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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↗
PubMed1984

Pulmonary involvement in chronic pancreatitis.

Although the association between acute pancreatitis and pleuropulmonary damage is well documented, so far no information on lung function in patients with chronic pancreatitis is available. In this study functional, radiological, and clinical investigations have been carried out in 42 patients affected by chronic calcific pancreatitis (CCP) and in 50 controls in a case-control study. An impairment of pulmonary diffusing capacity has been detected in CCP patients, while all the parameters of ventilatory function were not different from controls. This finding suggests the presence of early lung parenchymal damage in chronic pancreatitis secondary to either emphysema or pulmonary fibrosis.

Adult↗
PubMed1985

Chronic interstitial pulmonary fibrosis following Mycoplasma pneumoniae pneumonia.

An unusual case of chronic interstitial fibrosis that developed as a sequela of Mycoplasma pneumoniae pneumonia is described. Predominant manifestations included progressive exertional dyspnea, shortness of breath, persisting lung infiltrates, low lung volumes, and low pulmonary diffusing capacity. Open lung biopsy one year after the acute stage of mycoplasma pneumonia revealed focal interstitial fibrosis with early pleural thickening, hypertrophic alveolar lining cells, and peribronchiolar lymphoid cell infiltrates. Improvement in clinical manifestations, radiologic findings, and pulmonary function results occurred with steroid therapy.

Adult↗
PubMed1988

[Pregnancy and the respiratory function].

The respiratory function of pregnant women is changed for more than one reason. There is a mechanical effect due to the increase in the uterine volume and the elevation of the diaphragm. However, there are only modest functional consequences, because the pulmonary volumes are only little changed, with the exception of a reduction in the functional residual capacity. Bronchial permeability is unaltered due to the balancing of constrictors (mechanical, hypocapnia) and dilators (hormonal influences). As regards pulmonary haemodynamics, the hypovolaemia of the pregnant woman has no repercussions on pulmonary vascular pressure. Gas exchange and alveolar-capillary diffusion are normal or even improved as a consequence of chronic hyperventilation. The latter is the most important functional change, sometimes expressed as a sensation of dyspnoea. The origin of this hyperventilation relates to the diminution of the threshold of sensibility in the respiratory centres to CO2 due to the effect of raised progesterone levels.

Female↗
PubMed1978

Progressive interstitial lung disease from prolonged methotrexate therapy.

Progressive interstitial fibrosis with roentgenographic honeycombing developed in the case of a psoriatic patient who had been on a regimen of methotrexate for 18 years. Examination revealed a combined restrictive and obstructive defect in pulmonary mechanics and severe compromise of gas transfer across the pulmonary alveolar-capillary membrane. Improvement in the level of arterial blood gases and pulmonary diffusing capacity occurred after discontinuation of methotrexate therapy. Interstitial fibrosis of the lung is a potential complication of methotrexate therapy for psoriasis.

Aged↗
PubMed1994

Indications of reduced pulmonary function in type 1 (insulin-dependent) diabetes mellitus.

Abnormalities of pulmonary function tests have been described in type 1 (insulin-dependent) diabetes mellitus (IDDM). To better characterise such abnormalities and to verify whether these latter are associated with the presence of diabetic microvascular disease we compared 23 non-smoking patients who had IDDM with 24 non-smoking healthy control subjects strictly matched for sex, age, and body mass index. Compared with controls, diabetic patients had a reduced forced vital capacity (FVC) (87.5 +/- 13.1% vs. 96.4 +/- 13.6% of the predicted; P = 0.03) and forced expiratory volume in 1 s (FEV1) (90.5 +/- 17.7% vs. 101.2 +/- 13.2% of the predicted; P = 0.02). While within the group of patients the presence of retinopathy and autonomic neuropathy were not associated with modifications of pulmonary function tests, those with altered urinary albumin excretion rate (AER > or = 20 micrograms/min; range 21-589) (n = 7) had a significantly lower pulmonary diffusion capacity (DLCO) than the 16 normoalbuminuric subjects (62.6 +/- 7.2% vs. 88.7 +/- 20.1% of the predicted; P = 0.01). Moreover, in the group of patients, DLCO was inversely related with AER (r = -0.43; P = 0.04). In conclusion, IDDM is characterised by reduced FVC and FEV1, while a significant decrease in DLCO may be considered as selectively associated with renal disease.

Adult↗