TY - JOUR
T1 - Impaired lung diffusing capacity for nitric oxide and alveolar-capillary membrane conductance results in oxygen desaturation during exercise in patients with cystic fibrosis
AU - Wheatley, Courtney M.
AU - Foxx-Lupo, William T.
AU - Cassuto, Nicholas A.
AU - Wong, Eric C.
AU - Daines, Cori L.
AU - Morgan, Wayne J.
AU - Snyder, Eric M.
N1 - Funding Information:
We are sincerely grateful to the CF subjects who willingly donated their time and effort to be involved in this study. This study was funded by the University of Arizona Clinical Scholars program . CWW, WTL, NAC, ECW, and EMS were responsible for study design, data collection and analysis and manuscript writing. WJM and CLD were responsible for recruitment and manuscript writing.
PY - 2011/1
Y1 - 2011/1
N2 - Background: Exercise has been shown to be beneficial for patients with cystic fibrosis (CF), but for some CF patients there is a risk of desaturation, although the predicting factors are not conclusive or reliable. We sought to determine the relationship between the diffusion capacity of the lungs for nitric oxide and carbon monoxide (DLNO and DLCO) and the components of DLCO: alveolar-capillary membrane conductance (DM), and pulmonary capillary blood volume (VC) on peripheral oxygen saturation (SaO2) at rest and during exercise in CF. Methods: 17 mild/moderate CF patients and 17 healthy subjects were recruited (age=26±7 vs. 23±8 years, ht=169±8 vs. 166±8 cm, wt=65±9 vs. 59±8 kg, BMI=23±3 vs. 22±3 kg/m2, VO2PEAK=101±36 vs. 55±25%pred., FEV1=92±22 vs. 68±25%pred., for healthy and CF, respectively, mean±SD, VO2PEAK and FEV1 p<0.001). Subjects performed incremental cycle ergometry to exhaustion with continuous monitoring of SaO2 and measures of DLNO, DLCO, DM and VC at each stage. Results: CF patients had a lower SaO2 at rest and peak exercise (rest=98±1 vs. 96±1%, peak=97±2 vs. 93±5%, for healthy and CF, respectively, p<0.01). At rest, DLNO, DLCO, DM were significantly lower in the CF group (p<0.01). The difference between groups was augmented with exercise (DLNO=117±4 vs. 73±3ml/min/mmHg; DLCO=34±8 vs. 23±8ml/min/mmHg; DM=50±1 vs. 34±1, p<0.001, for healthy and CF respectively). Peak SaO2 was related to resting DLNO in CF patients (r=0.65, p=0.003). Conclusions: These results suggest a limitation in exercise-mediated increases in membrane conductance in CF which may contribute to a drop in SaO2 and that resting DLNO can account for a large portion of the variability in SaO2.
AB - Background: Exercise has been shown to be beneficial for patients with cystic fibrosis (CF), but for some CF patients there is a risk of desaturation, although the predicting factors are not conclusive or reliable. We sought to determine the relationship between the diffusion capacity of the lungs for nitric oxide and carbon monoxide (DLNO and DLCO) and the components of DLCO: alveolar-capillary membrane conductance (DM), and pulmonary capillary blood volume (VC) on peripheral oxygen saturation (SaO2) at rest and during exercise in CF. Methods: 17 mild/moderate CF patients and 17 healthy subjects were recruited (age=26±7 vs. 23±8 years, ht=169±8 vs. 166±8 cm, wt=65±9 vs. 59±8 kg, BMI=23±3 vs. 22±3 kg/m2, VO2PEAK=101±36 vs. 55±25%pred., FEV1=92±22 vs. 68±25%pred., for healthy and CF, respectively, mean±SD, VO2PEAK and FEV1 p<0.001). Subjects performed incremental cycle ergometry to exhaustion with continuous monitoring of SaO2 and measures of DLNO, DLCO, DM and VC at each stage. Results: CF patients had a lower SaO2 at rest and peak exercise (rest=98±1 vs. 96±1%, peak=97±2 vs. 93±5%, for healthy and CF, respectively, p<0.01). At rest, DLNO, DLCO, DM were significantly lower in the CF group (p<0.01). The difference between groups was augmented with exercise (DLNO=117±4 vs. 73±3ml/min/mmHg; DLCO=34±8 vs. 23±8ml/min/mmHg; DM=50±1 vs. 34±1, p<0.001, for healthy and CF respectively). Peak SaO2 was related to resting DLNO in CF patients (r=0.65, p=0.003). Conclusions: These results suggest a limitation in exercise-mediated increases in membrane conductance in CF which may contribute to a drop in SaO2 and that resting DLNO can account for a large portion of the variability in SaO2.
KW - Cystic fibrosis
KW - DLCO
KW - DLNO
KW - Exercise
KW - Lung diffusion
KW - Peripheral oxygen saturation
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U2 - 10.1016/j.jcf.2010.09.006
DO - 10.1016/j.jcf.2010.09.006
M3 - Article
C2 - 21050829
AN - SCOPUS:78651455569
VL - 10
SP - 45
EP - 53
JO - Journal of Cystic Fibrosis
JF - Journal of Cystic Fibrosis
SN - 1569-1993
IS - 1
ER -