Steady state uptake of the water soluble gas, dimethyl ether (DME), has previously been shown to measure blood flow in the trachael mucosa. To increase the utility of this methodology for studies of airway physiology and pathophysiology, we attempted to determine airway bloodflow in more peripheral airways. Single inspirations of DME were followed by breathholds of varied length to quantify the uptake of DME from 50ml expired volume segments. Simultaneously obtained single-breath N2 washout profiles were used to determine the relative contribution of alveolar and deadspace volumes to each expired volume segment Duplicate measurements of inspired and expired gas concentrations were performed in two anesthetized, paralyzed dogs for breathhold times of 5,10, 15, and 20 seconds. The average airway blood flow is shown below for per ml of airway volume, and for each 50ml segment. Airway blood flow (ml/min) Dog #1 Dog #2 Volume flow/ml gas flow/50ml gas flow/ml gas flow/50ml gas 1 0.105 5.26 0.042 2.11 2 0.275 13.75 0.354 17.71 3 0.305 15.23 0.302 15.10 4 0.357 17.86 0.440 22.00 The results reflected the increase in airway blood flow that is known to be present in more peripheral airways. A 3- to 10-fold increase in the blood flow was indicated for the more peripheral forth, as compared to the more proximal first, 50ml expired volume. The average difference hi the results of duplicate samples was ±25%. We conclude that combining DME uptake with single-breath N2 washout may be a useful method for the study of bloodflow in peripheral vs. proximal airways, (supported in part by NIH grant HL24163).
|Original language||English (US)|
|State||Published - Dec 1 1996|
ASJC Scopus subject areas
- Molecular Biology