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Biomedical subjects

R Pariente

Publications and source records attributed to R Pariente.

At least 109 records · Page 6Linked to original sources
PubMed1983

[Etiologic study of chronic nonspecific bronchopneumopathies in the work environment].

Epidemiological methods may be used to study the causes of respiratory troubles at work, to test the hypothesis that there is a statistically significant relationship between professional risk factors and respiratory disease. The prognostic value of certain indices and the impact of preventative measures may also be assessed. The choice of method, type of enquiry and selection of the population to be studied and the resources to be used depend on the aims of the study. The definitions both of occupational exposure and the disease should be clearly established in the protocol. The questionnaire, which is indispensable in all investigation into respiratory disorder, should be adapted to the specific research project (for contents, lay-out, relevance and order of questions, allowing for distorting factors). The final objective in the application of an epidemiological method to study occupational risk factors is to develop a preventative strategy at each stage, but most importantly at the very first stage to prevent the appearance of respiratory troubles.

Air Pollutants, Occupational↗
PubMed1982

Effects of airway anesthesia on pattern of breathing and blood gases in patients with chronic obstructive pulmonary disease during acute respiratory failure.

To assess the role played by airway receptors in the genesis of rapid and shallow breathing of patients with chronic obstructive pulmonary disease (COPD), we studied the effects of airway anesthesia in 14 patients with COPD during acute respiratory failure. Airway anesthesia was performed by fiberoptic xylocaine administration from the larynx to the subsegmental bronchi, all patients being intubated or tracheostomized. A small decrease in minute ventilation of 6 +/- 1% of the control values occurred after airway anesthesia. This was due to a decrease (p less than 0.01) in respiratory frequency (f) (14.5 +/- 1%). The latter resulted from an increase (p less than 0.0005) in the expiratory time, whereas the inspiratory time did not change significantly. On the other hand, tidal volume increased (p less than 0.02) by 10.1 +/- 0.6%. In all patients, these modifications were accompanied by arterial blood gas deterioration, mean PaO2 and PaCO2 of 42 +/- 3 mmHg and 62 +/- 3 mmHg, respectively, 15 min after xylocaine administration, as compared with 48 +/- 2 mmHg and 54 +/- 2 mmHg, respectively, during the control period. No correlation was found between the changes in minute ventilation and PaO2 or PaCO2. We conclude that (1) activation of airway receptors are involved in the determination of the rapid and shallow breathing observed in patients with COPD during acute respiratory failure, and (2) airway xylocaine anesthesia that worsens arterial blood gases is contraindicated in these patients.

Aged↗
PubMed1982

Comparison of esophageal, tracheal, and mouth occlusion pressure in patients with chronic obstructive pulmonary disease during acute respiratory failure.

In 14 acutely ill patients with chronic obstructive pulmonary disease who were either intubated or breathed via a tracheostomy, we measured the pressures generated in the esophagus and trachea during the first 0.1 s of spontaneous inspiratory efforts against closed airway (P0.1). No significant difference was found between P0.1 in the trachea and esophagus, where it was measured at 2 balloon levels (distance from balloon tip to nares: 35 and 45 cm). In 4 of the patients we also compared esophageal and mouth occlusion pressures during mouth breathing, the orifice of tracheostomy being temporarily obstructed. Mouth P0.1 in the 4 patients averaged approximately 47% of the esophageal occlusion pressure (4.4 +/- 1.7 versus 8.9 +/- 3.1 cm H2O, respectively). Because in patients with COPD with upper airways bypassed (tracheostomized or intubated) the changes in esophageal and tracheal pressure during occluded respiratory efforts were similar, it is concluded that the difference between esophageal and mouth occlusion pressure is due to the tissue compliance of the oropharynx.

Aged↗
PubMed1982

[Experimental animal pathology. Immuno-allergic asthma (author's transl)].

One of the interests of experimental animal work is the power to analyse a given pathophysiological mechanism and also the privilege of witnessing its appearance. Immuno-allergic asthma, mediated by specific IgE of an allergen only represents one aetiological form, among many others, that make up the clinical spectrum of asthma in the human species. It is, however, the type of asthma whose experimental reproduction, a priori, is the most easily reproduced and has been the most tested. The different protocols used an analysis of the results and the lines of current or projected research form the object of this review.

Allergens↗
PubMed1982

[Effect of sleep on respiration].

Physiologists as well as chest physicians are both interested in respiratory control and disturbances during sleep. Many studies have demonstrated episodic falls in oxygen saturation in lung disease during sleep related to episodic alveolar hypoventilation and/or apneas. A better understanding of these sleep-induced disorders has been possible since the use of electroencephalo-and oculogram (EEG-EOG) to separate the two stages of sleep i.e rapid eye movement sleep (REM sleep) and slow wave sleep (non-REM sleep), and of non invasive methods in assessment of respiratory parameters. Several mechanisms may explain respiratory disturbances during sleep: --a failure of respiratory control systems which differ between the two stages of sleep (central apnea); --a decrease in activity of all upper airway muscles, mainly during REM sleep (occlusive apnea); --a worsening in ventilation-perfusion inhomogeneities which may occur independently of the apnea periods. The detection of such falls in oxygen saturation in pulmonary patients, especially in hypoxemic ones appear to be very important to avoid the adverse effects of hypoxemia on pulmonary circulation. This could be realized by: --an evaluation of respiratory disorders during sleep; --a better assessment of the respiratory control systems in cold patients; --suppression of predisposing factors of occlusive apnea. These different investigations would lead us to a more logical management of respiratory disturbances during sleep, especially in patients suffering from chronic respiratory insufficiency.

Animals↗
PubMed1982

[Bacteriology of bronchial secretions. Proposals for a practical attitude in bacterial respiratory tract infections].

The inadequacy of the standard bacteriological method in the study of expectorations is unanimously accepted. Oropharyngeal contamination of specimens largely explains why this examination is a poor index of the causative organisms in bacterial respiratory infections. In a mixed clinical situation with few or non-specific signs of bacterial infection and of variable severity, the physician should answer two questions: 1) Is it a bacterial infection? 2) What is the causative organism? and their corollary: 1) Should one prescribe an antibiotic? 2) Which one? Only culture of blood or pleural fluid allow an accurate reply to these questions in about 50% of cases and they are the indispensable investigations of reference. Initial efforts undertaken to improve the standard examination of expectorations never overcome the stumbling block of oro-pharyngeal contaminations. The bacterial count of expectorated bacteria, a non traumatic method, represents some real progress. In 50% of cases it enables a predominant pathogen to be identified before any antibiotics are given. Bronchoscopy diminishes contamination, allows direct sampling and the inspection and biopsying of bronchial mucosal lesions and aids drainage in very suppurative disorders. Trans-tracheal puncture avoids oropharyngeal contamination in the majority of cases and appears to provide reliable results much more often. A pragmatic approach is recommended according to the clinical picture. Bronchial and limited alveolar infections which are well tolerated, heal without exception on blind antibiotic therapy. In suppurating infections (bronchiectasis, cavitating pneumonias), the yield and the reliability of the examinations are increased. Serious bacterial infections, by their extent or by their site, justify a more aggressive diagnostic and therapeutic attitude. It should be stressed, however, that death caused by inadequate antibiotic therapy remains the exception when one or two successive courses of antibiotics have been prescribed for the pathogens presumed responsible according to the clinical picture or found after one or more bacterial examinations.

Anti-Bacterial Agents↗
PubMed1981

[The place of respiratory analeptics in chronic respiratory failure (author's transl)].

The recent renewed interest in respiratory analeptic action in chronic respiratory failure raises the problem of the site of action and nature of these drugs. They lead to a direct or reflex increase in central nervous activity, which in consequence increases respiratory muscle activity. Indeed, patients with respiratory failure develop pressures two or three times greater than normal subjects to achieve adequate ventilation. During acute exacerbations the pressures generated are five or six times as large. This increase in pressure may risk precipitating fatigue. In general the anomalies of blood gases seem much more related to changes in ventilation-perfusion relationships than to global hypoventilation. Finally, a large increase in the force of muscular contraction may only have a minor effect on ventilation, given the alinear nature of the dynamic compliance curve. An increase of central respiratory activity may thus be ineffective and possibly even dangerous. In the overall assessment of drug considered as an analeptic one always ought to consider the possible non-analeptic actions on the bronchial calibre, the force of the respiratory muscles and the ventilation-perfusion relationships. Thus, it is possible that the therapeutic effects of certain analeptic drugs may be due to actions other than those of respiratory stimulation.

Central Nervous System↗
PubMed1981

[Bronchial arteriography in the localization and treatment of haemoptysis. Report of 34 observations (author's transl)].

34 bronchial arteriograms were performed in 34 patients over two years. The authors tried to assess the value of this technique in the localization and treatment of haemoptysis. The study confirms the excellent results which are obtained immediately by selective embolisation to achieve haemostasis in severe cases of haemoptysis studied acutely (12 out of 14 cases). The value of arteriography was mediocre when used to localize the lesion (12 times out of 31 assessable cases). Accordingly the authors currently limit bronchial arteriography to those cases where embolisation is indicated and cases in which previous investigation had failed to yield a cause.

Adult↗
PubMed1980

SO2-induced bronchopathy in the rat: abnormal permeability of the bronchial epithelium in vivo and in vitro after anatomic recovery.

The effects of different SO2 exposures on the uptake and transport of exogenous proteins by the tracheobronchial epithelium were investigated in vivo and in vitro using explanted tissue from rat lungs. By optical and electron microscopy, modifications in ferritin uptake and transport were observed, depending on SO2 exposure and on subsequent structural changes; these changes involved a considerable increase in mucosal permeability, both in vivo and in vitro, affecting the epithelium of the trachea and main bronchi. Such an increase, although reduced, was observed 3 months after SO2 exposure had been discontinued, at a time when the structure appeared normal. These findings suggested that SO2-induced changes in upper respiratory epithelium may be responsible for long-term abnormal permeability and that such changes may contribute to the pathogenesis of chronic bronchopathy.

Animals↗
PubMed1980

Central respiratory drive in acute respiratory failure of patients with chronic obstructive pulmonary disease.

Control of breathing was studied in patients with chronic obstructive pulmonary disease, both in the chronic state and during acute respiratory failure. The results were compared to those in a group of age-matched normal subjects. In patients breathing air, minute ventilation was not different during acute and chronic states, and was similar to that in normal subjects. The pattern of breathing, however, was different: acutely ill patients took shorter and smaller breaths, with a breathing frequency higher than that of normal subjects. The pattern of the chronic group was intermediate between that of acutely ill patients and that of normal subjects. Mouth occlusion pressure, an index of neuromuscular respiratory drive, was 5 times greater in acutely ill patients than in normal subjects. Administration of O2 at a flow of 5 L/min caused a small (14%), bus significant, decrease in minute ventilation due to decreased respiratory frequency. The tidal volume did not change, so the decrease in minute ventilation was the result of decreased inspiratory flow. This was associated with a decreased mouth occlusion pressure that was still 3 times greater than that of normal subjects. The increase in arterial PCO2, observed after administration of O2 was not correlated with the decrease in ventilation, indicating that other factors must be responsible for the increase in arterial PCO2. We concluded that (1) despite the poor mechanical advantage of the respiratory muscles in acute respiratory failure, the increased drive to breathe results in high mouth occlusion pressure and inspiratory flow, and (2) the increase in arterial PCO2, observed during administration of O2 is not related solely to changes in respiratory drive.

Aged↗
PubMed1980

Effects of the administration of O2 on ventilation and blood gases in patients with chronic obstructive pulmonary disease during acute respiratory failure.

The effects of the administration of 100% oxygen on minute ventilation (VE) and arterial blood gases were studied in patients with chronic obstructive pulmonary disease during acute respiratory failure. The administration of O2 resulted in an early decrease in VE, which averaged 18% +/- 2 SE of the control VE, and was due to a decrease in both tidal volume (VT) and respiratory frequency (f). This was followed by a slow increase in VE, such that after 15 min of breathing O2, VE rose to 93 +/- 6% of the control room air value, with both VT and f similar to control values. Despite the small difference between VE while breathing room air and that at the fifteenth minute of O2 inhalation, PaCO2 increased by 23 +/- 5 mmHg, and no significant correlation was found between the changes in VE and PaCO2. By the fifteenth minute of O2 inhalation the PaO2 averaged 225 +/- 23 mmHg, and it was concluded that despite the removal of the hypoxic stimulus of O2 inhalation, the activity of the respiratory muscles remained great enough to maintain VE at nearly the same degree as that while breathing room air. Consequently, the changes in PaCO2 after the administration of O2 were mainly due to increased inhomogeneity of VA/Q distribution within the lungs.

Aged↗
PubMed1980

[Assessment of chemoprophylaxis with intermittent tetracycline in chronic bronchitis. A functional follow-up for 3 years (author's transl)].

This study is a reappraisal for the value of intermittent tetracycline therapy in the reduction of the rate of pulmonary function alteration in patients with chronic obstructive lung disease. Two groups of patients with chronic bronchitis were randomly divided and followed up for three years. No significant differences in pulmonary function were observed between these two groups.

Adult↗
PubMed1980

Biochemical and anatomical study of collagen and associated macromolecules in pulmonary panacinar emphysema and spontaneous pneumothorax.

In collagen content of four emphysematous lungs as defined by radiological, physiological and anatomical tests were studied. They were compared to three control lungs and five lungs removed from patients with relapsing pneumothorax (PNO). Morphologically, emphysematous lungs were characterized by patchy disorganization of collagen fibers, involving microfibrillar areas or elastoid laminae. Elastic fibers were at times found in plugs. Such abnormalities were also present, but less frequently in the PNO group. Biochemically, emphysematous lungs showed an increase of soluble proteins removed by CaCl2 extraction, which were associated with a decrease in insoluble proteins in extracted by TCA. Total hydroxyproline, expressed as a fraction of deoxyribonucleic acid (DNA) content, was not modified, but an increase of dialyzable and undialyzable fraction was observed in MEM medium. The PNO group showed the same modifications in terms of mean values, but individual results were more scattered. Results of in vitro 14C-proline incorporation did not show any modification of collagen biosynthesis, except in 2 emphysematous lungs. The results indicate that the PNO group is nearer to the emphysematous group than the controls. This suggests that patients with relapsing PNO may develop emphysema but it has to be further substantiated. The results here presented indicate that soluble hydroxyproline is an index either of abnormal synthesis or of excessive collagenolysis.

Collagen↗