Panagiota Tzani

Dynamic hyperinflation is associated with a poor cardiovascular response to exercise in COPD patients

BackgroundPulmonary hyperinflation has the potential for significant adverse effects on cardiovascular function in COPD. The aim of this study was to investigate the relationship between dynamic hyperinflation and cardiovascular response to maximal exercise in COPD patients.MethodsWe studied 48 patients (16F; age 68 yrs ± 8; BMI 26 ± 4) with COPD. All patients performed spirometry, plethysmography, lung diffusion capacity for carbon monoxide (TLco) measurement, and symptom-limited cardiopulmonary exercise test (CPET). The end-expiratory lung volume (EELV) was evaluated during the CPET. Cardiovascular response was assessed by change during exercise in oxygen pulse (ΔO2Pulse) and double product, i.e. the product of systolic blood pressure and heart rate (DP reserve), and by the oxygen uptake efficiency slope (OUES), i.e. the relation between oxygen uptake and ventilation.ResultsPatients with a peak exercise EELV (%TLC) ≥ 75% had a significantly lower resting FEV1/VC, FEF50/FIF50 ratio and IC/TLC ratio, when compared to patients with a peak exercise EELV (%TLC) < 75%. Dynamic hyperinflation was strictly associated to a poor cardiovascular response to exercise: EELV (%TLC) showed a negative correlation with ΔO2Pulse (r = - 0.476, p = 0.001), OUES (r = - 0.452, p = 0.001) and DP reserve (r = - 0.425, p = 0.004). Furthermore, according to the ROC curve method, ΔO2Pulse and DP reserve cut-off points which maximized sensitivity and specificity, with respect to a EELV (% TLC) value ≥ 75% as a threshold value, were ≤ 5.5 mL/bpm (0.640 sensitivity and 0.696 specificity) and ≤ 10,000 Hg · bpm (0.720 sensitivity and 0.783 specificity), respectively.ConclusionThe present study shows that COPD patients with dynamic hyperinflation have a poor cardiovascular response to exercise. This finding supports the view that in COPD patients, dynamic hyperinflation may affect exercise performance not only by affecting ventilation, but also cardiac function.

Effects of beclomethasone/formoterol fixed combination on lung hyperinflation and dyspnea in COPD patients

Background Chronic obstructive pulmonary disease (COPD) is a common disease characterized by airflow obstruction and lung hyperinflation leading to dyspnea and exercise capacity limitation. Objectives The present study was designed to evaluate whether an extra-fine combination of beclomethasone and formoterol (BDP/F) was effective in reducing air trapping in COPD patients with hyperinflation. Fluticasone salmeterol (FP/S) combination treatment was the active control. Methods COPD patients with forced expiratory volume in one second <65% and plethysmographic functional residual capacity ≥120% of predicted were randomized to a doubleblind, double-dummy, 12-week, parallel group, treatment with either BDP/F 400/24 μg/day or FP/S 500/100 μg/day. Lung volumes were measured with full body plethysmography, and dyspnea was measured with transition dyspnea index. Results Eighteen patients were evaluable for intention to treat. A significant reduction in air trapping and clinically meaningful improvement in transition dyspnea index total score was detected in the BDP/F group but not in the FP/S group. Functional residual capacity, residual volume (RV) and total lung capacity significantly improved from baseline in the BDP/F group only. With regard to group comparison, a significantly greater reduction in RV was observed with BDP/F versus FP/S. Conclusion BDP/F extra-fine combination is effective in reducing air trapping and dyspnea in COPD patients with lung hyperinflation.

Measurement of Fractional Exhaled Nitric Oxide by a New Portable Device: Comparison with the Standard Technique

Background. Fractional exhaled nitric oxide (FeNO) measurement is a reliable, noninvasive marker of airway inflammation. The use of portable FeNO analyzers may enable the assessment of airway inflammation in primary care. Objective. The authors compared FeNO values obtained by a new portable device (NObreath, Bedfont, UK) to those of the standard stationary analyzer (NIOX, Aerocrine, Sweden) in a large cohort of asthmatic patients. Methods. One hundred and fifty-four (age range: 14–83 years, forced expiratory volume in one second [FEV1] range: 48–134% predicted, asthma control test [ACT] range: 7–25) out of 168 recruited patients completed the study. Each patient performed at least two valid FeNO measurements at a constant flow rate of 50 ml/s on each of the two analyzers. Results. A significant relationship between the FeNO values obtained by the two devices (r = .95, p < .001) was found. Altman-Bland plot confirmed this agreement. Within-patient repeatability was excellent in both devices. Intraclass correlation coefficients for NIOX and NObreath values were .925 and .967, respectively. By means of receiver operating characteristic curve analysis, the FeNO cutoff points that better identified patients with ACT ≥ 20 were 15 ppb (0.84 sensitivity and 0.42 specificity) by NIOX and 25 ppb (0.53 sensitivity and 0.69 specificity) by NObreath. Easiness to use of both devices, assessed by visual analogue scale was not different. Conclusion. FeNO measurements obtained by the new portable FeNO analyzer are reliable because they are directly comparable with those obtained by the stationary standard device. The use of portable instruments may facilitate the FeNO measurement in primary care.

Small airway dysfunction by impulse oscillometry in asthmatic patients with normal forced expiratory volume in the 1st second values.

Small airways are relevant to the pathophysiology of asthma. We investigated whether in asthmatic patients with normal forced expiratory volume in the 1st second (FEV(1)) values, impulse oscillometry system (IOS), as a measure of small airway function, contributed additional information to spirometry either at baseline or after bronchodilator, and whether it was related to the disease control. The fall in resistance from 5 to 20 Hz (R5-R20) and reactance at 5 Hz (X5) by IOS and spirometry measures of small airway function (forced expiratory flow at 25-75% [FEF(25-75)] and forced vital capacity/slow inspiratory vital capacity [FVC/SVC]) at baseline and after 400 micrograms of salbutamol were prospectively measured in 33 asthmatic patients (18 women; age range, 18-66 years). Disease control was assessed by the Asthma Control Test (ACT). R5-R20 but not X5 values were significantly related to FEF(25-75) and FVC/SVC values (p < 0.05 for both correlations). When the bronchodilator response was assessed, no correlation was found among IOS and spirometry changes. ACT scores were related to R5-R20, FEF(25-75), and FVC/SVC values (p < 0.01 for all correlations). In asthmatic patients with normal FEV(1) values, R5-R20 values were related to spirometry measures of small airway function. However, when the bronchodilator response was assessed, IOS and spirometry provided quite different results. Moreover, small airway dysfunction, as assessed by IOS and spirometry, was associated with poor disease control and history of asthma exacerbations. The results of this study confirm the value of IOS, as an investigative tool, and suggest that in asthmatic patients with normal FEV(1) values and poor disease control, small airway function should be investigated.

The Walking Capacity Assessment in the Respiratory Patient

Exercise testing is commonly used in respiratory patients to assess their degree of disability, prognosis for survival, presence of exercise-induced hypoxemia and response to treatment. Recently, simple exercise tests, which are based on walking, have been developed and are increasingly being used both for clinical and research purposes. The 6-min walk test (6-MWT) is the most widely used and simply consists in the measurement of the distance walked in 6 min. The 6-MWT is self-paced and differs from the shuttle walking test, which is externally paced via a recorded metronome and entails incrementally faster speeds. Although the field walking tests do not require complex equipment, they can provide reliable and useful clinical information. This review deals with the validity, reliability and interpretation of these walking tests in the assessment of patients with chronic respiratory disease.

Ventilatory Response to Carbon Dioxide Output in Subjects With Congestive Heart Failure and in Patients with COPD With Comparable Exercise Capacity

BACKGROUND: Patients with congestive heart failure or COPD may share an increased response in minute ventilation (V̇E) to carbon dioxide output (V̇CO2) during exercise. The goal of this study was to ascertain whether the V̇E/V̇CO2 slope and V̇E/V̇CO2 intercept can discriminate between subjects with congestive heart failure and those with COPD at equal peak oxygen uptake (V̇O2). METHODS: We studied 46 subjects with congestive heart failure (mean age 61 ± 9 y) and 46 subjects with COPD (mean age 64 ± 8 y) who performed a cardiopulmonary exercise test. RESULTS: The V̇E/V̇CO2 slope was significantly higher in subjects with congestive heart failure compared with those with COPD (39.5 ± 9.5 vs 31.8 ± 7.4, P < .01) at peak V̇O2 < 16 mL/kg/min, but not ≥ 16 mL/kg/min (28.3 ± 5.3 vs 28.9 ± 6.6). The V̇E/V̇CO2 intercept was significantly higher in both subgroups of subjects with COPD compared with the corresponding values in the subjects with congestive heart failure (3.60 ± 1.7 vs −0.16 ± 1.7 L/min, P < .01; 3.63 ± 2.7 vs 0.87 ± 1.5 L/min, P < .01). According to receiver operating characteristic curve analysis, when all subjects with peak V̇O2 < 16 mL/kg/min were considered, subjects with COPD had a higher likelihood to have the V̇E/V̇CO2 intercept > 2.14 L/min (0.92 sensitivity, 0.96 specificity). Regardless of peak V̇O2, the end-tidal pressure of CO2 (PETCO2) at peak exercise was not different in subjects with congestive heart failure (P = .42) and was significantly higher in subjects with COPD (P < .01) compared with the corresponding unloaded PETCO2. CONCLUSIONS: The ventilatory response to V̇CO2 during exercise was significantly different between subjects with congestive heart failure and those with COPD in terms of the V̇E/V̇CO2 slope with moderate-to-severe reduction in exercise capacity and in terms of the V̇E/V̇CO2 intercept regardless of exercise capacity.

Pulmonary Rehabilitation Improves Cardiovascular Response to Exercise in COPD

Background: Pulmonary rehabilitation (PR) has emerged as a recommended standard of care in symptomatic COPD. Objectives: We now studied whether PR may affect cardiovascular response to exercise in these patients. Methods: Twenty-seven patients (9 females aged 69 ± 8 years) with moderate-to-severe airflow obstruction admitted to a 9-week PR course performed a pre-to-post evaluation of lung function test and symptom-limited cardiopulmonary exercise test (CPET). Oxygen uptake (VO2), tidal volume (VT), dyspnea and leg fatigue scores were measured during CPET. Cardiovas-cular response was assessed by means of oxygen pulse (O2Pulse), the oxygen uptake efficiency slope and heart rate recovery at the 1st min. Results: A significant increase in peak VO2 and in all cardiovascular parameters (p < 0.05) was found following PR when compared to baseline. Leg fatigue (p < 0.05), but not dyspnea, was significantly reduced after PR. When assessed at metabolic and ventilatory iso levels [% VCO2max and % minute ventilation (VEmax)], O2Pulse and VT were significantly higher (p < 0.05) at submaximal exercise (75 and 50% of VCO2max and VEmax) after PR when compared to baseline. VT percent changes at 75% VCO2max and 75% VEmax after PR significantly correlated with corresponding changes in O2Pulse (p < 0.01). Conclusions: In COPD patients, a PR training program improved the cardiovascular response during exercise at submaximal exercise independent of the external workload. This change was associated with an enhanced ventilatory function during exercise.

Cough Efficacy Is Related to the Disability Status in Patients with Multiple Sclerosis

Background: Cough is an important defense mechanism, whose main function is to remove mucus and/or foreign bodies from the airways. In patients with multiple sclerosis (MS), respiratory muscle function may be affected and cough may be impaired. Objectives: Respiratory muscle strength and voluntary cough efficacy were determined in MS patients and controls, and the relationship between cough efficacy and patients’ degree of disability was investigated. Methods: We recruited 27 MS patients (age: 41 ± 11 years; 18 females) with mild-to-moderate disability, Expanded Disability Status Scale (EDSS) score range: 1–7, and 20 healthy controls (age: 37 ± 11 years; 12 females). The maximal inspiratory (PIMAX) and expiratory (PEMAX) pressures, maximal whistle mouth pressures (PMOW), cough peak flows (CPF), cough expiratory volumes (CEV) and cough gastric pressures (PGA) were measured in all subjects. Results: In MS patients, the EDSS score was significantly related to CPF, PEMAX, PMOW, cough PGA, PIMAX and CEV (p < 0.01, each correlation). The receiver-operating characteristic curve showed that an EDSS score ≧5.5 was consistent with impaired cough (CPF ≤5.6 l/s), with a sensitivity of 0.85 and a specificity of 0.95 (area under curve 0.90, p < 0.001). CPF was related to and predicted by PEMAX, PMOW, cough PGA and PIMAX in MS patients (p < 0.01 each correlation), but not in controls. Conclusions: MS can affect voluntary cough efficacy and respiratory muscle strength, which are inversely related to the patients’ degree of disability. In addition, this study shows that CPF is a measure of clinical relevance in MS patients.

Flying with respiratory disease.

Patients with respiratory diseases may be at risk during flight because at cruising altitude an important hypobaric hypoxia may occur. The only absolute contraindications to flying in these patients are pneumothorax, bronchogenic cyst and severe pulmonary hypertension. In order to evaluate the risks related to air travel in patients with respiratory diseases, an evaluation of their fitness to fly, including the hypoxia altitude simulation test, is required. The fitness to fly evaluation can identify patients requiring supplemental oxygen during flight which is provided by most airlines when prescribed by the passenger’s physician. This review deals with the cardiorespiratory effects of flight, the risks associated with respiratory diseases during air travel and the procedures to follow in order to assess fitness to fly in patients with respiratory disorders.

Resting Lung Function in the Assessment of the Exercise Capacity in Patients With Chronic Heart Failure

Background:Despite the lung involvement in patients with chronic heart failure (CHF), the significance of lung function abnormalities to functional status in these patients is still controversial. We postulated that in patients with CHF, resting lung function assessment may provide information of clinical relevance on exercise capacity, expressed as peak oxygen uptake (VO2) and ventilatory response to CO2 production (VE/VCO2) during a maximal exercise. Methods:We studied 49 clinically stable patients with CHF (38 men, age range: 25–78 years) (New York Heart Association class range: I-IV) with left ventricular ejection fraction <40%. Patients with chronic obstructive pulmonary disease were excluded. Patients performed pulmonary function tests and maximal incremental exercise test. Results:Resting spirometry was related to the exercise capacity (P < 0.05), expressed as peak VO2. By means of receiver operating characteristic curve analysis, the forced expiratory volume at first second (FEV1) cutoff point, which better identified patients with a peak VO2 ≤14 mL/kg/min, was <79% of predicted value (0.79 sensitivity and 0.73 specificity). Resting lung diffusion capacity for carbon monoxide and end-tidal pressure of CO2 (PETCO2) were inversely correlated to VE/VCO2 (P < 0.01). The lung diffusion capacity for carbon monoxide and PETCO2 cutoff points, which better identified patients with VE/VCO2 value >34, were <58% of predicted (0.92 sensitivity and 0.42 specificity) and <33 mm Hg (0.67 sensitivity and 0.92 specificity), respectively. Conclusions:In patients with CHF, resting lung function, including spirometry, lung diffusion capacity, and PETCO2, can provide clinically useful information on exercise capacity, by predicting peak VO2 and VE/VCO2 slope. The results of this study highlight the role of resting lung function in the assessment of the functional status of cardiac patients.