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Overall and peripheral inhomogeneity of ventilation in patients with stable cystic fibrosis
Author(s) -
Van Muylem Alain,
Baran D.
Publication year - 2000
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/1099-0496(200007)30:1<3::aid-ppul2>3.0.co;2-l
Subject(s) - medicine , nitrogen washout , cystic fibrosis , ventilation (architecture) , washout , functional residual capacity , exacerbation , peripheral , gastroenterology , respiratory system , respiratory disease , anesthesia , lung , lung volumes , mechanical engineering , engineering
We studied distribution of ventilation in patients with cystic fibrosis (CF) who had not had an exacerbation for some time. Patients performed either the vital capacity nitrogen (N 2 ) single‐breath washout test (VC test) or a modified single‐breath washout consisting of 1 L inspired from functional residual capacity (FRC test) of 90% oxygen (O 2 ), 5% helium (He), and 5% sulfur hexafluoride (SF 6 ). We computed the slopes of phase III of N 2 concentration from the VC test (S N2 (VC)) and the phase III slopes of the He (S He ): The SF 6 (S SF6 ), and curves from the FRC test. S N2 (VC) may be regarded as an index of overall ventilation and the difference (S SF6 − S He ) as an index of peripheral ventilation. Three groups were studied: CF, 28 CF patients (8–36 years of age); normal controls (NC), 33 normal nonsmokers (9–55 years of age); and a smoking group (SG), 42 non‐CF smoking patients (39–79 years of age). Compared to the NC group, S N2 (VC) is increased in the CF group, reflecting an overall ventilation impairment. There is no difference in S N2 (VC) between the CF group and the SG group, suggesting that S N2 , though sensitive, is nonspecific. Compared to both NC and SG groups, (S SF6 − S He ) is decreased in the CF group, being on the average negative. This may imply that there is a peripheral impairment in the distribution of ventilation that originates in terminal and respiratory bronchioles. Negative (S SF6 − S He ) is statistically associated with the youngest CF patients, suggesting that terminal and respiratory bronchiolar involvement is linked to early stages of the disease. In older CF patients, (S SF6 − S He ) is more often positive, suggesting that even more distal airways, such as alveolar ducts, become involved in peripheral inhomogeneity of ventilation. Pediatr Pulmonol. 2000; 30:3–9. © 2000 Wiley‐Liss, Inc.