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PubMed2000

The alveolar-capillary membrane diffusing capacity and the pulmonary capillary blood volume in heart transplant candidates.

OBJECTIVES: To determine the mechanism of impairment of pulmonary transfer factor for carbon monoxide (TL(CO)) in heart transplant candidates, as this is the most common lung function abnormality. SETTING: Regional cardiopulmonary transplant centre. METHODS: TL(CO) and its components (the diffusing capacity of the alveolar-capillary membrane (D(M)) and the pulmonary capillary blood volume (V(C))) were measured using the Roughton and Forster method and the single breath technique in 38 patients with severe chronic heart failure awaiting heart transplantation (mean age 51 years, range 19 to 61; mean left ventricular ejection fraction 12.8%). Results were compared with data from 26 normal subjects (mean age 47 years, range 27 to 62). RESULTS: Mean per cent predicted TL(CO), D(M), and V(C) were significantly reduced in patients (69.9%, 81.4%, and 80.2% of predicted, respectively) compared with controls (97.7%, 100.1%, and 102.3% of predicted, respectively, p < 0.001). The relative contribution of the two components of TL(CO) in patients was similar to that of normal subjects, with each component accounting for approximately 50% of the total resistance to diffusion (1/TL(CO)). CONCLUSIONS: TL(CO) impairment in patients with severe chronic heart failure awaiting heart transplantation results from a proportionate reduction in both D(M) and V(C), suggesting a significant disturbance of the pulmonary vascular bed.

Adult↗
PubMed1999

Understanding the limitation of O2 supply through comparative physiology.

Comparative physiology and morphometry are used to explore the role of the lung in the limitation of oxygen supply to working muscle as it is experienced at aerobic capacity and in hypoxia such as at high altitude or in subterraneous burrows. In the human lung, as in that of most mammals, the pulmonary diffusing capacity is about 1.5 times larger than what is needed at aerobic capacity. In athletic species (horse, dog) there is no such excess diffusing capacity. As an exception the pronghorn antelope from the Rocky Mountains is a high performance athletic mammal whose lung shows an excess diffusing capacity. This is interpreted as a means to develop hypoxia tolerance as this animal performs its vigorous runs at high altitude. Information on the fossorial mole rat demonstrates that the lung's diffusing capacity is important in developing hypoxia tolerance. It is concluded that the lung is designed in relation to both internal and external constraints.

Aerobiosis↗
PubMed1991

Is HLA B27 antigen a predictor of cardiac or pulmonary disease in patients with rheumatoid arthritis?

Pericarditis was a frequent echocardiographic finding in 20 HLA B27 positive patients with erosive, seropositive rheumatoid arthritis (RA) and in 20 B27 negative RA controls (35% and 30% respectively). There was no significant difference in echocardiographic 2-D or M-mode measurements between the groups. A 48 hour continuous electrocardiographic monitoring, showed that ventricular extrasystoles were more frequent (p less than 0.01) in the B27 negative patients. Pulmonary diffusion capacity was reduced in 25% of the patients in both groups. There were no association between clinical or laboratory data and the cardiac or pulmonary findings except for the finding of a higher frequency of treatment with corticosteroids in patients with pericarditis.

Arthritis, Rheumatoid↗
PubMed1995

Discrete lung involvement in systemic lupus erythematosus: CT assessment.

PURPOSE: To study the computed tomographic (CT) appearance of early lung involvement in systemic lupus erythematosus (SLE). MATERIALS AND METHODS: In a prospective study, 48 patients with serologically confirmed SLE but no prior clinical evidence of lung involvement underwent chest radiography, CT, and lung function tests. Radiographs and CT scans were compared, and CT scans were evaluated for signs suggestive of parenchymal and pleural disease. Extent and distribution of disease were determined. CT findings were correlated with clinical and functional data. RESULTS: Of 45 patients with normal chest radiographs, 17 (38%) had abnormal CT findings. Extent of disease was statistically significantly correlated with duration of clinical history (r = .93) and decreased single-breath diffusing capacity for carbon monoxide (r = .8) and ratio of forced expiratory volume in 1 second to forced vital capacity (r = .77). CONCLUSION: CT is superior to chest radiography for detection of functionally relevant pulmonary disease and is an important adjunct in early assessment of SLE.

Adult↗
PubMed1992

Novel tumor necrosis factor toxic effects. Pulmonary hemorrhage and severe hepatic dysfunction.

Recombinant human tumor necrosis factor is an investigational antitumor agent currently undergoing clinical trials. Previous reports of pulmonary and hepatic toxicities include mild reversible decline in pulmonary diffusing capacity and mild elevation of bilirubin and transaminases. This report describes two novel toxicities in patients receiving their first intravenous dose of tumor necrosis factor: pulmonary hemorrhage and severe hepatic dysfunction. These patients received no other antitumor therapy for at least 4 weeks before tumor necrosis factor treatment and no additional antitumor therapy concomitant with tumor necrosis factor. An analysis of the possible pathogenesis is presented.

Adult↗
PubMedDate not supplied

Follow-up of pulmonary function after "shock lung".

Long-term follow-up of pulmonary function has been performed in four patients having recovered from "shock lung". In three patients there is a progressive normalization of lung volumes and lung compliance, whereas the pulmonary diffusing capacity improves but without attaining predicted levels. In the fourth patient, a delayed reduction of total lung capacity, lung compliance and diffusion capacity occurred. During the follow-up period (from one month to four years) there was no complaint and physical examination, electrocardiogram, chest roentgenogram, conventional pulmonary perfusion scintigraphy and arterial blood gases at rest were quite normal. These results are compatible with the persistence of some degree of interstitial lung disease after recovery from "shock lung".

Adult↗
PubMed2002

Nocturnal periodic breathing in primary pulmonary hypertension.

Cheyne-Stokes respiration is frequently observed in congestive heart failure. Among other factors, prolongation of circulation time, hypocapnia and hypoxia are thought to underlie this sleep-related breathing disorder. Primary pulmonary hypertension (PPH) is also characterized by reduced cardiac output and blood gas alterations. Therefore, the aim of the present study was to determine whether a nocturnal periodic breathing (PB) occurs in PPH. A total of 20 consecutive patients with PPH who had been admitted for pharmacological investigation of pulmonary vasoreactivity were investigated by lung function testing, right heart catheterization and full-night attended polysomnography. PB was detected in six patients (30%) (mean +/- SEM: apnoea/hypopnoea index 37 +/- 5 h(-1); arterial oxygen saturation was <90% during 56 +/- 6.5% of total sleep time). The patients with PB had more severe haemodynamic impairment than those without. They also had a more marked reduction in the pulmonary diffusion capacity and greater arterial hypoxia. PB was markedly improved or even eradicated by nasal oxygen during the night. Periodic breathing occurs in patients with advanced primary pulmonary hypertension and can be reversed by nocturnal nasal oxygen. The clinical and prognostic significance of periodic breathing in primary pulmonary hypertension needs to be determined by further studies.

Cardiac Catheterization↗
PubMed1997

Working underground: respiratory adaptations in the blind mole rat.

Mole rats (Spalax ehrenbergi superspecies) perform the heavy work of digging their subterranean burrows in Israel under highly hypoxic/hypercapnic conditions. Unlike most other mammals, they can achieve high levels of metabolic rate under these conditions, while their metabolic rate at low work rates is depressed. We explored, by comparing mole rats with white rats, whether and how this is related to adaptations in the design of the respiratory system, which determines the transfer of O2 from the lung to muscle mitochondria. At the same body mass, mole rats were found to have a significantly smaller total skeletal muscle mass than ordinary white rats (-22%). In contrast, the fractional volume of muscle mitochondria was larger by 46%. As a consequence, both species had the same total amount of mitochondria and achieved, under normoxia, the same V(O2max). Whereas the O2 transport capacity of the blood was not different, we found a larger capillary density (+31%) in the mole rat muscle, resulting in a reduced diffusion distance to mitochondria. The structural pulmonary diffusing capacity for O2 was greater in the mole rat (+44%), thus facilitating O2 uptake in hypoxia. We conclude that structural adaptations in lung and muscle tissue improve O2 diffusion conditions and serve to maintain high metabolic rates in hypoxia but have no consequences for achieving V(O2max) under normoxic conditions.

Adaptation, Physiological↗
PubMed1994

The effect of exogenous surfactant therapy on lung function following cardiopulmonary bypass.

OBJECTIVE: Pilot study to investigate the effect of exogenous surfactant therapy on lung function following cardiopulmonary bypass (CPB). DESIGN: Prospective randomized controlled study. SETTING: Adult intensive care unit of a postgraduate cardiothoracic hospital. PATIENTS: Sixteen adult patients undergoing elective coronary artery revascularization surgery without a history of preoperative respiratory disease. INTERVENTIONS: Artificial lung-expanding compound (ALEC, Britannia Pharmaceuticals, Crawley, UK) 3.2 g, was given via a bronchoscope 60 min after bypass in eight patients. Eight control subjects received air. MAIN OUTCOME MEASUREMENTS: Lung function tests during IPPV (arterial blood gas tensions, Crs, FRC, TLco, KCO) were measured prior to CPB, before therapy, and at regular intervals up to 180 min afterwards. RESULTS: The CPB caused a significant impairment of lung function in both groups with an increase in A-a gradient (+47 +/- 11 mm Hg in the ALEC group and +44 +/- 17 mm Hg in controls) and reductions in FRC (-290 +/- 121 ml in the ALEC group and -470 +/- 132 ml in controls), TLco (-1.6 +/- 0.3 ml/min/mm Hg in the ALEC group and -2.2 +/- 0.3 ml/min/mm Hg in controls), and Crs (-10 +/- 1 ml/cm H2O in the ALEC group and -21 +/- 4 ml/cm H2O in controls). The ALEC therapy did not affect A-a gradient, FRC, and Crs compared with controls. However, TLco was significantly lower in the ALEC group following therapy (120 min after treatment -0.1 +/- 0.3 ml/min/mm Hg in ALEC group and +1.0 +/- 0.3 ml/min/mm Hg in controls). CONCLUSIONS: A single 3.2-g dose of ALEC administered as a bolus bronchoscopically does not improve lung function following CPB and may impair gas transfer.

Adult↗
PubMedDate not supplied

[External respiration and gas exchange in space flights].

This is an overview of investigations performed in actual and simulated flights to study the effects of microgravity and acceleration, space cabin and space suit artificial atmosphere on the respiratory function. The conceptual prediction of the effects that the space environment produces on the respiratory system suggests the following changes in respiration, gas exchange, and acid-base equilibrium: respiration biomechanics; gas diffusion and ventilation-perfusion ratios in the lungs; regulation of respiration and function of respiratory muscles; lung hydration and blood filling; respiratory changes in acid-base equilibrium and blood gases. Besides, the combined effect of microgravity, acceleration, low barometric pressure and modified gas composition may cause lung atelectases and concomitant disorders in pulmonary ventilation and gas exchange. These changes may have an adverse effect on the health condition and physical work capacity.

Acceleration↗
PubMed2001

N-acetylcysteine attenuates oxidative burst by neutrophils in response to ergometer rowing with no effect on pulmonary gas exchange.

This study evaluated whether the reduction of the neutrophil oxidative burst by N-acetylcysteine improves pulmonary gas exchange during a six minute maximal ergometer row. Healthy trained oarsmen were double-blinded randomized to either N-acetylcysteine (6 g daily for three days) or placebo groups. As determined by the relative changes of the zymosan-stimulated luminol-enhanced chemiluminescence response, N-acetylcysteine suppressed the exercise-induced enhanced neutrophil oxidative burst response to rowing (-7 +/- 6% vs. 17 +/- 8%; P < 0.05). This was the case although the concentration of neutrophils remained similarly elevated above the pre-exercise level in both trials (to 5.4+/-0.5 vs. 5.9+/-0.6 x 10(9) cells x l(-1), respectively, P>0.05). In the placebo and N-acetylcysteine groups, pulmonary ventilation increased and the arterial CO2 partial pressure decreased to the same extent during exercise. Also, at the end of exercise the arterial O2 partial pressure (77 1 vs. 78+/-1 mmHg), haemoglobin O2 saturation (92 +/- 1% vs. 93 +/- 1%) and O2 uptake (5.0 +/- 0.2 vs. 4.9 +/- 0.21 x min(-1)) were not significantly affected by N-acetylcysteine. Equally, two hours after exercise, the pulmonary diffusion capacity was reduced by 7 +/- 2% below the pre-exercise with no significant influence of N-acetylcysteine. We conclude that the neutrophil oxidative burst to exercise does not influence pulmonary gas exchange during and after maximal rowing.

Acetylcysteine↗
PubMed1984

Reduced lung function in leukaemia patients undergoing bone marrow transplantation.

20 patients with leukaemia in remission or early relapse received an allogeneic bone marrow graft. Patients were conditioned according to Seattle protocol with high dose cyclophosphamide and total body irradiation to a total dose of 8 Gray to the lungs delivered by a 6 MV linear accelerator at a dose rate of approximately 0.06 Gray/min. As prophylaxis against the graft versus host reaction, methotrexate and/or cyclosporin A were given. Lung function was studied prior to treatment and every 3 months thereafter. Before treatment a marked decrease was seen in the CO diffusion capacity when compared to the predicted value, while the flow volume relationships were within normal limits. The cause of this is unknown, but may be due to previous infections and the cytostatic treatment given. After bone marrow transplantation, a further irreversible decrease was seen in the CO diffusion capacity and vital capacity indicating an additive effect of the lung irradiation.

Adolescent↗
PubMed1990

Evaluation of elastase and antielastase balance in patients with chronic bronchitis and pulmonary emphysema.

On the basis of the "protease-antiprotease imbalance" theory for the pathogenesis of pulmonary emphysema, we hypothesized that measurement of elastase burden and antielastase capacity in the alveolar space might correlate with emphysema. To evaluate this, the severity of emphysema, the elastase burden, and the elastase inhibitory capacity were estimated in 28 patients with chronic bronchitis and variable degrees of emphysema, none of whom had congenital deficiency of alpha-1-protease inhibitor, and all of whom underwent bronchoalveolar lavage. Emphysema was assessed by both computed tomography and diffusing capacity. To examine "elastase burden," elastase:alpha-1-protease inhibitor complex and free elastase activity in alveolar lavage fluids were measured. To evaluate "antielastase" capacity, elastase inhibiting capacity in alveolar lavage fluid was measured. Elastase burden correlated directly and antielastase capacity correlated inversely with emphysema. These data provide direct support for the "protease-antiprotease imbalance" theory of emphysema in a group of smokers without congenital deficiency of alpha-1-protease inhibitor.

Adult↗
PubMed1986

The effect of transfusion on lung capacity, diffusing capacity, and arterial oxygen saturation in patients with thalassemia major.

Our previous cross-sectional study of patients with thalassemia major suggested progressive lung changes characterized by low total lung capacity, hypoxemia, and elevated transfer factor for carbon monoxide. We reevaluated nine of the patients for three reasons: to determine the relationship of the previous findings to the immediate effects of blood transfusion; to assess the longitudinal progression of the lung changes; and to evaluate the effect of splenectomy on lung volume changes in these patients, all of whom underwent splenectomy in the interval between the two studies. We found that during the 5- to 6-yr period between studies total lung capacity had decreased significantly (p less than 0.05) from a mean 86% predicted to a mean 79% predicted. However, vital capacity increased significantly (p less than 0.05) from a mean 81% predicted to 88% with no significant change in functional residual capacity. There was no significant immediate effect of transfusion on total lung capacity, vital capacity, or functional residual capacity. However, the diffusion constant for carbon monoxide increased significantly (p less than 0.005) immediately following transfusion and there was a positive correlation between the increase and the amount of blood transfused (r = 0.74, p less than 0.05). Arterial oxygen saturation was below 95% in five of eight patients and increased significantly with transfusion (p less than 0.05). We conclude: 1) thalassemia major and/or its treatment is associated with hypoxemia and a progressive reduction in total lung capacity. 2) Despite the progressive reduction in total lung capacity, splenectomy in patients with thalassemia major increases expiratory reserve volume and thereby increases vital capacity.

Adolescent↗
PubMed1995

Persistent reduction in lung function after Pneumocystis carinii pneumonia in AIDS patients.

By means of serial lung function tests we examined the changes in lung function and possible pulmonary long-term sequelae in AIDS patients with a primary episode of Pneumocystis carinii pneumonia (PCP). A total of 19 patients had lung function tests performed prospectively from the time of PCP diagnosis, at 7 days, 14 days, 1, 2, 3, 4.5, 6 and 9 months after PCP. Forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were both reduced to a median of 61% of predicted at PCP diagnosis, and were normalized within 1 month and 1 week respectively. The median pulmonary diffusing capacity for carbon monoxide (DLCO) was severely reduced to 43% of predicted during the acute infection. Although DLCO improved significantly during the first 2 months, it remained reduced at a median DLCO of 64% of predicted 9 months after PCP. We conclude that despite a general improvement in lung function during the first 2 months following the PCP diagnosis, ther was a persistent reduction in DLCO up to 9 months following PCP. The pathological mechanisms causing this reduction remain to be established.

AIDS-Related Opportunistic Infections↗