Orlando Díaz P

Prueba de caminata en seis minutos en sujetos chilenos sanos de 20 a 80 años

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.

Selective training of respiratory muscles in patients with chronic heart failure

Background: Patients with chronic heart failure have a lower inspiratory muscle strength and fatigue endurance. Aim: To assess the effects of selective training of respiratory muscles in patients with heart failure. Patients and methods: Twenty patients with stable chronic heart failure, aged 58.3 ± 3 years with an ejection fraction of 28 ± 9%, were subjected to respiratory muscle training with threshold valves. The load was fixed in 30% of maximal inspiratory pressure (PImax) in 11 and in 10% of PImax in nine. Two sessions of 15 minutes, 6 days per week, during 6 weeks were done. Degree of dyspnea (Mahler score), maximal oxygen uptake, distance walked in 6 minutes, respiratory muscle function and left ventricular ejection fraction were measured before and after training. Results: Both training loads were associated to an improvement in dyspnea (+2.7 ± 1.8 and +2.8 ± 1.8 score points with 30% Plmax and 10% PImax respectively), maximal oxygen uptake (from 19 ± 3 to 21.6 ± 5 and from 16 ± 5 to 18.6 ± 7 ml/kg/min with 30% PImax and 10% PImax respectively, p< 0.05), PImax (from 78 ± 22 to 99 ± 22 and from 72 ± 34 to 82.3 cm H20 with 30% Plmax and 10% PImax respectively), sustained PImax (from 63 ± 18 to 90 ± 22 and from 58 ± 3 to 69 ± 3 cm H20 with 30% PImax and 10% PImax respectively), and maximal sustained load (from 120 ± 67 to 195 ± 47 and from 139 ± 120 to 192 ± 154 g with 30% PImax and 10% PImax respectively). The distance walked in 6 min only increased in subjects trained at 30% PImax (from 451 ± 78 to 486 ± 68 m). Conclusions: Selective training of respiratory muscles results in a functional improvement of patients with chronic heart failure. (Rev Med Chile 2001; 129: 133-39).

Valor predictivo de la historia clínica y el examen físico en el diagnóstico de la neumonía del adulto adquirida en la comunidad: Revisión de la literatura

Distinguishing pneumonia from other causes of respiratory illnesses,such as bronchitis, influenza and upper respiratory tract infections, has important therapeuticand prognostic implications. This decision is usually made by clinical assessment alone or byperforming a chest x-ray. The reference standard for diagnosing pneumonia is chest radiography,but many physicians rely on history and physical examination to diagnose or exclude thisdisease. A review of published studies of patients suspected of having pneumonia reveals that thereare no individual clinical findings, or combination of findings, that can predict with certaintythe diagnosis of pneumonia. Prediction rules have been recommended to guide the order ofdiagnostic tests, to maximize their clinical utility. Thus, some studies have shown that the absenceof any vital sign abnormalities or any abnormalities on chest auscultation substantially reducesthe likelihood of pneumonia to a point where further diagnostic evaluation may be unnecessary.This article reviews the literature on the appropriate use of the history and physical examinationin diagnose community-acquired pneumonia (Rev Med Chile 2007; 135: 517-28).(

Efecto de la prueba de la caminata de seis minutos sobre la hiperinflación pulmonar en pacientes con enfermedad pulmonar obstructiva crónica avanzada

Background: Exercise tolerance in patients with COPD is highly variable and poorly related to airways obstruction assessed by FEV1. These patients develop dynamic hyperinflation (DH) during an incremental exercise test which can be evaluated through a reduction in inspiratory capacity (IC). Aim: to evaluate: a) if the six minute walking test (6 MWD) induce DH reducing IC, b) if the reduction in IC is related to tidal expiratory flow limitation at rest (FL). Subjects and methods: Thirty eight stable COPD patients (28 FL and ten non FL during resting breathing, determined by the negative pressure technique). Inspiratory capacity was measured before and immediately after the 6 MWD test. Dyspnea, SpO2 and heart rate were measured before and after the test. Results: Inspiratory capacity was lower in FL patients as compared to patients without FL (p <0,005). Although no differences were found between groups in 6 MWD, dyspnea and HR, a significant reduction in IC after the walking test was observed only in FL patients (p <0,0001). In addition, SpO2 fell significantly (p <0,0001) after walking in the same group. Conclusions: Our results demonstrate that a moderate exercise such as the walking test induces DH and hypoxemia in patients with COPD and FL and stresses the importance of assessing DH by measuring IC in these patients (Rev Med Chile 2001; 129: 1171-78)

Beneficios clínicos y funcionales de agregar teofilina a la terapia inhalatoria con broncodilatadores de acción corta en pacientes con enfermedad pulmonar obstructiva crónica

Thirty-eight stable COPD patients who accepted to participate in thestudy approved by the Ethics Committee of our institution were studied. Using a randomized double-blindplacebo-controlled study, theophylline (250 mg) or placebo was administered twice a day for 15 days inaddition to inhaled salbutamol and ipratropium bromide. Prior to and at the end of the study, patientsunderwent: a) a spirometry to evaluate changes in dynamic pulmonary hyperinflation using slow vitalcapacity (SVC) and inspiratory capacity (IC), b) the 6 min walking distance (6 MWD); and c)measurement of maximal inspiratory and expiratory pressures. Dyspnea and quality of life (QoL) wereevaluated using appropriate questionnaires.

Evaluación clínico-radiológica y clasificación de la bronquiolitis del adulto

Bronchiolar disorders are generally difficult to diagnose. A detailed clinical history may point toward a specific diagnosis. Pertinent clinical questions include history of smoking, collagen vascular disease, inhalation injury, medication use and organ transplantation. It is important also to evaluate possible systemic and pulmonary signs of infection, evidence of air trapping, and high-pitched expiratory wheezing, which may suggest small airways involvement. Pulmonary function tests and plain chest radiography may demonstrate abnormalities; however, they rarely prove sufficiently specific to obviate bronchoscopic or surgical biopsy. High-resolution CT (HRCT) scanning of the chest is often an important diagnostic tool to guide diagnosis in these difficult cases, because different subtypes of bronchiolar disorders may present with characteristic image findings. Some histopathologic patterns of bronchiolar disease may be relatively unique to a specific clinical context but others are nonspecific with respect to either etiology or pathogenesis. Primary bronchiolar disorders include acute bronchiolitis, respiratory bronchiolitis, follicular bronchiolitis, mineral dust airway disease, constrictive bronchiolitis, diffuse panbronchiolitis, and other rare variants. Prominent bronchiolar involvement may be seen in several interstitial lung diseases, including hypersensitivity pneumonitis, collagen vascular disease, respiratory bronchiolitis-associated interstitial lung disease, cryptogenic organizing pneumonia, and pulmonary Langerhans’ cell histiocytosis. Large airway diseases that commonly involve bronchioles include bronchiectasis, asthma, and chronic obstructive pulmonary disease. The clinical and prognostic significance of a bronchiolar lesion is best determined by identifying the etiology, underlying histopathologic pattern and assessing the correlative clinic-physiologic-radiologic context.

Valor predictivo de la historia clínica y oximetría nocturna en la pesquisa de pacientes con apneas obstructivas del sueño

Background: Obstructive sleep apnea syndrome (OSA) is an important cause of morbidity and mortality in adults. Aim: To evaluate the diagnostic value of clinical features and oximetric data to screen for obstructive sleep apnea before performing polysomnograpy or respiratory polygraphy. Material and Methods: We studied 328 consecutive adult patients referred for snoring or excessive daytime sleepiness to a sleep clinic in whom a standardized questionnaire and the Sleepiness Epworth Scale were performed and body mass index (BMI), cervical circumference (CC), and nocturnal oximetry were measured. Results: Fifty three percent (n = 173) had evidence of clinically significant OSA (apnea/hypopnea index (AHI) > 15 events/h). Patients with OSA were more likely to be male, obese (BMI ≥ 26 kg/m2), smokers, to have a thick neck (CC > 41 cm), and to have a significant greater prevalence of relative reported apneas and excessive daytime sleepiness, as determined by Epworth scale. Male gender (Odds ratio (OR): 4.00; 95% confidence intervals (CI): 1.59-10.0, p = 0.003), BMI ≥ 26 kg/m2 (OR: 3.68; 95%CI: 1.59-8.49, p = 0.002), smoking (OR: 2.29; 95% CI: 1.17-4.47, p = 0.015), Epworth index > 13 (OR: 2.65; 95% CI: 1.35-5.23, p = 0.005) and duration of symptoms over 2 years (OR: 2.35; 95% CI: 1.20-4.58, p = 0.012) were significant independent predictors of OSA. In nocturnal oximetry, the lowest SpO2 (SpO2 min) and the length of registries below 90% (CT-90) were independent predictors of OSA and both correlated significantly with AHI (r = -0.49 and r = 0.46 respectively, p < 0.001). Conclusions: No single factor was usefully predictive of obstructive sleep apnea. However, combining clinical features and oximetry data may be appropriate to detect clinically significant OSA patients.

Etiología y biomarcadores de inflamación sistémica en las exacerbaciones leves a moderadas de la enfermedad pulmonar obstructiva crónica

Background: The etiology of acute exacerbations of chronic obstructive pulmonary disease (COPD) is heterogeneous and still under discussion. Inflammation increases during exacerbation of COPD. The identification of inflammatory changes will increase our knowledge and potentially guide therapy. Aim: To identify which inflammatory parameters increase during COPD exacerbations compared to stable disease, and to compare bacterial and viral exacerbations. Material and Methods: In 85 COPD patients (45 males, mean age 68 ± 8 years, FEV1 46 ± 17% of predicted) sputum, nasopharyngeal swabs and blood samples were collected to identify the causative organism, during a mild to moderate exacerbation. Serum ultrasensitive C reactive protein (CRP), fibrinogen and interleukin 6 (IL 6), neutrophil and leukocyte counts were measured in stable conditions, during a COPD exacerbation, 15 and 30 days post exacerbation. Results: A total of 120 mild to moderate COPD exacerbations were included. In 74 (61.7%), a microbial etiology could be identified, most commonly Mycoplasma pneumoniae (15.8%), Rhinovirus (15%), Haemophilus influenzae (14.2%), Chlamydia pneumoniae (11.7%), Streptococcus pneumoniae (5.8%) and Gram negative bacilli (5.8%). Serum CRP, fibrinogen and IL 6, and neutrophil and leukocyte counts significantly increased during exacerbation and recovered at 30 days post exacerbation. Compared to viral exacerbations, bacterial aggravations were associated with a systemic inflammation of higher magnitude. Conclusions: Biomarkers of systemic inflammation increase during mild to moderate COPD exacerbations. The increase in systemic inflammation seems to be limited to exacerbations caused by bacterial infections.

Índices predictores de eventos adversos en el adulto inmunocompetente hospitalizado por neumonía neumocóccica adquirida en la comunidad

Resumen Streptococcus pneumoniae es el principal agente causal de la neumonia adquirida en la comunidad. Objetivos : Examinar el poder discriminativo de tres indices pronos-ticos en la prediccion de eventos adversos clinicamente relevantes en pacientes hospitalizados por neumonia neumococcica adquirida en la comunidad. Metodos : Evaluamos el indice de gravedad de la neumonia (IGN), CURB-65 y el indice de neumonia grave adquirida en la comunidad (INGAC) en una cohorte de 151 adultos inmunocompetentes hospitalizados por neumonia neu-mococcica. Los eventos adversos examinados fueron la admision a UCI, necesidad de ventilacion mecanica, complicaciones en el hospital y mortalidad a 30 dias. Las reglas predictoras fueron comparadas en base a su sensibilidad, especifi cidad y area bajo la curva receptor operador. Resultados: Se evaluaron 151 pacientes (64 ± 18 anos), 58% varones, 75% tenia co-morbilidad, 26% fueron admitidos a la UCI y 9% requirieron ventilacion mecanica. La tasa de eventos adversos fue mas elevada y la estadia en el hospital mas prolongada en las cate-gorias de alto riesgo de los tres indices predictores. Los tres indices permitieron, a su vez, predecir el riesgo de complicaciones y muerte en el seguimiento a 30 dias. El IGN fue mas sensible y el INGAC mas especifi co en la pesquisa de complicaciones en el hospital y en predecir el riesgo de muerte. El INGAC fue mas sensible y especi fi co en predecir el uso de ventilacion mecanica. El CURB-65 tuvo menor poder discriminatorio comparado con el IGN e INGAC.

Factores pronósticos, evolución y mortalidad en el adulto inmunocompetente hospitalizado por neumonía neumocócica adquirida en la comunidad

One hundred fifty one immunocompetent patients, aged 16 to 92 years, 58%males, were studied. Seventy five percent had other diseases, 26% were admitted to the intensive careunit and 9% needed mechanical ventilation. There were no differences in clinical features, ICUadmission or hospital length of stay among bacteremic and nonbacteremic patients. Thirty dayslethality for bacteremic and nonbacteremic patients, was 10.9% and 11.5%, respectively. Thepredictive values for lethality of Fine pneumonia severity index and CURB-65 (Confusion, Ureanitrogen, Respiratory rate, Blood pressure, 65 years of age and older) had an area under the ROCcurve of 0.8 and 0.69, respectively. Multivariate analysis disclosed blood urea nitrogen over 30 mg/dL (odds ratio (OR), 6.8), need for mechanical ventilation (OR, 7.4) and diastolic blood pressurebelow 50 mmHg (OR, 3.9), as significant independent predictors of death.