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Comparison of Four Methods for Calculating Diffusing Capacity by the Single Breath Method: Conclusion
Our results with the 3PIT method can be only loosely compared with results of Graham et al who documented the differences in Deo using Og, JM, ESP, and three-equation methods in patients with emphysema, asthma, and cystic fibrosis. For both Og and JM methods, Graham et al allowed a 1-L dead space washout volume and […]
Comparison of Four Methods for Calculating Diffusing Capacity by the Single Breath Method: Discussion
Our main findings are as follows: (1) the singlebreath Deo was largest using the ESP timing method compared with JM, 3PIT, and Og methods (in decreasing order of mean Deo); (2) the difference between Deo using Og, JM, and 3PIT methods was small in patients with normal pulmonary function and became less in patients with […]
Comparison of Four Methods for Calculating Diffusing Capacity by the Single Breath Method: Results
The mean percents of predicted values for pulmonary function variables are listed in Table 2, categorized by pulmonary function abnormalities. Mean and SD values for Deo and the mean WP-SD of Deo by the various protocols are listed in Table 3 using the same categorization. The ESP protocol resulted in the largest Deo, followed by […]
Comparison of Four Methods for Calculating Diffusing Capacity by the Single Breath Method: Standard Deviation
Predicted values were taken from Miller et al for Deo and TLC, and Miller for FVC and FEV,. Standing height (cm) without shoes and weight (kg) were measured immediately prior to pulmonary function evaluation. These categories are used as a framework within which to illustrate the dependence of the differences among Deo values on pulmonary […]
Comparison of Four Methods for Calculating Diffusing Capacity by the Single Breath Method: Pulmonary Function Abnormalities
For the 3PIT method, we used the iterative search procedure as described by Graham et al. The process started with a calculation of residual volume, RV = VA — IVC + VDS. Equations 6 (inspiration), 7 (breath hold), and 9 (expiration) of Graham et al were then used to iteratively calculate Deo. In equation 6, […]
Comparison of Four Methods for Calculating Diffusing Capacity by the Single Breath Method: Methods
Several technical abbreviations are used in the text (Table 1). Data were analyzed from diffusing capacity tests of patients referred to our outpatient pulmonary function testing laboratoiy. We did not screen the patients so that the patient population tested represents a typical sampling of patients referred to our laboratory for routine testing. The diffusing capacity […]
Comparison of Four Methods for Calculating Diffusing Capacity by the Single Breath Method
The diffusing capacity of the lungs for carbon monoxide (Deo) can be estimated by a number of techniques, including steady state, single breath, and rebreathing. The single-breath method is most commonly used in the United States, probably because of better standardization and because it does not require a rapid CO analyzer. In the singlebreath method, […]