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PubMed1987

Effect of indoor feeding season for cattle on lung function of dairy farmers.

The effect of the indoor feeding season for cattle on pulmonary function was studied in 91 randomly selected healthy, non-smoking dairy farmers who did not use personal dust respirators. All the farmers lived in the rural municipality of Pielavesi in eastern Finland. The reference group consisted of 90 healthy, non-smoking urban dwellers who were teachers randomly selected from all the teachers employed by the city of Kuopio (situated in the same administrative district as Pielavesi). Studies of pulmonary function included flow-volume spirometry and measurement of pulmonary diffusing capacity. Among farmers, even a follow-up period of only 6 months was long enough to reveal restrictive impairment in lung function; among teachers restrictive impairment was not found. No evidence of impairment of pulmonary diffusing capacity was found in either of the study groups during the follow-up. Among teachers, changes in lung function did not differ from those previously reported as physiologically normal.

Adult↗
PubMed1991

[Studies on wedged hepatic venous pressure, hemodynamics and pulmonary function in patients with chronic liver disease, with reference to the differences between liver cirrhosis with chronic hepatitis].

In 17 compensated liver cirrhosis and 8 chronic hepatitis cases (no histories of cardiac or pulmonary disease), wedged hepatic venous pressure (WHVP), hemodynamics, and pulmonary function were measured and their clinical significance and interrelations evaluated. Both diseases were comparatively analyzed. WHVP was determined by wedging a catheter from the right femoral vein into the right hepatic vein. Hemodynamics was measured with a Swan-Ganz catheter. Spirography, flow-volume curve, closing-volume curve and pulmonary diffusion capacity were measured and aortic blood gas analyzed to assess pulmonary function. Esophageal endoscopy was used to diagnose the presence or absence of esophageal varices. The results showed that the group of liver cirrhosis patients featured elevated WHVP and a hyperhemodynamic pattern and a positive correlation between WHVP on the one hand and cardiac index and right left ventricle stroke work indexes on the other; there was a negative correlation between WHVP and the systemic vascular resistance and pulmonary vascular resistance indexes. The results showed an increase in oxygen consumption in the group of patients with esophageal varices. In all chronic hepatitis cases, findings were normal. Pulmonary function was characterized by abnormal %VC, PaO2, and pulmonary diffusion capacity in both groups along with abnormal PaCO2 in the liver cirrhosis group; no significant differences were noted between the two groups. These results indicate that liver cirrhosis elevates intarahepatic pressure, affecting systemic hemodynamics and resulting in a circulatory distribution disorder, leading to right and left ventricle overload and a decline in potential cardiac function. The results also indicated that mild pulmonary function disorder can occur as early in a state of chronic hepatitis.

Adult↗
PubMed1975

Pulmonary microembolism associated with massive transfusion: II. The basic pathophysiology of its pulmonary effects.

In animals pulmonary hypertension, a decrease in total body O2 consumption and metabolic acidosis occur after transfusion of blood with an elevated screen filtration pressure (SFP) through standard blood transfusion filters. The purpose of this study was to define in detail the pulmonary abnormalities that develop following transfusion of blood with an elevated SFP through standard blood transfusion filters. Exchange transfusions of approximately twice blood volume were administered through standard commercially available blood transfusion filters (measured pore size--200 microns) to 6 animals. SFP measurements verified the presence of large numbers of aggregates in the transfusions. Although filters reduced SFP of the stored blood somewhat, numerous microaggregates passed the filters, and post-filtration SFP remained high. After transfusion average O2 consumption decreased to 77% of normal and metabolic acidosis developed. Pulmonary arterial hypertension was associated with an increase in pulmonary shunting of blood and a decrease in pulmonary diffusing capacity. The presence of extensive numbers of microemboli in the pulmonary arteriolar and capillary bed was confirmed by microscopic examination of lung tissue.

Acidosis↗
PubMed1977

Oxygen transport system during exhaustive exercise in Japanese boys.

The study was designed to investigate the age-related increase in maximal oxygen uptake with special reference to the other physiological parameters (ventilation, pulmonary diffusing capacity, cardiac output etc.). 77 normal boys aged 10-18 years were tested by the progressive loading method on a bicycle ergometer. VO2 max increased by approximately 55% with the age from 10-18 years. The increase in VO2 max was accompanied with increase in ventilation (49%), pulmonary diffusing capacity (45%) and cardiac output (5%).

Adolescent↗
PubMed1998

Stratification does not limit O2 uptake in rabbit lungs.

This study was performed to assess the role of stratification, i.e. axial gas mixing deficit within alveolar space, in limiting alveolar gas exchange for oxygen. The single-breath method for varying breath-holding time with oxygen-labelled carbon dioxide, C18O2, was applied to 10 anaesthetized, paralysed and artificially ventilated rabbits. Alveolar partial pressure of C18O2 was analysed using respiratory mass spectrometry. Starting from residual volume, the lungs were rapidly inflated using 40 mL of indicator gas mixture (1% C18O2 in nitrogen). After executing breath-holding, the lungs were rapidly deflated. Pulmonary diffusing capacity of carbon monoxide was determined in the same way. On the basis of a serial compartment model, the lower limit of the stratificational conductance of oxygen was estimated, using the rate constant of C18O2 removal from alveolar space (4 s-1) and Graham's law. We found that the stratificational conductance in rabbits amounts to at least 13.5 mL mmHg-1 min-1. The pulmonary diffusing capacity of oxygen was calculated by multiplying the carbon monoxide diffusing capacity of rabbit lungs by a factor of 1.2, yielding a value of 0.77 mL mmHg-1 min-1. These results show that stratificational conductance is at least 17.5 times higher than pulmonary oxygen diffusing capacity, indicating that stratification does not limit oxygen uptake in rabbit lungs.

Animals↗
PubMed1999

Arterial blood oxygenation, maximum exercise capacity and oxygen transport in patients before and after autologous peripheral blood progenitor cell transplantation.

Several studies have reported a reduced pulmonary diffusion capacity for carbon monoxide after total body irradiation (TBI) and/or high-dose chemotherapy (HDCT) and autologous peripheral blood progenitor transplantation (APBPC). The present study describes the oxygenation of arterial plasma (paO2), the maximum exercise capacity (Wmax) and maximum oxygen transport (VO2max) before and after such treatment. Pulmonary gas exchange and paO2 were measured in 15 patients at maximum dynamic bicycle exercise, performed before and at 8+/-0.9 (s.e.m.) months after TBI/HDCT (n = 12) and HDCT (n = 3) followed by APBPC. Wmax was 169+/-14 and 157+/-15 watts (P>0.05) before and after therapy, respectively. VO2max, 1.8+/-0.1 l/min before treatment, fell to 1.6+/-0.1 l/min (P<0.05) after therapy. The maximum exercise paO2 was 13.2+/-0.4 kPa before and 13.6+/-0.4 kPa (P>0.05) after the treatment period. The findings indicate no significant reduction of Wmax or pulmonary diffusion capacity for O2 after TBI/HDCT and APBPC while VO2max fell modestly by approximately 11%. The study was restricted to patients who remained in remission.

Adult↗
PubMed1976

Carbon monoxide diffusing capacity in newborn infants.

In order to test the role of diffusing capacity in determining the arterial oxygen tension of newborn infants, pulmonary diffusing capacity for carbonmonoxide (DLCO) was measured in 21 healthy infants ranging in weight from 765 to 4,720 g. DLCO infants without respiratory distress correlated well with lung volume (r=0.76, P less than 0.001). A smaller correlation (r = 0.39, P less than 0.01) was obtained between DLCO and arterial oxygen tension. DLCO per unit volume of lung is similar when healthy premature infants, full term infants, and normal adults are compared. The wide range of normal values obtained in resting infants and the lack of correlation with arterial oxygen tensions are similar to observations made in adults.

Birth Weight↗
PubMedDate not supplied

Alteration of pulmonary function by filtration of intravenous nutrient mixture.

In view of contradicting results concerning alteration in lung function during hyperalimentation and the administration of intravenous lipid emulsion, a study was planned to determine possible changes in pulmonary blood perfusion during administration of total nutrient admixture (TNA) and the effect of filtration. Sixteen patients (8 men, 8 women; mean age 65.6 yr) with no previous lung disease received TNA at the rate of 4-5 g lipid/h as preoperative treatment for 5-9 days (mean 6.7 days). The 5-microns filter was randomly used in eight patients. The lung blood perfusion parameters measured repeatedly during this period included blood gases, percentage of the predicted value of vital capacity (VC), and pulmonary diffusing capacity for carbon monoxide (DLCO), as well as the value of the dead space volume and the tidal volume ratio (VD/VT) and the calculated shunt (QS/QT). TNA infusion appears to cause only a slight decrease in PaO2 and DLCO and a similar increase in VC and QS/QT, whereas VD/VT decreased significantly. The latter effect was abolished by filtration of TNA. There were no significant differences between the two groups. We therefore conclude that short-term preoperative administration of TNA at the rate of 4-5 g lipid/h in patients without preexisting lung disease does not jeopardize lung functions. Filtration of the TNA is, however, recommended to avoid the potential hazardous effects of long-term treatment of TNA on lung function.

Aged↗
PubMed1991

Acute recovery profile of lung volumes and function after running 5 miles.

The purpose of this study was to characterize the acute changes and recovery profile of lung volumes and function subsequent to strenuous aerobic exercise. Eight experienced runners (X age = 25 yrs; wt = 73 kg; ht = 181 cm) completed three identical 5 mile runs. Determinations were made of forced vital capacity (FVC), residual volume (RV), closing capacity (CC), and pulmonary diffusion capacity (DLCO). Measurement of cardiac output (Q) and stroke volume (SV) occurred simultaneously with the 10 second DLCO breathhold maneuver. Measurements were obtained before and 5, 15 and 25 minutes after each run. FVC was reduced (-4.5%) 5 min post-run with a return to pre-run values by 15 min. CC (+16%) and RV (+18%) remained elevated for at least 30 min post-run. DLCO did not appear to be effected by the run. However, the single-breath DLCO breathhold maneuver consistently caused a fall in SV at rest and during recovery. The hypothesis has been forwarded that an increase in central blood volume post-run accounted for the acute reduction in FVC. The sustained elevation in RV resulted from early closure of the small airways possibly due to an increase in extra-vascular lung water.

Adult↗
PubMed1994

Alveolar-capillary gas transfer in lungs: development of concepts and current state.

Progress in research on pulmonary gas exchange, with special reference to the contribution of Gerhard Thews and associates, is reviewed. In particular, the following aspects are considered. (1) Oxygen transfer kinetics of red blood cells. Recent measurements, particularly on red blood cells in thin blood films, yield more rapid equilibration kinetics than previously recorded. A reevaluation of the roles of diffusion and chemical reaction in alveolar O2 uptake may become necessary. (2) Gas exchange in functionally inhomogeneous lungs. Besides the classical ventilation/perfusion (VA/Q) inequality, a variation of the diffusing capacity-to-perfusion ratio (DL/Q) appears to be of importance. The combination of VA/Q and DL 1Q inequalities may lead to a better understanding of alveolar gas exchange, particularly in diseased lungs. (3) Pulmonary diffusing capacity (DL) for oxygen. The rebreathing technique, which strongly reduces the effects of inequal VA/Q distribution effects, appears to be particularly suited for measurement of overall alveolar-capillary diffusion. But neither the factors determining DL, obtained by rebreathing or other methods, nor the relationships between DL for various gases are yet fully understood.

Animals↗
PubMed1996

Temporal course of gas exchange and mechanical compensation after right pneumonectomy in immature dogs.

To determine the temporal progression and magnitude of functional compensation in immature dogs raised to maturity after extensive lung resection, we performed right pneumonectomy (R-Pnx) or right thoracotomy without pneumonectomy (Sham) in matched foxhounds at 2 mo of age. At 4, 8, 20, 40, and 60 wk after surgery, static transpulmonary pressure-lung volume relationships were determined. Lung diffusing capacity, membrane diffusing capacity, pulmonary capillary blood volume, pulmonary blood flow, septal lung tissue volume, and lung volumes were measured simultaneously by a rebreathing technique. During maturation, total lung capacity, lung volume at a given distending pressure, and compliance were lower in the R-Pnx group than in the Sham group (P < 0.05). Pulmonary viscous resistance at maturity was elevated after R-Pnx. There were no significant differences in total lung diffusing capacity, membrane diffusing capacity, pulmonary capillary blood volume, pulmonary blood flow, and septal lung tissue volume between groups. Compensation of alveolar-capillary gas exchange was complete by 4-8 wk after R-Pnx, but compensation of mechanical properties remained incomplete throughout maturation. Relative magnitude of compensation after R-Pnx was greater in immature dogs than in adult dogs studied previously by similar techniques.

Airway Resistance↗
PubMed1998

[The inhalation versus systemic prevention of pneumonitis during thoracic irradiation].

BACKGROUND: Pneumonitis is a typical subacute reaction of healthy bronchial tissue to thoracic irradiation. The purpose of the present trial was to show whether prophylactic application of steroids in the course of and following radiotherapy would reduce the incidence of pneumonitis. PATIENTS AND METHODS: Fifty-seven patients receiving thoracic irradiation for bronchial carcinoma were assigned to 2 therapeutic groups; half of the patients were given 10 mg of oral prednisolone per day, while the other half received daily inhalative beclomethasone. All patients were evaluated for radiographic signs of pneumonitis. Thirty-two patients received additional investigations for pulmonary diffusion capacity of carbon monoxide. RESULTS: The overall incidence of pneumonitis was 17.6% (10/57 patients). Neither total radiation dose nor mode of fractionation did significantly contribute to the incidence of pneumonitis. Those patients showing a pulmonary diffusion capacity for carbon monoxide of less than 60% prior to radiotherapy had a significantly higher risk of developing pneumonitis (4/7) than patients with a higher diffusion capacity (3/25, p = 0.026). In follow-up period we did not see significant changes in diffusion capacity neither with patients who developed pneumonitis nor with those patients showing no evidence of pulmonary injury. Comparing the chest X-ray there were less radiographic changes consistent with pneumonitis in the inhalative beclomethasone (2/28) than in the oral prednisolone group (8/29, p = 0.045). DISCUSSION: In order to reduce the incidence of pneumonitis in patients receiving thoracic irradiation we support a continuous application of steroids in the course of and following radiotherapy. The inhalative use of beclomethasone has proved to be superior to oral prednisolone due to better local efficacy and decreased unwanted side effects.

Administration, Inhalation↗
PubMed1981

Nonlinear increases in diffusing capacity during exercise by seated and supine subjects.

To study the effects of exercise on pulmonary diffusing capacity, we measured the lungs' diffusing capacity for carbon monoxide (DLCO) during exhalation from 30 to 45% exhaled vital capacity in eight healthy subjects at rest and during exercise while both sitting and supine. We found that DLCO at these lung volumes in resting subjects was 26.3 +/- 3.2% (mean +/- SE) higher in the supine than in the sitting position (P less than 0.001). We also found that, in both positions, DLCO at these lung volumes increased significantly (P less than 0.001) with increasing exercise and approached similar values at maximal exercise. The pattern of increase in DLCO with an increase in oxygen consumption in both positions was curvilinear in that the rate of increase in DLCO during mild exercise was greater than the rate of increase in DLCO during heavy exercise (P = 0.02). Furthermore, in the supine position during exercise, it appeared that DLCO reached a physiological maximum.

Adult↗
PubMed1995

Critique of conceptual basis of diffusing capacity estimates: a finite element analysis.

We present a simple geometric model of a pulmonary capillary segment containing a variable number of red blood cells. The pattern of CO transfer from alveolar air to capillary red blood cells in this model is accurately computed by a finite element method and used to explore conceptual flaws in the Roughton-Forster (RF) and morphometric methods of estimating pulmonary diffusing capacity for CO. The CO uptakes calculated by the finite element method at two alveolar O2 tensions are introduced into the RF model to determine whether the anatomically defined membrane component of diffusing capacity for CO (DmCO) and pulmonary capillary blood volume (Vc) are recovered. The same capillary model is also subjected to standard morphometric analysis. Results are compared at different levels of capillary hematocrit (Hct). The RF method accurately recovers DmCO and Vc at a low Hct but modestly overestimates DmCO and underestimates Vc at higher Hct; errors arise because conductance of the tissue-plasma membrane for CO varies with alveolar O2 tension. The morphometric method seriously overestimates DmCO because the true tissue-plasma resistance to diffusion is underestimated and the effective membrane utilized for diffusion is overestimated; these errors are accentuated by a low Hct.

Animals↗
PubMed1994

Increased alveolar/capillary membrane resistance to gas transfer in patients with chronic heart failure.

OBJECTIVE: To investigate pulmonary diffusive resistance to gas exchange in patients with heart failure and healthy volunteers, assessing the relative contributions of the alveolar/capillary membrane and pulmonary capillary blood. SETTING: Hospital outpatient department and pulmonary function laboratory. PATIENTS: 38 patients (mean age 60) receiving treatment with loop diuretics and angiotensin converting enzyme inhibitors for stable symptomatic heart failure of > 6 months duration (New York Heart Association (NYHA) classes II and III). Results were compared with those of 17 healthy volunteers (mean age 52). METHODS: The alveolar/capillary membrane diffusive resistance and the pulmonary capillary blood volume available for physiological gas exchange were determined by the Roughton and Forster method, which measures the single breath pulmonary diffusing capacity for carbon monoxide at varying alveolar oxygen concentrations. RESULTS: Total pulmonary diffusive resistance was higher in patients than controls. Alveolar/capillary membrane resistance formed the main component of this increase, accounting for a mean (SD) of 63% (20%) and 86% (8%) of total pulmonary diffusive resistance in patients in NYHA II and III classes respectively, compared with 53% (10%) in controls. The pulmonary capillary blood volume was not significantly different between controls and patients in NYHA class II (66 (18) ml v 61 (18) ml), but was increased in those in NYHA class III (95(46) ml, P < 0.05). CONCLUSION: This study confirmed impairment of pulmonary diffusion at rest in patients with chronic heart failure and identified impaired alveolar/capillary membrane function as the main factor responsible.

Adult↗
PubMed1993

Optimal pulmonary arterial blood pressure.

Based on the principle of minimum power, a mathematical model of the functional state of the pulmonary circulatory and respiratory systems is presented. The optimization model minimizes the power expended by the right heart and respiratory muscles. The pulmonary diffusing capacity control mechanism is considered. Mean pulmonary arterial blood pressure and ventilation are determined depending on oxygen transport parameters for man under normal and chronic pathological conditions. Theoretical results are compared with clinical data.

Adult↗