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Multiple breath washout with a sidestream ultrasonic flow sensor and mass spectrometry: A comparative study
Author(s) -
Fuchs Susanne I.,
Buess Christian,
Lum Sooky,
Kozlowska Wanda,
Stocks Janet,
Gappa Monika
Publication year - 2006
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/ppul.20524
Subject(s) - flow sensor , medicine , tracer , ultrasonic sensor , mass spectrometry , nuclear medicine , chromatography , radiology , chemistry , acoustics , physics , nuclear physics
Over recent years, there has been renewed interest in the multiple breath wash‐out (MBW) technique for assessing ventilation inhomogeneity (VI) as a measure of early lung disease in children. While currently considered the gold standard, use of mass spectrometry (MS) to measure MBW is not commercially available, thereby limiting widespread application of this technique. A mainstream ultrasonic flow sensor was marketed for MBW a few years ago, but its use was limited to infants. We have recently undertaken intensive modifications of both hardware and software for the ultrasonic system to extend its use for older children. The aim of the current in vivo study was to compare simultaneous measurements of end‐tidal tracer gas concentrations and lung clearance index (LCI) from this modified ultrasonic device with those from a mass spectrometer. Paired measurements of three MBW, using 4% sulfur hexafluoride (SF 6 ) as the tracer gas and the two systems in series, were obtained in nine healthy adult volunteers. End‐tidal tracer gas concentrations (n = 675 paired values) demonstrated close agreement (95% CI of difference −0.23; −0.17%, r 2 = 1). FRC was slightly higher from the MS (95%CI 0.08;0.17 L), but there was no difference in LCI (95%CI −0.10; 0.3). We conclude, that this ultrasonic prototype system measures end‐tidal tracer gas concentration accurately and may therefore be a valid tool for MBW beyond early childhood. This prototype system could be the basis for a commercial device allowing more widespread application of MBW in the near future. Pediatr Pulmonol. 2006, 41: 1218–1225. © 2006 Wiley‐Liss, Inc.