MHz linear probe, an ultrasonic imaging system. The thickness of the muscles was converted into the percentage of change in muscle thickness (PCMT) and relative contribution ratio (RCR) using a calculation formula, and then the data were analysed. RESULTS: Significant differences were found between the two groups in the PCMT of the TrA and in the RCR of both TrA and IO. CONCLUSION: Smokers have a relatively higher degree of dependence on IO than TrA during forceful expiratory conditions compared with non-smokers. This relative overreaction of the IO is considered to likely cause problems in efficiently diffusing loads of the spine.

Efectos del entrenamiento de la musculatura respiratoria sobre el rendimiento. Revisión bibliográfica / Effects of respiratory muscles training on performance. Literature review

Actualmente, es aceptado por la comunidad científica que el sistema respiratorio puede limitar el ejercicio en personas con enfermedad pulmonar y/o cardiovascular. El objetivo del presente artículo es la revisión de algunos estudios realizados en relación al papel limitante del sistema respiratorio en el rendimiento físico de deportistas. Se realiza una breve descripción técnica de los dispositivos más utilizados para el entrenamiento de la musculatura respiratoria. Finalmente, se presentan los resultados más representativos, obtenidos por diversos investigadores y en distintas poblaciones, relacionados con el entrenamiento de la musculatura respiratoria y sus efectos en el rendimiento físico. Los resultados obtenidos en las distintas investigaciones consultadas sobre el entrenamiento de los músculos respiratorios son dispares, puesto que algunos han mostrado mejoras significativas, mientras otros no han mostrado grandes efectos en el rendimiento. En todos ellos se refleja cómo el sistema respiratorio es un factor limitante del rendimiento físico en deportistas y es preciso plantearse nuevas metodologías, protocolos y planificaciones en el entrenamiento deportivo. El entrenamiento de los músculos respiratorios, tanto mediante dispositivos umbral, de resistencia, o isocapnica, puede provocar mejoras en valores como la presión inspiratoria máxima y mejoras en el rendimiento de algunos deportes; sin embargo, son muy escasos los estudios que han encontrado mejoras en el consumo máximo de oxígeno (VO2max). Las discrepancias entre los estudios analizados pueden estar provocadas por diferencias en las intensidades y duración de los ejercicios utilizados, así como por diferencias en el diseño experimental y el nivel de condición física de los sujetos(AU)

It is currently accepted by the scientific community that the respiratory system may limit the exercise in people with lung disease and / or cardiovascular disease. The aim of this study is to review some studies about the limiting role of the respiratory system in the physical performance of athletes and the breath factors that can limit it. We make a brief technical description of the devices used for respiratory muscle training. Finally, we present the most representative results obtained by different researchers in different populations, related to respiratory muscle training and its effects on physical performance. Results obtained in different studies about respiratory muscles training are uneven as some have shown significant improvements, while others have shown no major effects on the performance. All of them reflect that respiratory system is a limiting factor in the physical performance of athletes and it is necessary to consider new methodologies, protocols and plans in sports training. Respiratory muscles training, either by a threshold device, resistance, or isocapnic, may cause improvements in the values of maximum inspiratory pressure and improvements in some sports performance, however, very few studies have found improvements in peak oxygen consumption. Disagreements between the analyzed studies may be caused due to differences in intensity and duration of the exercises used in the tests, as well as by differences between the experimental design and the physical fitness level of subjects(AU)

Respiratory dysfunction in ventilated patients: can inspiratory muscle training help?

Respiratory muscle dysfunction is associated with prolonged and difficult weaning from mechanical ventilation. This dysfunction in ventilator-dependent patients is multifactorial: there is evidence that inspiratory muscle weakness is partially explained by disuse atrophy secondary to ventilation, and positive end-expiratory pressure can further reduce muscle strength by negatively shifting the length-tension curve of the diaphragm. Polyneuropathy is also likely to contribute to apparent muscle weakness in critically ill patients, and nutritional and pharmaceutical effects may further compound muscle weakness. Moreover, psychological influences, including anxiety, may contribute to difficulty in weaning. There is recent evidence that inspiratory muscle training is safe and feasible in selected ventilator-dependent patients, and that this training can reduce the weaning period and improve overall weaning success rates. Extrapolating from evidence in sports medicine, as well as the known effects of inspiratory muscle training in chronic lung disease, a theoretical model is proposed to describe how inspiratory muscle training enhances weaning and recovery from mechanical ventilation. Possible mechanisms include increased protein synthesis (both Type 1 and Type 2 muscle fibres), enhanced limb perfusion via dampening of a sympathetically-mediated metaboreflex, reduced lactate levels and modulation of the perception of exertion, resulting in less dyspnoea and enhanced exercise capacity.

Respiratory muscle plasticity.

Muscle plasticity is defined as the ability of a given muscle to alter its structural and functional properties in accordance with the environmental conditions imposed on it. As such, respiratory muscle is in a constant state of remodeling, and the basis of muscle's plasticity is its ability to change protein expression and resultant protein balance in response to varying environmental conditions. Here, we will describe the changes of respiratory muscle imposed by extrinsic changes in mechanical load, activity, and innervation. Although there is a large body of literature on the structural and functional plasticity of respiratory muscles, we are only beginning to understand the molecular-scale protein changes that contribute to protein balance. We will give an overview of key mechanisms regulating protein synthesis and protein degradation, as well as the complex interactions between them. We suggest future application of a systems biology approach that would develop a mathematical model of protein balance and greatly improve treatments in a variety of clinical settings related to maintaining both muscle mass and optimal contractile function of respiratory muscles.

Mechanics of the respiratory muscles.

This article examines the mechanics of the muscles that drive expansion or contraction of the chest wall during breathing. The diaphragm is the main inspiratory muscle. When its muscle fibers are activated in isolation, they shorten, the dome of the diaphragm descends, pleural pressure (P(pl)) falls, and abdominal pressure (P(ab)) rises. As a result, the ventral abdominal wall expands, but a large fraction of the rib cage contracts. Expansion of the rib cage during inspiration is produced by the external intercostals in the dorsal portion of the rostral interspaces, the intercartilaginous portion of the internal intercostals (the so-called parasternal intercostals), and, in humans, the scalenes. By elevating the ribs and causing an additional fall in P(pl), these muscles not only help the diaphragm expand the chest wall and the lung, but they also increase the load on the diaphragm and reduce the shortening of the diaphragmatic muscle fibers. The capacity of the diaphragm to generate pressure is therefore enhanced. In contrast, during expiratory efforts, activation of the abdominal muscles produces a rise in P(ab) that leads to a cranial displacement of the diaphragm into the pleural cavity and a rise in P(pl). Concomitant activation of the internal interosseous intercostals in the caudal interspaces and the triangularis sterni during such efforts contracts the rib cage and helps the abdominal muscles deflate the lung.

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)

Airway narrowing assessed by anatomical optical coherence tomography in vitro: dynamic airway wall morphology and function.

Regulation of airway caliber by lung volume or bronchoconstrictor stimulation is dependent on physiological, structural, and mechanical events within the airway wall, including airway smooth muscle (ASM) contraction, deformation of the mucosa and cartilage, and tensioning of elastic matrices linking wall components. Despite close association between events in the airway wall and the resulting airway caliber, these have typically been studied separately: the former primarily using histological approaches, the latter with a range of imaging modalities. We describe a new optical technique, anatomical optical coherence tomography (aOCT), which allows changes at the luminal surface (airway caliber) to be temporally related to corresponding dynamic movements within the airway wall. A fiber-optic aOCT probe was inserted into the lumen of isolated, liquid-filled porcine airways. It was used to image the response to ASM contraction induced by neural stimulation and to airway inflation and deflation. Comparisons with histology indicated that aOCT provided high-resolution images of the airway lumen including mucosal folds, the entire inner wall (mucosa and ASM), and partially the cartilaginous outer wall. Airway responses assessed by aOCT revealed several phenomena in "live" airways (i.e., not fixed) previously identified by histological investigations of fixed tissue, including a geometric relationship between ASM shortening and luminal narrowing, and sliding and bending of cartilage plates. It also provided direct evidence for distensibility of the epithelial membrane and anisotropic behavior of the airway wall. Findings suggest that aOCT can be used to relate changes in airway caliber to dynamic events in the wall of airways.

Neuromechanical matching of drive in the scalene muscle of the anesthetized rabbit.

The scalene is a primary respiratory muscle in humans; however, in dogs, EMG activity recorded from this muscle during inspiration was reported to derive from underlying muscles. In the present studies, origin of the activity in the medial scalene was tested in rabbits, and its distribution was compared with the muscle mechanical advantage. We assessed in anesthetized rabbits the presence of EMG activity in the scalene, sternomastoid, and parasternal intercostal muscles during quiet breathing and under resistive loading, before and after denervation of the scalene and after its additional insulation. At rest, activity was always recorded in the parasternal muscle and in the scalene bundle inserting on the third rib (medial scalene). The majority of this activity disappeared after denervation. In the bundle inserting on the fifth rib (lateral scalene), the activity was inconsistent, and a high percentage of this activity persisted after denervation but disappeared after insulation from underlying muscle layers. The sternomastoid was always silent. The fractional change in muscle length during passive inflation was then measured. The mean shortening obtained for medial and lateral scalene and parasternal intercostal was 8.0 +/- 0.7%, 5.5 +/- 0.5%, and 9.6 +/- 0.1%, respectively, of the length at functional residual capacity. Sternomastoid muscle length did not change significantly with lung inflation. We conclude that, similar to that shown in humans, respiratory activity arises from scalene muscles in rabbits. This activity is however not uniformly distributed, and a neuromechanical matching of drive is observed, so that the most effective part is also the most active.

Severe restrictive lung disease and vertebral surgery in a pediatric population.

The aim of this study is to describe the outcome of surgical treatment for pediatric patients with forced vital capacity (FVC) <40% and severe vertebral deformity. Few studies have examined surgical treatment in these patients, who are considered to be at a high risk because of their pulmonary disease, and in whom preoperative tracheostomy is sometimes recommended. Inclusion criteria include FVC <40%, age <19 years and diagnosis of scoliosis. The retrospective study of 24 patients with severe restrictive lung disease, who underwent spinal surgery. Variables studied were age and gender, pre- and postoperative spirometry (FVC, FEV1, FEV1/FVC), preoperative, postoperative and late use of non-invasive ventilation (BiPAP) or mechanical ventilation, associated multidisciplinary treatment, type and location of the curve, pre- and postoperative curve values, type of vertebral fusion, intra- and postoperative complications, duration of intensive care unit (ICU) stay and length of postoperative hospitalization. Mean age was 13 years (9-19) of which 13 were males and 11 females. Mean follow-up was 32 months (24-45). The etiology was neuromuscular in 17 patients and other etiologies in 7 patients. Mean preoperative FVC was 26% (13-39%). Eight patients had preoperative home BiPAP, 15 preoperative in-hospital BiPAP, and 2 preoperative mechanical ventilation. Nine patients had preoperative nutritional support. Preoperative curve value of the deformity was 88 degrees (40 degrees -129 degrees ). Nineteen patients with posterior fusion alone and 5 with anterior and posterior fusion were found. Mean duration of ICU stay was 5 days (1-21). Total postoperative hospital stay was 17 days (7-33). Ventilatory support in the immediate postoperative includes 16 patients requiring BiPAP and 2 volumetric ventilation. None of the patients required a tracheostomy. The intraoperative complications include one death due to acute heart failure; immediate postoperative, four respiratory failures (2 required ICU readmission) and one respiratory infection; and other minor complications occurred in six patients. Overall, 58% of patients had complications. Percentage of angle correction was 56%. After a follow-up of 30 months, FVC was 29% (13-50%). In conclusion, corrective scoliosis surgery in pediatric patients with severe restrictive lung disease is well tolerated, but the management of this population requires extensive experience with the vertebral surgery involved, and a multidisciplinary approach that includes pulmonologists, nutritionists and anesthesiologists. Currently, there is no indication for routine preoperative tracheostomy.

Disfunción muscular esquelética en la EPOC / Skeletal muscle dysfunction in COPD

La función muscular se halla frecuentamente afectada en los pacientes con enfermedad pulmonar obstructivacrónica (EPOC), lo cual condiciona su semiología y pronóstico. La distribución y la gravedad de estadisfunción son heterogéneas, por lo que sus causas predominantes parecen en parte específi cas del grupomuscular examinado. Es el caso de la sobreactividad y una geometría desfavorable características de losmúsculos respiratorios, frente a la relativa inactividad de los músculos de las extremidades. También hayfactores que serían comunes a todos los músculos del organismo. Entre ellos destacarían la infl amaciónsistémica, las alteraciones nutricionales, el uso de determinados fármacos, la hipoxia y la presencia de comorbilidady/o edad avanzada. Sin embargo, mientras que los músculos respiratorios muestran un fenotipoadaptado a su situación desfavorable, y llegan a compensarla parcialmente, los músculos de las extremidadesmuestran cambios de tipo involutivo, que contribuirían a la disfunción. Por tanto, aunque la pérdidafuncional puede aparecer en diferentes territorios musculares, sus causas, y por tanto sus enfoques terapéuticos,serán diversos, incluidos el soporte nutricional, el entrenamiento y/o el reposo, según los casos(AU)

Muscle function is frequently affected in patients with chronic obstructive pulmonary disease (COPD),infl uencing the symptoms and prognosis of this disease. The distribution and severity of this dysfunctionare heterogeneous and therefore the main causes seem, in part, to be specifi c to the muscular groupexamined, which is the case of the overactivity and unfavorable geometry characteristic of respiratorymuscles, compared with the relative inactivity of the muscles of the limbs.There are also factors that are common to all the muscles in the body. Notable among these factors aresystemic infl ammation, nutritional alterations, the use of certain drugs, hypoxia and the presence ofcomorbidity and/or advanced age. However, while the respiratory muscles show a phenotype adapted totheir unfavorable situation and manage to partially compensate for this situation, the muscles of the limbsshow involutive changes, which contribute to dysfunction. Therefore, although functional loss can developin distinct muscular territories, the causes – and consequently the therapeutic approaches – differ,including nutritional support, muscle training and/or rest, depending on the muscle(AU)