PT  - JOURNAL ARTICLE
AU  - M. Pecchiari
AU  - T. Anagnostakos
AU  - E. D'Angelo
AU  - C. Roussos
AU  - S. Nanas
AU  - A. Koutsoukou
TI  - Effect of heliox breathing on flow limitation in chronic heart failure patients
AID  - 10.1183/09031936.00117508
DP  - 2009 Jun 01
TA  - European Respiratory Journal
PG  - 1367--1373
VI  - 33
IP  - 6
4099  - http://erj.ersjournals.com/content/33/6/1367.short
4100  - http://erj.ersjournals.com/content/33/6/1367.full
SO  - Eur Respir J2009 Jun 01; 33
AB  - Patients with chronic heart failure (CHF) exhibit orthopnoea and tidal expiratory flow limitation in the supine position. It is not known whether the flow-limiting segment occurs in the peripheral or central part of the tracheobronchial tree. The location of the flow-limiting segment can be inferred from the effects of heliox (80% helium/20% oxygen) administration. If maximal expiratory flow increases with this low-density mixture, the choke point should be located in the central airways, where the wave-speed mechanism dominates. If the choke point were located in the peripheral airways, where maximal flow is limited by a viscous mechanism, heliox should have no effect on flow limitation and dynamic hyperinflation. Tidal expiratory flow limitation, dynamic hyperinflation and breathing pattern were assessed in 14 stable CHF patients during air and heliox breathing at rest in the sitting and supine position. No patient was flow-limited in the sitting position. In the supine posture, eight patients exhibited tidal expiratory flow limitation on air. Heliox had no effect on flow limitation and dynamic hyperinflation and only minor effects on the breathing pattern. The lack of density dependence of maximal expiratory flow implies that, in CHF patients, the choke point is located in the peripheral airways.