RESUMEN
Our objective was to determine the prevalence of airway hyperreactivity (AHR) in patients with newly diagnosed rheumatoid arthritis (RA) who had received no disease-modifying antirheumatic drugs (DMARDs) and to characterise the spectrum of lung diseases identifiable in these patients at the time of presentation. Eighteen consecutive patients with newly diagnosed RA referred to our medical centre's rheumatology clinic over 2 years underwent pulmonary evaluation with arterial blood gas analysis, chest radiographs, spirometry before and after bronchodilator medication, and body plethysmography. They returned on subsequent days in random order for methacholine inhalation challenge (MIC) and eucapnic voluntary hyperventilation (EVH) as bronchoprovocation techniques. One patient had severe obstructive disease at presentation and therefore did not undergo bronchoprovocation. We found a wide variety of pulmonary abnormalities, including two patients with hypoxia (12%), two with obstruction (12%), three with restriction (18%) and four with AHR (23%). The data also suggest a strong association between pulmonary diseases in RA and cigarette smoking. Although no single characteristic lung disease such as AHR was identified in patients presenting with RA, the association between lung disease and cigarette smoking is striking and underscores the need to emphasise smoking cessation in this patient population.
Asunto(s)
Artritis Reumatoide/complicaciones , Hiperreactividad Bronquial/complicaciones , Hiperreactividad Bronquial/epidemiología , Adulto , Hiperreactividad Bronquial/diagnóstico , Hiperreactividad Bronquial/etiología , Pruebas de Provocación Bronquial/métodos , Broncoconstrictores , Femenino , Volumen Espiratorio Forzado , Humanos , Masculino , Maryland , Cloruro de Metacolina , Persona de Mediana Edad , Fumar/efectos adversos , Capacidad Pulmonar TotalRESUMEN
Typical pulmonary carcinoid tumors often present as proximal endobronchial masses discovered during the evaluation of cough and/or hemoptysis. We present a case of a carcinoid tumor that presented with spontaneous partial expectoration. A review of the literature revealed 16 cases of expectoration of fragments from various primary and metastatic tumors. Our case appears to be the first report of the expectoration of a carcinoid tumor.
Asunto(s)
Tumor Carcinoide , Tos , Neoplasias Pulmonares , Adulto , Broncoscopía , Tumor Carcinoide/complicaciones , Tumor Carcinoide/diagnóstico , Hemoptisis/etiología , Humanos , Neoplasias Pulmonares/complicaciones , Neoplasias Pulmonares/diagnóstico , MasculinoRESUMEN
A variety of dosing schedules have been reported for the hyperventilation method of broncho-provocation testing. To evaluate the effect of challenge technique on the bronchoconstrictive response, we had 16 subjects perform eucapnic voluntary hyperventilation (EVH) with dry, room temperature gas using four different dosing schedules. The hyperventilation challenge dosages included the following: (1) a target minute ventilation (VE) of 20 x FEV1 for 6 min; (2) a target VE of 15 x FEV1 for 12 min; (3) an interrupted challenge with a target VE of 30 x FEV1 for 2 min repeated 3 times; and (4) a target VE of 30 x FEV1 for 6 min. Challenges 2, 3, and 4 gave identical absolute ventilatory challenges (identical factor FEV1 x minutes) but at different VE dosages or time. Challenges 1 and 4 were of identical length, but different target VE. The mean postchallenge fall in FEV1 was 16.6 +/- 10.9%, 11.0 +/- 8.1%, 19.6 +/- 9.9%, and 26.7 +/- 11.3% for challenges 1, 2, 3, and 4, respectively. The response to an identical EVH challenge (FEV1 x 30 for 6 min) was reproducible when performed on separate days. We conclude that the challenge technique used for hyperventilation testing will have a significant impact on the bronchoconstrictive response and must be taken into account when interpreting study results. Tests may be quantitatively comparable over a narrow range of challenge time and VE. We recommend that a 6-min uninterrupted EVH challenge using dry, room temperature gas at a target VE of 30 x FEV1 be adopted as the "standard" challenge.
Asunto(s)
Asma/diagnóstico , Pruebas de Provocación Bronquial/métodos , Hiperventilación , Adulto , Asma/sangre , Asma/fisiopatología , Broncoconstricción , Dióxido de Carbono/sangre , Femenino , Volumen Espiratorio Forzado , Humanos , Masculino , Reproducibilidad de los Resultados , Capacidad VitalRESUMEN
Eucapnic voluntary hyperventilation (EVH) of dry gas is a physiologic bronchoprovocation challenge useful in the diagnosis of asthma. To determine the best parameter and threshold for diagnosis and the proper timing of postchallenge measurements, we reviewed 120 challenges, comparing the decrement from baseline in FVC, FEV1, mean forced expiratory flow during the middle half of the FVC (FEF25-75%), and peak expiratory flow rate (PEFR) each at 0, 5, 10, and 20 min postchallenge. After adjustment to a standard minute ventilation of 30 times the baseline FEV1 for 6 min, the mean response by 90 mild asthmatics differed from 30 normal subjects in all four parameters (p < 0.0001). In asthmatics, maximum decline from baseline (mean +/- SEM) was as follows: FVC, 12.1 +/- 1.2%; FEV1, 19.7 +/- 1.7%; FEF 25-75%, 33.5 +/- 2.5%; and PEFR, 29.0 +/- 1.9%. Normal subjects had a maximum fall as follows: FVC, 2.9 +/- 0.7%; FEV1, 3.8 +/- 0.7%; FEF25-75%, 11.8 +/- 2.0%; and PEFR, 11.5 +/- 1.0%. Based on comparison of receiver operator characteristic curves, FEV1 was more accurate than FEF25-75% and equivalent to FVC and PEFR. A threshold of 10% change or greater in FEV1 had a specificity of 90%, with a sensitivity of 63.3%. A threshold of 15% or greater had a specificity of 100%, with a sensitivity of 53.3%. The FEV1 fell by 10% or more in 55 of 90 asthmatics at 5 or 10 min after hyperventilation. Measurements at 0 or 20 min added two additional positive responses. We conclude that in the proper clinical setting, subjects whose FEV1 declines by 10% or more at 5 or 10 min after EVH should be diagnosed as having asthma.
Asunto(s)
Asma/diagnóstico , Pruebas de Provocación Bronquial/métodos , Adulto , Anciano , Anciano de 80 o más Años , Asma/fisiopatología , Femenino , Flujo Espiratorio Forzado , Volumen Espiratorio Forzado , Humanos , Hiperventilación , Masculino , Persona de Mediana Edad , Curva ROC , Estudios Retrospectivos , Sensibilidad y Especificidad , Espirometría , Capacidad VitalRESUMEN
To evaluate whether there is a refractory period (RP) after hyperventilation challenge, we compared the bronchoconstrictive response to repetitive eucapnic voluntary hyperventilation challenge with dry, room temperature air (EVH). The serial challenges were identical with 11 known asthmatics hyperventilating for 6 min at a target minute ventilation of 30 times their FEV1 measured before either challenge. There was a significant difference between the mean postchallenge fall in FEV1 to the initial EVH challenge (27.4 +/- 9.8%) and the response to the second EVH challenge (16.1 +/- 5.9%) (p = 0.0001), indicating refractoriness. We then evaluated whether 6 min of uninterrupted EVH challenge gives a similar bronchospastic response to that which results from an equivalent (by total minute ventilation) interrupted challenge of 2 min of EVH repeated three times. The mean post-challenge fall in FEV1 in response to this interrupted challenge was 18.9 +/- 10.6%, which was significantly different from the 27.4% fall in response to 6 consecutive minutes of EVH (p = 0.036). This study demonstrates that there is a refractory period after repeated EVH challenges and this refractoriness affects the response to interrupted, or dosed, EVH challenge.
Asunto(s)
Broncoconstricción/fisiología , Dióxido de Carbono/sangre , Hiperventilación/fisiopatología , Adulto , Aire , Asma/fisiopatología , Espasmo Bronquial/fisiopatología , Femenino , Volumen Espiratorio Forzado/fisiología , Humanos , Masculino , Persona de Mediana Edad , Espirometría/estadística & datos numéricos , Estadísticas no Paramétricas , Factores de TiempoRESUMEN
Eucapnic voluntary hyperventilation (EVH) and methacholine inhalation challenge (MIC) both cause bronchoconstriction in asthmatics. A refractory period, or time when the response to bronchoprovocation in a series of challenges is diminished, has been found after hyperventilation or exercise but not after MIC. We investigated whether EVH or MIC blunted the response to the other test. Sixteen asthmatics were studied on 2 d, taking both tests each day. They were randomized to either EVH or MIC first on Day 1, then the opposite order on Day 2, 6 to 14 d apart. After EVH as a first test, the mean decline in FEV1 from baseline was 18.66 +/- 4.76% (mean +/- SEM), but when EVH followed MIC, the response to EVH was reduced by 30%, to a decline in FEV1 of only 13.02 +/- 3.75% (p = 0.0026). During MIC, the mean provocation dose to cause 20% decrease in FEV1 (PD20) given as the initial challenge was 54.77 +/- 21.60 breath units, compared with 46.94 +/- 19.55 breath units when MIC followed EVH (p = 0.54). However, the subset of patients most sensitive to methacholine (PD20 < 0.1 breath unit) had changes suggestive of a refractory period after EVH, with a mean increase in the PD20 from 0.06 +/- 0.01 to 3.35 +/- 1.43 (p = 0.069). Our data show that MIC attenuates the response to subsequent challenge with EVH. Conversely, EVH may only affect subsequent MIC in those most sensitive to methacholine.
Asunto(s)
Asma/diagnóstico , Asma/fisiopatología , Pruebas de Provocación Bronquial/normas , Dióxido de Carbono , Hiperventilación/complicaciones , Cloruro de Metacolina , Adulto , Anciano , Análisis de Varianza , Sesgo , Pruebas de Provocación Bronquial/métodos , Constricción Patológica , Femenino , Volumen Espiratorio Forzado , Humanos , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Factores de Tiempo , Capacidad VitalRESUMEN
Methacholine inhalation challenge (MIC) is probably the most widely used and best standardized test for nonspecific bronchoprovocation challenge (BPC). There has been increasing interest in developing "physical" stimuli such as eucapnic voluntary hyperventilation (EVH) with dry gas to assess airway hyperreactivity (AHR), because of inherent problems with using a pharmacologic agent in epidemiologic surveys. To our knowledge, no studies exist that compare MIC with EVH in known asthmatics. We conducted a prospective, randomized, crossover trial with a group of subjects (n = 16) who met the American Thoracic Society definition of asthma with these objectives: (1) to compare the sensitivity of EVH with MIC; (2) to compare the quantitative response of one test with the response to the other challenge; and (3) to correlate the response of both tests with symptoms, serum IgE levels, and serum eosinophil counts. We found that (1) EVH was positive in 75 percent of cases and MIC was positive in 81 percent of cases; one subject reacted to EVH but not to MIC and vice-versa. (2) The quantitative response to one test correlated with the response to the other test (r = -0.60, p = 0.01). (3) There was a correlation between severity of asthma symptoms and the response to EVH (r = 0.62; p = 0.01), but not to MIC. (4) Response to MIC (log PD20), but not EVH, correlated with serum IgE level (r = -0.53, p = 0.04). We suggest that EVH may be used for the initial assessment of AHR in the evaluation of asthma. Eucapnic voluntary hyperventilation is a sensitive measure of AHR and it correlates well with symptoms. Furthermore, though these points were not addressed in our study, it is more physiologic than MIC, and it is easy and less expensive to perform.