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1.
Lung ; 198(1): 113-120, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31728632

RESUMO

PURPOSE: Aerosol furosemide may be an option to treat refractory dyspnea, though doses, methods of delivery, and outcomes have been variable. We hypothesized that controlled delivery of high dose aerosol furosemide would reduce variability of dyspnea relief in patients with underlying pulmonary disease. METHODS: Seventeen patients with chronic exertional dyspnea were recruited. Patients rated recently recalled breathing discomfort on a numerical rating scale (NRS) and the multidimensional dyspnea profile (MDP). They then performed graded exercise using an arm-ergometer. The NRS was completed following each exercise grade, and the MDP was repeated after a pre-defined dyspnea threshold was reached. During separate visits, patients received either aerosol saline or 80 mg of aerosol furosemide in a randomized, double-blind, crossover design. After treatment, graded exercise to the pre-treatment level was repeated, followed by completion of the NRS and MDP. Treatment effect was defined as the difference between pre- and post-treatment NRS at end exercise, expressed in absolute terms as % Full Scale. "Responders" were defined as those showing treatment effect ≥ 20% of full scale. RESULTS: Final analysis included 15 patients. Neither treatment produced a statistically significant change in NRS and there was no significant difference between treatments (p = 0.45). There were four "responders" and one patient whose dyspnea worsened with furosemide; two patients were responders with saline, of whom one also responded to furosemide. No adverse events were reported. CONCLUSIONS: High dose controlled delivery aerosol furosemide was not statistically different from saline placebo at reducing exercise-induced dyspnea. However, a clinically meaningful improvement was noted in some patients.


Assuntos
Dispneia/tratamento farmacológico , Furosemida/administração & dosagem , Inibidores de Simportadores de Cloreto de Sódio e Potássio/administração & dosagem , Administração por Inalação , Adulto , Aerossóis , Idoso , Idoso de 80 Anos ou mais , Asma/complicações , Doença Crônica , Estudos Cross-Over , Método Duplo-Cego , Dispneia/etiologia , Teste de Esforço , Feminino , Humanos , Doenças Pulmonares Intersticiais/complicações , Neoplasias Pulmonares/complicações , Masculino , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/complicações , Embolia Pulmonar/complicações , Receptores Pulmonares de Alongamento
2.
Respir Physiol Neurobiol ; 247: 146-155, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29031573

RESUMO

Aerosolized furosemide has been shown to relieve dyspnea; nevertheless, all published studies have shown great variability in response. This dyspnea relief is thought to result from the stimulation of slowly adapting pulmonary stretch receptors simulating larger tidal volume. We hypothesized that better control over aerosol administration would produce more consistent dyspnea relief; we used a clinical ventilator to control inspiratory flow and tidal volume. Twelve healthy volunteers inhaled furosemide (40mg) or placebo in a double blind, randomized, crossover study. Breathing Discomfort was induced by hypercapnia during constrained ventilation before and after treatment. Both treatments reduced breathing discomfort by 20% full scale. Effectiveness of aerosol furosemide treatment was weakly correlated with larger tidal volume. Response to inhaled furosemide was inversely correlated to furosemide blood level, suggesting that variation among subjects in the fate of deposited drug may determine effectiveness. We conclude that control of aerosol delivery conditions does not improve consistency of treatment effect; we cannot, however, rule out placebo effect.


Assuntos
Dispneia/tratamento farmacológico , Furosemida/administração & dosagem , Inibidores de Simportadores de Cloreto de Sódio e Potássio/administração & dosagem , Administração por Inalação , Aerossóis , Estudos Cross-Over , Método Duplo-Cego , Dispneia/fisiopatologia , Feminino , Humanos , Hipercapnia/tratamento farmacológico , Hipercapnia/fisiopatologia , Masculino , Dor/tratamento farmacológico , Dor/fisiopatologia , Medição da Dor , Cuidados Paliativos , Respiração/efeitos dos fármacos , Volume de Ventilação Pulmonar , Resultado do Tratamento
3.
Respir Physiol Neurobiol ; 247: 24-30, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28843675

RESUMO

Published studies have shown great variability in response when aerosolized furosemide has been tested as a palliative treatment for dyspnea. We hypothesized that a higher furosemide dose with controlled aerosol administration would produce consistent dyspnea relief. We optimized deposition by controlling inspiratory flow (300-500mL/s) and tidal volume (15% predicted vital capacity) while delivering 3.4µm aerosol from either saline or 80mg of furosemide. We induced dyspnea in healthy subjects by varying inspired PCO2 while restricting minute ventilation. Subjects rated "Breathing Discomfort" on a Visual Analog Scale (BDVAS, 100% Full Scale≡intolerable). At the PETCO2 producing 60% BDVAS pre-treatment, furosemide produced a clinically meaningful reduction of BDVAS (i.e., >20% FS) in 5/11 subjects; saline reduced dyspnea in 3/11 subjects; neither treatment worsened dyspnea in any subject. Furosemide and saline treatment effects were not statistically different. There were no significant adverse events. Higher furosemide dose and controlled delivery did not improve consistency of treatment effect compared with prior studies.


Assuntos
Dispneia/tratamento farmacológico , Furosemida/administração & dosagem , Inibidores de Simportadores de Cloreto de Sódio e Potássio/administração & dosagem , Administração por Inalação , Adolescente , Adulto , Aerossóis , Albuterol/administração & dosagem , Relação Dose-Resposta a Droga , Dispneia/fisiopatologia , Feminino , Furosemida/efeitos adversos , Humanos , Inalação , Masculino , Modelos Biológicos , Medição da Dor , Cuidados Paliativos , Inibidores de Simportadores de Cloreto de Sódio e Potássio/efeitos adversos , Volume de Ventilação Pulmonar , Resultado do Tratamento , Adulto Jovem
4.
J Appl Physiol (1985) ; 117(9): 1074-9, 2014 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-25213641

RESUMO

Pneumoperitoneum for laparoscopic surgery is known to stiffen the chest wall and respiratory system, but its effects on resting pleural pressure in humans are unknown. We hypothesized that pneumoperitoneum would raise abdominal pressure, push the diaphragm into the thorax, raise pleural pressure, and squeeze the lung, which would become stiffer at low volumes as in severe obesity. Nineteen predominantly obese laparoscopic patients without pulmonary disease were studied supine (level), under neuromuscular blockade, before and after insufflation of CO2 to a gas pressure of 20 cmH2O. Esophageal pressure (Pes) and airway pressure (Pao) were measured to estimate pleural pressure and transpulmonary pressure (Pl = Pao - Pes). Changes in relaxation volume (Vrel, at Pao = 0) were estimated from changes in expiratory reserve volume, the volume extracted between Vrel, and the volume at Pao = -25 cmH2O. Inflation pressure-volume (Pao-Vl) curves from Vrel were assessed for evidence of lung compression due to high Pl. Respiratory mechanics were measured during ventilation with a positive end-expiratory pressure of 0 and 7 cmH2O. Pneumoperitoneum stiffened the chest wall and the respiratory system (increased elastance), but did not stiffen the lung, and positive end-expiratory pressure reduced Ecw during pneumoperitoneum. Contrary to our expectations, pneumoperitoneum at Vrel did not significantly change Pes [8.7 (3.4) to 7.6 (3.2) cmH2O; means (SD)] or expiratory reserve volume [183 (142) to 155 (114) ml]. The inflation Pao-Vl curve above Vrel did not show evidence of increased lung compression with pneumoperitoneum. These results in predominantly obese subjects can be explained by the inspiratory effects of abdominal pressure on the rib cage.


Assuntos
Pulmão/fisiologia , Pneumoperitônio Artificial , Mecânica Respiratória/fisiologia , Adulto , Idoso , Feminino , Humanos , Laparoscopia , Medidas de Volume Pulmonar , Masculino , Pessoa de Meia-Idade , Respiração com Pressão Positiva , Adulto Jovem
5.
Am J Ind Med ; 57(7): 748-56, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24909863

RESUMO

OBJECTIVES: To assess the association between exposure, oxidative stress, symptoms, and cardiorespiratory function in wildland firefighters. METHODS: We studied two Interagency Hotshot Crews with questionnaires, pulse wave analysis for arterial stiffness, spirometry, urinary 8-iso-prostaglandin F2α (8-isoprostane) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), and the smoke exposure marker (urinary levoglucosan). Arterial stiffness was assessed by examining levels of the aortic augmentation index, expressed as a percentage. An oxidative stress score comprising the average of z-scores created for 8-OHdG and 8-isoprostane was calculated. RESULTS: Mean augmentation index % was higher for participants with higher oxidative stress scores after adjusting for smoking status. Specifically for every one unit increase in oxidative stress score the augmentation index % increased 10.5% (95% CI: 2.5, 18.5%). Higher mean lower respiratory symptom score was associated with lower percent predicted forced expiratory volume in one second/forced vital capacity. CONCLUSIONS: Biomarkers of oxidative stress may serve as indicators of arterial stiffness in wildland firefighters.


Assuntos
Poluentes Ocupacionais do Ar/efeitos adversos , Bombeiros , Exposição Ocupacional/efeitos adversos , Estresse Oxidativo , Fumaça/efeitos adversos , Rigidez Vascular , Adulto , Biomarcadores/sangue , Biomarcadores/urina , Estudos Transversais , Inquéritos Epidemiológicos , Humanos , Masculino , Análise Multivariada , Exposição Ocupacional/análise , Exposição Ocupacional/estatística & dados numéricos , Análise de Onda de Pulso , Espirometria , Inquéritos e Questionários
6.
COPD ; 10(5): 604-10, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23837455

RESUMO

Morbid obesity may influence several aspects of airway function. However, the effect of morbid obesity on expiratory tracheal collapse in COPD patients is unknown. We thus prospectively studied 100 COPD patients who underwent full pulmonary function tests (PFTs), 6-minute walk test (6MWT), Saint George's Respiratory Questionnaire (SGRQ), and low-dose CT at total lung capacity and during dynamic exhalation with spirometric monitoring. We examined correlations between percentage dynamic expiratory tracheal collapse and body mass index (BMI). The association between tracheal collapse and BMI was compared to a control group of 53 volunteers without COPD. Patients included 48 women and 52 men with mean age 65 ± 7 years; BMI 30 ± 6; FEV1 64 ± 22% predicted and percentage expiratory collapse 59 ± 19%. Expiratory collapse was significantly associated with BMI (69 ± 12% tracheal collapse among 20 morbidly obese patients with BMI ≥ 35 compared to 57 ± 19% in others, p = 0.002, t-test). In contrast, there was no significant difference in collapse between healthy volunteers with BMI ≥ 35 and < 35. COPD patients with BMI ≥ 35 also demonstrated shorter 6MWT distances (340 ± 139 m vs. 430 ± 139 m, p = 0.003) and higher (worse) total SGRQ scores (48 ± 19 vs. 36 ± 20, p = 0.013) compared to those with BMI < 35. In light of these results, clinicians should consider evaluating for excessive expiratory tracheal collapse when confronted with a morbidly obese COPD patient with greater quality of life impairment and worse exercise performance than expected based on functional measures.


Assuntos
Obesidade Mórbida/fisiopatologia , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Traqueomalácia/fisiopatologia , Idoso , Índice de Massa Corporal , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade Mórbida/complicações , Estudos Prospectivos , Doença Pulmonar Obstrutiva Crônica/complicações , Doença Pulmonar Obstrutiva Crônica/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Traqueia/diagnóstico por imagem , Traqueomalácia/complicações , Traqueomalácia/diagnóstico por imagem
7.
Chest ; 142(1): 168-174, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22194588

RESUMO

BACKGROUND: A recent estimate for the normal range of forced expiratory tracheal collapse differs substantially from that in an earlier study performed with comparable measurement methods. Given differences in subject characteristics between the two samples, we hypothesized that these discrepant findings may reflect a heretofore unrecognized association between forced expiratory tracheal collapse and age or sex. METHODS: We enrolled 40 female and 41 male healthy volunteers between 25 and 75 years of age who were without respiratory symptoms or known risk factors for tracheomalacia. Subjects underwent low-dose CT scanning at total lung capacity (TLC) and during forced exhalation (Expdyn) with spirometric monitoring and coaching. Percentage forced expiratory collapse was regressed on age for the total sample and separately within sex. RESULTS: Mean tracheal cross-sectional area (CSA) was 2.54 cm(2) ± 0.57 cm(2) at TLC and 1.15 cm(2) ± 0.53 cm(2) at Expdyn. Mean percentage forced expiratory collapse (%collapse) was 54% ± 20%. Men aged 24 to 31 years (n = 12) had mean %collapse of 36% ± 19%, comparable to results previously reported for similarly aged men (35% ± 18%). Men, but not women, showed a significant positive correlation (R(2) = 0.40, P < .001) between %collapse and age. Older men had both greater CSA at TLC (P = .02) and smaller CSA at Expdyn (P = .001) than younger men. CONCLUSIONS: Men exhibit positive age dependence of forced expiratory tracheal collapse. The influence of age and sex on forced expiratory tracheal collapse should be considered in the diagnostic evaluation of expiratory dynamic airway collapse and/or tracheomalacia.


Assuntos
Envelhecimento/fisiologia , Volume Expiratório Forçado/fisiologia , Caracteres Sexuais , Traqueomalácia/epidemiologia , Traqueomalácia/fisiopatologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos , Fatores de Risco , Tomografia Computadorizada Espiral , Capacidade Pulmonar Total/fisiologia , Traqueia/diagnóstico por imagem , Traqueomalácia/diagnóstico por imagem
8.
J Thorac Imaging ; 26(4): 278-89, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22009081

RESUMO

Tracheobronchomalacia (TBM) results from weakness of the airway walls and/or supporting cartilage and affects both adult and pediatric populations. Diagnosing TBM is challenging because symptoms are nonspecific and overlap with those of other chronic respiratory disorders. Recent advances in multidetector computed tomography have facilitated the noninvasive diagnosis of TBM, and concurrent advances in management have improved clinical outcomes and created a need for greater awareness of the posttreatment appearance of the airways. This review discusses the physiology, histopathology, epidemiology, and clinical features of TBM; it also describes current methods of diagnosis, available therapies, and postoperative imaging evaluation.


Assuntos
Traqueobroncomalácia , Humanos , Tomografia Computadorizada Multidetectores , Fatores de Risco , Traqueobroncomalácia/diagnóstico , Traqueobroncomalácia/patologia
9.
Radiology ; 257(2): 560-7, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20829540

RESUMO

PURPOSE: To assess forced-expiratory bronchial collapsibility in healthy volunteers by using multidetector computed tomography (CT) and to compare the results with the current diagnostic criterion for bronchomalacia. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant study. Following informed consent, 51 healthy volunteers with normal pulmonary function and no history of smoking were imaged by using a 64-detector row scanner with spirometric monitoring at total lung capacity and during forced exhalation. The total study population (in whom both main bronchi were imaged) included 25 men and 26 women (mean age, 50 years). Each scan was analyzed at a workstation by a fellowship-trained thoracic radiologist. Cross-sectional area measurements were obtained from end-inspiratory and forced-expiratory CT images for the right main bronchus (RMB), left main bronchus, (LMB), and bronchus intermedius (BI), and the mean percentage of expiratory collapse was calculated for each bronchus. The number of participants who exceeded the current diagnostic threshold level (>50% expiratory reduction in cross-sectional area) for bronchomalacia was calculated. Comparisons of airway dimensions and airway collapse according to bronchial segment and sex were made by using repeated-measures analysis of variance. RESULTS: Mean percentage of expiratory collapse was 66.9% ± 19.0 (standard deviation) for the RMB and 61.4% ± 16.7 for the LMB. Thirty-seven (73%) of 51 participants exceeded the diagnostic threshold level for bronchomalacia. Significant differences were observed in mean percentage of expiratory collapse between the RMB (66.9% ± 19.0) and LMB (61.4% ± 16.7) (P = .0005). Among a subgroup of 37 participants in whom the BI was also imaged, the mean percentage of expiratory collapse was 61.8% ± 22.8, and 27 (73%) participants exceeded the diagnostic threshold level for bronchomalacia. CONCLUSION: Healthy volunteers demonstrate a wide range of forced-expiratory bronchial collapse, frequently exceeding the current diagnostic threshold level for bronchomalacia.


Assuntos
Broncomalácia/diagnóstico por imagem , Broncomalácia/fisiopatologia , Tomografia Computadorizada Espiral/métodos , Adulto , Idoso , Análise de Variância , Expiração , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Interpretação de Imagem Radiográfica Assistida por Computador , Espirometria
10.
Chest ; 138(6): 1322-6, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20651025

RESUMO

OBJECTIVE: Tracheobronchomalacia (TBM) is increasingly recognized as a condition associated with significant pulmonary morbidity. However, treatment is invasive and complex, and because there is no appropriate animal model, novel diagnostic and treatment strategies are difficult to evaluate. We endeavored to develop a reliable airway model to simulate hyperdynamic airway collapse in humans. METHODS: Seven 20-kg male sheep were enrolled in this study. Tracheomalacia was created by submucosal resection of > 50% of the circumference of 10 consecutive cervical tracheal cartilage rings through a midline cervical incision. A silicone stent was placed in the trachea to prevent airway collapse during recovery. Tracheal collapsibility was assessed at protocol-specific time points by bronchoscopy and multidetector CT imaging while temporarily removing the stent. Esophageal pressure and flow data were collected to assess flow limitation during spontaneous breathing. RESULTS: All animals tolerated the surgical procedure well and were stented without complications. One sheep died at 2 weeks because of respiratory failure related to stent migration. In all sheep, near-total forced inspiratory airway collapse was observed up to 3 months postprocedure. Esophageal manometry demonstrated flow limitation associated with large negative pleural pressure swings during rapid spontaneous inhalation. CONCLUSIONS: Hyperdynamic airway collapse can reliably be induced with this technique. It may serve as a model for evaluation of novel diagnostic and therapeutic strategies for TBM.


Assuntos
Obstrução das Vias Respiratórias/prevenção & controle , Modelos Animais de Doenças , Atelectasia Pulmonar/prevenção & controle , Stents , Traqueobroncomalácia/cirurgia , Traqueostomia/métodos , Animais , Broncoscopia/métodos , Masculino , Atelectasia Pulmonar/etiologia , Mecânica Respiratória/fisiologia , Ovinos , Tomografia Computadorizada por Raios X , Traqueobroncomalácia/complicações , Traqueobroncomalácia/diagnóstico por imagem , Traqueostomia/instrumentação , Resultado do Tratamento
11.
Radiology ; 252(1): 255-62, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19420322

RESUMO

PURPOSE: To assess forced expiratory tracheal collapsibility in healthy volunteers by using multidetector computed tomography and to compare the results with the current diagnostic criterion for tracheomalacia. MATERIALS AND METHODS: An institutional review board approved this HIPAA-compliant study. After informed consent was obtained, 51 healthy volunteers (age range, 25-75 years) with normal spirometry results and no history of smoking or risk factors for tracheomalacia were prospectively studied. Volunteers were imaged with a 64-detector row scanner, with spirometric monitoring at total lung capacity and during forced exhalation, with 40 mAs, 120 kVp, and 0.625-mm detector collimation. Cross-sectional area and sagittal and coronal diameters of the trachea were measured 1 cm above the aortic arch and 1 cm above the carina. The percentage of expiratory collapse, the reduction in sagittal and coronal diameters, and the number of participants exceeding the current diagnostic criterion (>50% expiratory reduction in cross-sectional area) for tracheomalacia were calculated. RESULTS: The final study population included 25 men and 26 women (mean age, 50 years). The mean percentage of expiratory reduction in tracheal lumen cross-sectional area was 54.34% +/- 18.6 (standard deviation) in the upper trachea and 56.14% +/- 19.3 in the lower trachea. Forty (78%) participants exceeded the current diagnostic criterion for tracheomalacia in the upper and/or lower trachea. Decreases in cross-sectional area of the upper and lower trachea correlated well with decreases in sagittal (r = 0.807 and 0.688, respectively) and coronal (r = 0.779 and 0.751, respectively) diameters (P < .001 for each correlation). CONCLUSION: Healthy volunteers demonstrate a wide range of forced expiratory tracheal collapse, frequently exceeding the current diagnostic criterion for tracheomalacia.


Assuntos
Volume Expiratório Forçado , Tomografia Computadorizada por Raios X/métodos , Traqueomalácia/diagnóstico por imagem , Traqueomalácia/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
12.
Chest ; 132(5): 1434-9, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17925413

RESUMO

BACKGROUND: There are reports of rigors and/or clinical deterioration following recruitment maneuvers (RMs), leading us to question whether the use of sustained high-pressure inflation could lead to release of inflammatory mediators. METHODS: Prospective cohort study of 26 patients with ARDS receiving mechanical ventilation. A single RM was performed during which the mean airway pressure was increased to 40 cm H2O and held constant for a period of 30 s. The concentration of nine cytokines (interleukin [IL]-1, IL-6, IL-8, IL-10, tumor necrosis factor [TNF]-alpha, Fas ligand, vascular endothelial growth factor, TNF receptor 1, TNF receptor 2) was measured longitudinally at three time points: prior to initiation of the RM, 5 min after the RM, and 60 min after the RM. RESULTS: RMs were tolerated well from a hemodynamic perspective. Oxygenation improved as reflected by an increased Pao2/fraction of inspired oxygen (Fio2) ratio from 140+/-49 at baseline to 190+/-78 (mean+/-SD) at 5 min after the RM (p=0.01). At 60 min, the increase in Pao2/Fio2 ratio, to 172+/-76, was no longer significant (p=0.1). There were no important changes in the levels of any of the measured cytokines at 5 min or 60 min following RM as compared with the baseline levels. CONCLUSIONS: The results of our study demonstrate that recruitment maneuvers are well tolerated in patients with ARDS. Our data suggest no major hemodynamic or immunologic evidence of deterioration within the first hour of RM. In particular, cytokines, previously related to worsening lung injury and distal organ failure in patients with ARDS, are not elevated by use of an RM. Registered at: www.clinicaltrials.gov as NCT00127491.


Assuntos
Citocinas/sangue , Respiração Artificial/métodos , Síndrome do Desconforto Respiratório/metabolismo , Síndrome do Desconforto Respiratório/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Síndrome do Desconforto Respiratório/fisiopatologia , Mecânica Respiratória , Volume de Ventilação Pulmonar/fisiologia
13.
Chest ; 131(4): 1118-24, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17426218

RESUMO

BACKGROUND: Acquired tracheobronchomalacia (TBM) can cause central airway collapse in patients with COPD and may worsen airflow obstruction and symptoms. It is usually not known whether central airway malacia contributes to airflow obstruction. This study was undertaken to quantify central airway collapsibility and relate it to expiratory flow limitation in patients with TBM. METHODS: Eighty patients evaluated for acquired TBM and 4 healthy control subjects were studied with measurements of central airway narrowing derived from bronchoscopic videotapes and simultaneous pressure measurements in the trachea and esophagus. Tracheal narrowing was assessed by a shape index and plotted against the transtracheal pressure to measure collapsibility. Subsequently, airflow and transpulmonary pressure (PL) were measured to identify expiratory flow limitation during quiet breathing and to determine the critical PL required for maximum expiratory flow. RESULTS: Tracheal collapsibility varied widely among patients. Some had profound tracheal narrowing during quiet breathing, and others showed substantial collapse only during forced exhalation. Of the patients, 15% were not flow limited during quiet breathing, 53% were flow limited throughout exhalation, and 30% were flow limited only during the latter part of the exhalation. Patients with flow limitation at rest showed greater tracheal narrowing than those without (p = 0.009), but the severity of expiratory flow limitation was not closely related to tracheal collapsibility. Twenty-three patients were flow limited during quiet exhalation at PLs that did not cause central airway collapse. CONCLUSIONS: In TBM, central airway collapse is not closely related to airflow obstruction, and expiratory flow limitation at rest often occurs in peripheral airways without central airway collapse.


Assuntos
Broncopatias/fisiopatologia , Doenças das Cartilagens/fisiopatologia , Mecânica Respiratória/fisiologia , Doenças da Traqueia/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Obstrução das Vias Respiratórias/etiologia , Obstrução das Vias Respiratórias/fisiopatologia , Broncopatias/complicações , Broncopatias/patologia , Broncoscopia , Doenças das Cartilagens/complicações , Doenças das Cartilagens/patologia , Feminino , Seguimentos , Fluxo Expiratório Forçado/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Índice de Gravidade de Doença , Doenças da Traqueia/complicações , Doenças da Traqueia/patologia , Gravação em Vídeo
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