RESUMO
BACKGROUND: The principal obstacle to long-term survival after lung transplant is chronic lung allograft dysfunction (CLAD), which primarily affects the small airways. After transplant, patients are monitored with spirometry, which is a generally insensitive detector of small airways obstruction. The lung clearance index (LCI) is a measure obtained during multiple breath washout (MBW) maneuvers. We hypothesized that among lung allograft recipients, LCI would detect small airways disease not detected with spirometry. METHODS: This study enrolled 15 patients, 5 of whom already had a diagnosis of CLAD. We added MBW as an additional index of peripheral airway function to the established post-transplant routine care protocol. RESULTS: Of trials, 87.9% yielded valid measurements, and single maneuvers were 2-8 minutes. LCI did not yield any false-negative findings-no patients were considered obstructed by forced expiratory volume in 1 second (FEV1) but normal by LCI. At enrollment, 6 patients without CLAD had an elevated LCI, and 4 progressed to CLAD. Only 2 of these 4 patients would have been identified by a decrease in FEV1. CONCLUSIONS: LCI identified lung allograft dysfunction in more patients than the use of standardized spirometric measures, including patients with abnormal FEV1. These data suggest that LCI from MBW may be a more sensitive means to detect allograft peripheral airway disease than standard methods for measurement of small airways function.
Assuntos
Bronquíolos/fisiopatologia , Broncospirometria/métodos , Volume Expiratório Forçado/fisiologia , Transplante de Pulmão/efeitos adversos , Transplantados , Adolescente , Aloenxertos , Criança , Pré-Escolar , Estudos de Coortes , Fibrose Cística/diagnóstico , Fibrose Cística/cirurgia , Feminino , Rejeição de Enxerto , Sobrevivência de Enxerto , Humanos , Hipertensão Pulmonar/diagnóstico , Hipertensão Pulmonar/cirurgia , Modelos Lineares , Transplante de Pulmão/métodos , Masculino , Pediatria , Valor Preditivo dos Testes , Disfunção Primária do Enxerto/mortalidade , Disfunção Primária do Enxerto/fisiopatologia , Prognóstico , Estudos Prospectivos , Medição de Risco , Taxa de Sobrevida , Resultado do TratamentoRESUMO
OBJECTIVES: To assess the Pre-bronchodilator criteria and the Post-bronchodilator criteria of FEV1/FVC ratio in diagnosing Airflow obstruction. METHODS: An observational study was conducted from 1988 to 2006 at the Aga Khan University Hospital Patients referred to the pulmonary function test laboratory for spirometry with bronchodilator reversibility at the hospital during the above said period were enrolled. Forced spirometry was performed according to ATS guidelines. All patients who had pre-bronchodilator criteria of airflow obstruction were analyzed and compared with the post bronchodilator criteria. RESULTS: A total of 4222 individuals underwent spirometry out of which 4072 individuals were studied. Using the pre bronchodilator criteria, 1375 (34%) patients had airflow obstruction. Applying the post bronchodilator criteria on the same patients, 1098 (27%) had evidence of airway obstruction. Out of these 1375 patients who had airflow obstruction by using pre-bronchodilator criteria, 277 (20%) patients had no airflow obstruction by using the post bronchodilator criteria. Out of these 277 patients, 52% had significant airways reversibility as evidenced by >12% increase in their FEV1 pre and post bronchodilator. CONCLUSION: Pre bronchodilator criteria for detection of airflow obstruction overestimate the diagnosis of airflow obstruction and by using post bronchodilator criteria for airway obstruction on spirometry, decreases this over diagnosis of the condition
Assuntos
Obstrução das Vias Respiratórias/diagnóstico , Broncodilatadores , Adolescente , Adulto , Idoso , Obstrução das Vias Respiratórias/fisiopatologia , Broncospirometria/métodos , Feminino , Volume Expiratório Forçado/efeitos dos fármacos , Volume Expiratório Forçado/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Capacidade Vital/efeitos dos fármacos , Capacidade Vital/fisiologia , Adulto JovemRESUMO
A method to assess nasal airflow resistance is presented that provides a continuous resistance value and applies a novel minimally obtrusive measurement technique. Instead of calculating the resistance once for each breathing cycle conventionally, it is calculated for each signal sample at any sampling frequency. The continuous pressure recording is produced with a nasopharyngeal catheter inserted 8 cm deep along the floor of the other nasal cavity and the flow recording is produced with respiratory effort bands. A least-mean-square (LMS) extension for the resistance model of Broms is developed that dynamically adapts to the time-varying characteristics of the nasal functioning and produces the continuous resistance values. Experimental results are shown that demonstrate the uniqueness and applicability of the new technique in assessing quickly changing resistance in a histamine/xylometatsolin challenges, the differences between normal and symptomatic patients, and the effect of nasal treatment of patients.
Assuntos
Resistência das Vias Respiratórias/fisiologia , Monitorização Fisiológica/métodos , Cavidade Nasal/fisiologia , Ventilação Pulmonar/fisiologia , Adulto , Idoso , Broncospirometria/instrumentação , Broncospirometria/métodos , Cateterismo Periférico/instrumentação , Cateterismo Periférico/métodos , Feminino , Humanos , Inalação/fisiologia , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica/instrumentação , Nasofaringe/fisiologia , Rinite/diagnóstico , Rinite/fisiopatologia , Adulto JovemAssuntos
Asma/diagnóstico , Broncospirometria/métodos , Serviços Médicos de Emergência/métodos , Serviço Hospitalar de Emergência/normas , Doença Aguda , Obstrução das Vias Respiratórias/diagnóstico , Obstrução das Vias Respiratórias/fisiopatologia , Asma/fisiopatologia , Volume Expiratório Forçado/fisiologia , Humanos , Pico do Fluxo Expiratório/fisiologia , Prognóstico , Índice de Gravidade de DoençaRESUMO
Low antioxidant levels and oxidative stress due to airway inflammation may be determinant of asthma severity. The study was conducted to find the extent of lipid peroxidation and change in the levels of plasma iron in asthmatic patients with severity of disease. Study included 155 asthmatic and 156 healthy volunteers of the age groups 18-45 of either sex. Asthmatic patients were grouped into mild, moderate and severe groups on the basis of Forced Expiratory Volume in first second percent (FEV1%). Level of plasma malondialdhyde (MDA) was used as index of lipid peroxidation. A significant increase (P<0.01) in plasma MDA and plasma iron levels was found in asthmatic subjects as compared to controls. There was maximum increase in plasma MDA and iron levels in moderate asthmatic group. A positive correlation between plasma MDA and iron (r = +0.3) has been found in asthmatic patients. An increased plasma iron levels in asthmatics may contribute to aggravate lipid peroxidation.
Assuntos
Asma/sangue , Ferro/sangue , Peroxidação de Lipídeos , Adolescente , Adulto , Análise de Variância , Asma/fisiopatologia , Broncospirometria/métodos , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Malondialdeído/sangue , Pessoa de Meia-Idade , Análise de Regressão , Índice de Gravidade de DoençaRESUMO
BACKGROUND: Very late antigen-4 (VLA(4)) plays a key role in the recruitment of eosinophils in allergic responses in animal studies. OBJECTIVE: We investigated whether pretreatment with multiple doses of a VLA(4) receptor antagonist, HMR 1031, protects against allergen-induced airway responses and airway inflammation in humans. METHODS: Fourteen asthmatics (7F/7M), 18-49 years, PC(20) forced expiratory volume in 1 s (FEV(1)) methacholine (M) (<8 mg/mL; FEV(1) 82.3-116.1% predicted) with dual responses to inhaled allergen participated in a double-blind, placebo-controlled, cross-over study. Each treatment period consisted of 9 days, separated by >or=2 weeks. Exhaled nitric oxide (eNO), PC(20)FEV(1)(M) and hypertonic saline-induced sputum was obtained on Days 1, 7 and 9. Subjects inhaled HMR 1031 (20 mg b.i.d.) or placebo (P) on Days 1--8. On Day 8, an allergen bronchoprovocation test was performed, the airway response was measured by FEV(1), and expressed as %fall from baseline. Data from 12 evaluable subjects are presented here. RESULTS: Both treatments were well tolerated. There was no significant difference between HMR 1031 and P in the early asthamatic response: mean AUC (0-3 h)+/-SEM (%fall h): 26.01+/-4.26 and 17.41+/-4.26, respectively (P=0.18), nor in the late response: mean AUC (3-9 h)+/-SEM (%fall h): 97.09+/-8.63 and 97.61+/-8.63, respectively, P=0.97. This corresponded to the absence of significant allergen-induced changes in PC(20)FEV(1)(M), eNO, sputum eosinophils and soluble inflammation markers between both treatment periods. CONCLUSIONS: Treatment with multiple inhaled doses of the VLA(4) antagonist, HMR 1031, did not result in detectable protection against allergen-induced airway responses or airway inflammation in asthma.
Assuntos
Alérgenos/imunologia , Asma/imunologia , Imidazóis/imunologia , Integrina alfa4beta1/imunologia , Propionatos/imunologia , Receptores de Antígeno muito Tardio/antagonistas & inibidores , Administração por Inalação , Adolescente , Adulto , Brônquios/imunologia , Testes de Provocação Brônquica/métodos , Broncospirometria/métodos , Estudos Cross-Over , Método Duplo-Cego , Feminino , Volume Expiratório Forçado/imunologia , Humanos , Imidazóis/administração & dosagem , Masculino , Cloreto de Metacolina/imunologia , Pessoa de Meia-Idade , Óxido Nítrico/imunologia , Propionatos/administração & dosagem , Receptores de Antígeno muito Tardio/imunologia , Escarro/imunologiaRESUMO
Several indices have been suggested to express the bronchodilator response but there is no agreement on what is the ideal expression. The forced expiratory volume in I s (FEV1) was measured in 190 patients of bronchial asthma before and after inhalation of 200 micrograms salbutamol. Four different indices of bronchodilator response were calculated. The change in FEV1 was expressed as absolute value (delta FEV1), as a percentage of initial FEV1 (delta FEV1% initial), as a percentage of the predicted normal value (delta FEV1% predicted) and as a percentage of maximum achievable reversibility, i.e. the difference between predicted and initial values (delta FEV1% [predicted-initial]). A significant negative correlation was observed between delta FEV1 initial and initial FEV1% predicted (r = -0.33, P < 0.0001) but not delta FEV1 and initial FEV1% predicted, or between delta FEV1% predicted and initial FEV1% predicted. The values of delta FEV1% [predicted-initial] tended to reach towards infinity as the initial FEV1% predicted approached 100%. delta FEV1% predicted had similar sensitivity but greater specificity than delta FEV1% initial in detecting a true bronchodilator response. It was concluded that being dependent on the initial value, delta FEV1% initial was not an appropriate method to express the bronchodilator response. Although all other methods had limitations, delta FEV1 and delta FEV1% predicted appeared to be better indices.
Assuntos
Albuterol/uso terapêutico , Asma/tratamento farmacológico , Broncodilatadores/uso terapêutico , Adulto , Broncospirometria/métodos , Feminino , Volume Expiratório Forçado/efeitos dos fármacos , Humanos , Masculino , Sensibilidade e EspecificidadeRESUMO
There continues to be a great deal of interest in the anti-asthmatic role of antihistamines. Antihistamines have recently been shown to have anti-inflammatory properties that are more extensive than simply the blocking of histamine receptors. For example, new evidence suggests that the suppression of cell adhesion molecule expression occurs with these drugs. The anti-inflammatory and anti-asthmatic effects of antihistamines have been evaluated in patients with both allergic asthma and rhinitis, given the established association between allergic inflammation of the upper and lower airways, with evidence to suggest that antihistamines have clinically relevant anti-asthmatic properties. As well as conferring benefits in asthma symptom control and the measurement of lung function, studies assessing the effect of histamine receptor antagonists on bronchial hyperresponsiveness suggest that there is bronchoprotection during both methacholine and mannitol challenges. Recently, there has also been considerable interest in the effect of combining an antihistamine with a leukotriene receptor antagonist. This combination has an anti-asthmatic effect that is greater than that of either drug given alone and may be comparable to inhaled corticosteroid therapy.
Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Asma/tratamento farmacológico , Antagonistas dos Receptores Histamínicos H1/uso terapêutico , Loratadina/metabolismo , Manitol/metabolismo , Terfenadina/análogos & derivados , Acetatos/agonistas , Acetatos/metabolismo , Anti-Inflamatórios não Esteroides/administração & dosagem , Asma/prevenção & controle , Broncospirometria/métodos , Cetirizina/farmacologia , Ciclopropanos , Quimioterapia Combinada , Antagonistas dos Receptores Histamínicos H1/metabolismo , Antagonistas dos Receptores Histamínicos H1/farmacologia , Humanos , Loratadina/agonistas , Loratadina/análogos & derivados , Loratadina/farmacologia , Manitol/administração & dosagem , Quinolinas/agonistas , Quinolinas/metabolismo , Rinite/metabolismo , Sulfetos , Terfenadina/farmacologiaRESUMO
We prospectively considered 65 patients admitted for a spontaneous pneumothorax (SP) to describe the pragmatic management of SP, the first recurrence-free interval after medical therapeutic procedure and to specify the first recurrence risk factors over a 7-year period in these patients treated medically. The treatment options were observation alone (9%), needle aspiration (6%), small calibre chest tube (Pleurocatheter) drainage (28%) or thoracic tube drainage (49%), and pleurodesis with video-assisted thoracic surgery procedure (8%). Duration of the drainage and length of hospital stay were shorter in the Pleurocatheter group than in the thoracic tube group (P < 0.01). Among the 47 patients (72%) with a first SP and treated medically, nine patients (19%) had a first homolateral recurrence (FHR) during a mean follow-up of 84+/-13 months. Recurrence-free intervals ranged from 1 to 24 months (mean +/- SD: 9.3+/-8.4 months). FHR cases were more frequent in the Pleurocatheter group (P < 0 04). Analysis of potential risk factors showed that the patient's height and a previous homolateral SP episode are independent recurrence risk factors.
Assuntos
Pleurodese/métodos , Pneumotórax/terapia , Cirurgia Torácica Vídeoassistida/métodos , Adolescente , Adulto , Idoso , Análise de Variância , Estatura , Broncospirometria/métodos , Tubos Torácicos , Distribuição de Qui-Quadrado , Feminino , Humanos , Tempo de Internação , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Recidiva , Fatores de Risco , Resultado do TratamentoRESUMO
Determining risks of bronchial asthma is one of the main tasks in contemporary occupational pulmonology. The important risk factor is nonspecific increased reactivity of bronchi. The work was aimed to determine occurrence of nonspecific increased reactivity of bronchi in individuals working with pneumotropic polluters and to test a new method determining.
Assuntos
Asma/diagnóstico , Asma/fisiopatologia , Brônquios/fisiopatologia , Doenças Profissionais/diagnóstico , Exposição Ocupacional/efeitos adversos , Acetilcolina , Adulto , Amônia/efeitos adversos , Broncospirometria/métodos , Feminino , Humanos , Masculino , Curvas de Fluxo-Volume Expiratório Máximo , Pessoa de Meia-Idade , Dióxido de Silício/efeitos adversosRESUMO
The ratio of expiratory time at tidal peak flow to total expiratory time (t(ptef)/t(e)) correlates with conventional measures of airway obstruction. It is usually assessed using a facemask and pneumotachograph system which may be poorly tolerated in young children and hence limits the usefulness of this technique. We therefore determined in young asthmatic children the accuracy of t(ptef)/t(e), using an uncalibrated respiratory inductance plethysmograph (RIP), and compared the results with those from a facemask-pneumotachograph system. We also assessed whether age influenced the agreement between measurements using the two devices. Forty-seven children aged between 1 month and 12 years were recruited: 39 were inpatients recovering from an acute wheezy episode, and 8 were recruited from the asthma clinic. All were receiving bronchodilators. Tidal breathing parameters t(ptef)/t(e), the duty cycle (t(i)/t(tot)), and respiratory rate were initially measured using the Respitrace alone and then simultaneously with both the Respitrace and the facemask-pneumotachograph system. Eight children did not tolerate the facemask, and in two others it was impossible to analyze the Respitrace trace due to artefacts. In the remaining 37 children, the reliability coefficients and coefficients of variation of the two techniques were similar. Similar values of t(i)/t(tot) and respiratory rate were obtained using the two devices. The mean t(ptef)/t(e) obtained using the Respitrace was lower than with the facemask-pneumotachograph system (P < 0.01), although this was age group-dependent (P < 0.05), as the difference was less apparent in the 1 to 2-year-old children than in other age groups. Application of the facemask-pneumotachograph system did not significantly influence the results obtained using the Respitrace. We conclude that uncalibrated respiratory inductance plethysmography can measure tidal breathing parameters as reliably as a facemask-pneumotachograph system in young asthmatic children, and is better tolerated than the pneumotachograph system. The results obtained using the two devices are not interchangeable.
Assuntos
Asma/diagnóstico , Broncospirometria/métodos , Máscaras , Pletismografia/métodos , Volume de Ventilação Pulmonar/fisiologia , Fatores Etários , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Mecânica Respiratória , Sensibilidade e EspecificidadeRESUMO
Bronchodilator therapy on inspiratory indices has not been documented so far. Reduction in inspiratory airflow resistance following inhalation of bronchodilator giving the most consistent and significant changes in emphysematous patients has been demonstrated in the present study.
Assuntos
Albuterol/uso terapêutico , Broncospirometria/métodos , Enfisema Pulmonar/tratamento farmacológico , Administração por Inalação , Resistência das Vias Respiratórias , Albuterol/administração & dosagem , Humanos , Capacidade Inspiratória , Enfisema Pulmonar/fisiopatologia , Ventilação PulmonarRESUMO
This report describes the development of a portable spirometer capable of collecting primarily alveolar breath into 1.8-L canisters for subsequent gas chromatographic/mass spectrometric (GC/MS) analysis. Based on CO2 measurements, greater than 97% of the breath collected is alveolar in origin. Sample collection takes place in approximately two minutes. Clean air for inhalation is provided by two organic vapor respirator cartridges. Studies of the breakthrough volume of test compounds at both the 5- and 50-micrograms/m3 levels indicate that each cartridge filter can be used to sample over 300 L of air and that this volume is not altered by intermittent use and storage of the filter for up to five days. In experiments designed to mimic human breathing, recoveries of test compounds through the device at the 5-mu/m3 level ranged from 87 to 112%. Essentially no volatile organic compound (VOC) memory (i.e., adsorption carryover by the device) was measured at the 50-micrograms/m3 level. The data suggest that the device can be used successfully for organic compounds with volatilities greater than that of p-dichlorobenzene.
Assuntos
Testes Respiratórios/instrumentação , Broncospirometria/instrumentação , Hidrocarbonetos/análise , Alvéolos Pulmonares/química , Poluentes Atmosféricos/análise , Testes Respiratórios/métodos , Broncospirometria/métodos , Dióxido de Carbono/análise , Carvão Vegetal , Filtração/instrumentação , Humanos , Hidrocarbonetos Clorados/análise , VolatilizaçãoAssuntos
Broncospirometria/métodos , Adulto , Fluxo Expiratório Forçado , Humanos , Masculino , Fatores de TempoAssuntos
Asma/fisiopatologia , Respiração , Adulto , Broncospirometria/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Several reports have shown that a prior deep inspiration exerts a blunting effect on pharmacologically induced bronchoconstriction. Inspiration to total lung capacity is a mandatory requirement for valid determination of the FEV1, and thus, the FEV1 may underestimate the magnitude of induced airway obstruction. The present study was designed to assess the effect that the performance and separate analysis of 2 consecutive FEV1 maneuvers (FEV(1)1, FEV(1)2), obtained at different levels of histamine-induced bronchoconstriction, may have on the final interpretation of a histamine challenge. Eight asymptomatic nonsmoking asthmatics (mean age, 24 yr; range, 19 to 27 yr) underwent a total of 16 histamine challenges. Paired FEV1 measurements (FEV(1)1, FEV(1)2) were obtained after inhalation of buffer solution (control) and 3 min after inhalation of aerosolized, serially diluted, histamine diphosphate solutions. A significant airways response (FEV1 decreasing by 20% or more from the control value) was observed in all subjects after inhalation of 5 mg/ml of histamine or less, indicating histamine airway hypersensitivity. At lower doses of histamine the mean values for FEV(1)1 and FEV(1)2 were similar to the control value. At higher histamine doses FEV(1)2 was consistently higher than FEV(1)1 (p = 0.007) and exceeded FEV1 1 by a mean of 9% after inhalation of the provocational histamine concentration; delta FEV1(FEV(1)2-FEV(1)1) was correlated with the log10 of cumulative inhaled histamine dose units (p = 0.040). Assuming that the difference between corresponding FEV1 determinations at a given level of induced bronchoconstriction is a direct consequence of changes in lung mechanics induced by deep inspiration, we are led to conclude that during histamine inhalation challenges, only 1 spirogram should be performed at each level of induced bronchoconstriction.