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Gerard J Criner

Publications and source records attributed to Gerard J Criner.

At least 19 recordsLinked to original sources
PubMed2023

A blood and bronchoalveolar lavage protein signature of rapid FEV1 decline in smoking-associated COPD.

Accelerated progression of chronic obstructive pulmonary disease (COPD) is associated with increased risks of hospitalization and death. Prognostic insights into mechanisms and markers of progression could facilitate development of disease-modifying therapies. Although individual biomarkers exhibit some predictive value, performance is modest and their univariate nature limits network-level insights. To overcome these limitations and gain insights into early pathways associated with rapid progression, we measured 1305 peripheral blood and 48 bronchoalveolar lavage proteins in individuals with COPD [n = 45, mean initial forced expiratory volume in one second (FEV1) 75.6 ± 17.4% predicted]. We applied a data-driven analysis pipeline, which enabled identification of protein signatures that predicted individuals at-risk for accelerated lung function decline (FEV1 decline ≥ 70 mL/year) ~ 6 years later, with high accuracy. Progression signatures suggested that early dysregulation in elements of the complement cascade is associated with accelerated decline. Our results propose potential biomarkers and early aberrant signaling mechanisms driving rapid progression in COPD.

Humans↗
PubMed2006

Cardiac safety of formoterol 12 microg twice daily in patients with chronic obstructive pulmonary disease.

BACKGROUND: Some evidence suggests an increased risk of myocardial infarction and dysrhythmia events associated with beta(2)-agonist use in patients with chronic obstructive pulmonary disease (COPD). This prospective, multicenter, randomized, double-blind, placebo-controlled study compared the cardiac safety of formoterol and placebo in patients with COPD. METHODS: After a 3-14-day run-in, 204 patients were randomized to receive formoterol 12 microg dry powder inhalation or matching placebo twice daily for 8 weeks. Twenty four-hour continuous electrocardiography (Holter monitoring) was performed at screening and after 2 and 8 weeks of treatment. RESULTS: Only a small number of patients met the predefined criteria for a proarrhythmic event (4 formoterol and 2 placebo patients). No patients had sustained postbaseline ventricular tachycardia events, postbaseline run of ventricular ectopic beats associated with relevant symptoms (e.g. hypotension, syncope), or an episode of ventricular flutter or fibrillation. Holter monitoring data were variable but showed no clinically meaningful differences between the formoterol and placebo groups, respectively, for variables such as (mean+/-SD at end of treatment): heart rate (80+/-8.6 vs. 80+/-10.6 bpm), number and rate of ventricular premature beats (total 732+/-2685.4 vs. 650+/-2090.6; rate 35+/-131.0 vs. 30+/-101.3 per h), ventricular tachycardia events (total 0.4+/-1.70 vs. 1.0+/-9.23; rate 0.02+/-0.082 vs. 0.05+/-0.479 per h), and supraventricular premature beats (total 504+/-1844.1 vs. 823+/-2961.8; rate 22+/-80.6 vs. 37+/-129.6 per h). Vital signs and electrocardiogram data, including corrected QT intervals (Bazett and Fridericia), were similar across treatment groups. The overall adverse event experience was similar in the formoterol (n=26 [27%]) and placebo (n=33 [31%]) groups. The most common adverse events, infections and respiratory events, were expected for this patient population. The incidence of cardiac adverse events was low (1 formoterol and 4 placebo patients). CONCLUSIONS: The results of this study confirm the good cardiovascular safety profile of formoterol in patients with COPD.

Administration, Inhalation↗
PubMed2006

Long-term follow-up of patients receiving lung-volume-reduction surgery versus medical therapy for severe emphysema by the National Emphysema Treatment Trial Research Group.

BACKGROUND: The National Emphysema Treatment Trial defined subgroups of patients with severe emphysema in whom lung-volume-reduction surgery (LVRS) improved survival and function at 2 years. Two additional years of follow-up provide valuable information regarding durability. METHODS: A total of 1218 patients with severe emphysema were randomized to receive LVRS or medical treatment. We present updated analyses (4.3 versus 2.4 years median follow-up), including 40% more patients with functional measures 2 years after randomization. RESULTS: The intention-to-treat analysis of 1218 randomized patients demonstrates an overall survival advantage for LVRS, with a 5-year risk ratio (RR) for death of 0.86 (p = 0.02). Improvement was more likely in the LVRS than in the medical group for maximal exercise through 3 years and for health-related quality of life (St. George's Respiratory Questionnaire [SGRQ]) through 4 years. Updated comparisons of survival and functional improvement were consistent with initial results for four clinical subgroups of non-high-risk patients defined by upper-lobe predominance and exercise capacity. After LVRS, the upper-lobe patients with low exercise capacity demonstrated improved survival (5-year RR, 0.67; p = 0.003), exercise throughout 3 years (p < 0.001), and symptoms (SGRQ) through 5 years (p < 0.001 years 1 to 3, p = 0.01 year 5). Upper-lobe-predominant and high-exercise-capacity LVRS patients obtained no survival advantage but were likely to improve exercise capacity (p < 0.01 years 1 to 3) and SGRQ (p < 0.01 years 1 to 4). CONCLUSIONS: Effects of LVRS are durable, and it can be recommended for upper-lobe-predominant emphysema patients with low exercise capacity and should be considered for palliation in patients with upper-lobe emphysema and high exercise capacity.

Aged↗
PubMed2006

Advanced emphysema in African-American and white patients: do differences exist?

BACKGROUND: Emphysema is the only smoking-related disease in which white patients have higher prevalence and higher attributable mortality rates than African-American patients. Epidemiologic studies have not addressed, nor explained, the observed racial differences in emphysema. STUDY OBJECTIVES: To determine whether white and African-American patients differ with respect to the magnitude, anatomic distribution, and physiologic impairments of emphysema. PATIENTS: Characteristics of patients with severe and very severe emphysema enrolled in the National Emphysema Treatment Trial were examined and compared. Patient demographics, cardiopulmonary function, quality of life, and severity/distribution of the emphysema by quantitative CT were analyzed. RESULTS: Of the 1,218 patients enrolled in the trial, 42 were African American (3.4%) and 1,156 were white (95%). African Americans were younger (mean age +/- SD, 63 +/- 7 years vs 67 +/- 6 years) and smoked less (26 +/- 14 cigarettes per day vs 32 +/- 14 cigarettes per day) than white patients (p = 0.01). There was no difference between the two racial groups in pulmonary function (FEV1, 27 +/- 6% predicted vs 27 +/- 7% predicted), gas exchange (Pa(O2), 66 +/- 11 mm Hg vs 65 +/- 10 mm Hg), and exercise (33 +/- 14 W vs 36 +/- 21 W), respectively. Quality of life measures were similar between the groups, but African Americans had a lower socioeconomic status, lower education level, and fewer were married. Radiographic analysis of the extent of emphysema in African Americans, who were matched with selected white patients, revealed significantly less emphysema in the former group and different distribution of severe emphysema. CONCLUSIONS: African Americans with emphysema were younger and had a similar degree of lung impairment as the white study population despite smoking less. In a subgroup of matched patients, the severity and distribution of emphysema by quantitative radiographic analysis were different.

Black or African American↗
PubMed2006

Conversion to bosentan from prostacyclin infusion therapy in pulmonary arterial hypertension: a pilot study.

STUDY OBJECTIVES: We assessed the efficacy of bosentan in transitioning from prostacyclin infusions in patients with pulmonary arterial hypertension (PAH). METHODS: Twenty-two PAH patients were recruited from five PAH centers if they had been clinically stable while receiving therapy with IV epoprostenol or subcutaneous treprostinil for at least 3 months. Patients were observed in an open-label prospective trial while bosentan was added to therapy, and then epoprostenol or treprostinil were tapered after 2 months. RESULTS: Ten of the 22 patients were transitioned off prostacyclin infusion therapy after a mean (+/- SEM) duration of 6.1 +/- 1.2 months. Of those patients, seven patients have continued not receiving prostacyclin infusion therapy for a mean duration of 17.7 +/- 5.3 months, with no significant changes in pulmonary artery (PA) pressure estimated by echocardiography, World Health Organization (WHO)/New York Heart Association (NYHA) functional class, 6-min walk distance (6MWD), or Borg dyspnea score. The conditions of three patients deteriorated, necessitating the resumption of prostacyclin therapy, and two patients subsequently died. Twelve patients failed to transition or even lower the prostacylin infusion rate and had worsening of their WHO/NYHA functional class and estimated systolic PA pressures, and had a trend toward deterioration in their mean 6MWD (294 +/- 41 to 198 +/- 34 m, respectively; p = 0.2). Of these, two patients subsequently died. The baseline characteristics of those who transitioned successfully vs those who transitioned unsuccessfully were a lower prostacyclin infusion rate, and less severe elevations in the mean and estimated systolic PA pressures. CONCLUSION: Transitioning from therapy with prostacyclin to bosentan is possible in some PAH patients, mainly in those receiving lower prostacyclin doses and having less pulmonary hypertension at baseline. Careful patient selection and close interim monitoring is needed because the conditions of patients can deteriorate, and they may not respond to the resumption of therapy with prostacyclin.

Administration, Oral↗
PubMed2005

Predictors of operative mortality and cardiopulmonary morbidity in the National Emphysema Treatment Trial.

OBJECTIVE: We sought to identify predictors of operative mortality, pulmonary morbidity, and cardiovascular morbidity after lung volume reduction surgery. METHODS: Univariate and multivariate logistic regression analyses were performed. Candidate predictors included demographic characteristics, physical condition characteristics, pulmonary function measures, measures of the distribution of emphysema as determined by radiologists and by means of computerized analysis of chest computed tomographic scans, and measures of exercise capacity, dyspnea, and quality of life. End points analyzed were operative mortality (death within 90 days of the operation), major pulmonary morbidities (tracheostomy, failure to wean, reintubation, pneumonia, and ventilator for > or =3 days), and cardiovascular morbidities (infarction, pulmonary embolus, or arrhythmia requiring treatment). RESULTS: Five hundred eleven patients in the non-high-risk group of the National Emphysema Treatment Trial underwent lung volume reduction. The incidence of operative mortality was 5.5%, major pulmonary morbidity occurred in 29.8% of patients, and cardiovascular morbidity occurred in 20.0% of patients. Predictors for these end points are as follows: [table: see text]. CONCLUSIONS: Although lung volume reduction can be performed in selected patients with acceptable mortality, the incidence of major cardiopulmonary morbidity remains high. The lone predictor for operative mortality of lung volume reduction was the presence of non-upper-lobe-predominant emphysema, as assessed by the radiologist. Pulmonary morbidity can be expected in elderly patients who have a low diffusing capacity for carbon monoxide and forced expiratory volume in 1 second. When assessing morbidity, the computer-assisted chest computed tomographic analysis proved useful only in predicting cardiovascular complications.

Aged↗
PubMed2005

Treatment of Guillain-Barré syndrome induced by cyclosporine in a lung transplant patient.

We report the case of a 58-year-old man with severe chronic obstructive pulmonary disease who developed acute quadriparesis during the post-operative period following bilateral lung transplantation after receiving cyclosporine for immunosuppression. Electromyography with nerve conduction study and cerebrospinal fluid analysis supported a diagnosis of Guillain-Barré Syndrome, which improved upon the discontinuation of cyclosporine, replacement with tacrolimus, and initiation of plasmapheresis. We propose the discontinuation of cyclosporine and initiation of plasmapheresis as a treatment for cyclosporine-associated Guillain-Barré syndrome.

Cyclosporine↗
PubMed2005

Impact of whole-body rehabilitation in patients receiving chronic mechanical ventilation.

OBJECTIVE: To evaluate the prevalence and magnitude of weakness in patients receiving chronic mechanical ventilation and the impact of providing aggressive whole-body rehabilitation on conventional weaning variables, muscle strength, and overall functional status. DESIGN: Retrospective analysis of 49 consecutive patients. SETTING: Multidisciplinary ventilatory rehabilitation unit in an academic medical center. PATIENTS: Forty-nine consecutive chronic ventilator-dependent patients referred to a tertiary care hospital ventilator rehabilitation unit. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Patients were 58 +/- 7 yrs old with multiple etiologies for respiratory failure. On admission, all patients were bedridden and had severe weakness of upper and lower extremities measured by a 5-point muscle strength score and a 7-point Functional Independence Measurement. Postrehabilitation, patients had increases in upper and lower extremity strength (p < .05) and were able to stand and ambulate. All weaned from mechanical ventilation, but three required subsequent intermittent support. Six patients died before hospital discharge. Upper extremity strength on admission inversely correlated with time to wean from mechanical ventilation (R = .72, p < .001). CONCLUSIONS: : Patients receiving chronic ventilation are weak and deconditioned but respond to aggressive whole-body and respiratory muscle training with an improvement in strength, weaning outcome, and functional status. Whole-body rehabilitation should be considered a significant component of their therapy.

Adult↗
PubMed2005

Effects of lung volume reduction surgery on sleep quality and nocturnal gas exchange in patients with severe emphysema.

STUDY OBJECTIVES: We hypothesized that associated with improvements in respiratory mechanics, lung volume reduction surgery (LVRS) would result in an improvement in both sleep quality and nocturnal oxygenation in patients with severe emphysema. DESIGN: Prospective randomized controlled trial. SETTING: University hospital. PATIENTS: Sixteen patients (10 men, 63 +/- 6 years [+/- SD]) with severe airflow limitation (FEV(1), 28 +/- 10% predicted) and hyperinflation (total lung capacity, 123 +/- 14% predicted) who were part of the National Emphysema Treatment Trial. INTERVENTIONS AND MEASUREMENTS: Patients completed 6 to 10 weeks of outpatient pulmonary rehabilitation. Spirometry, measurement of lung volumes, arterial blood gas analysis, and polysomnography were performed prior to randomization and again 6 months after therapy. Ten patients underwent LVRS and optimal medical therapy, while 6 patients received optimal medical therapy only. RESULTS: Total sleep time and sleep efficiency improved following LVRS (from 184 +/- 111 to 272 +/- 126 min [p = 0.007], and from 45 +/- 26 to 61 +/- 26% [p = 0.01], respectively), while there was no change with medical therapy alone (236 +/- 75 to 211 +/- 125 min [p = 0.8], and from 60 +/- 18 to 52 +/- 17% [p = 0.5], respectively). The mean and lowest oxygen saturation during the night improved with LVRS (from 90 +/- 7 to 93 +/- 4% [p = 0.05], and from 83 +/- 10 to 86 +/- 10% [p = 0.03], respectively), while no change was noted in the medical therapy group (from 91 +/- 5 to 91 +/- 5 [p = 1.0], and from 84 +/- 5 to 82 +/- 6% [p = 0.3], respectively). There was a correlation between the change in FEV(1) and change in the lowest oxygen saturation during the night (r = 0.6, p = 0.02). In addition, there was an inverse correlation between the change in the lowest oxygen saturation during the night and the change in residual volume (- r = 0.5, p = 0.04) and functional residual capacity (- r = 0.6, p = 0.03). CONCLUSION: In patients with severe emphysema, LVRS, but not continued optimal medical therapy, results in improved sleep quality and nocturnal oxygenation. Improvements in nocturnal oxygenation correlate with improved airflow and a decrease in hyperinflation and air trapping.

Female↗
PubMed2005

Effect of bilateral lung volume reduction surgery on FEV1 decline in severe emphysema.

STUDY OBJECTIVE: To examine whether lung volume reduction surgery (LVRS) alters the anticipated natural rates of decline in FEV1. DESIGN: Retrospective analysis of spirometry results (188 studies) in patients before and after bilateral LVRS. Setting. Large, urban, academic medical center. PATIENTS: 25 patients with severe emphysema (mean (SD) age 60+/-8 yrs; FEV1 0.74+/-0.29 L, 29% predicted). INTERVENTIONS: Bilateral LVRS performed via median sternotomy, with areas targeted for resection based on preoperative evaluation using high-resolution computed tomography, quantitative perfusion scans, and intraoperative inspection of the lungs. Linear regression analysis was performed on each patient using all serial postbronchodilator FEV1 values from before and after LVRS. RESULTS: Lung function data were available between 2-1001 days prior to LVRS and 71-1169 days after LVRS. Comparison of single pre- and post-LVRS FEV1 results confirmed a significant post-operative (3 month) improvement in lung function. The calculated rate of decline in FEV1 prior to LVRS was 202+/-205 mL/yr. Following LVRS, the rate of decline in FEV1 was unchanged at 178+/-150 mL/yr (p = 0.64). CONCLUSIONS: In patients with severe emphysema, bilateral LVRS does not appear to significantly alter the rate of FEV1 decline.

Aged↗
PubMed2004

Small airway morphometry and improvement in pulmonary function after lung volume reduction surgery.

We examined small airway morphometry from resected lung specimens in 25 patients with severe emphysema undergoing lung volume reduction surgery (LVRS) and correlated their pathologic findings to changes in FEV(1) 6 months after LVRS. Patients were classified into two groups: responders had a more than 12% and a more than 200-ml change in FEV(1) at 6 months, and nonresponders had 12% or less and/or 200 ml or less change in FEV(1). Epithelial height (EH) and perimeters and areas of peribronchial smooth muscle, epithelium, and subepithelial space were measured quantitatively. The degrees of interstitial fibrosis, vascular sclerosis, goblet cell hyperplasia, squamous metaplasia, chronic inflammation, peribronchial fibrosis, and bullous disease were assessed semiquantitatively. Despite similar baseline characteristics, nonresponders had a greater EH (0.045 vs. 0.035 mm, p = 0.025), greater EH adjusted for basement membrane perimeter (0.040 vs. 0.011, p = 0.016), greater epithelial area adjusted for basement membrane area (0.561 vs. 0.499, p = 0.040), and less bullous disease (1.7 vs. 2.6, p = 0.011) compared with responders. We found a linear relationship between percentage change in FEV(1) and bullous disease and inverse relationships between percentage change in FEV(1) and interstitial fibrosis, goblet cell hyperplasia, peribronchial fibrosis, and vascular sclerosis. We conclude that small airway morphometry and lung histopathology in patients with severe emphysema have an important influence on changes in FEV(1) 6 months after LVRS.

Basement Membrane↗
PubMed2004

Low-dose inhaled nitric oxide in patients with acute lung injury: a randomized controlled trial.

CONTEXT: Inhaled nitric oxide has been shown to improve oxygenation in acute lung injury. OBJECTIVE: To evaluate the clinical efficacy of low-dose (5-ppm) inhaled nitric oxide in patients with acute lung injury. DESIGN AND SETTING: Multicenter, randomized, placebo-controlled study, with blinding of patients, caregivers, data collectors, assessors of outcomes, and data analysts (triple blind), conducted in the intensive care units of 46 hospitals in the United States. Patients were enrolled between March 1996 and September 1999. PATIENTS: Patients (n = 385) with moderately severe acute lung injury, a modification of the American-European Consensus Conference definition of acute respiratory distress syndrome (ARDS) using a ratio of PaO2 to FiO2 of < or =250, were enrolled if the onset was within 72 hours of randomization, sepsis was not the cause of the lung injury, and the patient had no significant nonpulmonary organ system dysfunction at randomization. INTERVENTIONS: Patients were randomly assigned to placebo (nitrogen gas) or inhaled nitric oxide at 5 ppm until 28 days, discontinuation of assisted breathing, or death. MAIN OUTCOME MEASURES: The primary end point was days alive and off assisted breathing. Secondary outcomes included mortality, days alive and meeting oxygenation criteria for extubation, and days patients were alive following a successful unassisted ventilation test. RESULTS: An intent-to-treat analysis revealed that inhaled nitric oxide at 5 ppm did not increase the number of days patients were alive and off assisted breathing (mean [SD], 10.6 [9.8] days in the placebo group and 10.7 [9.7] days in the inhaled nitric oxide group; P =.97; difference, -0.1 day [95% confidence interval, -2.0 to 1.9 days]). This lack of effect on clinical outcomes was seen despite a statistically significant increase in PaO2 that resolved by 48 hours. Mortality was similar between groups (20% placebo vs 23% nitric oxide; P =.54). Days patients were alive following a successful 2-hour unassisted ventilation trial were a mean (SD) of 11.9 (9.9) for placebo and 11.4 (9.8) for nitric oxide patients (P =.54). Days alive and meeting criteria for extubation were also similar: 17.0 placebo vs 16.7 nitric oxide (P =.89). CONCLUSION: Inhaled nitric oxide at a dose of 5 ppm in patients with acute lung injury not due to sepsis and without evidence of nonpulmonary organ system dysfunction results in short-term oxygenation improvements but has no substantial impact on the duration of ventilatory support or mortality.

Administration, Inhalation↗
PubMed2004

Characterization of functional, radiologic and lung function recovery post-treatment of hot tub lung. A case report and review of the literature.

Hot tub lung is described as an acute pulmonary illness that is characterized by fever, dyspnea and interstitial nodular infiltrates. Although not entirely clear, the etiology may be a hypersensitivity pneumonitis, an infection secondary to Mycobacterium avium intracellulare (MAC), or possibly both. Herein we describe the most well-characterized physiologic, radiographic, and functional recovery from hot tub lung reported in the literature to date. Pulmonary function testing and CT scans of the chest were obtained after each therapeutic intervention, and the patient had the most dramatic improvement with simply avoiding the hot tub. Prednisone therapy offered minimal further improvement while anti-MAC therapy provided no further improvement. These results are suggestive of a hypersensitivity pneumonitis rather than an infectious etiology.

Alveolitis, Extrinsic Allergic↗
PubMed2004

Smoking patterns in African Americans and whites with advanced COPD.

BACKGROUND: The prevalence and mortality associated with COPD increases with age, with higher rates observed in whites than African Americans. Causes and explanations for smoking-related racial differences on the respiratory system have not been determined. OBJECTIVE: To investigate racial differences in smoking patterns and lung function in patients with advanced COPD. DESIGN: Retrospective record review of patients with advanced COPD. SETTING: Outpatient pulmonary clinic in a tertiary-care urban hospital. PATIENTS: One hundred sixty patients with advanced COPD (80 African Americans and 80 whites) referred for either lung volume reduction surgery or transplantation evaluation. DATA COLLECTION: Demographics, smoking profile, pulmonary function testing, arterial blood gases, and exercise stress tests were compared between African-American and white patients. RESULTS: Despite comparable pulmonary function, African Americans were younger at presentation and had lower overall pack-years of smoking than whites (58 +/- 10 years vs 62 +/- 8 years, and 44 +/- 23 pack-years vs 66 +/- 31 pack-years, respectively; p < 0.05 [mean +/- SD]). Additionally, African Americans started smoking later in life than whites (18 +/- 5 years vs 16 +/- 4 years). Similarly, women presented at a younger age and smoked less compared to men (58 +/- 9 years vs 62 +/- 9 years, and 49 +/- 28 pack-years vs 61 +/- 29 pack-years, respectively; p < 0.05), without showing any difference in lung function or exercise performance. CONCLUSION: Among susceptible patients with advanced COPD, African Americans and women seem more prone to the effects of tobacco smoke than their counterparts.

Black or African American↗
PubMed2004

The effects of high-flow vs low-flow oxygen on exercise in advanced obstructive airways disease.

STUDY OBJECTIVES: Current options to enhance exercise performance in patients with COPD are limited. This study compared the effects of high flows of humidified oxygen to conventional low-flow oxygen (LFO) delivery at rest and during exercise in patients with COPD. DESIGN: Prospective, nonrandomized, nonblinded study. SETTING: Outpatient exercise laboratory. PATIENTS: Ten patients with COPD, stable with no exacerbation, and advanced airflow obstruction (age, 54 +/- 6 years; FEV(1), 23 +/- 6% predicted [mean +/- SD]). INTERVENTIONS: After a period of rest and baseline recordings, patients were asked to exercise on a cycle ergometer for up to 12 min. Exercising was started on LFO first; after another period of rest, the patients repeated exercising using the high-flow oxygen (HFO) system, set at 20 L/min and matched to deliver the same fraction of inspired oxygen (Fio(2)) as that of LFO delivery. MEASUREMENTS AND RESULTS: Work of breathing and ventilatory parameters (tidal volume, respiratory rate, inspiratory time fraction, rapid shallow breathing index, pressure-time product) were measured and obtained from a pulmonary mechanics monitor. Borg dyspnea scores, pulse oximetry, blood gases, vital signs were also recorded and compared between the two delivery modes. Patients were able to exercise longer on high flows (10.0 +/- 2.4 min vs 8.2 +/- 4.3 min) with less dyspnea, better breathing pattern, and lower arterial pressure compared to LFO delivery. In addition, oxygenation was higher while receiving HFO at rest and exercise despite the matching of Fio(2). CONCLUSION: High flows of humidified oxygen improved exercise performance in patients with COPD and severe oxygen dependency, in part by enhancing oxygenation.

Exercise Test↗
PubMed2003

Six-minute walk distance in chronic obstructive pulmonary disease: reproducibility and effect of walking course layout and length.

The 6-minute walk test is used in clinical practice and clinical trials of lung diseases; however, it is not clear whether replicate tests need to be performed to assess performance. Furthermore, little is known about the impact of walking course layout on test performance. We conducted 6-minute walks on 761 patients with severe emphysema (mean +/- SD FEV1% predicted = 26.3 +/- 7.2) who were participants in the National Emphysema Treatment Trial. Four hundred seventy participants had repeated walks on a separate day. The second test was improved by an average of 7.0 +/- 15.2% (66.1 +/- 146 feet, p < 0.0001, by paired t test), with an intraclass correlation coefficient of 0.88 between days. The course layout had an effect on the distance walked. Participants tested on continuous (circular or oval) courses had a 92.2-foot longer walking distance than those tested on straight (out and back) courses. Course length had no significant effect on walking distance. The training effect found in these patients with severe emphysema is less than in previous reports of patients with chronic obstructive pulmonary disease. Furthermore, the layout of the track may influence the 6-minute walk performance.

Aged↗
PubMed2003

Cor pulmonale and sleep-disordered breathing in patients with restrictive lung disease and neuromuscular disorders.

Cor pulmonale frequently develops in patients with restrictive lung disease and neuromuscular disorders. Sleep disordered breathing, including nocturnal hypoventilation and obstructive apnea, has been associated with the development of cor pulmonale and may affect morbidity. The mechanisms responsible for sleep disordered breathing include defects in the control of breathing, respiratory muscle dysfunction, and abnormalities in chest wall and lung compliance. Symptoms of disturbed sleep may allow patients with sleep disordered breathing to be appropriately diagnosed and treated, often with nocturnal ventilation, before the development of right-sided heart failure.

Journal Article↗