摘要:

The pulmonary diffusing capacity (DLCO – steady state method according to Bates and coworkers) was measured at the time of heart catheterization in 12 patients with mitral stenosis without mitral incompetence. DLCO correlates with the tidal volume at rest and during exercise and with pulmonary vascular resistance during exercise only. DLCO and left atrial pressure exhibit a positive correlation up to 22.5 mm Hg only. In patients with mitral stenosis DLCO depends on the alveolar surface area and DLCO is influenced by regional changes in the pulmonary vascular resistanc

ISSN:0025-7931    

DOI:10.1159/000193852

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

A fast P02 tracing with 95% delay times of 15–20 msec in routine is necessary for measurement of the PO, jumps in the expired air, particularly for the precise measurement of the so-called dead-air plateau. A Clark type PO, electrode has been developed which has the demanded property. This electrode has four characteristic features: (1) a glass-coated Pt cathode with a tip diameter of 0.3 mm (diameter of the Pt wire = 0.1 mm); (2) a differential screwdrive for feeding the cathode 50 μm per turn; (3) a 0.2- to 0.3-μm-thin polytetrafluoroethylene membrane, and (4) a special polishment of the surface of the cathode. The electrode has a 95% response time of 15–20 msec in routine when tracing PO2 changes from 150 to 750 mm Hg. About 30% of the prepared electrodes have response times of 7–10 msec. The output of the electrode in air is stable within the first 3 h (deviation smaller than 0.2%) and then decreases within 10 h approximately 1% per hour. The response times are constant for more than 48 h. The output of the electrode is linear from 0 to 760 mm Hg PO2. Within the accuracy of measurement the output is independent of PCO

ISSN:0025-7931    

DOI:10.1159/000193853

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

in 15 patients with chronic bronchitis with or without emphysema breathing of room air was compared with breathing of 20.9% O2 in helium and in argon. Minute ventilation and alveolar ventilation showed no differences, whereas the alveolar and arterial pO2 and PCO2 showed an improvement of the CO2 gas exchange and a deterioration of the O2 gas exchange. This contradictory behaviour cannot be explained by shunts or inhomogeneities or influence of gaseous or alveolo-capillary diffusion. Perhaps the physico-chemical properties of the alveolo-capillary membrane change by the depletion of nitrogen. The recommendation of helium-oxygen breathing, proposed by other authors for patients with obstructive airway diseases, cannot be supported, when the gas exchange for O2is deteriorated.

ISSN:0025-7931    

DOI:10.1159/000193854

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

Pressures at which the peripheral airways (PA) and terminal bronchioles (TB), open and closed, were studied in rats’ lungs in vitro. Airway luminal diameter was directly measured at diminishing transbronchial pressure (closing) and increasing transbronchial pressure (opening) by means of a stereomicroscope with a calibrated eyepiece. The PA and TB had internal diameters at 100 mm H2O ranging from 173 to 306 μm and 122 to 204 μm, respectively. Most of the airways closed suddenly in the pressure range between 75 and 5 mm H2O and only a few were still open at zero pressure. Closure began in the distal portion of the PA and mid-portion of the TB usually in a concentric manner. Terminal bronchioles and PA that initially were prepared at room temperature instead of at 0 °C often contained air at zero pressure and showed a decreased response to acetylcholine. Subthreshold concentrations of acetylcholine increased the critical closing pressure by more than 100%. The critical opening pressure was considerably higher than the corresponding closing pressure. It is proposed that bronchiolar closure depends on the tone of the airway smooth muscle, the elasticity of the airway wall and probably on the surface tension of the liquid lining the mucosal memb

ISSN:0025-7931    

DOI:10.1159/000193855

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

Measurements of maximum expiratory flows and lung volumes were made on 6 occasions at weekly intervals in 14 children who were known over several years to have severe chronic asthma. 11 of the 14 had persistent lung hyperinflation and marked reduction in maximum expiratory flow rates although there was considerable variability in individual measurements. The other 3 usually had hyperinflation and reduced expiratory flow rates. 3 times daily measurements at home of peak expiratory flow rate did not contribute further to assessment. The results of the study indicated that one or two measurements of maximum expiratory flow calculated from a maximum expiratory flow volume curve and of lung volumes recorded in a body plethysmograph are of value in identifying the child with severe chronic asthma.

ISSN:0025-7931    

DOI:10.1159/000193856

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

Ventilatory response to central and peripheral chemoreceptor stimulation by carbon dioxide was assessed in 15 severely and chronically anaemic subjects before and after the correction of anaemia. Whereas the central CO2 responsiveness was found to be normal in the anaemic state, the peripheral response to CO2 was remarkably depressed. This blunted peripheral response to CO2 was restored to normal with the correction of anaemia.

ISSN:0025-7931    

DOI:10.1159/000193857

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

15 healthy adults (5 women, 10 men) have been exposed to each of four experimental conditions: rebreathing of air or carbon monoxide, and the smoldng of two low-nicotine (0.3 mg) or medium-nicotine (1.2 mg) cigarettes. The dose of carbon monoxide selected (80 ml) had no effect on resting heart rate or electrocardiogram, nor did it modify the exercise heart rate, ventilation, oxygen consumption or electrocardiogram. Both types of cigarette produced variable changes in the blood carboxyhaemoglobin level, increments being greatest in heavy smokers, and least in former smokers, pipe and cigar smokers. Gains of carboxyhaemoglobin were less with low-nicotine than with medium-nicotine cigarettes. Both types of cigarette produced some increase of resting heart rate, but the smoking of two cigarettes was insufficient to modify the exercise heart rate, ventilation, or oxygen consumption. The electrocardiogram also showed no signs of ischaemia during either rest or effort. It is suggested that, for the light and moderate smoke, the ‘safest’ cigarette may be one with a low tar and a very low nicotine yield. On the present data, this would also induce only small increments of blood carboxyhaemoglobin lev

ISSN:0025-7931    

DOI:10.1159/000193858

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

Pulmonary function testing is needed to determine the pathophysiology present in the patient with cardiopulmonary disease. Blood gases and pH should be obtained during emergency situations and during cranial, thoracic, and extensive cervical or abdominal surgery. Lung function tests can be divided in global such as spirometry and diffusing capacity which study the ventilation and transfer of gases and regional determinations of ventilation and perfusion. Both types of tests complement each other and should be used together. The spirometry should consist at least of determination of the vital capacity and is determined in the first second to ascertain if there is obstructive lung disease. Some tests such as flow-volume curves, alveolar-arterial gradients and closing volume are very useful to detect early pulmonary disease before any symptoms or findings are present. This is probably one of the most important medical indications for pulmonary function testing. Before certain types of surgery pulmonary function testing is indicated; if the spirometry and diffusing capacity tests are normal, there is no pulmonary contraindication for the planned surgery. In chest surgery if there is significant compromise of the spirometry and diffusing capacity regional lung function tests are indicated to study the pathophysiology at regional level, thus trying to circumscribe the lung resection to the diseased areas.

ISSN:0025-7931    

DOI:10.1159/000193859

出版商:S. Karger AG    

年代:1978

数据来源: Karger

ISSN:0025-7931    

DOI:10.1159/000193860

出版商:S. Karger AG    

年代:1978

数据来源: Karger