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At least 19 recordsLinked to original sources
PubMed1975

Smoking and pulmonary diffusing capacity.

The pulmonary diffusing capacity (DLCO SB) and its two components, the capillary blood volume (Vc) and the diffusing capacity of the membrane (DMCO), expressed in absolute values and per litre of alveolar volume (VA'), were measured at rest and on exercise in healthy male smokers and nonsmokers of similar age and height, and with identical values for haemoglobin and spirographic data. DLCO, DLCO/VA', DMCO and DMCO/VA' are significantly lower in smokers, at rest and on exercise; the decrease in Vc and thetaVc/VA' in smokers at rest is due to a higher level of carboxyhaemoglobin. The decrease of DLCO, DLCO/VA', DMCO and DMCO/VA' is apparently not due to carboxyhaemoglobin or distributional factors but to anatomical lesions, probably of emphysematous nature, altering the pulmonary membrane. Formulas predicting DLCO, DMCO, Vc, DLCO/VA', DMCO/VA' and thetaVc/VA' in terms of age and height were established in smokers and in nonsmokers.

Adult↗
PubMed1992

Recovery of pulmonary diffusing capacity after maximal exercise.

Pulmonary diffusing capacity (DICO), together with spirometric variables, arterial oxygen tension (paO2) and cardiac output were determined before and at intervals after maximal arm cranking, treadmill running and ergometer rowing. Independent of the type of exercise, D1CO increased immediately post-exercise from a median 13.6 (range 7.3-16.3) to 15.1 (9.3-19.6) mmol min-1 kPa-1 (P < 0.01). However, it decreased to 11.6 (6.9-15.5) mmol min-1 kPa-1 (P < 0.01) after 24 h with cardiac output and paO2 at resting values, and D1CO normalized after 20 h. Thoracic electrical impedance at 2.5 and 100 kHz increased slightly post-exercise, indicating a decrease in thoracic fluid balance, and there were no echocardiographic signs of left ventricular failure at the time of the decrease in D1CO. Also, active muscle (limb) circumference and volume, and an increase in haematocrit from 43.8 (38.0-47.0) to 47.1 (42.7-49.8) (P < 0.01), had normalized at the time of the decrease in D1CO. Vital capacity, forced vital capacity, forced expiratory volume in 1 s, peak and peak mid-expiratory flows did not change. However, total lung capacity increased from 6.8 (5.0-7.6) to 7.0 (5.1-7.8) litres (P < 0.05) immediately after exercise and remained elevated at 6.9 (5.1-8.7) litres (P < 0.05) when a decrease in D1CO was noted. The results demonstrate that independent of the type of maximal exercise, an approximate 15% reduction in D1CO takes place 2-3 h post-exercise, which normalizes during the following day of recovery.

Adult↗
PubMed1976

Time delay effects in the estimation of pulmonary diffusing capacity.

Steady state estimates of the pulmonary diffusing capacity for carbon monoxide require measurement of the uptake and the average partial pressure of CO in the lung. The expired alveolar sample obtained by different experimental methods and/or breathing patterns rarely represents the actural average alveolar partial pressure. This error in choosing the correct alveolar sample arises in the sampling time chosen by the experimental method. The time (TAV) at which the correct alveolar sample (FAV) is obtained occurs one-half of a breathing period after the effective inspiration time. If TAV and the sample time chosen by the experimental method are known then the measured diffusing capacity can be corrected to the actual diffusing capacity.

Carbon Monoxide↗
PubMed1977

Temporal effects in the estimation of pulmonary diffusing capacity.

Steady state estimates of the pulmonary diffusing capacity for carbon monoxide (DLCO) require measurement of the uptake and the average alveolar partial pressure of carbon monoxide (PACO). The expired alveolar sample obtained by different experimental methods and/or breathing patterns rarely represents the actual PACO. It is widely accepted that nonuniform distribution of ventilation, diffusion and perfusion causes discrepancies in the measurement of diffusing capacity. tan additional source of error in choosing PACO arises in the sampling time chosen by the experimental method. A theoretical study of a ramp-with-pause and a square breathing pattern demonstrates that the sample-time error exists even in the homogeneous lung. The study shows for the homogeneous lung that the correct fractional concentration of alveolar carbon monoxide (FAV) occurs at a time (TAV), one-half of a breathing period after the effective inspiration time (TI) for the two very different breathing patterns. TI is well-defined in relation to any breathing pattern which can be approximated by ramps and pauses. If TAV and the sample time chosen by the experimental method are known, then the measured DLCO can be corrected to the actual diffusing capacity (DL). The theory agrees with experimental results and computer simulations of inhomogeneous lungs from the literature. This agreement suggests that the theory for the homogeneous lung is also relevant to the inhomogeneous lung.

Carbon Monoxide↗
PubMed1978

Influence of pulmonary hypertension on pulmonary diffusing capacity in patients with mitral stenosis.

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 resistance.

Adult↗
PubMed1975

Pulmonary diffusing capacity and capillary blood volume in aging dogs.

Single-breath carbon monoxide diffusing capacity (DLco), pulmonary capillary blood volume (Vc), and membrane diffusing capacity (Dm) were measured in 24 beagle dogs aged 289-3,882 days. DLco and Vc were a function of age and alveolar volume (Va). Vc decreased with age resulting in changes in DLco. Changes in Vc may have been due to pulmonary morphological changes or to an exaggerated decrease in pulmonary blood flow in old dogs in response to 20-30 cmH-2O transpulmonary pressure. There was no age-related change in Dm.

Age Factors↗
PubMed1977

Relations of pulmonary diffusing capacity to ventilation and haemodynamics in healthy subjects.

The pulmonary diffusing capacity (DLCO) was measured in 13 healthy subjects during heart catheterization by the steady-state method (according to Bates and his coworkers). The DLCO shows the closest correlation to the tidal volume at rest, and to the central blood volume during exercise. Further, the DLCO correlates with the cardiac index both at rest and during exercise and with the stroke index at rest only. The DLCO did not show any relationship to the pressures in central circulation, pulmonary vascular resistance, total and alveolar ventilation. Statistical analysis shows that DLCO is most consistently related to the tidal volume at rest, whereas relation to central blood volume is much more stable during exercise.

Adolescent↗
PubMed1992

Changes in pulmonary diffusing capacity and blood gases in chronic obstructive lung diseases.

Pulmonary diffusing capacity (TLco) of 19 cases of chronic obstructive lung diseases (Chronic obstructive bronchitis and chronic obstructive emphysema) in the age group of 39 to 58 years (mean age: 49.8 +/- 5.5 SD years) are reported at rest in this investigation. The diffusing capacity for carbon monoxide (TLco) measured by standard methods was significantly reduced in all cases. The mean was 13.1 +/- 2.3 SD ml/min/mmHg. The blood gas findings revealed low arterial oxygen saturation (mean value: 90.2 +/- 2.2%). Arterial carbon dioxide tension was higher than in normal subjects. The mean for this series was 44.8 +/- 4.9 SD mmHg. The mean for normal subjects was 37.5 mmHg and the range 28.2 to 41.5.

Adult↗
PubMed1992

A test for the measurement of pulmonary diffusion capacity during high-intensity exercise.

The most commonly used technique for the measurement of pulmonary diffusing capacity (DL) is the single-breath hold technique requiring a 10-s breath-hold after the maximal inspiration of carbon monoxide (0.3% CO) and helium (10% He). To measure pulmonary diffusing capacity in our experiments, we had the added advantage of the use of the Gould Pulmonary Function Laboratory that automates the collection and recording of data and the calibration of equipment for each test. However, this technique, DL(CO), is difficult to use during exercise of moderate or elevated intensity because of the lengthy breath-hold. Thus, the purpose of the present study was to compare DL(CO) with 3-s and 5-s breath-holds to a 10-s breath-hold at rest and during moderate and intense exercise in 14 subjects. As expected, an increase in the DL(CO) was observed during moderate and intense exercise when compared to resting values (45.7 +/- 10.0 and 53.0 +/- 7.6 vs 32.1 +/- 7.7 ml CO min-1 mmHg-1). No difference was observed between values for DL(CO) measured at varying breath-hold times at rest (3 s: 32.9 +/- 7.4; 5 s: 32.0 +/- 7.5; 10 s: 31.4 +/- 8.2 ml CO min-1 mmHg-1) or during moderate exercise (3 s: 45.9 +/- 10.1; 5 s: 45.9 +/- 10.6; 10 s: 45.2 +/- 10.4 ml CO min-1 mmHg-1) or intense exercise (3 s: 52.1 +/- 8.3; 5 s: 54.3 +/- 9.3; 10 s: 52.6 +/- 5.2 ml CO min-1 mmHg-1). Reliability coefficients indicated that the use of a 3-s breath-hold was appropriate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Pulmonary diffusion capacity in patients with previous myocardial infarct (with respect to the influence of smoking and pulmonary congestion)].

Pulmonary diffusive capacity by the carbon monoxide method was evaluated in 43 patients two years after myocardial infarction, and without evidence of other types of heart disease. The patients did not have primary lung disease or clinic bronchitis. Special interest was given to the effects of cigarrette smoking and moderate pulmonary congestion. A significant decrease in diffusion capacity was observed in smokers and former smokers compared to none smokers. In moderate pulmonary congestive the oposite effects was registered. pO2 was decreased in half the patients with old myocardial infarction but there was no significant statistical correlations with D1co values. Mean values for pO2, pCO2, pH, EB did not show statistically valid differences among the subgroups under study. Different factors which may influence the evaluation of diffusion capacity are discussed.

Adult↗
PubMed1978

Pulmonary diffusing capacity in lambs during the early neonatal period.

A rebreathing method was used to make 53 measurements of pulmonary diffusing capacity (DLco) and functional residual capacity (FRC) in 17 newborn lambs during the first 2 days of life. DLco, FRC, and DLco/FRC all increased in studies made at 24--48 hr of age compared to those at 2--4 hr of age: DLco 0.86 +/- 0.18 to 1.52 +/- 0.09 ml/min/torr; FRC 37 +/- 10 to 60 +/- 8 ml and DLco/FRC 2.52 +/- 0.75 to 2.89 +/- 0.37 ml/min/torr/ml X 10(-2). DLco measured using 0.005% CO in the test gas was not different than that measured using 0.5% CO.

Animals↗
PubMed1992

A chronic pulmonary syndrome associated with graft-versus-host disease after allogeneic marrow transplantation.

Of 143 consecutive patients who survived at least 6 months after bone marrow transplantation (allogeneic [n = 131]; syngeneic [n = 5]; or autologous [n = 7]) and whose pulmonary function was evaluated before and on at least 2 occasions after BMT, 29 (20%) developed a chronic pulmonary syndrome without evidence for an infectious etiology. Twenty-eight (97%) presented with cough and 22 (76%) with dyspnea; abnormal chest signs were crackles in 23 (79%) and wheeze in 22 (76%). Chest roentgenogram showed pulmonary infiltrates in 15 (52%) cases but was normal in 14 (48%). All patients had major reductions in lung volumes (forced expiratory volume in 1 sec [FEV1]; relaxed vital capacity [VC]; and alveolar volume [VA]), and/or diffusing capacity (pulmonary diffusing capacity [TLCO] and single-breath carbon monoxide coefficient [KCO]). The obstructive component varied with only 18 (62%) patients developing overt airways obstruction (FEV1/VC < 75%), and in 6 of this group the fall in lung volumes preceded the onset of airways obstruction. Open lung biopsy (n = 4) showed both bronchiolitis obliterans and chronic patchy interstitial pneumonitis. The development of this syndrome was associated with acute (P < 0.001) and chronic (P < 0.0001) graft-versus-host disease of other organ systems. Twenty-four (83%) patients had a partial or complete response to immunosuppressive agents. Six (21%) have died, five (17%) of pulmonary complications. We suggest that this syndrome may be a manifestation of chronic GVHD involvement of the lung.

Adolescent↗
PubMed1979

Effect of hyperlipidaemia on pulmonary diffusing capacity for carbon monoxide.

There is conflicting evidence on the effect of hyperlipidaemia on pulmonary diffusing capacity for carbon monoxide (DLCO or TLCO) in man. We have measured the carbon monoxide transfer factor per unit alveolar volume (TLCO/VA or KCO) by the single breath method in 25 patients with hyperlipidaemia, and in three normal subjects before and after infusions of an intravenous fat emulsion, Intralipid. Non-smokers with hyperlipidaemia had normal levels of TLCO/VA, whereas some of the smokers showed a slight reduction. In neither group was there any correlation of TLCO/VA with serum triglyceride or cholesterol concentrations. A reduction in triglyceride concentrations of up to five-fold produced by plasma exchange (three studies in two patients) or by dietary manipulation (one patient) had no significant effect on the levels of TLCO/VA. Intralipid infusion in three normal subjects caused a four- to five-fold increase in serum triglyceride concentration but had no effect on TLCO/VA. We conclude that moderate degrees of hyperlipidaemia have no effect on pulmonary diffusion.

Adult↗
PubMedDate not supplied

Comparison of single breath and steady state methods for the measurement of pulmonary diffusing capacity for carbon monoxide in normal subjects, patients with bronchial asthma and chronic obstructive airway disease.

The results of pulmonary diffusing capacity (DLCO) measurements by the steady state (DLCOss) and single breath (DLCOsb) methods were compared in 50 normal subjects (Group A), 50 patients with bronchial asthma (Group B) and 50 patients with chronic obstructive lung disease (COAD) (Group C). A significant correlation was observed between DLCOss and DLCOsb in all the three groups of subjects. This relationship was stronger in Groups A and B as compared to Group C. Both DLCOsb and DLCOss were significantly correlated to parameters of air-flow obstruction. Both measurements of DLCO appear valid in normal subjects and in patients with bronchial asthma. In patients with COAD, on the other hand, DLCOsb may be valid measurement, since it is less likely to be influenced by airways obstruction.

Adult↗