Ninety subjects (40 men and 50 women) were studied. All subjects lived in Chonnam Province. They were mainly members of the Chonnam University Hospital, medical students, relatives of patients, and persons visiting the hospital for regular physical checkups.
Subjects were screened to select a population of disease-free nonsmokers. Normal was defined as having no history of (1) smoking, (2) asthma, chronic bronchitis, pneumonia or cardiac disease, (3) persistent cough, (4) recent treatment for any respiratory or cardiac symptoms, (5) chest injury or operation, (6) working in a polluted atmosphere for any extended period, finally, no evidence of cardiopulmonary disease on a physical examination, an EKG, or a chest radiograph.
Height, weight, and hemoglobin concentration were measured. The DLCO was measured by the modified Krogh’s single-breath method, using the SRL 1000IV Computerized Pulmonary Function Laboratory, Gould Co., USA.
With the subjects in the sitting position, their noses were clamped and initial maximal exhalation was followed by maximal inhalation of the test gas (contained 0.3%CO and 10%He). After a 10-second holding of the breath the exhaled gas was collected in a sample bag, and the sampling was analyzed for CO and He. Then the DLCO was calculated as follows:
The correlations based on the diffusion capacity of the lung and the physical characteristics, such as age, height, weight and body surface area were observed. And prediction formulas were derived from the variables for both sexes, using a computer system (SPSS Batch System).
Subjects were screened to select a population of disease-free nonsmokers. Normal was defined as having no history of (1) smoking, (2) asthma, chronic bronchitis, pneumonia or cardiac disease, (3) persistent cough, (4) recent treatment for any respiratory or cardiac symptoms, (5) chest injury or operation, (6) working in a polluted atmosphere for any extended period, finally, no evidence of cardiopulmonary disease on a physical examination, an EKG, or a chest radiograph.
Height, weight, and hemoglobin concentration were measured. The DLCO was measured by the modified Krogh’s single-breath method, using the SRL 1000IV Computerized Pulmonary Function Laboratory, Gould Co., USA.
With the subjects in the sitting position, their noses were clamped and initial maximal exhalation was followed by maximal inhalation of the test gas (contained 0.3%CO and 10%He). After a 10-second holding of the breath the exhaled gas was collected in a sample bag, and the sampling was analyzed for CO and He. Then the DLCO was calculated as follows:
VA: Alveolar volume (STPD)
60: Correction from seconds to minutes
PB: Barometric pressure
47: Water vapor pressure (PH2O)
t2–t1: Breath holding interval
Ln: Natural logarithm
FACOt1: Fraction of CO in alveolar gas before diffusion
FACOt2: Fraction of CO in alveolar gas at the end of diffusion
The correlations based on the diffusion capacity of the lung and the physical characteristics, such as age, height, weight and body surface area were observed. And prediction formulas were derived from the variables for both sexes, using a computer system (SPSS Batch System).
