Latest data on lung mechanics in patients with chronic obstructive pylmonary diasease

Chronic Obstructive Pulmonary Disease (COPD) is a major cause of chronic morbidity and mortality throughout the world. However, COPD is generally a progressive disease, especially if a patient’s exposure to noxious agents continues. COPD is characterized by chronic airflow limitation and a range of pathological changes in the lung, some significant extra-pulmonary effects, and important comorbidities which may contribute to the severity of the disease in individual patients. Spirometry is essential for the severity and classification of the disease, and particularly the post-bronchodilation FEV1/FVC ratio and FEV1, according to GOLD.Dyspnea is the predominant complaint of patients with COPD and is commonly the reason for seeking medical attention. However, dyspnea and lung function should be regarded as separate factors, because FEV1 and FVC are poor predictors of hyperinflation, which is the major cause of dyspnea. The slope of phase III (single breath nitrogen test), an index of ventilation inhomogeneity, has been used for early detection of COPD. Tidal airway closure (cyclic opening and closure of the peripheral airways during tidal breathing; ACT) and expiratory flow limitation (attainment of maximal expiratory flow during tidal expiration; EFLT) cause small airways disease (SAD). The relationships of these indices with COPD severity may reflect the progress from SAD to overt COPD. In this cross-sectional study we have assessed for the first time the phase III slope, ACT and EFLT in 10 smokers with normal spirometry (group O) and 40 COPD patients with GOLD scores from I to IV. The study was taken place in the Respiratory Function Laboratory of the1st Dept of Respiratory Medicine, University of Athens Medical School, at “Sotiria” Hospital.Η χρόνια αποφρακτική πνευμονοπάθεια (ΧΑΠ) αποτελεί σημαντική αιτία χρόνιας νοσηρότητας και θνησιμότητας παγκοσμίως. Ωστόσο, αποτελεί σταδιακή νόσο, και ειδικότερα όταν οι ασθενείς συνεχίζουν την έκθεση σε επιβλαβείς παράγοντες. Η ΧΑΠ χαρακτηρίζεται από χρόνια στένωση των αεραγωγών και από εύρος παθολογικών μεταβολών στον πνεύμονα, από κάποιες αξιοσημείωτες εξωπνευμονικές επιδράσεις και σημαντικές συνοσηρότητες, οι οποίες μπορεί να συμβάλλουν στη σοβαρότητα της νόσου σε κάποιους ασθενείς. Η διάγνωση και σταδιοποίηση της ΧΑΠ γίνεται με βάση τη σπιρομέτρηση και συγκεκριμένα με τη μέτρηση των FEV1/FVC και FEV1 μετά βρογχοδιαστολή, σύμφωνα με τη GOLD. Ο πιο συχνός λόγος που οι ασθενείς οδηγούνται στην αναζήτηση ιατρικής βοήθειας είναι τα συμπτώματα, και κυρίως η δύσπνοια. Η δύσπνοια μπορεί να αποτελεί ανεξάρτητο παράγοντα από τη σπιρομέτρηση, καθώς οι FEV1 και FVC έχουν πτωχή πρόγνωση της δυναμικής υπερδιάτασης, η οποία αποτελεί τη σημαντικότερη αιτία δύσπνοιας.Η κλίση της φάσης ΙΙΙ (αζωτογράφημα), ως δείκτης ανομοιογένειας αερισμού, έχει χρησιμοποιηθεί για την πρώιμη ανίχνευση της ΧΑΠ. Η σύγκλιση των αεραγωγών κατά την ήρεμη αναπνοή (περιοδική διάνοιξη και σύγκλιση των περιφερικών αεραγωγών στην αναπνοή, tidal airway closure, ACT) και ο περιορισμός της ροής κατά την εκπνοή (επίτευξη της μέγιστης εκπνευστικής ροής κατά την αναπνοή, tidal expiratory flow limitation, EFLT) προκαλούν νόσο μικρών αεραγωγών (small airway disease, SAD). Η σχέση αυτών των δεικτών στη βαρύτητα της ΧΑΠ μπορεί να αντανακλά τη μετάβαση της SAD σε εμφανή ΧΑΠ. Σε αυτήν τη μελέτη εκτιμήσαμε για πρώτη φορά την κλίση της φάσης ΙΙΙ, την ACT και τον EFLT σε 10 καπνιστές με φυσιολογική σπιρομέτρηση και σε 40 ασθενείς με ΧΑΠ σταδίων από Ι έως IV. Η μελέτη διενεργήθηκε στο Εργαστήριο Λειτουργικού Ελέγχου της Αναπνευστικής Λειτουργίας της Α΄ Πανεπιστημιακής Πνευμονολογικής Κλινικης στο Νοσοκομείο «Η Σωτηρία»

Methods for assessing expiratory flow limitation during tidal breathing in COPD patients

Patients with severe COPD often exhale along the same flow-volume curve during quite breathing as during forced expiratory vital capacity manoeuvre, and this has been taken as indicating expiratory flow limitation at rest (EFL(T)). Therefore, EFL(T), namely, attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFL(T) leads to small airway injury and promotes dynamic pulmonary hyperinflation with concurrent dyspnoea and exercise limitation. In fact, EFL(T) occurs commonly in COPD patients (mainly in GOLD III and IV stage) in whom the latter symptoms are common. The existing up-to-date physiological methods for assessing expiratory flow limitation (EFL(T)) are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure (NEP) has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, non invasive, most practical, and accurate new technique

Methods for Assessing Expiratory Flow Limitation during Tidal Breathing in COPD Patients

Patients with severe COPD often exhale along the same flow-volume curve during quite breathing as during forced expiratory vital capacity manoeuvre, and this has been taken as indicating expiratory flow limitation at rest (EFL T ). Therefore, EFL T , namely, attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFL T leads to small airway injury and promotes dynamic pulmonary hyperinflation with concurrent dyspnoea and exercise limitation. In fact, EFL T occurs commonly in COPD patients (mainly in GOLD III and IV stage) in whom the latter symptoms are common. The existing up-to-date physiological methods for assessing expiratory flow limitation (EFL T ) are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure (NEP) has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, non invasive, most practical, and accurate new technique

Acute effects of short term use of e-cigarettes on airways physiology and respiratory symptoms in smokers with and without airways obstructive diseases and in healthy non smokers

Introduction Although the use of e-cigarettes is increasing worldwide, their short and long-term effects remain undefined. We aimed to study the acute effect of short-term use of e-cigarettes containing nicotine on lung function and respiratory symptoms in smokers with airways obstructive disease (COPD, asthma), “healthy” smokers, and healthy never smokers. Methods Respiratory symptoms, vital signs, exhaled NO, airways temperature, and airways resistance (Raw), specific airway conductance (sGaw) and single nitrogen breath test were assessed before and immediately after short term use of an e-cigarette containing 11 mg of nicotine in COPD, asthma, ‘’healthy” smokers, and never-smokers. The effect of nicotine-free e-cigarettes in healthy never smokers was also studied. Results Acute cough was reported by the majority of participants. Short-term use of nicotine e-cigarettes was associated: a) with increased heart rate in all subjects except COPD, b) decreased oxygen saturation in “healthy” and COPD smokers, c) increased Raw in asthmatic, “healthy” smokers, and healthy never smokers, d) decreased sGaw in healthy subjects, and e) changed slope of phase III curve in asthmatic smokers. Short-term use of nicotine-free e-cigarette increased Raw, decreased sGaw and created a pleasant feeling. Conclusions Short term use of e-cigarette has acute effects on airways physiology and respiratory symptoms in COPD smokers, asthmatic smokers, “healthy” smokers and healthy never smokers. E-cigarette use is associated with health effects in healthy never smokers irrespectively of nicotine concentration. More studies are needed to investigate both short and long term effects of e-cig

Acute effects of short term use of ecigarettes on Airways Physiology and Respiratory Symptoms in Smokers with and without Airway Obstructive Diseases and in Healthy non smokers

BACKGROUND Although the use of e-cigarettes is increasing worldwide, their short and long-term effects remain undefined. We aimed to study the acute effect of short-term use of e-cigarettes containing nicotine on lung function and respiratory symptoms in smokers with airways obstructive disease (COPD, asthma), “healthy” smokers, and healthy never smokers. METHODS Respiratory symptoms, vital signs, exhaled NO, airway temperature, airway resistance (Raw), specific airway conductance (sGaw) and single nitrogen breath test were assessed before and immediately after short term use of an e-cigarette containing 11mg of nicotine among adults with COPD, asthma, “healthy” smokers, and never-smokers. The effect of the use of nicotine-free e-cigarettes among “healthy” never smokers was also studied. RESULTS The majority of participants reported acute cough. Short term use of nicotine e-cigarettes was associated: a) with increased heart rate in all subjects except in the COPD group, b) decreased oxygen saturation in “healthy” and COPD smokers, c) increased Raw in asthmatic smokers, “healthy” smokers, and healthy never smokers, d) decreased sGaw in healthy subjects, and e) changed slope of phase III curve in asthmatic smokers. Short-term use of nicotine-free e-cigarettes increased Raw and decreased sGaw among healthy never smokers. CONCLUSIONS Short-term use of an e-cigarette has acute effects on airways physiology and respiratory symptoms in COPD smokers, asthmatic smokers, “healthy” smokers and healthy never smokers. Ercigarette use was associated with effects in “healthy” never smokers irrespectively of nicotine concentration. More studies are needed to investigate both short and long-term effects of e-cigarette us

Dyspnea and respiratory muscle strength in end-stage liver disease

AIM: To investigate the prevalence of chronic dyspnea and its relationship to respiratory muscle function in end-stage liver disease. METHODS: Sixty-eight consecutive, ambulatory, Caucasian patients with end-stage liver disease, candidates for liver transplantation, were referred for preoperative respiratory function assessment. Forty of these (29 men) were included in this preliminary study after applying strict inclusion and exclusion criteria. Seventeen of 40 patients (42%) had ascites, but none of them was cachectic. Fifteen of 40 patients (38%) had a history of hepatic encephalopathy, though none of them was symptomatic at study time. All patients with a known history and/or presence of co-morbidities were excluded. Chronic dyspnea was rated according to the modified medical research council (mMRC) 6-point scale. Liver disease severity was assessed according to the Model for end-stage liver disease (MELD). Routine lung function tests, maximum static expiratory (Pemax) and inspiratory (Pimax) mouth pressures were measured. Respiratory muscle strength (RMS) was calculated from Pimax and Pemax values. In addition, arterial blood gases and pattern of breathing (V(E): minute ventilation; V(T): tidal volume; V(T)/T(I): mean inspiratory flow; T(I): duration of inspiration) were measured. RESULTS: Thirty-five (88%) of 40 patients aged (mean ± SD) 52 ± 10 years reported various degrees of chronic dyspnea (mMRC), ranging from 0 to 4, with a mean value of 2.0 ± 1.2. MELD score was 14 ± 6. Pemax, percent of predicted (%pred) was 105 ± 35, Pimax, %pred was 90 ± 29, and RMS, %pred was 97 ± 30. These pressures were below the normal limits in 12 (30%), 15 (38%), and 14 (35%) patients, respectively. Furthermore, comparing the subgroups of ascites to non-ascites patients, all respiratory muscle indices measured were found significantly decreased in ascites patients. Patients with ascites also had a significantly worse MELD score compared to non-ascites ones (P = 0.006). Significant correlations were found between chronic dyspnea and respiratory muscle function indices in all patients. Specifically, mMRC score was significantly correlated with Pemax, Pimax, and RMS (r = -0.53, P < 0.001; r = -0.42, P < 0.01; r = -0.51, P < 0.001, respectively). These correlations were substantially closer in the non-ascites subgroup (r = -0.82, P < 0.0001; r = -0.61, P < 0.01; r = -0.79, P < 0.0001, respectively) compared to all patients. Similar results were found for the relationship between mMRC vs MELD score, and MELD score vs respiratory muscle strength indices. In all patients the sole predictor of mMRC score was RMS (r = -0.51, P < 0.001). In the subgroup of patients without ascites this relationship becomes closer (r = -0.79, P < 0.001), whilst this relationship breaks down in the subgroup of patients with ascites. The disappearance of such a correlation may be due to the fact that ascites acts as a “confounding” factor. PaCO(2) (4.4 ± 0.5 kPa) was increased, whereas pH (7.49 ± 0.04) was decreased in 26 (65%) and 34 (85%) patients, respectively. PaO(2) (12.3 ± 0.04 kPa) was within normal limits. V(E) (11.5 ± 3.5 L/min), V(T) (0.735 ± 0.287 L), and V(T)/T(I) (0.449±0.129 L/s) were increased signifying hyperventilation in both subgroups of patients. V(T)/T(I) was significantly higher in patients with ascites than without ascites. Significant correlations, albeit weak, were found for PaCO(2) with V(E) and V(T)/T(I) (r = -0.44, P < 0.01; r = -0.41, P < 0.01, respectively). CONCLUSION: The prevalence of chronic dyspnea is 88% in end-stage liver disease. The mMRC score closely correlates with respiratory muscle strength

Impact of Hemodialysis on Dyspnea and Lung Function in End Stage Kidney Disease Patients

Background. Respiratory symptoms are usually underestimated in patients with chronic kidney disease undergoing maintenance hemodialysis. Therefore, we set out to investigate the prevalence of patients chronic dyspnea and the relationship of the symptom to lung function indices. Methods. Twenty-five clinically stable hemodialysis patients were included. The mMRC dyspnea scale was applied before and after hemodialysis. Spirometry, single breath nitrogen test, arterial blood gases, static maximum inspiratory (Pimax⁡) and expiratory (Pemax⁡) muscle pressures, and mouth occlusion pressure (P0.1) were also measured. Results. Despite normal spirometry, all patients (100%) reported mild to moderate degree of chronic dyspnea pre which was reduced after hemodialysis. The sole predictor of (Δ) mMRC was the (Δ) P0.1 (r=0.71,  P<0.001). The Pimax⁡ was reduced before and correlated with the duration of hemodialysis (r=0.614,  P<0.001), whilst after the session it was significantly increased (P<0.001). Finally (Δ) weight was correlated with the (Δ) Pimax⁡  %pred (r=0.533,  P=0,006) and with the (Δ) CV (%pred) (r=0.65,  P<0.001). Conclusion. We conclude that dyspnea is the major symptom among the CKD patients that improves after hemodialysis. The neuromechanical dissociation observed probably is one of the major pathophysiologic mechanisms of dyspnea

Impact of Hemodialysis on Dyspnea and Lung Function in End Stage Kidney Disease Patients

Background. Respiratory symptoms are usually underestimated in patients with chronic kidney disease undergoing maintenance hemodialysis. Therefore, we set out to investigate the prevalence of patients chronic dyspnea and the relationship of the symptom to lung function indices. Methods. Twenty-five clinically stable hemodialysis patients were included. The mMRC dyspnea scale was applied before and after hemodialysis. Spirometry, single breath nitrogen test, arterial blood gases, static maximum inspiratory (P-i max) and expiratory (P-e max) muscle pressures, and mouth occlusion pressure (P-0.1) were also measured. Results. Despite normal spirometry, all patients (100%) reported mild to moderate degree of chronic dyspnea pre which was reduced after hemodialysis. The sole predictor of (Delta) mMRCwas the (Delta) P-0.1 (r = 0.71, P &lt; 0.001). The P-i max was reduced before and correlated with the duration of hemodialysis (r = 0.614, P &lt; 0.001), whilst after the session it was significantly increased (P &lt; 0.001). Finally (Delta) weight was correlated with the (Delta) P-i max % pred (r = 0.533, P = 0, 006) and with the (Delta) CV (% pred) (r = 0.65, P &lt; 0.001). Conclusion. We conclude that dyspnea is the major symptom among the CKD patients that improves after hemodialysis. The neuromechanical dissociation observed probably is one of the major pathophysiologic mechanisms of dyspnea