Impacto del Entrenamiento Respiratorio de Hiperpnea Isocápnica Voluntaria sobre el Costo Energético asociado a la Respiración inducido por Ejercicio Físico / Impact of Voluntary Isocapnic Hyperpnea training on the cost of breathing

Introducción. Determinar el efecto de ocho semanas de entrenamiento por hiperpnea isocápnica voluntaria (HIV) sobre el costo energético asociado a la respiración (COB) reflejado en los cambios en la oxigenación de los músculos intercostales (∆SmO2-m. intercostales) inducida por ejercicio físico de intensidad incremental. Métodos. Doce participantes físicamente activos fueron entrenados durante ocho semanas de HIV 3 días x semana, 12 minutos, al 60% de ventilación voluntaria máxima (VVM). En la semana previa y posterior al entrenamiento HIV se realizó un test cardiopulmonar (CPET) de intensidad incremental en cicloergómetro, durante esta prueba se registró la ∆SmO2-m. intercostales mediante el dispositivo MOXY®. El efecto de HIV sobre la ∆SmO2-m. intercostales se analizó mediante la prueba two-way mixed ANOVA considerando los factores (fase × tarea). Resultados. ∆SmO2-m.intercostales fue significativamente menor a partir del 30% (­5,0±4,7%; p<0.01) hasta el 100% (­10,6±12,8%; p<0.01) de la tarea luego de ocho semanas de HIV. Además, se reportó un aumento de la presión inspiratoria máxima (PIM)=16,5±11,4 cmH2O (p<0.01); y de la resistencia muscular respiratoria=106,6±149,0 s (p<0.01). El tiempo total de ejercicio aumentó en 106,6±149,0 s (p=0.04), así como la carga total en 10,50± 10,12 vatios (p<0.01). Conclusión. El HIV disminuye el COB inducido por ejercicio incremental asociado a un incremento en la performance física y de los músculos respiratorios. En futuros estudios se sugiere estudiar esta estrategia de entrenamiento analítico de los músculos respiratorios en usuarios con limitación física relacionada al aumento prematuro del COB.

Background. Objetive. To determine the effect of eight weeks of voluntary isocapnic hyperpnea (VIH) training on cost of breathing (COB) as reflected by intercostales muscles deoxygenation (∆SmO2-m. intercostales) induced by incremental-intensity physical exercise. Methods. Twelve physically active participants underwent eight weeks of VIH training, three days a week, for 12 minutes each session, at 60% of maximal voluntary ventilation (MVV). In the week before and after VIH training, a cardiopulmonary test (CPET) of incremental intensity was performed on a cycloergometer. During this test, intercostal ∆SmO2-m.intercostales was recorded using the MOXY® device. The effect of VIH on ∆SmO2-m.intercostales were analyzed using a two-way mixed ANOVA test considering the factors (phase × task). Results. ∆SmO2-m.intercostales significantly decreased from 30% (­5.0±4.7%; p<0.01) to 100% (­10.6±12.8%; p<0.01) of the task after eight weeks of VIH. Additionally, an increase in maximal inspiratory pressure (MIP) of 16.5±11.4 cmH2O (p<0.01) and respiratory muscle endurance of 106.6±149.0 s (p<0.01) was reported. Total exercise time increased by 106.6±149.0 s (p=0.04), as well as total workload by 10.50±10.12 watts (p<0.01). Conclusion. VIH reduces COB induced by incremental exercise and is associated with increased physical and respiratory muscle performance. Future studies should explore this respiratory muscle training strategy for individuals with physical limitations related to a premature increase in COB.

Monitoring Changes in Oxygen Muscle during Exercise with High-Flow Nasal Cannula Using Wearable NIRS Biosensors.

Exercise increases the cost of breathing (COB) due to increased lung ventilation (V˙E), inducing respiratory muscles deoxygenation (∇SmO2), while the increase in workload implies ∇SmO2 in locomotor muscles. This phenomenon has been proposed as a leading cause of exercise intolerance, especially in clinical contexts. The use of high-flow nasal cannula (HFNC) during exercise routines in rehabilitation programs has gained significant interest because it is proposed as a therapeutic intervention for reducing symptoms associated with exercise intolerance, such as fatigue and dyspnea, assuming that HFNC could reduce exercise-induced ∇SmO2. SmO2 can be detected using optical wearable devices provided by near-infrared spectroscopy (NIRS) technology, which measures the changes in the amount of oxygen bound to chromophores (e.g., hemoglobin, myoglobin, cytochrome oxidase) at the target tissue level. We tested in a study with a cross-over design whether the muscular desaturation of m.vastus lateralis and m.intercostales during a high-intensity constant-load exercise can be reduced when it was supported with HFNC in non-physically active adults. Eighteen participants (nine women; age: 22 ± 2 years, weight: 65.1 ± 11.2 kg, height: 173.0 ± 5.8 cm, BMI: 21.6 ± 2.8 kg·m-2) were evaluated in a cycle ergometer (15 min, 70% maximum watts achieved in ergospirometry (V˙O2-peak)) breathing spontaneously (control, CTRL) or with HFNC support (HFNC; 50 L·min-1, fiO2: 21%, 30 °C), separated by seven days in randomized order. Two-way ANOVA tests analyzed the ∇SmO2 (m.intercostales and m.vastus lateralis), and changes in V˙E and ∇SmO2·V˙E-1. Dyspnea, leg fatigue, and effort level (RPE) were compared between trials by the Wilcoxon matched-paired signed rank test. We found that the interaction of factors (trial × exercise-time) was significant in ∇SmO2-m.intercostales, V˙E, and (∇SmO2-m.intercostales)/V˙E (p < 0.05, all) but not in ∇SmO2-m.vastus lateralis. ∇SmO2-m.intercostales was more pronounced in CTRL during exercise since 5' (p < 0.05). Hyperventilation was higher in CTRL since 10' (p < 0.05). The ∇SmO2·V˙E-1 decreased during exercise, being lowest in CTRL since 5'. Lower dyspnea was reported in HFNC, with no differences in leg fatigue and RPE. We concluded that wearable optical biosensors documented the beneficial effect of HFNC in COB due to lower respiratory ∇SmO2 induced by exercise. We suggest incorporating NIRS devices in rehabilitation programs to monitor physiological changes that can support the clinical impact of the therapeutic intervention implemented.

Effectiveness of Respiratory Muscles Training by Voluntary Isocapnic Hyperpnea Versus Inspiratory Threshold Loading on Intercostales and Vastus Lateralis Muscles Deoxygenation Induced by Exercise in Physically Active Adults.

Respiratory muscle training (RMT) improves physical performance, although it is still debated whether this effect depends on the type of training. The purpose of this study was to compare the effects of two different types of RMT, i.e., voluntary isocapnic hyperpnea (VIH) and inspiratory threshold loading (ITL), on the deoxygenation of intercostal (ΔSmO2-m. intercostales) and vastus lateralis (ΔSmO2-m. vastus lateralis) muscles during exercise. Twenty-four participants performed eight weeks of RMT by: (i) VIH (3 days·week-1 for 12 min at 60% maximal voluntary ventilation) or (ii) ITL (5 sets·week-1 of 30 breaths·minute-1 at 60% maximal inspiratory pressure). Cardiopulmonary exercise testing (CPET) included ΔSmO2 (the change from baseline to end of test) of intercostal and vastus lateralis muscles. After RMT, both groups showed decreased ΔSmO2-m. intercostales (VIH = 12.8 ± 14.6%, p = 0.04 (effect size, ES = 0.59), and ITL = 8.4 ± 9.8%, p = 0.04 (ES = 0.48)), without a coincident change of ∆SmO2-m. vastus lateralis. ITL training induced higher V˙O2-peak absolute values than VIH (mean Δ post-pre, ITL = 229 ± 254 mL·min-1 [95% CI 67-391] vs. VIH, 39 ± 153 mL·min-1 [95% CI -58-136.0], p = 0.01). In conclusion, both RMT improved the balance between supply and oxygen consumption levels of m. intercostales during CPET, with ITL also inducing an increase of aerobic capacity.

Terapia de alto flujo ¿Una alternativa en rehabilitación? / High flow therapy: An option to rehabilitation?

La pandemia por el virus SARS-COV2 que causó la enfermedad COVID-19 ha traído grandes desafíos al sistema de salud tanto a nivel nacional como mundial. En Chile, gracias al esfuerzo de organismos gubernamentales e instituciones privadas, los centros de salud se han equipado con distintos dispositivos de terapia ventilatoria (ventilación mecánica invasiva y no invasiva, y terapia de alto flujo de oxígeno mediante cánula nasal (TAF) con la finalidad de abarcar mayor atención de pacientes tras un periodo de crisis sanitaria que colapsó las redes de atención secundaria y terciaria de salud. En concordancia a esto, es interesante evaluar qué utilidad puede darse a estos equipos posterior a la pandemia, considerando que en varios centros de salud se duplicó o triplicó la disponibilidad de recursos técnicos. En este contexto, la TAF entrega efectos fisiológicos favorables y útiles en escenarios clínicos que implican aumento de las demandas ventilatorias, no sólo en condiciones de insuficiencia respiratoria hipoxémica aguda, sino en condiciones en donde el ejercicio aeróbico es un pilar fundamental, como es el caso de los diferentes programas de rehabilitación (cardiovascular, respiratorio, metabólico, etc.) incluidos como Garantías Explícitas de Salud (GES). Así, la incorporación de TAF en la rehabilitación pulmonar sería una opción adecuada en pacientes con disfunciones respiratorias crónicas, ampliando la cobertura sanitaria que estos programas tienen hoy en día.

The SARS-COV2 pandemic that caused the COVID-19 disease has brought significant challenges to the health system nationally and globally. In Chile, thanks to the efforts of government agencies and private institutions, health centres have been equipped with di-fferent ventilatory therapy devices (invasive and non-invasive mechanical ventilation, and high-flow oxygen therapy by nasal cannula (HFOT)), in order to cover more patient care after a period of a health crisis that collapsed secondary and tertiary health care networks. Accordingly, it is interesting to evaluate concerning what use can be given to these teams after the pandemic, even more considering that the availability of technical resources doubled or tripled in several health centres. In this context, HFOT provides favourable and useful physiological effects in clinical scenarios that involve increased ventilatory demands, not only in conditions of acute hypoxemic respiratory failure but also in conditions where aerobic exercise is a fundamental pillar, as is the case of the different rehabilitation programs (cardiovascular, respiratory, metabolic, etc.) included as Health Guarantees (Garantías Explicitas en Salud, GES). Thus, incorporating HFOT in pulmonary rehabilitation would be an appropriate option in patients with chronic respiratory dysfunctions, expanding the health coverage that these programs have today.

Eccentric Training in Pulmonary Rehabilitation of Post-COVID-19 Patients: An Alternative for Improving the Functional Capacity, Inflammation, and Oxidative Stress.

The purpose of this narrative review is to highlight the oxidative stress induced in COVID-19 patients (SARS-CoV-2 infection), describe longstanding functional impairments, and provide the pathophysiologic rationale that supports aerobic eccentric (ECC) exercise as a novel alternative to conventional concentric (CONC) exercise for post-COVID-19 patients. Patients who recovered from moderate-to-severe COVID-19 respiratory distress demonstrate long-term functional impairment. During the acute phase, SARS-CoV-2 induces the generation of reactive oxygen species that can be amplified to a "cytokine storm". The resultant inflammatory and oxidative stress process causes organ damage, particularly in the respiratory system, with the lungs as the tissues most susceptible to injury. The acute illness often requires a long-term hospital stay and consequent sarcopenia. Upon discharge, muscle weakness compounded by limited lung and cardiac function is often accompanied by dyspnea, myalgia, anxiety, depression, and sleep disturbance. Consequently, these patients could benefit from pulmonary rehabilitation (PR), with exercise as a critical intervention (including sessions of strength and endurance or aerobic exercises). Unfortunately, conventional CONC exercises induce significant cardiopulmonary stress and increase inflammatory and oxidative stress (OS) when performed at moderate/high intensity, which can exacerbate debilitating dyspnoea and muscle fatigue post-COVID-19. Eccentric training (ECC) is a well-tolerated alternative that improves muscle mass while mitigating cardiopulmonary stress in patients with COPD and other chronic diseases. Similar benefits could be realized in post-COVID-19 patients. Consequently, these patients could benefit from PR with exercise as a critical intervention.

Cánula Nasal de Alto Flujo en Adultos con Enfermedades Respiratorias Crónicas durante el Ejercicio Físico: Protocolo de Revisión Sistemática y Metaanálisis / High-Flow Nasal Cannula in Adults with Chronic Respiratory Diseases during Physical Exercise: A Protocol Systematic Review and Meta-analysis

Introducción. El entrenamiento físico puede mejorar la capacidad de ejercicio, la disnea y la calidad de vida (CV) en pacientes con enfermedades respiratorias crónicas (ERC). En este contexto, el uso de oxígeno suplementario a través de una cánula nasal de alto flujo (CNAF) podría ser un dispositivo que permita tolerar mayores niveles de actividad con menos síntomas de esfuerzo físico, optimizando en última instancia la capacidad de ejercicio y la CV. Objetivo. Este protocolo pretende conducir una revisión sistemática para evaluar el efecto terapéutico de la CNAF durante el ejercicio físico en pacientes con ERC. Fuente de búsqueda. Se realizarán búsquedas en el Registro Cochrane Central de Ensayos Controlados (CENTRAL), PUBMED, Embase, Lilacs, Physiotherapy Evidence Database (PEDro), International Clinical Trials Registry Platform (ICTRP), ClinicalTrials.gov y literatura gris. Criterios de elegibilidad. Examinaremos los ECA de acuerdo con los criterios de elegibilidad para su inclusión en nuestra revisión. Dos revisores examinarán de forma independiente cada estudio para la elegibilidad, la extracción de datos y la evaluación del riesgo de sesgo. Se combinarán los resultados mediante un metanálisis y se aplicará el sistema GRADE para evaluar la certeza de las pruebas para cada resultado. La medida de resultado primaria será la capacidad de ejercicio, y las medidas de resultado secundarias serán la calidad de vida, la disnea, la funcionalidad, la comodidad, las complicaciones y adherencia. Se realizarán metaanálisis para determinar la diferencia de medias (DM) o la DM estandarizada para los datos continuos y la razón de riesgo para los datos dicotómicos. Se realizarán análisis de subgrupos según los tipos y la gravedad de la enfermedad, las condiciones de ejercicio físico y el estado de los dispositivos de oxigenoterapia. Ética y difusión. Como los investigadores no accederán a información que pueda conducir a la identificación de un participante individual, no fue necesario a obtener aprobación ética. Número de registro de PROSPERO: CRD42022336263.

Background. Physical training can improve exercise capacity, dyspnoea, and quality of life (QoL) in patients with chronic respiratory diseases (CRDs). It has been suggested that using supplemental oxygen through a high-flow nasal cannula (HFNC) could lead to higher levels of activity to be tolerated with fewer symptoms of physical exertion, ultimately optimizing exercise capacity and QoL. Objective. To conduct a systematic review to assess the therapeutic effect of HFNC during physical exercise in patients with CRDs. We will search the Cochrane Central Register of Controlled Trials (CENTRAL), PUBMED, Embase, Lilacs, Physiotherapy Evidence Database (PEDro), International Clinical Trials Registry Platform (ICTRP), ClinicalTrials.gov, and grey literature. Eligibility criteria. We will examine RCTs according to the eligibility criteria for inclusion in our review. Two reviewers will independently examine each study for eligibility, data extraction, and risk of bias assessment. We will combine the results using meta-analysis and apply the GRADE system to assess the certainty of the evidence for each outcome. The primary outcome will be exercise capacity, and secondary outcomes will be QoL, dyspnoea, functionality, comfort, complications, and adherence. We will perform meta-analyses to determine the mean difference (MD) or standardized MD for continuous data and the risk ratio for dichotomous data. Subgroup analyses will be performed according to types and severity of disease, physical exercise conditions, and condition of oxygen therapy devices. Ethics and Dissemination. As researchers will not access information that could lead to the identification of an individual participant, obtaining ethical approval was waived. Prospero registration number: CRD42022336263.

Determination of the Respiratory Compensation Point by Detecting Changes in Intercostal Muscles Oxygenation by Using Near-Infrared Spectroscopy.

This study aimed to evaluate if the changes in oxygen saturation levels at intercostal muscles (SmO2-m.intercostales) assessed by near-infrared spectroscopy (NIRS) using a wearable device could determine the respiratory compensation point (RCP) during exercise. Fifteen healthy competitive triathletes (eight males; 29 ± 6 years; height 167.6 ± 25.6 cm; weight 69.2 ± 9.4 kg; V˙O2-máx 58.4 ± 8.1 mL·kg−1·min−1) were evaluated in a cycle ergometer during the maximal oxygen-uptake test (V˙O2-máx), while lung ventilation (V˙E), power output (watts, W) and SmO2-m.intercostales were measured. RCP was determined by visual method (RCPvisual: changes at ventilatory equivalents (V˙E·V˙CO2−1, V˙E·V˙O2−1) and end-tidal respiratory pressure (PetO2, PetCO2) and NIRS method (RCPNIRS: breakpoint of fall in SmO2-m.intercostales). During exercise, SmO2-m.intercostales decreased continuously showing a higher decrease when V˙E increased abruptly. A good agreement between methods used to determine RCP was found (visual vs NIRS) at %V˙O2-máx, V˙O2, V˙E, and W (Bland-Altman test). Correlations were found to each parameters analyzed (r = 0.854; r = 0.865; r = 0.981; and r = 0,968; respectively. p < 0.001 in all variables, Pearson test), with no differences (p < 0.001 in all variables, Student's t-test) between methods used (RCPvisual and RCPNIRS). We concluded that changes at SmO2-m.intercostales measured by NIRS could adequately determine RCP in triathletes.

Sex-Differences in the Oxygenation Levels of Intercostal and Vastus Lateralis Muscles During Incremental Exercise.

This study aimed to examine sex differences in oxygen saturation in respiratory (SmO2-m.intercostales) and locomotor muscles (SmO2-m.vastus lateralis) while performing physical exercise. Twenty-five (12 women) healthy and physically active participants were evaluated during an incremental test with a cycle ergometer, while ventilatory variables [lung ventilation ( V . E), tidal volume (Vt), and respiratory rate (RR)] were acquired through the breath-by-breath method. SmO2 was acquired using the MOXY® devices on the m.intercostales and m.vastus lateralis. A two-way ANOVA (sex × time) indicated that women showed a greater significant decrease of SmO2-m.intercostales, and men showed a greater significant decrease of SmO2-m.vastus lateralis. Additionally, women reached a higher level of ΔSmO2-m.intercostales normalized to V . E (L⋅min-1) (p < 0.001), whereas men had a higher level of ΔSmO2-m.vastus lateralis normalized to peak workload-to-weight (watts⋅kg-1, PtW) (p = 0.049), as confirmed by Student's t-test. During an incremental physical exercise, women experienced a greater cost of breathing, reflected by greater deoxygenation of the respiratory muscles, whereas men had a higher peripheral load, indicated by greater deoxygenation of the locomotor muscles.

Intercostal Muscles Oxygenation and Breathing Pattern during Exercise in Competitive Marathon Runners.

The study aimed to evaluate the association between the changes in ventilatory variables (tidal volume (Vt), respiratory rate (RR) and lung ventilation (V.E)) and deoxygenation of m.intescostales (∆SmO2-m.intercostales) during a maximal incremental exercise in 19 male high-level competitive marathon runners. The ventilatory variables and oxygen consumption (V.O2) were recorded breath-by-breath by exhaled gas analysis. A near-infrared spectroscopy device (MOXY®) located in the right-hemithorax allowed the recording of SmO2-m.intercostales. To explore changes in oxygen levels in muscles with high demand during exercise, a second MOXY® records SmO2-m.vastus laterallis. The triphasic model of exercise intensity was used for evaluating changes in SmO2 in both muscle groups. We found that ∆SmO2-m.intercostales correlated with V.O2-peak (r = 0.65; p = 0.002) and the increase of V.E (r = 0.78; p = 0.001), RR (r = 0.54; p = 0.001), but not Vt (p = 0.210). The interaction of factors (muscles × exercise-phases) in SmO2 expressed as an arbitrary unit (a.u) was significant (p = 0.005). At VT1 there was no difference (p = 0.177), but SmO2-m.intercostales was higher at VT2 (p < 0.001) and V.O2-peak (p < 0.001). In high-level competitive marathon runners, the m.intercostales deoxygenation during incremental exercise is directly associated with the aerobic capacity and increased lung ventilation and respiratory rate, but not tidal volume. Moreover, it shows less deoxygenation than m.vastus laterallis at intensities above the aerobic ventilatory threshold.

Asociación entre el Material Particulado y la Función Pulmonar durante el Ejercicio en Sujetos Físicamente Activos / Association between particulate matter and lung function during exercise in physically active subjects

Introducción: El material particulado (MP) es una mezcla de partículas potencialmente peligrosas debido a su capacidad de penetrar el sistema respiratorio. La cantidad de MP que ingresa al organismo depende de su concentración ambiental, tiempo de exposición y la ventilación pulmonar. Esta última aumenta fisiológicamente durante el ejercicio físico. Objetivo: Determinar la asociación entre el MP y la función pulmonar. Métodos: Los participantes completaron un protocolo de actividad física en condiciones ambientales con concentraciones de MP habituales durante 4 días consecutivos (24-km). La función pulmonar fue evaluada antes (día-0) y después de una exposición aguda (día-1, post 6-km) y exposición prolongada (día-4, post 24-km). Para determinar la correlación entre los niveles de MP y las variables de función pulmonar, se aplicó la prueba de correlación de Spearman. El nivel de significancia se estableció en p<0.05. Resultados: La función pulmonar, evaluada a través de las variables de espirometría de volumen espiratorio forzado al primer segundo (VEF1), su relación con la capacidad vital forzada (VEF1/CVF) y flujo espiratorio medio (FEF25-75%), se asoció inversamente con las concentraciones de MP en el día-1 (p<0.05), pero no en el día-4 (p>0.05). Conclusión: Este estudio encontró que a mayor dosis efectiva de MP inhalado, mayor es la disminución en variables de función pulmonar evaluadas con espirometría. Este efecto fue más notorio posterior a la exposición aguda que a la exposición prolongada, infiriendo una posible habituación por parte del sistema respiratorio a la inhalación permanente de material particulado.

Introduction: Particulate matter (PM) is a mixture of potentially dangerous particles due to its ability to penetrate the respiratory system. The amount of PM that enters the body depends on its environmental concentration, the exposure time and pulmonary ventilation. The latter increase physiologically during physical exercise. Objective: To determine the association between MP and lung function in physically active young adults during physical exercise. Methods: the subjects completed a physical activity protocol in environmental conditions with habitual PM concentrations for four consecutive days (24-km). Lung function was evaluated before (day-0) and after acute exposure (day-1, post-6-km) and prolonged exposure (day-4, post-24-km). To determine the correlation between MP levels and lung function variables, the Spearman correlation test was applied. The level of significance was established at p <0.05. Results: Lung function, evaluated through the spirometry variables of forced expiratory volume in the first second (FEV1), its relationship with forced vital capacity (FEV1 / FVC) and mean expiratory flow (FEF25-75%) was inversely associated with MP concentrations on day-1 (p<0.05), but not on day-4 (p>0.05). Conclusion: This study found that the higher the effective dose of inhaled PM, the greater the decrease in lung function variables evaluated with spirometry. This effect is more noticeable after acute exposure than after prolonged exposure, inferring the respiratory system's possible habituation to permanent inhalation of particulate matter.

Humidity prevents the exercise-induced formation of hydrogen peroxide and nitrite in exhaled breath condensate in recreational cyclists.

PURPOSE: The aerobic exercise affects the respiratory redox-state. The influence of different relative humidity (RH) levels on the formation of respiratory reactive chemical species associated with redox-state altered by exercise has been poorly explored. Our aim was to evaluate the effect of two different RH conditions (40% vs. 90%) on the concentration of hydrogen peroxide and nitrite in exhaled breath condensate ([H2O2]EBC and [NO2-]EBC) and spirometry parameters in recreational cyclists. METHODS: Sixteen men and women (12/4) (mean age ± SD: 23.5 ± 2.2 years) completed 60-min of cycling at 166.3 ± 26.9 watts (70% of maximum load of [Formula: see text]-max. test, 49.3 ± 7.6 mL·min-1·kg-1) at random 40%-RH and 90%-RH conditions separated by 7 days. The two-way RM-ANOVA test was applied to compare [H2O2]EBC, [NO2-]EBC, [NO2-]EBC/[NO2-]Plasma at rest and 80-min post-exercise (80-post); and spirometry parameters at rest, 20-post and 80-post. RESULTS: The interaction of factors (humidity × time) was significant in [H2O2]EBC, [NO2-]EBC, [NO2-]EBC/[NO2-]Plasma (p = 0.005, p = 0.030, p = 0.043, respectively). At 40%-RH conditions, the same parameters were higher in 80-post than at rest (p < 0.001, p = 0.001, p = 0.014, respectively). At the same time, the [H2O2]EBC and [NO2-]EBC/[NO2-]Plasma were higher in 40%-RH than 90%-RH (p = 0.010, p < 0.001, respectively). The interaction was significant in FEV1 (p = 0.013) and FEF25-75% (p = 0.023), but not in FEV1/FVC (p = 0.362). At 80-post, the changes are kept in 90%-RH (p < 0.001), diminishing in 40%-RH being similar to rest. CONCLUSION: In recreational cyclists, 90%-RH prevents the increase of hydrogen peroxide and nitrite in exhaled breath condensate samples observed at 40%-RH and prolonging the bronchodilation until 80-post cycling exercise.

Nonalcoholic fatty liver disease and sarcopenia: pathophysiological connections and therapeutic implications.

INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) is currently one of the most common liver diseases worldwide. Recent data suggest that loss of skeletal muscle mass and function (i.e. sarcopenia) is highly prevalent and frequently overlooked in NAFLD patients. Experimental and clinical data suggest that the relationship between NAFLD and sarcopenia is pathophysiologically complex and bi-directional and there is a growing interest in unveiling how sarcopenia could influence NAFLD development and progression. AREAS COVERED: PubMed/MEDLINE was searched for articles related to concomitant occurrence of NAFLD and sarcopenia between January 2013 and April 2020. Areas covered in this review include: (1) updated sarcopenia diagnosis strategy, (2) discussion of current data on pathophysiological connections between NAFLD and sarcopenia, and (3) analysis of current and future therapeutic implications of this knowledge. EXPERT OPINION: Clinical studies describe a consistent association between NAFLD and sarcopenia, although a cause-effect relation remains to be determined. Active implementation of current diagnosis algorithms and optimized treatment can prevent sarcopenia related complications in subjects with NAFLD. Pathogenic pathways implicated in this relation are multiple and complex, a better understanding of them can provide novel biomarkers and targeted therapies that will hopefully have an important impact in NAFLD management.

Razonamiento clínico en kinesiología mediante aprendizaje basado en casos / Clinical reasoning in kinesiology by case-based learning

Introducción: En cursos clínicos con gran número de estudiantes, las experiencias clínicas con pacientes reales son limitadas, dificul-tando el logro de objetivos de aprendizaje. La didáctica aprendizaje basado en casos (ABC) promueve el pensamiento crítico y trabajo coolaborativo, aspectos esenciales para desarrollar competencias profesionales. El objetivo de este estudio fue reportar si la incorpo-ración de la metodología ABC en una asignatura clínica curricular promueve el razonamiento clínico en la formación en kinesiología. Metodología: En la asignatura curricular "evaluación cardiorrespiratoria en kinesiología", 10 grupos de 7 estudiantes desarrollaron casos clínicos de temas disciplinares seleccionados bajo criterio de jueces por expertos del área, y lo presentaron al resto de sus compañeros. Un académico guió la reflexión del tema tratado en el ABC, fomentando la discusión entre los estudiantes. Al finalizar la asignatura se evaluó la percepción de la didáctica educativa mediante encuesta y logro de objetivos de aprendizaje con indicadores académicos. Resultados: Los estudiantes reportaron gran satisfacción con la metodología, mayor preparación para actividades de campo clínico y mejoras en sus habilidades comunicacionales. El promedio obtenido en las interrogaciones y en las actividades clínicas fue superior a versiones previas de la asignatura, aumentando el porcentaje de aprobación y satisfacción con el curso. Conclusión: La incorporación de la didáctica de ABC fomentó el razonamiento clínico, reflexión y habilidades comunicacionales mejorando el rendimiento académico y promoviendo competencias profesionales. Como producto final se elaboró un libro de descarga libre con los temas tratados en los ABC, titulado: "Identificando problemas kinesiológicos: aprendizaje basado en casos".

Introduction: In clinical courses with a large number of students, clinical experiences with real patients are limited, difficult to achieve the learning objectives. The 'Case-Based Learning' (CBL), like educational methodology, promotes critical thinking and improve collaborative work, which are essential aspects of the development of professional skills. The objective of this study was to report how the incorporation of the CBL methodology in a clinical course promoted the clinical reasoning in kinesiology students. Methodology: In the curriculum subject ten groups of seven students analyzed different clinical cases and presented them to their classmates. The CBL topics were selected by academic experts, who also guided and encouraged the discussion among the students. An online survey at the end of the course assessed perceptions students participated in this methodology. The final academic indicators assessed the learning objectives of the course achieved by students that participated with this methodology. Results: The students reported high satisfaction with the CBL methodology. They showed better preparation for clinical experiences and an improvement in their communication skills. The final marks obtained in the interrogations and the clinical practice activities were higher than in previous years. There was an increase in academic approval and student satisfaction with the course. Conclusion: The incorporation of the CBL methodology enhanced clinical reasoning, reflection, and communication skills, improving academic performance, and promoting professional skills. The topics covered in the CBLs conformed a free download book, entitled: «Identifying kinesiology problems: case-based learning.

Fichas clínicas simuladas en kinesiología / Simulated clinical records in kinesiology

Introducción: la normativa actual de docencia clínica regula el desarrollo de actividades curriculares disminuyendo el tiempo de con-tacto estudiante-paciente, requiriendo entre otras destrezas del estudiante la lectura eficiente de información clínica. La simulación permite desarrollar competencias clínicas en los estudiantes de ciencias de la salud. El objetivo de este estudio es describir la experiencia de talleres de fichas clínicas simuladas (FCS) en estudiantes curriculares y reportar indicadores de logro de objetivos de aprendizaje relacionados al reconocimiento de las partes de la ficha clínica e identificación y extracción de información relevante. Metodología: en una asignatura de carácter mínimo previo al encuentro de estudiantes con pacientes reales, se desarrollaron cuatro talleres de FCS en grupo pequeño. Un académico guió la actividad consistente en responder cuestionarios de ubicación de información presente en las FCS. Al finalizar la asignatura, se evaluó la percepción de la didáctica educativa y logro de objetivos de aprendizaje en tutores clínicos y estudiantes mediante encuesta. Resultados: los estudiantes reportaron alta satisfacción con la metodología, facilidad para extraer información relevante y mayor tiempo de contacto clínico con pacientes reales. Los tutores clínicos informaron que los estudiantes logran reconocer las partes de la ficha clínica. Ambos consideran que el tiempo ideal para lectura de ficha clínica es de 10 a 20 minutos.Conclusión: la incorporación de talleres de fichas clínicas simuladas desarrolló habilidades clínicas de reconocimiento de las partes que componen la ficha clínica, optimizando el tiempo necesario para identificar y extraer información relevante a diferentes escenarios clínicos.

Reliability of NIRS portable device for measuring intercostal muscles oxygenation during exercise.

This study assessed the intra-individual reliability of oxygen saturation in intercostal muscles (SmO2-m.intercostales) during an incremental maximal treadmill exercise by using portable NIRS devices in a test-retest study. Fifteen marathon runners (age, 24.9 ± 2.0 years; body mass index, 21.6 ± 2.3 kg·m-2; V̇O2-peak, 63.7 ± 5.9 mL·kg-1·min-1) were tested on two separate days, with a 7-day interval between the two measurements. Oxygen consumption (V̇O2) was assessed using the breath-by-breath method during the V̇O2-test, while SmO2 was determined using a portable commercial device, based in the near-infrared spectroscopy (NIRS) principle. The minute ventilation (VE), respiratory rate (RR), and tidal volume (Vt) were also monitored during the cardiopulmonary exercise test. For the SmO2-m.intercostales, the intraclass correlation coefficient (ICC) at rest, first (VT1) and second ventilatory (VT2) thresholds, and maximal stages were 0.90, 0.84, 0.92, and 0.93, respectively; the confidence intervals ranged from -10.8% - +9.5% to -15.3% - +12.5%. The reliability was good at low intensity (rest and VT1) and excellent at high intensity (VT2 and max). The Spearman correlation test revealed (p ≤ 0.001) an inverse association of SmO2-m.intercostales with V̇O2 (ρ = -0.64), VE (ρ = -0.73), RR (ρ = -0.70), and Vt (ρ = -0.63). The relationship with the ventilatory variables showed that increased breathing effort during exercise could be registered adequately using a NIRS portable device.

[Analysis of nasal cytology in children and adolescents with rhinitis]. / Análisis de la citología nasal en niños y adolescentes con rinitis.

BACKGROUND: Nasal cytology in a easy-to apply method to differentiate rhinitis phenotypes from a physiopathogenic and diagnostic perspective. There are controversies about the relationship between clinical severity of rhinitis and inflammatory patterns expressed in the nasal cytology. OBJECTIVES: To study the characteristic of the eosinophil and neutrophil patterns in the nasal scraping for Allergic Rhinitis (AR) and Non Allergic Rhinitis (NAR) and its relationship with the clinical grades of rhinitis established by the Allergic Rhinitis and its Impact on Asthama Guideline (ARIA) Methods: In a observational, cross-sectional study we included patients aged 5 to 18 years presenting symptoms of either allergic (AR) or non- allergic rinitis (NAR) without asthma. Cytology was performed by analyzing nasal scraping obtained from the mucosal surface of the inferior turbinate and samples were stained using thr hematoxylin and eosin stain procedure. Inflammatory patterns between AR and NAR and between clinical grades of rhinitis classified by ARIA guide were compared. RESULTS: A total of 231 patients were included. Patients with AR exhibited higher percentage of eosinophils in nasal cytology than those with NAR (p = 0.0012) but no differences were observed in neutrophil count (p = 0.4011). No differences in the percentage of eosinophils and neutrophils between different grades of AR (p = 0.7342 and p = 0.0797 respectively) and NAR (p = 0.1010 and p = 0.1422 respectively) were observed. CONCLUSION: Eosinophil count in the nasal cytology was useful to differentiate rhinitis with a positive allergen skin test from rhinitis with negative skin test, but as neutrophils count, does not help to distinguish clinical grades of AR and NAR as classified by ARIA.

Síndrome urémico hemolítico atípico del adulto. Presentación de un caso y revisión de la bibliografía / Atypical hemolytic uremic syndrome in adults. Case report and literature review

El SHUa (Síndrome Hemolítico atípico) se caracteriza por la tríada anemia hemolítica no inmune, trombocitopenia e injuria renal aguda (IRA), en la cual el daño tisular está mediado por una microangiopatía trombótica (MAT). Es una entidad con afectación sistémica, muy poco frecuente, originada en la desregulación del sistema del complemento. Presentamos el caso de una paciente portadora de anemia hemolítica, plaquetopenia, IRA oligoanúrica, cuadro neurológico con evolución tórpida, diagnóstico de SHUa, una revisión bibliográfica, y las sugerencias terapéuticas para esta enfermedad

Atypical hemolytic uremic syndrome (aHUS) consists of the triad of non-immune hemolytic anemia, thrombocytopenia and acute kidney injury (AKI) and is characterized by tissue injury as a result of thrombotic microangiopathy (TMA). It is a very rare systemic disease triggered by complement system dysregulation. This report describes the case of a patient with hemolytic anemia, thrombocytopenia, oligo-anuric AKI, a neurological disorder with torpid course and an aHUS diagnosis. A literature review and therapeutic recommendations for this disease are also presented

Analysis of the flow-volume curve in children and adolescents with allergic rhinitis without asthma.

INTRODUCTION: There is epidemiological, functional and pathologic evidence that relates upper and lower airways, clinically known as a single respiratory tract. Patients with allergic rhinitis without asthma may present subclinical abnormal spirometry parameters. OBJECTIVES: To describe the results of the flow-volume curve in a group of patients with allergic rhinitis without asthma and analyze the possible associations between anthropometric, clinical and biochemical outcome measures with abnormal spirometry results. POPULATION AND METHODS: Observational, descriptive study including children and adolescents aged 6 to 18 years old with symptoms of allergic rhinitis without asthma. Age, gender, body mass index and duration of rhinitis were determined as per the subject's medical record. Allergen skin tests, flow-volume curve spirometry, determination of eosinophil count in blood and in nasal secretions, and total serum IgE were performed. RESULTS: A total of 84 patients were studied; 21 (25%; 95% CI: 15.1-34.8) presented at least one altered spirometry outcome measure. The FEV1/FVC ratio was the most affected outcome measure (10/84; 12%; 95% CI: 4.3-19.4). The multiple logistic regression analysis determined that spirometry alterations were associated with the number of blood eosinophils (OR: 1.00229; 95% CI: 1.00022-1.00436; p= 0.03) and the body mass index (OR: 1.31282; 95% CI: 1.08611-1.58685; p= 0.0049). CONCLUSIONS: Our results showed spirometry alterations in a considerable percentage of children and adolescents with allergic rhinitis without asthma. The blood eosinophil count and the body mass index could be associated with a sub-clinical alteration of pulmonary function.

Análisis de la curva flujo-volumen en niños y adolescentes con rinitis alérgica sin asma / Analysis of the fow-volume curve in children and adolescents with allergic rhinitis without asthma

Introducción. Existen evidencias epidemiológicas, funcionales y patológicas que vinculan las vías aéreas superior e inferior, reconocidas clínicamente como una vía aérea única. Los pacientes con rinitis alérgica sin asma podrían presentar anormalidades espirométricas subclínicas. Objetivos. Describir los resultados de las curvas fujo-volumen en un grupo de pacientes con rinitis alérgica sin asma y analizar las posibles asociaciones entre las variables antropométricas, clínicas y bioquímicas con los resultados anormales de las pruebas espirométricas. Población y métodos. Estudio observacional descriptivo, en el que se incluyeron niños y adolescentes de entre 6 y 18 años con síntomas de rinitis alérgica sin asma. Se estableció la edad, el sexo, el índice de masa corporal y la duración de la rinitis por la historia clínica. Se realizaron pruebas cutáneas con alérgenos, espirometría por curva fujo-volumen, determinación de eosinóflos en la sangre y la secreción nasal, e IgE sérica total. Resultados. Se estudiaron 84 pacientes; 21 (25%; IC 95% 15,1 a 34,8) presentaron alguna variable espirométrica alterada. El índice FEV1/FVC fue el más afectado (10/84; 12% IC 95% 4,3 a 19,4). El análisis de regresión logística múltiple determinó que la alteración espirométrica se asoció con el número de eosinóflos en la sangre (OR 1,00229; IC 95% 1,00022 a 1,00436; p= 0,03) y el índice de masa corporal (OR 1,31282; IC 95% 1,08611 a 1,58685; p= 0,0049). Conclusiones. Los resultados muestran la presencia de alteraciones espirométricas en un importante porcentaje de niños y adolescentes con rinitis alérgica sin asma. El recuento absoluto de eosinóflos en la sangre y el índice de masa corporal estarían asociados a la alteración subclínica de la función pulmonar.

Introduction. There is epidemiological, functional and pathologic evidence that relates upper and lower airways, clinically known as a single respiratory tract. Patients with allergic rhinitis without asthma may present subclinical abnormal spirometry parameters. Objectives. To describe the results of the fow-volume curve in a group of patients with allergic rhinitis without asthma and analyze the possible associations between anthropometric, clinical and biochemical outcome measures with abnormal spirometry results. Population and Methods. Observational, descriptive study including children and adolescents aged 6 to 18 years old with symptoms of allergic rhinitis without asthma. Age, gender, body mass index and duration of rhinitis were determined as per the subject's medical record. Allergen skin tests, fow-volume curve spirometry, determination of eosinophil count in blood and in nasal secretions, and total serum IgE were performed. Results. A total of 84 patients were studied; 21 (25%; 95% CI: 15.1-34.8) presented at least one altered spirometry outcome measure. The FEV1/FVC ratio was the most affected outcome measure (10/84; 12%; 95% CI: 4.3-19.4). The multiple logistic regression analysis determined that spirometry alterations were associated with the number of blood eosinophils (OR: 1.00229; 95% CI: 1.00022-1.00436; p= 0.03) and the body mass index (OR: 1.31282; 95% CI: 1.08611-1.58685; p= 0.0049). Conclusions. Our results showed spirometry alterations in a considerable percentage of children and adolescents with allergic rhinitis without asthma. The blood eosinophil count and the body mass index could be associated with a sub-clinical alteration of pulmonary function.