RESUMEN
BACKGROUND: Persistent impairment of pulmonary function and exercise capacity has been known to last for months or even years in the survivors who recovered from other coronavirus pneumonia. Some reports showed that subjects with coronavirus disease 2019 pneumonia after being discharged could have several sequelae, but there are few studies on gas exchange and exercise capacity complications in these subjects. AIMS: To describe residual gas exchange abnormalities during recovery from coronavirus disease 2019 pneumonia. METHODS: In an observational study, â¼90 d after onset of disease, we scheduled almost 200 subjects for an out-patient visit with pulmonary function testing and computed tomography of the lungs. Lung mechanics by using body plethysmography, gas exchange with diffusing lung capacity for carbon monoxide determined by the single-breath technique (DLCOsb) and diffusing lung capacity for nitric oxide determined by the single-breath technique (DLNOsb), and exercise ability by using the 6-min walk test (6MWT) were measured in the subjects. The results were compared between those who required invasive mechanical ventilation and those who did not. RESULTS: A total of 171 subjects were included, the majority (96%) had signs of residual pneumonia (such as an excess of high attenuation areas) on computed tomography of the lungs. The DLCOSB results were below the lower limit of the normal range in 29.2% of the subjects; during the 6MWT, 67% experienced oxygen desaturation ([Formula: see text]) > 4%; and, in 81 (47%), the dropped below 88%. Subjects who required invasive mechanical ventilation (49.7%) were more likely to have lower lung volumes, more gas exchange abnormality, less exercise capacity and more radiologic abnormality. CONCLUSIONS: Subjects who recovered from severe COVID-19 pneumonia continued to have abnormal lung function and abnormal radiologic findings.
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COVID-19 , Humanos , Pulmón/diagnóstico por imagen , Capacidad de Difusión Pulmonar , Intercambio Gaseoso Pulmonar , Pruebas de Función Respiratoria , SARS-CoV-2 , Prueba de PasoRESUMEN
BACKGROUND: Measured maximum voluntary ventilation (MVV) correlates with maximum ventilatory capacity during exercise. As a shortcut, MVV is often estimated by multiplying measured FEV1 times 35 or 40, but this index varies with altitude due to reduced air density. The objective was to describe MVV in healthy individuals residing at 2,240 m above sea level and compare it with the reference values customarily employed. METHODS: We recruited a convenience sample of respiratory-healthy, non-obese volunteers >10 y of age who had resided for >2 y in Mexico City. All participants performed forced spirometry and MVV according to current standards. Multiple regression models were fitted, including age, height, and measured FEV1, separately for males and females to obtain reference values. The impact of lower air density on MVV at this elevation was estimated from the reported increase in peak flow in relation to altitude. RESULTS: We studied 381 individuals (210 females [55.1%]) age 10-80 y with a mean MVV of 145.6 ± 48 L/min. Both FEV1 × 35 and FEV1 × 40 underestimated the MVV observed: in males by approximately 26% and in females by approximately 10%. MVV for our population approached FEV1 × 45 (98 ± 15.6% of real MVV). Multiple regression models including height, weight, and measured FEV1 explained 70% of residual variability once sex was taken into account. CONCLUSIONS: At an altitude of 2,240 m, MVV is about 45 times the measured FEV1, and it can be estimated for other altitudes. The best predicting equations for MVV were calculated separately for females and males and included the following predictors: age, age2, and measured FEV1. The study found that reference values for MVV from studies conducted at sea level are inaccurate at this altitude.
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Altitud , Volumen Espiratorio Forzado/fisiología , Ventilación Voluntaria Máxima/fisiología , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Estatura , Peso Corporal , Niño , Femenino , Voluntarios Sanos , Humanos , Masculino , México , Persona de Mediana Edad , Valores de Referencia , Análisis de Regresión , Espirometría , Adulto JovenRESUMEN
RATIONALE: Accurate reference values for spirometry are important because the results are used for diagnosing common chronic lung diseases such as asthma and chronic obstructive pulmonary disease, estimating physiologic impairment, and predicting all-cause mortality. Reference equations have been established for Mexican Americans but not for others with Hispanic/Latino backgrounds. OBJECTIVES: To develop spirometry reference equations for adult Hispanic/Latino background groups in the United States. METHODS: The HCHS/SOL (Hispanic Community Health Study/Study of Latinos) recruited a population-based probability sample of 16,415 Hispanics/Latinos aged 18-74 years living in the Bronx, Chicago, Miami, and San Diego. Participants self-identified as being of Puerto Rican, Cuban, Dominican, Mexican, or Central or South American background. Spirometry was performed using standardized methods with central quality control monitoring. Spirometric measures from a subset of 6,425 never-smoking participants without respiratory symptoms or disease were modeled as a function of sex, age, height, and Hispanic/Latino background to produce background-specific reference equations for the predicted value and lower limit of normal. MEASUREMENTS AND MAIN RESULTS: Dominican and Puerto Rican Americans had substantially lower predicted and lower limit of normal values for FVC and FEV1 than those in other Hispanic/Latino background groups and also than Mexican American values from NHANES III (Third National Health and Nutrition Examination Survey). CONCLUSIONS: For patients of Dominican and Puerto Rican background who present with pulmonary symptoms in clinical practice, use of background-specific spirometry reference equations may provide more appropriate predicted and lower limit of normal values, enabling more accurate diagnoses of abnormality and physiologic impairment.
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Emigrantes e Inmigrantes , Enfermedades Pulmonares/diagnóstico , Enfermedades Pulmonares/etnología , Estándares de Referencia , Adolescente , Adulto , Anciano , América Central , Femenino , Hispánicos o Latinos , Humanos , Masculino , Americanos Mexicanos , México , Persona de Mediana Edad , América del Sur , Espirometría , Estados Unidos/etnología , Adulto JovenRESUMEN
The present study was undertaken to test the hypothesis that chronic, low-level paraquat exposure causes restrictive lung function with gas transfer impairment. Three hundred thirty-eight Costa Rican farm workers from banana, coffee, and palm oil farms completed a questionnaire, spirometry, and a test of single-breath carbon monoxide diffusing capacity. Subjects 40 years of age or older, without other medical risk factors, completed maximal cardiopulmonary exercise tests. Most (66.6%) were paraquat handlers; 24.8% of handlers and 27.3% of nonhandlers reported current cigarette smoking. In linear regression models, cumulative paraquat exposure was not an independent predictor of VA, carbon monoxide diffusing capacity, peak oxygen uptake, FVC, or oxygen pulse peak. However, the ventilatory equivalent for CO(2), although within normal range, was significantly higher with increased cumulative paraquat exposure. Oxygen desaturation greater than 5% from rest to peak exercise had an odds ratio of 1.7 (95% confidence interval = 0.9-3.0) with the cumulative paraquat exposure index in models adjusted for age, weight, and smoking status. The association of paraquat exposure with ventilatory equivalent and oxygen desaturation suggests that paraquat may be associated with subclinical gas exchange abnormalities, but overall these findings are consistent with no clinically significant increases in interstitial thickening or restrictive lung disease among this population.