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At least 199 records · Page 11Linked to original sources
PubMed1991

Failure of vasoldilator infusion to alter pulmonary diffusing capacity in systemic sclerosis.

PURPOSE: Patients with systemic sclerosis (SSc) do not exhibit a normal increase in the diffusing capacity for carbon monoxide (DLCO) on assuming the supine position. We sought to determine whether a potent prostacyclin derivative and vasodilator, iloprost, would reverse this defect. PATIENTS AND METHODS: Fourteen patients with SSc were enrolled in a randomized, double-blind, placebo-controlled study of iloprost. Patients were tested before and during 3 days of iloprost or placebo infusion with both upright and supine pulmonary function studies. RESULTS: The results of baseline pulmonary function studies including DLCO were not significantly altered by iloprost. Furthermore, iloprost did not alter the abnormal postural DLCO response. CONCLUSION: These results suggest that the pulmonary vascular defects seen in this group of patients are not a consequence of reversible pulmonary vasospasm.

Adult↗
PubMed1993

[Pulmonary diffusing capacity in normal smoking Chinese].

Single-breath carbon monoxide diffusing capacity parameters including DLCO, VA and DLCO/VA were studied in 131 asymptomatic healthy smoking Chinese men aged 25-70 years. Measurements were conducted with a rolling-sealed, computer-based pulmonary function analyzer and were in accordance with testing procedures recommended by the American Thoracic Society. Diffusing capacity in smokers was compared with that in normal nonsmoking adults. Cigarette smoking caused a reduction in DLCO and DLCO/VA, but not in VA. Therefore, the change in diffusing capacity was not related to a decrease in lung volume. Twenty-one percent of all smoking subjects showed an abnormally low DLCO value. The onset of this defect in pulmonary diffusion appears to occur early in cigarette smokers. Since older smokers with evidence suggestive of pulmonary emphysema or chronic bronchitis were excluded due to their respiratory symptoms, the accumulated effect of smoking on DLCO cannot be demonstrated in this study. The prediction equations of DLCO, VA and DLCO/VA were generated for Chinese male smokers, using age, height and weight as the independent variables. The present study was unable to include any tobacco smoking parameters in the regressing equations. It is postulated that the modest increase in carboxyhemoglobin (COHb %) in smokers may explain the immediately lower DLCO values observed in smokers shortly after they begin smoking.

Adult↗
PubMed1980

Pulmonary diffusing capacity and its components (DM and Vc) in young, healthy smokers.

We have studied the diffusing capacity and its components (DM and Vc) in two groups of 9 males, healthy, smokers and nonsmokers, with similar age, biometric characteristics and spirographic values. Also, BT was not different between the two groups, because the smokers were asked to stop smoking 12 h before the test. Our data showed that TF and DM are significantly lower in smokers than in nonsmokers (p less than 0.005 and less than 0.01, respectively, while Vc was not different between the two groups and confirm that Vc is influenced by COhb level.

Adult↗
PubMed1975

Morphometric estimation of pulmonary diffusion capacity. VII. The normal Guinea pig lung.

A study of 15 normal adult guinea pig lungs fixed by instillation of fixatives via the airways is described. The morphological appearance of the guinea pig lung is similar to that of other mammals apart from quantitative differences in the mass of connective tissue in the alveolar-capillary barrier whose mean thickness was estimated at 1.59 mum. Lung volume, alveolar volume, capillary volume and the surface areas of alveoli and capillaries are shown to be linearly related to body weight. Analysis of the morphometric diffusion capacities of the alveolar-capillary membrane and of the lung shows that these are also linearly related to body weight. For a mean body weight of 429 g the lung volume was 13 ml, the alveolar surface 0.91 m2, the capillary volume 1.5 ml, the harmonic mean barrier thickness 0.42 mum, and DL 2.13 ml/min.mm Hg. These parameters are compared with those of other mammalian species and discussed in the context of normal activity levels as a probable important adaptive factor determining the size of the gas exchange apparatus.

Animals↗
PubMed1981

Design of the mammalian respiratory system. IV Morphometric estimation of pulmonary diffusing capacity; critical evaluation of new sampling method.

The quality of morphometric data obtained by stereological methods depends on the sampling scheme adopted. In the light of recent advances in sampling theory for stereology a sampling strategy has been developed which differs significantly from that used in previous studies. It operates with a cascade of four sampling levels and adopts the principle of A-weighted sampling, a method that should eliminate bias and possibly yield smaller variances. This method is described and discussed in detail. When compared with the old simpler sampling approach it is found that the new method (1) is at least as efficient and (2) that the estimates of morphometric parameters obtained by this method are similar to the data generated by the old method.

Animals↗
PubMed1981

Pulmonary diffusing capacity and physical working capacity in swimmers and non-swimmers during growth.

We measured physical working capacity at a heart rate of 170 bpm (PWC170) and diffusing capacity for carbon monoxide (DLCO) in two groups of children ranging in age from 9 to 17 years. One group was formed of highly trained competitive swimmers and the other of age, sex and size matched untrained counterparts. Bicycle ergometry was used to establish PWC170. The DLCO was measured at rest (DLCO rest) and while pedalling at 170 bpm (DLCO ex). The PWC 170, DLCO rest and DLCO ex were significantly higher in swimmers than in non-swimmers. Repeated measurements in the same subjects show that individual increases in DLCO rest and DLCO ex were result of both growth and training.

Adolescent↗
PubMed1990

Pulmonary diffusing capacity in left ventricular dysfunction.

The purpose of this study was to determine whether there are any consistent spirometric or Dsb findings in patients with LV dysfunction characterized by a clinical diagnosis of CHF and an EF less than 40 percent. We performed spirometry and Dsb in 34 patients, and found that EF correlated only with Dsb. When we separated the patients into those with rales and those without, Dsb correlated strongly with EF only in those with rales. There was no correlation with other spirometric values. Mean Dsb percent predicted was significantly lower in patients with rales despite similar mean EF. Only two of 23 patients without rales had a reduced Dsb while only one of 11 with rales had a normal Dsb. We conclude that Dsb is a good predictor of clinically evident heart failure. When rales are absent, Dsb should be normal in patients with LV dysfunction; when present, Dsb will be diminished in proportion to the EF.

Aged↗
PubMed1993

Pulmonary diffusing capacity after maximal exercise.

To determine the effect of maximal exercise on alveolocapillary membrane diffusing capacity (Dm), 12 professional handball players aged 23.4 +/- 3.3 (SD) yr were studied before and during early recovery from a progressive maximal exercise [immediately (t0), 15 min, and 30 min (t30) after exercise]. Lung capillary blood volume and Dm were determined in a one-step maneuver by simultaneous measurement of CO and NO lung transfer (DLCO and DLNO, respectively) with use of the single-breath breath-hold method. At t0, DLCO was elevated (13.1 +/- 12.0%; P < 0.01) but both DLNO and Dm for CO remained unchanged. Between t0 and t30, both DLCO and DLNO decreased significantly. At t30, DLCO was not different from the control resting value. DLNO (and consequently Dm for CO) was significantly lower than the control value at t30 (-8.9 +/- 8.1%; P < 0.01). Lung capillary blood volume was elevated at t0 (18.0 +/- 19.0%; P < 0.01) but progressively decreased to near control resting values at t30. Differences in the postexercise kinetics of both DLCO and DLNO point to a role of the transient increase in pulmonary vascular recruitment during the recovery period. We concluded that Dm was somewhat decreased in the 30 min after maximal exercise of short duration, but the exact pulmonary mechanisms involved remain to be elucidated.

Adult↗
PubMed1983

Maximal oxygen consumption and pulmonary diffusing capacity: a direct comparison of physiologic and morphometric measurements in canids.

The purpose of this study was to check the validity of the morphometric model for estimating physiological conductances for gases, DL. We make a direct comparison between the lung's conductance for carbon monoxide, measured physiologically using the single breath method, DLCO (sb), and that measured morphometrically using the previously published model, DLCO(mm). We also make a direct comparison between the maximum rate of oxygen uptake by the lung during exercise, VO2max, and the lung's conductance for oxygen DLO2(mm). We made these measurements on four species of canids (foxes, coyotes, dogs and wolves). We find a direct proportionality between morphometric and physiologic DLCO measurements, the morphometric being consistently larger by a factor of two. We also find that both DLCO and DLO2 increase more steeply with body mass than VO2max, the difference between the allometric slopes being the same as we had found previously in a wide range of mammalian species ranging from 2 g to 700 kg, although the slopes themselves were different. We conclude that the discordant scaling of DLO2 and VO2max with respect to body mass is not an artifact of the model for calculating DLO2 from morphometric data.

Animals↗
PubMedDate not supplied

[The effect of hemoglobin levels in the blood in pulmonary diffusing capacity].

Using a "single breath" method, diffusing lung capacity (DLCO) and unit DLCO (KCO) were measured in 19 patients with chronic sideropenic anemia and 19 healthy women who were without any clinical or radiologic evidence suggestive of cardiorespiratory disease. Anemic patients, compared to the control group, had significantly reduced DLCO (% predicted) and KCO (% predicted) (p < 0.01). Each 10 g/L hemoglobin (Hb) reduction below a normal value of 136 g/L corresponded to 2% DLCO% and 3% KCO% reductions. For all examinees, where the range of Hb was from 50 to 150 g/L, a significant positive low linear correlation was noted between DLCO% and HB (r = 0.31; p = 0.049) and KCO% and Hb (r = 0.43; p = 0.005). Analyzing only anemic patients, where the range of Hb was from 50 to 109 g/L, no significant correlation was found between Hb and DLCO% or KCO%. Therefore, in patients with chronic sideropenic anemia DLCO is lowered less then expected, so one should not adjust measured DLCO or KCO values to standard Hb concentration, because probably various pathophysiological compensatory mechanisms affect DLCO components in unknown manner, changing the relationship between Hb and DLCO.

Adult↗
PubMedDate not supplied

Pulmonary diffusing capacity for carbon monoxide in simple coal workers' pneumoconiosis.

The lung diffusing capacity for carbon monoxide (DLCO single-breath) and its two components, the capillary blood volume (Vc) and the diffusing capacity of the membrane (DMCO) were measured at rest in 43 miners and 141 control subjects, the values in whom enabled reference formulae to be established; in 30 control subjects and in the majority of the miners these indices were measured during exercise. The main results are as follows: the diffusion indices are on average slightly decreased in simple coal workers' pneumoconiosis; both DMCO and Vc contribute to the lowering of DLCO, at rest and during exercise; individually Vc is more often significantly altered than DMCO; on effort the percentage increase of DLCO is normal in coal miners; the data during exercise suggest that smoking habit contributes more to lowering DLCO than does pneumoconiosis itself; lastly the diffusion indices are lower in miners with "pin-head" than those with micronodular opacities: this tendency is more pronounced during exercise. These findings are discussed.

Adult↗
PubMedDate not supplied

[Pulmonary diffusing capacity in normal aged subjects of both sexes: the effect of smoking habit].

The diffusing capacity of the lung (DL) or transfer factor for the lung (T1) for carbon monoxide (DLCO) was determined, at rest, by single-breath method in 65 normal subjects ranging in age from 60 to 84 years. The subjects were divided into four groups: 15 male smokers (MS); 20 male non-smokers (MNS); 10 female smokers (FS); 20 female non-smokers (FNS). The DLCO was determined using the "Collins Computerized Modular Lung Analyser". The inspired mixture consisted of 0.3 per cent carbon monoxide, 10.0 per cent helium, 21.0 per cent oxygen and 68.7 per cent nitrogen. The mean values and the standard derivations for DLCO (ml/min/mmHg) were: 23.31 +/- 6.48 in MS; 29.33 +/- 6.27 in MNS; 19.74 +/- 5.87 in FS; 19.55 +/- 4.86 in FNS. The DLCO was found to be dependent upon age and body surface area (BSA). Regression equations for predicting normal DLCO have been determined for every one of the four groups (MS, MNS, FS, FNE). Difference, statistically significant was found for MS as compared to MNS, FS and FNS. Therefore two regression equations for predicting normal DLCO have been determined; one for male smokers (MS) and other for male non-smokers (MNS), female smokers (FS) and female non-smokers (FNS). The regression equation for predicting normal DLCO for male smokers (MS) was: DLCO (ML/min/mmHg) = 9.37 - 0.22 Age (Years) + 19.99 BSA (M2). The regression equation for predicting normal DLCO for male non-smokers (MNS), female smokers (FS) and female non-smokers (FNS) was: DLCO (ml/min/mmHg) = 25.05 - 0.27 Age (Years) + 8.41 BSA (m2).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMedDate not supplied

[The effect of cigarette smoking on pulmonary diffusing capacity in asymptomatic smokers].

Ninety-seven subjects of which 72 smokers and 25 nonsmokers attending the Laboratory for Respiratory Functional Diagnostics of the University Hospital for Lung Diseases, Jordanovac, Zagreb were examined. The selection criteria were normal standard spirometric test values (FEV1, FVC, FEV1/FVC) in asymptomatic healthy, young smokers/nonsmokers who showed no signs of hematological, cardiovascular and chronic or acute pulmonary symptoms or diseases (according to a standardized questionnaire), and were not exposed to harmful environmental factors. The single-breath carbon monoxide diffusing capacity was measured in all patients. The results of our study confirm the findings of those authors who report reduced values of DLCO and DL/VA in smokers in comparison with the nonsmokers. A linear value diminution has been noticed in smokers and nonsmokers with increasing age, with the values being much lower in smokers. Our results also demonstrate a significant correlation between DLCO and DL/VA in young healthy smokers vs the duration of smoking and the number of cigarettes smoked per day (p < 0.01). The possibility to detect early reversible damages of lung function in young healthy smokers is an important contribution to the prevention of all diseases in which causal consecutive relation with cigarette smoking is confirmed.

Adult↗
PubMed1994

Normal values for single exhalation diffusing capacity and pulmonary capillary blood flow in sitting, supine positions, and during mild exercise.

Previous approaches to the measurements of pulmonary diffusing capacity (DL) and pulmonary capillary blood flow (QC) utilized either the rebreathing or the single inhalation technique in conjunction with radioisotope gas and mass spectrometry. In the present study, we utilized a newly developed rapid infrared analyzer in conjunction with the slow single exhalation technique on 100 healthy volunteers to establish normal values for DL and QC under sitting, supine, and exercise conditions. The exercise level was determined by a target heart rate: HRex = ([HRmax - HRrest]/3) + HRrest. Prediction equations based on regressions on age, sex, height, or weight were then computed for sitting, supine, and exercise values. We found that mean DL and QC increased by approximately 12 percent and 8 percent, respectively, from sitting to supine posture, and by approximately 30 percent and 100 percent, respectively, from sitting (rest) to mild exercise. These results provided a database for further studies in the single exhalation method in various clinical settings.

Acetylene↗