Prueba de caminata en seis minutos en sujetos chilenos sanos de 20 a 80 años / Reference values for the 6-minutes walking test in healthy subjects 20-80 years old

Background: The six minute walking distance test (6MWD) is widely used to evaluate exercise capacity in several diseases due to its simplicity and low cost. Aim: To establish reference values for 6MWD in healthy Chilean individuals. Material and methods: We studied 175 healthy volunteers aged 20-80 years (98 women) with normal spirometry and without history of respiratory, cardiovascular or other diseases that could impair walking capacity. The test was performed twice with an interval of 30 min. Heart rate, arterial oxygen saturation (with a pulse oxymeter) and dyspnea were measured before and after the test. Results: Walking distance was 576 ± 87 m in women and 644 ± 84 m in men (p < 0.0001). For each sex, a model including age, height and weight produced 6MWD prediction equations with a coefficient of determination (R²) of 0.63 for women and 0.55 for men. Conclusions: Our results provide reference equations for 6MWD that are valid for healthy subjects between 20 and 80 years old.

Guía para realizar oximetría de pulso en la práctica clínica / Guideline for performing pulse oximetry in the clinical practice

A brief guideline for carrying out pulse oximetry in the clinical practice is presented. This guideline was written by the Pulmonary Function Commission of the Chilean Respiratory Disease Society. Basic aspects for applying this non-invasive measurement to adults and infants as well as carefulness in interpreting its results are briefy described.

Se presenta una guía práctica resumida para efectuar la oximetría de pulso en la práctica clínica. Esta guía fue redactada por la Comisión de Función Pulmonar de la Sociedad Chilena de Enfermedades Respiratorias. Se describen resumidamente los aspectos básicos para aplicar esta medición no invasiva a adultos y a niños y también se consideran las precauciones que se deben tener presente al interpretar los resultados de esta medición.

Prueba de caminata de seis minutos / Guidelines for the six-minute walk test

The six-minute walk test has been shown as a very useful tool in the functional assessment of patients with chronic respiratory diseases enclosing patients with pulmonary hypertension. Methodological standardization of this test is fundamental for interpreting its results, as well as for using it in the short and long-term clinical follow up of our patients. The purpose of these guidelines is justly to spread out in our country the proper way to perform this useful test. In this context, indications, contraindications, limitations, security measures and detailed instructions about how to carry out, how to report and how to interpret the 6 minute walk test are described in these guidelines.

La prueba de caminata de 6 minutos ha demostrado ser una herramienta muy útil en la evaluación funcional de los pacientes con enfermedades respiratorias crónicas, incluyendo pacientes con hipertensión pulmonar. Para su correcta interpretación y uso clínico en el seguimiento de pacientes, es fundamental estandarizar la técnica. El propósito de este instructivo es justamente difundir a nivel nacional, la manera de efectuar esta técnica en forma correcta. En este contexto, este instructivo describe las indicaciones, contraindicaciones, limitaciones, medidas de seguridad y entrega detalles sobre la ejecución, informe e interpretación de la prueba de caminata de 6 minutos.

Espirometría: Manual de procedimientos. Sociedad Chilena de Enfermedades Respiratorias, 2006 / Manual of Procedures on Spirometry: Chilean Society of Respiratory Diseases, 2006

La espirometría es una prueba fundamental en la evaluación funcional respiratoria. Este test es utilizado frecuentemente en la práctica clínica y en estudios de poblaciones. Entre los diversos índices derivados de una espiración forzada, el VEF1 y la CVF son los más usados debido a su buena reproducibilidad, facilidad de su medición, y su grado de correlación con la etapa de la enfermedad, condición funcional, morbilidad y mortalidad. Considerando la importancia de aplicar procedimientos estandarizados para realizar espirometrías, un comité de especialistas en función pulmonar de la Sociedad Chilena de Enfermedades Respiratorias, elaboró este manual de procedimientos para realizar espirometrías. El objetivo de este manual es comunicar las normas internacionales para realizar espirometrías, a fin de promover su aplicación en la práctica clínica y de laboratorio. Además se propone una manera consensuada para informar e interpretar los valores espirométricos tanto en la práctica clínica como en el trabajo de laboratorio.

Spirometry is a essential test for assessing pulmonary function. This test is frequently used in clinical practice and population studies. Among the several indices derived from forced expiration, forced expiratory volume in the 1st second (FEV1) and forced vital capacity (FVC)) are the most commonly used because of good reproducibility, ease of measurement, and correlation with disease stage, functional condition, morbidity and mortality. Considering the importance to apply standardized techniques for measuring spirometric indices, a committee of specialists on pulmonary function from the Chilean Society of Respiratory Diseases, has elaborated this manual of procedures on spirometry. The aim of this manual is to report the international standards for carrying out spirometry, to promote their application in clinical and laboratory practice. Besides a general assent way for interpreting and reporting spirometric values at clinical and at laboratory work is proposed.

Función de los músculos inspiratorios, parámetros hemodinámicos y disnea en pacientes con estenosis mitral / Inspiratory muscle function, hemodynamic parameters and dyspnea in patients with mitral valve stenosis

Background: The mechanism involved in dyspnea in patients with mitral valve stenosis (MS) is not completely understood. Aim: To evaluate in patients with MS, changes in hemodynamic parameters during the assessment of inspiratory muscle endurance (IME) and the relationship between IME, hemodynamics and dyspnea. Subjects and methods: We studied 13 patients (9 in NYHA class II and 4 in class III). Endurance was evaluated using a two minute incremental threshold loading test, to obtain the maximal sustainable inspiratory pressure (SIP), and maximal inspiratory load (MIL). During the test, cardiac output (CO), mean pulmonary and capillary pressures (PAP and PCP, respectively), were evaluated. Results: Compared to six normal subjects, MS patients had reduced SIP and MIL (p <0.01), which correlated with baseline index of dyspnea (r= 0.57 and r=0.52, respectively, p <0.05). At the end of the test period, basal CO, cardiac index (CI), PAP and PCP increased from 3.4 to 4.0 l/min-1; 2.1 to 2.5 l/min-1/m-2; 15 to 25 and 11 to 18 mmHg, respectively (p <0.01). No relationship between IME and hemodynamic parameters was found. Conclusions: IME is reduced and is closely related to dyspnea in these patients with MS. The observed low CI, suggests that muscle underperfusion could contribute to this dysfunction during the inspiratory effort.

Mejoría de la función muscular inspiratoria en pacientes con estenosis mitral cerrada después de valvuloplastia mitral percutánea: comunicación preliminar / Improvement in inspiratory muscle function after percutaneous mitral valvuloplasty in mitral stenosis: preliminary report

Background: It has been proved that there is an inspiratory muscle dysfunction in mitral stenosis; Although its causes still remain unknown. Aim: to evaluate the effect of percutaneous balloon mitral valvuloplasty (PMV) on inspiratory muscle performance (IMP) in patients with mitral stenosis (mitral area < 1.5 cm2). Patients and methods: We studied IMP in 8 patients (35 ñ 10 years) before and 3 months after successful PMV. Inspiratory muscle strength was studied by measuring maximal statistical inspiratory mouth pressure (MIP). Endurance was evaluated using a two minute incremental threshold loading test in order to obtain the maximal sustainable inspiratory pressure (SIP), with the maximal sustainable load (MSL) the patients could sustain for 2 minutes. Results: Mitral valvuloplasty increased mean cardiac index from 3.1 ñ 0.3 to 4.15 ñ 0.3 l/min/m2 (p<0.01), and significantly decreased mean pulmonary and capillary pressures. The MIP value(118 ñ 6 cmH2O), similar to that of normal group, increased to 137 ñ 7 cmH2O (p<0.01). SIP and maximal sustainable load were 52 ñ 3 cmH2O and 294 ñ 29 g respectively, lower than normal subjects (p<0.05) They increased after PMV to 80 ñ 3 cmH2O and 463 ñ 26 g respectively (p<0.001). Conclusions: PMV improved inspiratory muscle function in patients with severe mitral stenosis, probably secondary to a decrease work of breath and improvement of ventricular function