UMLS:C0034067 - FACTA Search

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Query: UMLS:C0034067 (emphysema)
11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Single breath nitrogen washout tests were analyzed in dogs (n = 8) with healthy lungs and after development of emphysema. The animals were in the supine position and studied during anaesthesia and mechanical ventilation (FiO2 = 0.4, FiN2 = 0.6). During controlled expiration with constant flow (VE = 0.15 l/s) onset of phase IV of the alveolar plateau was related to airway closure of dependent lung regions (closing volume CV). In the control state, CV accounted for 6.2 +/- 1.5% VC, and closing capacity (CC) was lower than functional residual capacity (FRC). Likewise, gas exchange was normal in all animals (PaO2 = 24.7 +/- 3.32 kPa, PaCO2 = 5.18 +/- 0.53 kPa, PA-aO2 = 2.6 +/- 0.3 kPa). Panlobular emphysema (PLE) was induced by inhalation of papain (100 mg/kg). After three weeks development of PLE was documented by measurements of lung volumes (functional residual capacity (FRC), expired vital capacity (EVC), total lung capacity (TLC), residual volume (RV], pulmonary mechanics (dynamic and static compliance (Cdyn, Cstat), mean airway resistance (Raw], gas exchange (PaO2, PaCO2, PA-aO2), and by radiomorphological analysis. In the PLE-group, FRC and RV (p less than or equal to 0.05), and Cstat (p less than or equal to 0.01) were significantly elevated. CV increased to 16.2 +/- 2.7% VC (p less than or equal to 0.01) and CC exceeded FRC by 80 ml, indicating that tidal volume breathing took place within the range of closing volume. Oxygenation was significantly impaired (PaO2 = 18.6 +/- 3.72 kPa, PA-aO2 = 6.5 +/- 1.1 kPa, p less than or equal to 0.05), but not CO2-elimination. Pathological analysis by radiomorphological means showed dissiminate parenchymal lesions compatible with emphysema of grade II severity located predominantly in subpleural areas. In dogs with papain-induced PLE, premature closure of dependent airways is enhanced, which is due to structural changes and a loss of elastic recoil in the lungs.
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PMID:Single breath N2 washout in papain-induced pulmonary emphysema. 276 46

A total of 179 cases given HOT after introduction of health insurance coverage in 1985 were reported from 12 medical institutes in Okinawa and were compared with 110 cases followed at Okinawa Chubu Hospital during 1976-1985, prior to insurance coverage. The number of patients on HOT have rapidly increased after insurance coverage not only in our institute but also in other institutes in Okinawa and the patients with emphysema formed the largest group. The oxygen enricher is now utilized more than the compressed gas system, accounting for about 70% of all patients compared with the previous figure of 7.3%. Average PaO2 on room air was higher (from 42 Torr to 49 Torr) and the levels of PaO2 maintained by HOT had 2 peaks, one in the 60-65 Torr range and the other in the 75-80 Torr range in patients newly given HOT. The patients with emphysema, who had the worst prognosis in the past, remarkably improved and showed no statistical difference from patients with chronic bronchitis or bronchiectasis in terms of long-term survival. The female patients had better prognosis than males, but the reason is still unclear to us. The absolute volume of FEV1.0 and the presence or absence of cor pulmonale have not affected the long-term survival. A group of the patients with CO2 retention (bronchitic in type) did not benefit from HOT in terms of long-term survival unless their PaO2 levels on room air were below 50 Torr and it was felt that PaO2 levels of 50-59 were too mild in severity for application of HOT.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[New trends in home oxygen therapy (HOT) after the introduction of health insurance coverage in Okinawa and factors contributing to long-term survival]. 279 46

The efficacy of constant-flow ventilation (CFV) was investigated in eight mongrel dogs before (control-phase) and after development of papain-induced panlobular emphysema (PLE-phase). For CFV, heated, humidified and oxygen-enriched air was continuously delivered via two catheters positioned within each mainstem bronchus at flow rates (V) of 0.33, 0.5 and 0.66 l/s. Data obtained during intermittent positive pressure ventilation (IPPV) served as reference. In the control-phase, Pao2 was lower (P less than or equal to 0.05) and alveolo-arterial O2 difference (P(A-a)O2) was higher (P less than or equal to 0.01) during CFV at all flow rates when compared with IPPV. This may be due to inhomogeneities of intrapulmonary gas distribution and increased ventilation-perfusion (VA/Q) mismatching. Paco2 and V showed a hyperbolic relationship; constant normocapnia (5.3 kPa) was achieved at 0.48 +/- 0.21 l/s (V53). Development of PLE resulted in an increase of functional residual capacity (FRC), residual volume (RV) and static compliance (Cstat) (P less than or equal to 0.05). PaO2 had decreased and P(A-a)O2 had increased (P less than or equal to 0.05), indicating moderate pulmonary dysfunction. Oxygenation during CFV was not significantly different in the PLE-phase when compared with the control-phase. Paco2 and V showed a hyperbolic relationship and V5.3 was even lower than in the control-group (0.42 +/- 0.13 l/s). In dogs with emphysematous lungs CFV maintains sufficient gas exchange. This may be due to preferential ventilation of basal lung units, thereby counterbalancing the effects of impaired lung morphometry and increased airtrapping. Conventional mechanical ventilation is more effective in terms of oxygenation and CO2-elimination.
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PMID:Constant-flow ventilation in canine experimental pulmonary emphysema. 280 Sep 79

The deformation of expiratory partial pressure curves of respiratory and inert gases (O2, CO2, He, Ar, SF6), as measured by means of mass spectrometry, was analysed in healthy subjects and in patients with asthma, chronic bronchitis and/or pulmonary emphysema. Patients with emphysema could best be distinguished from the other groups when the comparison was based on the shape of expirogram phase II. Phase II was characterized by the volume V25-50 which was expired between 25% and 50% of the inspiratory/end-tidal partial pressure difference. Comparative measurements of V25-50 of O2, CO2, He and SF6 in 10 healthy subjects (mean age: 30.8 yr) and in 10 patients with advanced emphysema (mean age: 60.8 yr) showed a linear increase of V25-50 with increasing inspired volume (VI) being 3-5 times higher in the patients than in normals. V25-50 increased with the sequence He less than SF6 approximately equal to CO2 less than O2 in both groups. The separation between phase II volumes of He and SF6 was more pronounced in the patients with emphysema than in the healthy subjects. Variations of the breathing pattern in eight healthy subjects revealed a linear increase of V25-50 with increasing VI and, to a lower extent, with increasing respiratory frequency, while a decrease of V25-50 with increasing breath-holding time and only very small changes with variations of inspiratory as well as expiratory duration were observed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cournand lecture. Expiratory partial pressure curves in the diagnosis of emphysema. 301 Nov 56

Exposure of animals to oxidant gases produces a mild emphysema, and O2-derived free radicals are capable of degrading connective tissues in vitro. It is postulated that degradation of connective tissue by O2-derived free radicals leads to emphysema in these models. To determine whether exposure of lung tissue slices to an oxidant gas results in degradation of collagen and to investigate factors mediating this degradation, we exposed lung tissue slices from normal rats to hyperoxia (95% O2, 5% CO2) and measured hydroxyproline release into the medium. After a 4-h exposure, the hydroxyproline released was 5.3 +/- 0.2 micrograms/g lung tissue (n = 10) in normoxia and 8.1 +/- 0.6 micrograms/g tissue (n = 13) in hyperoxia (p less than 0.05), suggesting degradation of collagen. The addition of 0.1% trypsin to the initial incubation medium caused a synergistic increase in hydroxyproline release from O2-exposed slices: normoxia/trypsin, 46.2 +/- 3.6 micrograms/g tissue (n = 10); hyperoxia/trypsin, 61.4 +/- 3.6 micrograms/g tissue (n = 11) (p less than 0.05). The addition of proteinase inhibitors completely suppressed the O2-induced release of hydroxyproline, suggesting that proteolytic enzymes are involved in hyperoxia-mediated degradation of lung collagen.
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PMID:Degradation of collagen in lung tissue slices exposed to hyperoxia. 303 77

Chronic obstructive pulmonary disease (COPD) is equated with chronic bronchitis and emphysema as one disease entity. In COPD airflow limitation is relatively persistent--unlike asthma. Tests for "small-airways disease" form no part of routine practice, for their accuracy in detecting pathological change is debatable. The proteolytic theory of the pathogenesis of emphysema highlights the role of neutrophil elastase, antielastases, oxidants, antioxidants, and thus of potential new treatments. Clinical features of COPD include breathlessness, cough, and sputum, with airflow obstruction and lung hyperinflation. The differential diagnosis includes bronchiectasis, cystic fibrosis, and pulmonary hypertension, but pulmonary fibrosis, etc., is distinguished by radiological infiltrates. Plain chest radiography cannot reliably diagnose emphysema in life, but a new method measuring lung density from the computed tomographic (CT) scan allows location, quantitation, and diagnosis of emphysema (defined by enlargement of distal air spaces) in humans in life. "Pink puffers" with breathlessness, hyperinflation, mild hypoxemia, and a low PCO2 are contrasted with "blue bloaters" with hypoxemia, secondary polycythemia, CO2 retention, and pulmonary hypertension and cor pulmonale. Antismoking measures are a major aim in management. A bronchodilator regimen combining a slow-release oral theophylline with an inhaled beta 2-agonist, ipratropium, and high-dose inhaled steroids is proposed because even modest improvement in obstruction can help these patients. In acute exacerbations with purulent sputum, antimicrobials against Streptococcus pneumoniae and Hemophilus influenzae are used with controlled oxygen therapy aiming to keep the arterial PO2 over 50 mm Hg without the pH falling below 7.25. Influenza prophylaxis is recommended, but pneumococcal vaccination remains debatable. Chronic under-nutrition in "emphysema" implies controlled trials of feeding regimens--but these remain to be assessed. Long-term oxygen therapy is the only treatment known to prolong life in blue bloaters, and oxygen concentrators and transtracheal oxygen delivery are discussed. Pulmonary vasodilators (e.g., beta 2-agonists, hydralazine, nifedipine, angiotensin-converting enzyme [ACE] inhibitors, etc.) have not yet been proved to provide long-term reduction in pulmonary arterial pressure. Blue bloaters have severe nocturnal hypoxemia in rapid eye movement (REM) sleep that is corrected by oxygen or the investigational drug almitrine.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Chronic obstructive pulmonary disease. 304 40

In four normal subjects and 51 patients with chronic bronchitis-emphysema, bronchial asthma and pulmonary fibrosis, the VD/VT ratio was measured by a helium washout technique (wVD/VT) and by the conventional Bohr's method using the arterial CO2 tension (VD/VT). In 16 patients the wVD/VT ratio was compared with that calculated from Bohr's equation with the alveolar CO2 tension measured by the rebreathing technique (AVD/VT). It was found that the values for the VD/VT ratio obtained by the helium washout technique were very close to those obtained by the conventional method using the PaCO2 or PACO2 values.
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PMID:Calculation of the VD/VT ratio by the helium washout technique. 308 19

A knowledge of the relationship between nutrition and the respiratory system applied in chronic airflow obstruction (BCO) enables a better understanding of the increased frequency (30 to 50%) of protein-energy malnutrition (MEP) in this population. The physiology of the wasting in chronic airflow obstruction seems to relate to hypermetabolism (HMB) which is not compensated by an increased alimentary intake. The HMB is linked to a rise in the work of the respiratory muscles whose efficiency is altered by intrathoracic hyperinfiltration and also the consequences of MEP on the mass and function of the respiratory muscles. In the animal MEP induced by alimentary restrictions leads to a model of pulmonary emphysema and to the diminution of the synthesis of surfactant. This emphysema seems to be principally due to an alteration of the process of protein synthesis and to a diminution of lysyl-oxydase activity. The nutrients (utilised notably by the venous route) have their own pharmacological role, and in addition they have an effect on the natural equilibrium of the energy and nitrogen balance. Lipids (rich in polyunsaturated fatty acids) intervene in the synthesis of prostaglandins, and exercise some effects on the inflammatory process and the activity in the bronchial and vascular smooth muscles. Based on this fact they have been used for their anti-inflammatory role at the pulmonary level in the treatment of mucoviscidosis. The administration of amino acids changes ventilation by acting on the central neuro-muscular command mechanism (VT/TI). The perfusion of amino acids enables a restoration of the chemo-sensitivity to oxygen and to CO2 abolished by the prolonged restricted diet. Finally the partial pressure of oxygen ought to be interpreted with respect to meal times because an oral dose of glucose can provoke an increase in the PaO2 of around 10 mmHg for healthy subjects and those with BCO. A preventive and therapeutic attitude vis a vis BCO should take account of the relationship between nutrition and the respiratory system in parallel with a correction of hypoxaemia in order to avoid the development of wasting.
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PMID:[Malnutrition and chronic obstructive bronchopathies]. 314 Mar 15

Thirty subjects with severe chronic obstructive airways disease participated in a study to identify differences in symptoms and life quality between those with high and low emergent use of institutional health care resources. Emergent use was defined as care obtained through unscheduled, nonroutine methods of access to health care providers. There were 15 subjects in each group; the groups had similar sex distribution and were not significantly different for percent predicted forced expiratory volume in 1 second (mean 29.8%), use of home oxygen (15 of 30 subjects), or prevalence of CO2 retention (nine of 30). Symptoms and life quality were measured by using three paper and pencil tests, the Bronchitis-Emphysema Symptom Checklist, the Sickness-Impact Profile, and the Katz Adjustment Scale for relatives. Findings demonstrated consistently more symptoms and impairment of life quality in the "high emergent" group. The differences reached statistical significance for irritability, anxiety, helplessness, nervousness, peripheral sensory complaints, alienation, social interaction, and emotional behavior. Discriminant analysis provided a prediction formula that yielded 80% correct prediction for the two groups.
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PMID:Measures of symptoms and life quality to predict emergent use of institutional health care resources in chronic obstructive airways disease. 319 15

A localized area of hypertransradiance often leads to surgical referral. Among 608 cases, 115 were due to local lesions of airways, blood vessels, or parenchyma. Among the remaining 493 with bullae from diffuse emphysema, 21% underwent surgery. Good restoration of function occurred in patients with rapidly progressive dyspnea who did not have a bronchitic component, recurrent infections, or CO2 retention. Physiologically, preoperative findings suggestive of tension pneumothorax, including severe restriction, marked air trapping, and little ventilation/perfusion mismatch suggested good results. Favorable radiographic findings included well-defined, large air spaces without stigmata of diffuse emphysema, serial films showing rapid enlargement of bullae, and expiration films with good thoracic motion and obscuration of lung around bullae. Compressed but otherwise intact lung was best demonstrated by angiography and CT scans. Palliative bullectomy in severe diffuse emphysema sometimes had gratifying clinical results. Resection of small bullae never caused improvement. Localized giant bullae most often were associated with paraseptal or periacinar emphysema, and the best surgical results were obtained in this group.
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PMID:Patient work-up for bullectomy. 359 38

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