Effect of exercise-induced bronchoconstriction on the configuration of the maximal expiratory flow-volume curve in adults with asthma.

We determined the effect of exercise-induced bronchoconstriction (EIB) on the shape of the maximal expiratory flow-volume (MEFV) curve in asthmatic adults. The slope-ratio index (SR) was used to quantitate the shape of the MEFV curve. We hypothesized that EIB would be accompanied by increases in SR and thus increased curvilinearity of the MEFV curve. Adult asthmatic ( n  = 10) and non-asthmatic control subjects ( n  = 9) cycled for 6-8 min at 85% of peak power. Following exercise, subjects remained on the ergometer and performed a maximal forced exhalation every 2 min for a total 20 min. In each MEFV curve, the slope-ratio index (SR) was calculated in 1% volume increments beginning at peak expiratory flow (PEF) and ending at 20% of forced vital capacity (FVC). Baseline spirometry was lower in asthmatics compared to control subjects (FEV1 % predicted, 89.1 ± 14.3 vs. 96.5 ± 12.2% [SD] in asthma vs. control; p  < 0.05). In asthmatic subjects, post-exercise FEV1 decreased by 29.9 ± 13.2% from baseline (3.48 ± 0.74 and 2.24 ± 0.59 [SD] L for baseline and post-exercise nadir; p  < 0.001). At baseline and at all timepoints after exercise, average SR between 80 and 20% of FVC was larger in asthmatic than control subjects (1.48 ± 0.02 vs. 1.23 ± 0.02 [SD] for asthma vs. control; p < 0.005). This averaged SR did not change after exercise in either subject group. In contrast, post-exercise SR between PEF and 75% of FVC was increased from baseline in subjects with asthma, suggesting that airway caliber heterogeneity increases with EIB. These findings suggest that the SR-index might provide useful information on the physiology of acute airway narrowing that complements traditional spirometric measures.

Reference value for expiratory time constant calculated from the maximal expiratory flow-volume curve.

BACKGROUND: The expiratory time constant (RCEXP), which is defined as the product of airway resistance and lung compliance, enable us to assess the mechanical properties of the respiratory system in mechanically ventilated patients. Although RCEXP could also be applied to spontaneously breathing patients, little is known about RCEXP calculated from the maximal expiratory flow-volume (MEFV) curve. The aim of our study was to determine the reference value for RCEXP, as well as to investigate the association between RCEXP and other respiratory function parameters, including the forced expiratory volume in 1 s (FEV1)/ forced vital capacity (FVC) ratio, maximal mid-expiratory flow rate (MMF), maximal expiratory flow at 50 and 25% of FVC (MEF50 and MEF25, respectively), ratio of MEF50 to MEF25 (MEF50/MEF25). METHODS: Spirometric parameters were extracted from the records of patients aged 15 years or older who underwent pulmonary function testing as a routine preoperative examination before non-cardiac surgery at the University of Tokyo Hospital. RCEXP was calculated in each patient from the slope of the descending limb of the MEFV curve using two points corresponding to MEF50 and MEF25. Airway obstruction was defined as an FEV1/FVC and FEV1 below the statistically lower limit of normal. RESULTS: We retrospectively analyzed 777 spirometry records, and 62 patients were deemed to have airway obstruction according to Japanese spirometric reference values. The cut-off value for RCEXP was 0.601 s with an area under the receiver operating characteristic curve of 0.934 (95% confidence interval = 0.898-0.970). RCEXP was strongly associated with FEV1/FVC, and was moderately associated with MMF and MEF50. However, RCEXP was less associated with MEF25 and MEF50/MEF25. CONCLUSIONS: Our findings suggest that an RCEXP of longer than approximately 0.6 s can be linked to the presence of airway obstruction. Application of the concept of RCEXP to spontaneously breathing subjects was feasible, using our simple calculation method.

Métodos de análisis gráfico de obstrucción espirométrica: ¿una imagen vale más que mil palabras? / Graphical Analysis Methods in Obstructive Spirometry: Does a Picture Speak More Than a Thousand Words?

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Graphic analysis of flow-volume curves: a pilot study.

BACKGROUND: Conventional spirometric parameters have shown poor correlation with symptoms and health status of chronic obstructive pulmonary disease (COPD). While it is well-known that the pattern of the expiratory flow-volume curve (EFVC) represents ventilatory dysfunction, little attempts have been made to derive quantitative parameters by analyzing the curve. In this study, we aimed to derive useful parameters from EFVC via graphic analysis and tried to validate them in patients with COPD. METHODS: Using Graphical Analysis 3.4 Vernier Software, we derived from the EFVC such parameters as area of obstruction (Ao), area of triangle (AT), area of rectangle (AR) and ratio of volume at 75 and 25% peak expiratory flow (PEF) (0.25/0.75 V). For validation, we reviewed clinical and spirometric data of 61 COPD patients from Seoul National University Airway Registry (SNUAR) and Korean obstructive Lung Disease (KOLD) cohorts. RESULTS: Of all parameters, only RV/TLC significantly correlated with scores from St. George's Respiratory Questionnaire (SGRQ) (r = 0.447, p = 0.037). Six-minute walking distance (6MWD) highly correlated with Ao/AR (r = -0.618, p = 0.005) and Ao/PEF (r = -0.581, p = 0.009) whereas neither FEV1 nor FEV1/FVC had significant correlation with 6MWD. CONCLUSIONS: Ao/AR and Ao/PEF are promising parameters which correlate well with the exercising capacity of COPD patients.

Quantifying the shape of maximal expiratory flow-volume curves in healthy humans and asthmatic patients.

Differences in the absolute flow and volume of maximal expiratory flow-volume (MEFV) curves have been studied extensively in health and disease. However, the shapes of MEFV curves have received less attention. We questioned if the MEFV curve shape was associated with (i) expiratory flow limitation (EFL) in health and (ii) changes in bronchial caliber in asthmatics. Using the slope-ratio (SR) index, we quantified MEFV curve shape in 84 healthy subjects and 8 matched asthmatics. Healthy subjects performed a maximal exercise test to assess EFL. Those with EFL during had a greater SR (1.15 ± 0.20 vs. 0.85 ± 0.20, p<0.05) yet, there was no association between maximal oxygen consumption and SR (r=0.14, p>0.05). Asthmatics average SR was greater than the healthy subjects (1.35 ± 0.03 vs. 0.90 ± 0.11, p<0.05), but there were no differences when bronchial caliber was manipulated. In conclusion, a greater SR is related to EFL and this metric could aid in discriminating between groups known to differ in the absolute size of MEFV curves.

Evaluación de flujos y volúmenes dinámicos en pacientes con compromiso muscular respiratorio / Dynamic flows and volumes evaluation in patients with respiratory muscle impairment

Spirometry measures the forced expiratory volumes and flows. In patients with neuromuscular disease, these are altered since there is some respiratory muscle involvement. The usefulness of this test is based on the interpretation of the shape of the flow / volume loop and values of spirometric variables. In patients with neuromuscular disease, Forced Vital Capacity is the most used especially for its prognosis value.

La espirometría mide volúmenes y flujos espiratorios forzados. En los pacientes con enfermedad neuromuscular (ENM) estos se ven alterados debido al compromiso muscular respiratorio. La utilidad de este examen se basa en la interpretación de la forma de la curva flujo/volumen y los valores de las variables espirométricas. En los pacientes con ENM la Capacidad Vital Forzada es la más utilizada ya que otorga valor pronóstico.

Physical fitness, adiposity and testosterone concentrations are associated to playing position in professional basketballers / Condición física, adiposidad y concentraciones de testosterona están asociadas a la posición de juego en baloncestistas profesionales

The effects of basketball on basal concentrations of testosterone and cortisol and its associations to body composition and physical performance remain to be determined. Aim: the main aim of this study was to determine the effects of playing position on physical fitness, percentage of body fat and hormonal profile in professional basketball players (BP). Method: jump performance (SJ, CMJ and ABK), 30 m running speed and treadmill VO2 max tests were conducted in 12 male BP (24.1 years) from the first division league of Spain (ACB). The percentage of body fat was determined from anthropometry, and hemoglobin, glucose, testosterone and cortisol concentrations were measured from fasting blood samples. BP were divided into 3 groups depending on playing positions: guards (GU), forwards (FW) and centers (CE) (n = 4 in each group). Results: GU had greater percentage of body fat (%BF) than CE (p< 0.05). CE developed greater positive mechanical impulse than GU in all jump types (p < 0.05) and achieved higher maximal instantaneous power than GU and FW in the SJ and ABK (p< 0.05). Centers had more plasma testosterone than guards (p< 0.05). All groups a similar relative VO2 max. Conclusion: center position was associated to lower adiposity and higher jumping performance than playing as guards. All playing positions induced a similar effect on aerobic power (AU)

Los efectos de jugar al baloncesto sobre las concentraciones basales de testosterona y cortisol, así como su asociación a la composición corporal y el rendimiento físico aún están por determinarse. Objetivo: el principal objetivo de este estudio fue determinar los efectos de la posición de juego sobre la condición física, el porcentaje de grasa coporal y el perfil hormonal en jugadores de baloncesto profesionales (BP). Metodología: la capacidad de salto (SJ, CMJ y ABK), la velocidad en 30 m y el VO2max en tapiz rodante se midió en 12 varones BP (24,1 años) pertenecientes a la primera división de la liga de España (ACB). El porcentaje de grasa corporal se determinó a partir de la antropometría, y las concentraciones de hemoglobina, glucosa, testosterona y cortisol se midieron a partir de muestras de sangre en ayunas. Los baloncestistas se dividieron en tres grupos en función de las posiciones de juego: bases (GU), aleros (FW) y pivots (CE). Resultados: GU tuvo mayor porcentaje de grasa corporal (% GC) que CE (p< 0,05). CE desarrolló mayor impulso positivo mecánico que GU en todos los tipos de saltos (p < 0,05) y logró mayor potencia instantánea máxima que GU y FW en el SJ y ABK (p< 0,05). Los pivots tenían más testosterona plasmática que los bases (p < 0,05). Todos los grupos mostraron similar VO2 máx. Conclusión: la posición de pivots fue asociada a una menor adiposidad y a una mayor capacidad de salto en comparación con los bases. Todas las posiciones de juego indujeron un efecto similar sobre la potencia aeróbica (AU)

Reference ranges for shape indices of the flow-volume loop of healthy children.

BACKGROUND: The concavity of the descending limb of the maximum expiratory flow-volume loop (MEFVL) is the earliest change associated with airflow obstruction in small airways (ATS/ERS Task Force). The shape of the MEFVL changes with age but there are no reference values for shape indices for preschool and school children. OBJECTIVES: To define pediatric reference values for spirometric data and 3 shape indices of MEFVL: 2 geometric indices: the ß angle i.e., the angle between the first ½ part and the 2nd part of the MEFVL and the forced expiratory flow after 50% of the forced vital capacity (FVC) has been exhaled/peak expiratory flow (FEF50 /PEF) ratio; and a ratio that describes relative growth between airway and lung parenchyma, the forced expiratory flow between 25 and 75% of FVC/FVC ratio (FEF25-75 /FVC ratio). METHODS: Data were obtained from 446 Caucasian children (2.5 to 15-year-old). The lambda, mu, sigma method was applied. RESULTS: References for spirometric parameters and 3 shape indices. The geometric indices decreased with age from 3 years of age (mean ß angle was 215° and FEF50 /PEF ratio was 0.82) until 8 years of age (mean ß angle was 191° and FEF50 /PEF ratio was 0.60) and then remained constant. The FEF25-75 /FVC ratio also decreased with age. Sex was a significant determinant for FEF25-75 /FVC ratio predicted values. CONCLUSIONS: This study provides standard reference equations for indices of mid-expiratory flows in children and we suggest using the FEF50 /PEF index.

Asma en el niño y adolescente (controversias): Atención Primaria versus Atención Hospitalaria. A favor del manejo en el hospital / Asthma in children and adolescents (controversy): Primary Care versus Hospital Care. In favour of the management by the Hospital

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Fisiología de la curva flujo/volumen espirométrica / Flow-volume curve: its physiological basis

We describe physiological basis to explain flow/volume curve obtained by forced spirometry. The main factors involved are alveolar and intraluminal airway pressure and transthoracic pressure, whose interrelationship determines dynamic airway compression. Lung and thoracic elastic recoil pressure and lung volumes also participate.

Se describen las bases fisiológicas de la curva flujo/volumen obtenida mediante espirometría forzada. Los principales factores involucrados son la presión alveolar y de la vía aérea y la presión transtorácica, cuyo balance determina la compresión dinámica de la vía aérea. Además intervienen la presión de retracción elástica pulmonar y de la caja torácica y los volúmenes pulmonares.

Valoración de la condición aeróbica del corredor de orientación a pie de alto nivel español / Aerobic conditioning assessment of the spanish high-level foot orienteer athlete

Objetivo: La orientación a pie es un deporte que difiere de otras modalidades de carrera en el componente cognitivo y en el tipo de terreno encontrado. Existen aspectos de la condición física del corredor de orientación que difieren en relación a los presentados por corredores de pista o de campo a través. El objetivo del trabajo fue la valoración de la condición aeróbica del corredor de orientación a pie. Material y métodos: Participaron en el estudio 10 corredores varones (20,3 ± 5,6 años), a los que se aplicó un protocolo incremental máximo en rampa sobre tapiz rodante, con análisis de la ventilación pulmonar y del intercambio de gases respiratorios. Resultados: Los valores medios encontrados fueron: Consumo máximo de oxígeno (VO2max): 70,2 ± 5,8 ml/kg.min; VO2 en el umbral ventilatorio 1(VT1): 49,5 ± 3,9 ml/kg.min (70,8% del VO2max); VO2 en el umbral ventilatorio 2 (VT2): 61,2 ± 6,7 (87,1%del VO2max); frecuencia cardíaca (FC) en el VT 1: 158,4 ± 4,8 lat/min (84% de la FC máxima obtenida en la prueba); FC en elVT2: 176,8 ± 6,7 lat/min (93,7% de la FC máxima de la prueba). Conclusiones: El corredor de orientación a pie de elite tiene altamente desarrollado el sistema de transporte y utilización del oxígeno, siendo capaz de trabajar a porcentajes cercanos a su VO2max durante un tiempo prolongado. La valoración desde el punto de vista fisiológico en el laboratorio se considera un elemento fundamental para la elaboración de un perfil del corredor de orientación, evaluar su condición física y obtener datos para la prescripción individualizada del entrenamiento con el fin de obtener mejoras en el rendimiento (AU)

Purpose: Foot orienteering differs from other running events both in its cognitive element and in the type of terrain encountered. Some aspects of the fitness required for orienteering may differ from track and cross country running. The aim of this study was to assess the orienteer´s aerobic conditioning. Methods: Ten male orienteers (age 20,3 ± 5,6 years) participated in the study. They performed a maximal incremental treadmill test with pulmonary ventilation and respiratory gas exchange measures. Results: The average values were: Maximal oxygen uptake (VO2max): 70,2 ± 5,8 ml/kg.min; VO2 at the first ventilatory threshold(VT1): 49,5 ± 3,9 ml/kg.min (70,8% of VO2max); VO2 at the second ventilatory threshold (VT2): 61,2 ± 6,7 (87,1% of VO2max); Heart rate (HR) at VT1: 158,4 ± 4,8 lat/min (84% of maximal HR measured in the test); HR at VT2: 176,8 ± 6,7 lat/min (93,7% of maximal HR measured in the test).Conclusion: Elite orienteers have highly developed oxygen transport and utilization systems and perform at a high percentage of their VO2max for prolonged periods. Laboratory physiological assessment is considered fundamental in profiling orienteers, assess their physical conditioning and in providing data that are helpful in development of individualized training prescriptions to improve orienteering performance (AU)

Quantification of shape of flow-volume loop of healthy preschool children and preschool children with wheezing disorders.

BACKGROUND: The earliest change associated with airflow obstruction in small airways is reflected in a concave shape on the maximum expiratory flow-volume loop (MEFVL). The shape of the MEFL changes with age but reference values for curvilinearity indices (CI) for preschool children have not been published. We aimed to describe the normal curvilinearity of healthy preschool MEFVL by CI (the ß angle and the ratio of maximum expiratory flow when 50% of forced vital capacity remains to be expired/peak expiratory flow (MEF(50%) /PEF)) and to test their capacity in detecting concavity in preschool children with wheezing disorders. METHODS: Spirometric data were obtained from 132 healthy preschool children and 171 3-to-5-year-old preschool children with wheezing disorders and reference values for CI calculated. RESULTS: Mean (SD) ß angle of healthy children was 203° (16°) and mean MEF(50%) /PEF of healthy children was 0.71 (0.12) indicating convexity of MEFVL, both decreased with increasing age (P = 10(-4) ). Children with wheezing disorders had lower z-score values of CI (P ≤ 10(-6) ) indicating more concave MEFVL. Among the two CI, MEF(50%) /PEF allowed for the best discrimination between healthy children and children with wheezing disorders (Wilks' lambda = 0.898, P = 10(-7) ). CONCLUSION: These CI can detect and quantify the concavity of the descending limb of the MEFVL in preschool children with wheezing disorders, MEF(50%) /PEF having the highest sensitivity in detecting the concavity.

Effect of carrying a weighted backpack on lung mechanics during treadmill walking in healthy men.

Weighted backpacks are used extensively in recreational and occupational settings, yet their effects on lung mechanics during acute exercise is poorly understood. The purpose of this study was to determine the effects of different backpack weights on lung mechanics and breathing patterns during treadmill walking. Subjects (n = 7, age = 28 ± 6 years), completed two 2.5-min exercise stages for each backpack condition [no backpack (NP), an un-weighted backpack (NW) or a backpack weighing 15, 25 or 35 kg]. A maximal expiratory flow volume curve was generated for each backpack condition and an oesophageal balloon catheter was used to estimate pleural pressure. The 15, 25 and 35 kg backpacks caused a 3, 5 and 8% (P < 0.05) reduction in forced vital capacity compared with the NP condition, respectively. For the same exercise stage, the power of breathing (POB) requirement was higher in the 35 kg backpack compared to NP (32 ± 4.3 vs. 88 ± 9.0 J min(-1), P < 0.05; respectively). Independent of changes in minute ventilation, end-expiratory lung volume decreased as backpack weight increased. As backpack weight increased, there was a concomitant decline in calculated maximal ventilation, a rise in minute ventilation, and a resultant greater utilization of maximal available ventilation. In conclusion, wearing a weighted backpack during an acute bout of exercise altered operational lung volumes; however, adaptive changes in breathing mechanics may have minimized changes in the required POB such that at an iso-ventilation, wearing a backpack weighing up to 35 kg does not increase the POB requirement.

Use of flow-volume curves to predict oral appliance treatment outcome in obstructive sleep apnea: a prospective validation study.

PURPOSE: Flow-volume curves have been shown to relate to upper airway physiology during sleep and may be useful for predicting the response to treatment of obstructive sleep apnea (OSA) with mandibular advancement splints (MAS). The aim of this study was to prospectively assess the potential clinical utility of a previously derived prediction method using flow-volume curves performed during wakefulness. METHODS: Patients with newly diagnosed OSA interested in undertaking treatment with a custom-made MAS were approached to participate in the study. Response to treatment was defined by a 50% or greater reduction in the apnea-hypopnea index. Flow-volume curves were performed in the erect position prior to construction of the MAS. RESULTS: Flow-volume curves were performed in 35 patients. Of these, 25 patients were responders, and 10 patients were non-responders. A combined cut-off of an inspiratory flow rate at 50% of vital capacity (MIF50) less than 6.0 L/s and a ratio of the expiratory flow rate at 50% of vital capacity to MIF50 of greater than 0.7 correctly classified 48.6% of the patients. It had a sensitivity of 36.0%, specificity of 80.0%, positive predictive value of 81.8%, and negative predictive value of 33.3%. CONCLUSIONS: These results suggest that the previously derived prediction model, using flow-volume curves performed during wakefulness, was not sufficient to reliably predict the response to treatment of OSA with MAS. A combination of a functional assessment using flow-volume curves and a structural evaluation of the upper airway with imaging modalities may result in a prediction model with better performance characteristics.

A model-based method for flow limitation analysis in the heterogeneous human lung.

Flow limitation in the airways is a fundamental process constituting the maximal expiratory flow-volume curve. Its location is referred to as the choke point. In this work, expressions enabling the calculation of critical flows in the case of wave-speed, turbulent or viscous limitation were derived. Then a computational model for the forced expiration from the heterogeneous lung was used to analyse the regime and degree of flow limitation as well as movement and arrangement of the choke points. The conclusion is that flow limitation begins at similar time in every branch of the bronchial tree developing a parallel arrangement of the choke points. A serial configuration of flow-limiting sites is possible for short time periods in the case of increased airway heterogeneity. The most probable locations of choke points are the regions of airway junctions. The wave-speed mechanism is responsible for flow choking over most of vital capacity and viscous dissipation of pressure for the last part of the test. Turbulent dissipation, however, may play a significant role as a supporting factor in transition between wave-speed and viscous flow limitation.

Correlation of spirometry and symptom scores in childhood asthma and the usefulness of curvature assessment in expiratory flow-volume curves.

BACKGROUND: Spirometry, and in particular forced expiratory volume in the first second (FEV(1)), are standard tools for objective evaluation of asthma. However, FEV(1) does not correlate with symptom scores, and hence its value in the assessment of childhood asthma may be limited. Therefore, some clinicians subjectively assess the presence of curvature in the maximum expiratory flow-volume (MEFV) curves obtained from spirometry, where concave patterns are observable despite normal FEV(1) values. OBJECTIVE: To evaluate the usefulness of subjective and objective measures of the curvature in the descending phase of the MEFV curve for the assessment of asthma. METHODS: We obtained symptom scores and performed spirometry in 48 patients with asthma (21 females, mean +/- SD age 10.8 +/- 2.4 y). We measured FEV(1), the ratio of FEV(1) to forced vital capacity (FEV(1)/FVC), maximum expiratory flow at one quarter of the way, and at halfway, through the forced expiratory maneuver (MEF(25) and MEF(50), respectively), and maximum expiratory flow in the middle half of the forced expiratory maneuver (MEF(25-75)). Expiratory obstruction was ranked independently by 3 pediatric pulmonologists, by subjective assessment of the MEFV curve. In addition, the curvature of the descending limb of the MEFV curve was quantitatively estimated by introducing an "average curvature index." RESULTS: No significant correlations were found between FEV(1), MEF(50), MEF(25), and MEF(25-75,) respectively, and symptom score (r = -0.22, p = 0.14; r = -0.23, p = 0.11; r = -0.28, p = 0.057; r = -0.27, p = 0.06). A weak correlation was found for FEV(1)/FVC and symptom score (r = -0.33, p = 0.021). However, quantitatively determined average curvature index (ACI) correlated significantly better with measured symptom scores (r = 0.53, p < 0.001) and were in good agreement with the assessment of expiratory obstruction from subjective curvature assessment. CONCLUSIONS: Our general findings show that individual lung function variables do not correlate well with symptoms, whereas subjective curvature assessment is thought to be helpful. With the average curvature index we have illustrated a potential clinical usefulness of quantifying the curvatures of MEFV curves.

Evaluación funcional respiratoria (obstrucción y atrapamiento) / No disponible

La disminución del calibre de las vías aéreas y la pérdida de retracción elástica del parénquima pulmonar favorecen el desarrollo de obstrucción al flujo aéreo en pacientes con enfermedad pulmonar obstructiva crónica (EPOC). La espirometría continúa siendo el procedimiento de primera elección para la evaluación de la obstrucción de forma rutinaria. Sin embargo, el análisis de la curva flujo-volumen a volumen corriente o la técnica de presión espiratoria negativa permiten detectar de forma temprana a pacientes con limitación al flujo aéreo espiratorio. La dificultad para completar el vaciamiento alveolar origina atrapamiento aéreo e hiperinsuflación, tanto estática como dinámica. Este fenómeno, que guarda una relación más estrecha con la disnea y la tolerancia al ejercicio que la obstrucción al flujo aéreo, puede evaluarse mediante la determinación de los volúmenes pulmonares estáticos. Sin embargo, la capacidad inspiratoria, obtenida de una espirometría lenta, proporciona una estimación indirecta de la magnitud de la hiperinsuflación, más sencilla y reproducible (AU)

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Mid-term survival after abdominal aortic aneurysm surgery predicted by cardiopulmonary exercise testing.

BACKGROUND: Cardiopulmonary exercise (CPX) testing measures how efficiently subjects meet increased metabolic demand. This study aimed to determine whether preoperative CPX testing predicted postoperative survival following elective abdominal aortic aneurysm (AAA) repair. METHODS: Some 130 patients had CPX testing before elective open AAA repair. Additional preoperative, operative and postoperative variables were recorded prospectively. Median follow-up was 35 months. The correlation of variables with survival was assessed by single and multiple regression analyses. RESULTS: CPX testing identified 30 of 130 patients who had been unfit before surgery. Two years after surgery the Kaplan-Meier survival estimate was 55 per cent for the 30 unfit patients, compared with 97 per cent for the 100 fit patients. The absolute difference in survival between these two groups at 2 years was 42 (95 per cent confidence interval 18 to 65) per cent (P < 0.001). CONCLUSION: Preoperative CPX testing, combined with simple co-morbidity scoring, identified patients unlikely to survive in the mid-term, even after successful AAA repair.

Estudio de la función pulmonar en el paciente colaborador. Parte I / Respiratory function assessment in cooperative patients. Part I. Spiromery and bronchodilator reversibility testing

La exploración de la función pulmonar es una herramienta fundamental en el estudio de los pacientes con problemas neumológicos. Permite detectar alteraciones fisiopatológicas, valorar la gravedad de un proceso, su evolución y la respuesta al tratamiento. En la actualidad forma parte de las exploraciones utilizadas por los pediatras españoles. El grupo de Técnicas de la Sociedad Española de Neumología Pediátrica (SENP) se propuso elaborar un protocolo de estudio de la función pulmonar en el paciente pediátrico que incorpore los últimos estándares acordados, fundamentalmente, sobre la práctica de estudios de la función pulmonar básica (espirometría y prueba broncodilatadora) y sobre el estudio de la hiperreactividad de la vía aérea mediante pruebas de provocación inespecífica. Con él se pretende obtener una guía de buena práctica clínica como referencia hasta que se produzcan cambios basados en nuevas evidencias científicas

Assessment of respiratory function is the principal tool in the study of patients with lung diseases, allowing physiopathological alterations to be detected, and the severity of the process, its clinical course, and treatment response to be identified. Nowadays, assessment of respiratory function is among the investigations used by Spanish pediatricians. The Techniques Group of the Spanish Society of Pediatric Pneumology undertook the design of a protocol for the study of pulmonary function in children that would incorporate the most recent published consensus documents on basic pulmonary function assessment (spirometry and bronchodilator reversibility testing) and on airway hyperreactivity evaluation using nonspecific provocation tests. The aim of this protocol is to provide a guide to good clinical practice until new changes, based on scientific evidence, are produced

The maximum expiratory flow-volume loop in natives of Ladakh and acclimatized lowlanders.

Differences in static and dynamic volumes may exist between high altitude residents of Indian Himalayas and their South American counterparts, as well as with acclimatized lowlander sojourners. Maximum expiratory flow-volume loops were recorded in healthy native highlanders of Ladakh (NH, N = 75) and in healthy acclimatized lowlanders (AL, N = 32) at an altitude of 3450 m in the western Indian Himalayas. The forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1), both corrected for a height of 168 cm, were significantly higher in NH [FVC: 5.02 (0.51) vs. 3.89 (0.45) L, p < 0.0001; FEV1: 4.27 (0.47) vs. 3.44 (0.37) L, p < 0.0001]. The flow rates at larger lung volumes (PEFR, FEF25, and FEF50) were similar in the two groups. The NH showed significantly higher flow rates at low lung volumes, that is, FEF75 and FEF75-85% [FEF75: 2.03 (0.69) vs. 1.70 (0.52) L/s, p = 0.0092; FEF75-85%: 1.42 (0.54) vs. 1.06 (0.35) L/s, p = 0.0001]. The exact mechanisms allowing the higher flow rates at low lung volumes remain to be elucidated, but it is possible that these findings may indicate an inherited adaptive response in the Ladakhi highlander.