Reliability of blood eosinophil count in steady-state bronchiectasis.

RATIONALE: The baseline value of eosinophils in peripheral blood (BEC) has been associated with different degrees of severity, prognosis and response to treatment in patients with bronchiectasis. It is not known, however, if this basal value remains constant over time. OBJECTIVES: The aim of this study was to assess whether the BEC remains stable in the long term in patients with bronchiectasis. METHODS AND MEASUREMENTS: Patients from the RIBRON registry of bronchiectasis diagnosed by computed tomography with at least 2 BEC measurements one year apart were included in the study. Patients with asthma and those taking anti-eosinophilic drugs were excluded. Reliability was assessed using the intra-class correlation coefficient (ICC). A patient with a BEC of at least 300 cells/uL or less than 100 cells/uL was considered eosinophilic or eosinopenic, respectively. Group changes over time were also calculated. MAIN RESULTS: Seven hundred and thirteen patients were finally included, with a mean age of 66.5 (13.2) years (65.8 % women). A total of 2701 BEC measurements were performed, with a median number of measurements per patient of 4 (IQR: 2-5) separated by a median of 12.1 (IQR: 10.5-14.3) months between two consecutive measurements. The ICC was good (>0.75) when calculated between two consecutive measurements (approximately one year apart) but had dropped significantly by the time of the next annual measurements. Similarly, the change from an eosinophilic or eosinopenic patient to a non-eosinophilic or non-eosinopenic patient, respectively, was less than 30 % during the first year with respect to the baseline value but was close to 50 % in later measurements. CONCLUSIONS: Given the significant changes observed in the baseline value of the BEC over time, its monitoring is necessary in patients with bronchiectasis in order to more reliably assess its usefulness.

Tabaquismo / Smoking

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Avances en el tratamiento del tabaquismo / Advances in the treatment of the smoking habit

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¿Disponemos del marcador biológico ideal para valorar la exposición al humo del tabaco? / Do we have the ideal biological marker to assess exposition to tobacco smoke?

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Effects of two types of training on pulmonary and cardiac responses to moderate exercise in patients with COPD.

The effects of two 8-week programmes of exercise reconditioning on the time constants (tau) of the pulmonary gas exchange, ventilatory and heart rate responses to moderate intensity exercise in patients with chronic obstructive pulmonary disease (COPD) were studied. Thirty-five subjects (mean+/-SD 64+/-5 yrs; forced expiratory volume in one second (FEV1) 1.09+/-0.17 L; 41+/-6.2% predicted) were randomly assigned either to supervised (s) training on a treadmill, 4 days x week(-1) (group S; n=21) or self-monitored (SM) walking 3 or 4 km in 1 h 4 days x week(-l) (group SM; n=20). The different levels of supervision resulted in a different estimated intensity of training (35+/-10 W in the SM group and 70+/-22 W in the S group). The kinetics were evaluated with a constant-load exercise test on a cycle-ergometer at a work rate corresponding to 80% the highest oxygen consumption (V'O2) that can be achieved without blood lactic acidosis (V'O2,LAT) or 50% of V'O2,max, if maximum oxygen consumption V'O2,LAT was not found. Mean endurance time at a work rate equivalent to 70% of the pretraining V'O2,max increased by 493+/-281 s in the S group and 254+/-283 s in the SM group (p<0.001). Mean tauV'O2 decreased from 83+/-17 s to 67+/-11 s (p<0.0001) in the S group and from 84+/-12 to 79+/-16 (p=0.04) in the SM group. Mean tau for carbon dioxide output minute ventilation and heart rate were also speeded after training, again more markedly in the S group. In the S group there was a significant correlation between the decrease in tauV'O2 and the increase in endurance time (r=-0.56, SEM=0.21). It is concluded that training speeds the kinetic response of oxygen consumption, carbon dioxide production, minute ventilation and heart rate to moderate exercise and that the effect is greater after supervised, more intense training.

[A comparison of several measurement scales for assessing dyspnea in their daily activities in patients with chronic obstructive lung disease]. / Comparación de varias escalas de medición para valorar la disnea en las actividades diarias en los pacientes con enfermedad pulmonar obstructiva crónica.

The objective of this study was to compare two instruments for measuring dyspnea to functional capacity, defined as maximal oxygen uptake in a stress test limited by symptoms. We carried out a descriptive study to determine correlation between the methods. Subjects with severe chronic obstructive pulmonary disease were enrolled and dyspnea during daily activities was evaluated using the Medical Research Council (MRC) scale and the chronic respiratory disease health perception questionnaire (CRQ). Dyspnea was also assessed on a visual analog scale (VAS) and the Borg scale. Patients performed a progressive treadmill test limited by symptoms to measure peak VO2 and VE. Correlation analysis of the two measures of dyspnea and the objective measures of functional capacity (peak VO2 and VE) showed that the clinical dyspnea measures (CRQ and MRC) correlated well with peak aerobic capacity and with maximal ventilation, whereas the VAS and Borg scale were not significantly related to the aforementioned variables. We also observed that the clinical scales for dyspnea correlated with each other, as did the VAS and Borg scale, but that there was no correlation between the two types of measurement. We conclude that clinical dyspnea indexes (CRQ and MRC) correlate well with maximal aerobic capacity and with each other. However, the VAS and Borg scale do not correlate with functional capacity measured by peak VO2 and VE.

Comparación de varias escalas de medición para valorar la disnea en las actividades diarias en los pacientes con enfermedad pulmonar obstructiva crónica / Comparison of several scales for assessing dyspnea during daily activities in patients with chronic obstructive pulmonary disease

Objetivo: Comparar dos clases de instrumentos de medición de la disnea con la capacidad funcional definida como la captación máxima de oxígeno en una prueba de esfuerzo limitada por síntomas. Método: Se realizó un estudio descriptivo para evaluar la correlación entre métodos. Se seleccionaron sujetos con EPOC grave y se evaluó la disnea en las actividades diarias mediante la escala del Medical Research Council (MRC) y se administró el cuestionario de percepción de salud en enfermedades respiratorias crónicas (CRQ). También se evaluó la disnea mediante la escala visual analógica (VAS) y mediante la escala de Borg. Se realizó una prueba progresiva de esfuerzo en tapiz rodante, limitada por síntomas, para medir la captación de O2 pico (VO2 pico) y la ventilación-minuto pico (VE pico). Resultados: Al analizar la relación existente entre las medidas obtenidas en las escalas de medición de la disnea y las medidas objetivas de la capacidad funcional (VO2 pico y VE pico), encontramos que las escalas de disnea clínica (CRQ, MRC) tienen una buena correlación tanto con la capacidad aeróbica máxima como con la ventilación máxima, mientras que las escalas de Borg y VAS tienen una correlación no significativa con dichas variables. También observamos que las escalas de medición de la disnea clínica tienen una correlación entre ellas excelente, al igual que ocurre entre las escalas de Borg y VAS, pero no existe correlación entre los dos tipos de escalas de medición. Conclusiones: Se concluye que los índices de disnea clínica (CRQ y MRC) tienen una correlación buena con la capacidad aeróbica máxima del sujeto y entre sí. Sin embargo, las escalas de Borg y VAS no se correlacionan con la capacidad funcional medida pro el VO2 pico y la VE pico. (AU)

[Relationship between tobacco smoke exposure and the concentrations of carboxyhemoglobin and hemoglobin]. / Relación entre la exposición al humo del tabaco y las concentraciones de carboxihemoglobina y hemoglobina.

To determine the carboxyhemoglobin (CO-Hb) predictive intervals in active and passive smokers and to obtain an equation expressing the relation of CO-Hb to number of cigarettes smoked, we studied 233 outpatients referred to an urban university hospital for arterial gas measurement. Patients were excluded if they were receiving oxygen therapy or had been hospitalized in the two months before the study. The patients were classified as non smokers (57), passive smokers (54), smokers of less than 11 cigarettes (22), smokers of 11 to 20 (41) smokers of 21 to 40 (44) and smokers of over 40 (15). All patients answered a questionnaire on exposure to tobacco smoke or other sources of CO. Blood gases and co-oximetry were measured in all patients. Mean CO-Hb and 95% confidence intervals were 1.53% (0.78-1.85%) in smokers and 2.59% (1.89-3.29%) in passive smokers. The linear equation that best expressed the relationship was CO-Hb = 0.153 x number of cigarettes + 1.1 exposure to other sources (1 or 0) + 1.39 (SD 0.84)%. Hemoglobin level was significantly higher in the two groups smoking more than 21 cigarettes. We conclude that the predictive intervals is 1.9% in non smokers who are not exposed to other sources of CO. Passive smokers have significantly higher levels of CO-Hb than non smokers. Heavy smokers have polycythemia.

[Role of postoperative estimate of maximum oxygen uptake in predicting cardiorespiratory insufficiency in the immediate postoperative period in thoracic surgery]. / Valor de la estimación de la captación de oxígeno máxima postoperatoria en la predicción de insuficiencia cardiorrespiratoria en el postoperatorio inmediato de cirugía de tórax.

We sought to determine if predicted post-operative maximal oxygen uptake (VO2max/kg-PPO) was associated to the occurrence of respiratory or cardiac failure within the 60 days following lung surgery and to evaluate its validity as operability criterion. We studied 47 patients with chronic air-flow limitation (COPD) with FEV1 > 0.8 1 and without hypercapnia, that underwent lung surgery. Age was 56 (SD 11) years, FEV1 = 1.8 (SD 0.5) 1 (61% predicted (SD 13%) and FEV1/FVC = 55 (SD 7.5). Ten patients presented serious cardiac or respiratory complications (3 died). Significant correlation with complications was found for RV, TL-COsb-PPO, VO2max/kg, resection size and VO2max/kg-PPO. VO2max/kg-PPO correlation (-0.73) was significantly higher (p = 0.0016) than all the pulmonary function test (PFT) correlation and than VO2max/kg correlation (p = 0.049) as well. Cut-off points, positive and negative predictive values were respectively: 12.6 ml/min/kg, 0.75 y 0.90% for VO2max/kg-PPO; 17 ml/min/kg 0.83 and 0.87 for VO2max/kg and 148%, 0.67 and 0.82 for RV (the best of the pulmonary function tests). Multivariable models did not improve discriminant power. We conclude that, out of the studied variables, VO2max/kg-PPO showed higher correlation with the complications sought than PFT or VO2max/kg. As criterion to predict cardiac or respiratory failure, with the observed prevalence, its negative predictive values is good, but its positive predictive value is relatively low. None parameter was able to predict all the complications.

[Prediction of exercise capacity after lung resection in patients with chronic airflow limitation]. / Predicción de capacidad de esfuerzo tras resección pulmonar en pacientes con limitación crónica al flujo aéreo.

To assess the usefulness of a method for predicting postoperative peak oxygen uptake based on lost lung function after lung resection (VO2peak-PPO) and to establish the underlying physiological foundation for the relation between VO2peak-PPO and the measured postoperative value VO2peak-PO), we studied 29 patients (26 men) [age 60 (SD9)] with chronic airflow limitation [FEV1 = 66 (SD13)%] undergoing lobectomy or major pulmonary resection to treat lung cancer. The patients were assigned to groups according to whether postoperative exercise tolerance was considered to be limited by exhaustion of ventilatory reserve (LV) or not (NLV). Data to estimate postoperative pulmonary function was obtained one week before surgery: patients performed pulmonary function tests and exercise tests on a treadmill; dyspnea was also evaluated and perfusion scintigraphs were obtained. Pulmonary function, exercise tolerance and dyspnea were evaluated again approximately five months after surgery. The mean difference between VO2peak-PPO and VO2peak-PO was -0.034 (CI 0.293 to -0.348) l.min-1 and the between-group correlation coefficient was 0.76. The correlation between VO2peak-PPO and VO2peak-PO was 0.86 (SE 0.1) [0.89 (SE 0.13) for LV (n = 14) patients and 0.85 (SE 0.16) for NLV (n = 15) patients]. The correlations after adjusting for preoperative VO2peak-PPO were 0.73 (SE 0.2) and 0.35 (SE 0.27) for LV and NLV patients, respectively. We conclude that VO2peak-PPO provides a valid but only moderately precise estimate of VO2peak-PO. Only in LV patients is there a true relation between a decrease in VO2peak and loss of lung function.