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PubMed1991

[Hemodynamics and gas exchange in pulmonary embolism: physiopathology and treatment].

Pulmonary emboli can cause severe hemodynamic and respiratory disorders whose physiopathologic mechanisms need to be well understood to ensure appropriate treatment. In previously healthy subjects only massive obstructions (greater than 50%) have dangerous effects due to the very large functional reserve of the pulmonary vascular bed. The same is not always true where there are previous anomalies of pulmonary circulation. In man, vascular obstruction appears to be primarily mechanical, although the presence of emboli may also trigger the release of vasoconstrictor mediators. In the animal it is accepted that these mediators may play an important role, in particular by increasing the critical closing pressure in pulmonary microcirculation. Apart from resistance to continuous bloodflow, the vascular obstruction may accentuate a number of dynamic phenomena specifically obstructing the passage of a pulsatile flow. The aggregate obstacles to right ventricular ejection are known by the term pulmonary artery impedance. Gas exchanges can be disturbed by a wide variety of mechanisms. Arterial hypoxemia chiefly results from maldistribution of the ventilation/perfusion ratio and, in severe forms associated with a fall in cardiac output, from diminution of the partial oxygen pressure of mixed venous blood. The right auricular pressure increase may sometimes contribute to hypoxemia by causing reopening of a permeable ductus Botalli with onset of right-left shunt. This possibility should be considered if oxygen administration does not correct hypoxemia. The dead space effect is not always in relation to the size of the vascular obstruction due to hypocapnic bronchoconstriction in the hypoperfused areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Output↗
PubMed1990

[Hypoxic pulmonary vasoconstriction following lung damage by xanthine oxidase--studies in rats].

The main reason for an insufficient oxygenation of the arterial blood during acute lung injury should be an increased shunt fraction. The aim of this study was to check if in this connection the magnitude of hypoxic pulmonary vasoconstriction is reduced--a fact, which could be causal involved in the arising of increased shunt fraction. 21 male rats were anaesthetized (pentobarbitone) and ventilated artificially (F1O2 = 0.6). In 10-minute-intervals hypoxia (F1O2 = 0.06) was applied. After the first hypoxic exposure the animals were divided into 4 groups according to the application of 3 U xanthine oxidase (XO) or 0.5 ml physiological saline (NaCl) intratracheally (i.t.) or intravascularly (i.v.)--group A: XO i.t.; group B: XO i.v.; group C.: NaCl i.t.; group D: NaCl i.v. At the end of each hypoxic or hyperoxic period (steady state) mean blood pressure in the right ventricle (Prv) and in the A. carotis communis (Psa) were measured. Then blood samples (100 microliters each) were drawn from the artery and the right ventricle and pH, PO2, PCO2, SO2 and hemoglobin concentration were determined. During hyperoxic conditions from the latter values we calculated the shunt fraction. Additional the lung-thorax compliance before and after the application was measured body plethysmographically. As an indirect measure of the reagibility of the pulmonary vasculature the increase of Prv during hypoxic exposure was considered. In the groups B, C and D no significant changes between the measured parameters before and after the application procedure could be observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Experimental and clinical data of the pulmonary toxicity of mitomycin C].

The pathological-anatomical development of injuries to the lung induced by mitomycin-C, begins with an irregular thickening of the endothelial cells of the capillaries and progresses to the liberation of surfactant and to the activation of alveolar macrophages. When the macrophages break down, the resulting liberation of mediators initiated the fibrotic process in the lungs. In animal experiments, it has been shown that simultaneous administration of steroids can completely prevent this development. Clinical investigations have shown that, with the aid of aggressive diagnostic procedures, as also thorough lung function studies and bronchoscopy with lavage, pulmonary damage can be detected early on, before clinical symptoms have occurred. In the clinical investigations, too, prophylactic administration of steroids has been shown--in a randomised comparison with urokinase and no accompanying treatment--to be able statistically significantly to reduce the occurrence of toxic injuries in the lungs.

Animals↗
PubMedDate not supplied

Pulmonary functions in tropical pulmonary eosinophilia.

Abnormalities in pulmonary functions in a group of ten patients with tropical pulmonary eosinophilia were analysed. Mild obstruction was observed in four, restrictive pattern in three, combined defect in one and two had normal study. Except in one patient in whom mild obstructive defect persisted, functions in all others reverted to normal on treatment with diethylcarbamazine.

Adolescent↗
PubMed1990

Class-specific antibodies during follow up of patients with farmer's lung.

Sequential serum samples of 13 patients with acute farmer's lung (FL) taken during a follow-up of 18-36 months, were tested for antibodies of immunoglobulin G (IgG), IgA, IgM and IgE classes against Thermoactinomyces vulgaris and Micropolyspora faeni, and compared with contemporary lung function parameters. In the acute phase, antibodies of several Ig classes were present, those of IgG and IgA being most common. At the end of the follow-up, the mean values of all antibody titres were lower than in the acute phase, and antibodies were now mostly of one or two Ig classes only. The reduction in antibody levels was most often detectable in IgG and IgA antibodies against T. vulgaris. Antibody titres correlated inversely with tested lung function parameters, especially IgA antibodies with pulmonary diffusing capacity. Our results show that a follow-up of levels of class-specific antibodies, especially of IgG and IgA gives valuable information on causative microbes and on temporal changes of the exposure.

Adult↗
PubMed1990

[Characteristics of impaired gas exchange in patients with chronic obstructive pulmonary disease].

Eleven patients with chronic obstructive pulmonary disease (COPD), placed in a supine position, were given a mixture of 0.1% CO and 21% O2 in N2 as inspired gas and normal saline containing the six inert gases including SF6, ethane, cyclopropane, halothane, diethyl ether and acetone via the antecubital vein. After the steady state was established, the expired gas was collected and both arterial and mixed venous blood were simultaneously sampled through the catheter inserted either into the femoral or pulmonary artery. Assuming that mass transfer efficiency of a given indicator gas at each gas exchange unit would be limited by the ratio of ventilation to perfusion (VA/Q) and by that of diffusive conductance to perfusion (G/Q), the data were analyzed by means of a lung model with 20 units along the VA/Q and G/Q axes, respectively. By application of the method of weighted least-squares combined with the idea of constrained optimization, the data were transformed into a virtually continuous distribution of Q against VA/Q and G/Q axes. Analytical results revealed that: 1) patients with advanced COPD show widening of VA/Q distribution accompanied with a significant contribution of either high VA/Q (emphysematous change) or low VA/Q area (peripheral airway involvement). and 2) their Q distributions along the G/Q axis are unimodal but have an area with a relatively low G/Q, indicating a small but appreciable contribution of diffusion limitation to their hypoxemia. In conclusion, the findings consistently suggest that inhomogeneity of G/Q may partly be responsible for the impaired gas exchange in the cases of COPD.

Humans↗
PubMed1990

[Pathophysiological classification of external respiratory failure].

On the basis of literature analysis and clinical experience, a classification of external respiratory failure (ERF) is suggested. The types of ERF can be as follows: 1) pulmonary ventilation failure; 2) gas diffusion failure; 3) pulmonary blood flow failure; 4) respiration control failure; and 5) ambient air gas composition change. The forms of ERI can be classified as acute, subacute and chronic. The stages of ERF include the following: I (compensatory) with pulmonary ventilation function drop of degree I-III (of an obstructive, restrictive and mixed type) and without hypoxemia, normo- or hypocapnia; II (subcompensatory) with the same pulmonary ventilation failures, moderate or serious hypoxemia, normo- or hypocapnia; III (decompensatory) with hypoxemia and hypercapnia or extremely severe hypoxemia in combination with normo- or hypocapnia.

Humans↗
PubMed1989

The presence of Sjögren's syndrome is a major determinant of the pattern of interstitial lung disease in scleroderma and other connective tissue diseases.

A number of patients with scleroderma, Sjögren's syndrome and other connective tissue diseases (CTD) were assessed to ascertain the prevalence of respiratory abnormalities as defined by bronchoalveolar lavage (BAL), standard respiratory function studies and gallium scan of the lung, and the relationship of these abnormalities to the presence or absence of dyspnea. These results suggest that respiratory symptoms are very common in CTD and in scleroderma, particularly if Sjögren's syndrome is also present. Our findings also suggest the presence of 2 patterns of interstitial lung involvement in scleroderma. In scleroderma alone this appears to be characterized by the presence of increased neutrophil proportions in the BAL, decreased DLCO, and no increase in gallium uptake within the lung. Where scleroderma is associated with Sjögren's syndrome, there is an increase in the proportion of lymphocytes in the BAL and respiratory symptoms are very prominent, the latter associated with an increase in gallium uptake within the lung. This suggests that Sjögren's is a major determinant of the pattern of interstitial lung disease seen in CTD.

Bronchoalveolar Lavage Fluid↗
PubMed1989

The lung of the emu, Dromaius novaehollandiae: a microscopic and morphometric study.

Qualitative and quantitative characteristics suggest that the lung of the emu is poorly adapted for gas exchange when compared with that of other birds. The granular epithelial cells extend over the air capillaries, and the squamous epithelial cells have microvilli indicating a poor differentiation of the epithelium of the exchange tissue. The surface area of the blood-gas tissue barrier per unit body mass was only 5.4 cm2/g, the volume of the pulmonary capillary blood per unit body mass was only 0.93 cm3/kg, and the tissue barrier was unusually thick (0.232 micron). These parameters produce a relatively small total morphometric pulmonary diffusing capacity for oxygen of 0.014 ml O2/sec/mbar/kg. The findings conform to the evolution of a very large flightless bird in a warm environment lacking effective predators.

Animals↗
PubMed1989

[Simultaneous analysis of the distribution of ventilation and diffusive conductance to perfusion in the lungs].

Theoretical analysis and experimental observations were performed to establish an essential method allowing demonstration of the characteristics of distribution of ventilation (VA) as well as of diffusive conductance (G) to perfusion (Q) in the lungs. O2, CO2 and CO binding to hemoglobin molecules within erythrocytes, together with six inert gases including SF6, ethane, cyclopropane, halothane, diethyl ether and acetone, possessing various degrees of solubility in blood and different degrees of diffusibility in lung tissue were used as indicator gases. Fifteen patients with interstitial pneumonia of unknown etiology, placed in a supine position, were given a mixture of 21% O2 and 0.1% CO in N2 as the inspired gas and normal saline containing appropriate amounts of the six inert gases via the antecubital vein. After a steady state was established, the expired gas was collected and both arterial and mixed venous blood were simultaneously sampled through the catheter inserted either into the femoral or pulmonary artery. The concentrations of the indicator gases in the samples were measured by gas chromatography, with electrodes or with Scholander gas analyzer. Assuming that the mass transfer efficiency of a given indicator gas at each gas exchange unit would be limited by the ratio of VA to Q (VA/Q) and by that of G/Q, the data obtained from the human subjects were analyzed in terms of a lung model having 20 units along the VA/Q and G/Q axes, respectively. The numerical analysis including the procedure of a simultaneous Bohr integration for O2, CO2 and CO in a pulmonary capillary and the method of weighted least-squares combined with the idea of constrained optimization permitted the data to be transformed into a virtually continuous distribution of Q against VA/Q and G/Q axes. The numerical procedure was strictly tested based on many artificial distributions of VA/Q and G/Q ratios, showing that it could characterize distributions containing up to at least two modes in the VA/Q-G/Q field with a substantial accuracy. Analytical results estimated from the patients with interstitial lung disease revealed: 1) most of the lung is operating in the range of normal VA/Q in an early stage of their illness, while widening of VA/Q distribution accompanied with a significant contribution of both high and low VA/Q areas is observed in an advanced stage of the disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Humans↗
PubMed1989

[Diagnosis of interstitial lung diseases with special reference to children].

An increase in the number of children with interstitial lung diseases observed over the last twelve months has prompted us to review the clinical and diagnostic aspects of this condition. Our aim is to increase the awareness of the fact that these diseases occur in childhood too where they are not diagnosed often enough, mainly because the necessary lung function tests are rarely done. Pulmonary disorders resulting from systemic diseases often improve with treatment of the underlying problem, but sometimes failure to improve cannot be detected because pulmonary function tests are not done. The presented not broad aetiologic spectrum of interstitial lung diseases shows that only the lung specialist, but also internists and paediatricians in all subspecialties should know about these entities, to avoid their being diagnosed by a specialist only when fibrosis has developed.

Adolescent↗
PubMed1989

Cardiopulmonary assessment of the critically ill trauma patient.

The adequacy of tissue oxygenation status of trauma patients requires close surveillance of cardiopulmonary functioning. A thorough assessment includes the parameters that evaluate pulmonary gas exchange, oxygen delivery to the tissues, and oxygen utilization by the tissues.

Cardiac Output↗