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Background Pulmonary function testing is an integral part of evaluating patients who are being considered for cardiac transplantation. The accurate measurement of diffusing capacity (D lco ) and alveolar volume (VA) is dependent on a 10-s breath-holding maneuver that may be difficult for patients with congestive heart failure to perform. The intrabreath (IB) technique is not dependent on a breath-holding maneuver and may provide more accurate pulmonary function testing results in chronically debilitated patients. Methods Seventy-five patients performed maneuvers with IB and single-breath (SB) techniques during evaluation for heart transplantation and at 3 and 12 months following transplantation. The D lco , VA, and total lung capacity (TLC) were compared using Pearson correlation coefficients, a Student t test, and intercorrelation coefficients. Results The D lco and VA, when determined with the IB technique, had excellent correlations to the SB technique over all ranges of D lco values. VA values that were determined by the IB technique were greater than those determined by the SB technique and more closely approximated the TLC values. The satisfactory correlation between the two techniques was maintained when D lco was corrected for VA. However, due to the lower values for VA as determined by the SB method, the corrected measurements were consistently higher for the SB technique. Conclusion Pulmonary function can be measured accurately in a population of patients with long-standing congestive heart failure, both before and after cardiac transplantation, using the IB technique. Furthermore, the IB technique may provide a more accurate measurement of VA.

Background Serial measurements of pulmonary function to indicate decreasing respiratory muscle strength in patients with amyotrophic lateral sclerosis (ALS) is well documented. Quantitative outcome measures include declining FVC, FEV1, maximal inspired pressure, maximal expired pressure, and maximal voluntary ventilation. Increasing peak expiratory flow time (PEFT) may represent a further sensitive measure of declining respiratory muscle strength in ALS. Methods Fifty-five patients with ALS performed flow-volume loops serially after presentation. The percentage change from baseline values for FVC, peak expiratory flow (PEFR), and PEFT were compared using Spearman correlation coefficients. The prolongation of PEFT with serial tests was analyzed using a Kruskal-Wallis with a Dunn multiple comparison test. Bulbar-onset and limb-onset PEFT was compared using the Mann-Whitney test. Results PEFT was significantly increased from baseline values at all follow-up tests. However, PEFTs measured at the third, fourth, fifth, and sixth visits, although higher, were not significantly different. Significant negative correlations existed between the increase in PEFT and the decrease in PEFR and FVC. Significant positive correlations existed between the increase in PEFT and days from diagnosis and the decrease in PEFR and decrease in FVC. Conclusion PEFT increases significantly and linearly with time in patients with ALS and may begin to plateau with bulbar symptoms. PEFT increases at a faster rate than the rate of decline in both FVC and PEFR. PEFT is a quantitative measure of decreasing pulmonary function in ALS that is easily measured.