Distal lung dysfunction at night in nocturnal asthma.

Published

Journal Article

We have previously shown that patients with nocturnal worsening of asthma (nocturnal asthma) exhibit increased parenchymal inflammation at night. To evaluate the functional significance of this parenchymal inflammation, 10 subjects with nocturnal asthma (NA), four subjects with non-nocturnal asthma (NNA), and four normal control subjects underwent bronchoscopy with measurement of peripheral airways resistance (Rp) at 4:00 P.M. and at 4:00 A.M. Employing a wedged bronchoscope technique, Rp was measured. Flow was stopped, and the pressure reached after 10 s of decay was termed the plateau pressure. The time constant of this decay (tau) was measured, and the peripheral compliance (Cp) was calculated as tau/Rp. The NA group exhibited the highest Rp values at 4:00 P.M. and at 4:00 A.M. as compared with the NNA and control groups, but all groups were significantly different from each other at 4:00 P.M.: NA, 0.113 +/- 0.02 cm H(2)O/ml/min; NNA, 0.033 +/- 0.005 cm H(2)O/ml/min; Control subjects, 0.010 +/- 0.001 cm H(2)O/ ml/min; p = 0.0001; and at 4:00 A.M.: NA, 0.129 +/- 0.023 cm H(2)O/ ml/min; NNA, 0.035 +/- 0.007 cm H(2)O/ml/min; Control subjects, 0.009 +/- 0.002 cm H(2)O/ml/min; p = 0.0003. None of the groups exhibited statistically significant differences in Rp between 4:00 P.M. and 4:00 A.M. The plateau pressure increased significantly from 4:00 P.M. to 4:00 A.M., but only in the NA group (7.7 +/- 0.9 cm H(2)O at 4:00 P.M. versus 16.9 +/- 4.6 cm H(2)O at 4:00 A.M.; p = 0.0004). Cp was decreased in the NA group as compared with the NNA and control groups at both 4:00 P.M. (p = 0.0003) and 4:00 A.M. (p = 0.003). The Rp positively correlated with the residual volume at both 4:00 P.M. (r = 0.71, p = 0.004) and 4:00 A.M. (r = 0.59, p = 0.03). We conclude that the distal lung units, specifically the collateral channels, and may be functionally altered at night in NA.

Full Text

Cited Authors

  • Kraft, M; Pak, J; Martin, RJ; Kaminsky, D; Irvin, CG

Published Date

  • June 2001

Published In

Volume / Issue

  • 163 / 7

Start / End Page

  • 1551 - 1556

PubMed ID

  • 11401872

Pubmed Central ID

  • 11401872

Electronic International Standard Serial Number (EISSN)

  • 1535-4970

International Standard Serial Number (ISSN)

  • 1073-449X

Digital Object Identifier (DOI)

  • 10.1164/ajrccm.163.7.2008013

Language

  • eng