28 research outputs found
Within-subject difference in FRC measured by multiple breath nitrogen washout (FRC<sub>N2</sub>) and body plethysmography (FRC<sub>pleth</sub>).
<p>The mean within-subject difference FRC<sub>N2</sub>—FRC<sub>pleth</sub> decreased after the three tissue N<sub>2</sub> excretion equations were applied to washout data from healthy and CF populations.</p
Characteristics of study participants.
<p>Values are presented as mean (SD) unless otherwise indicated. P value indicates group difference between health and CF.</p
Correcting for tissue nitrogen excretion in multiple breath washout measurements - Fig 6
<p><b>Relationship between the contribution of tissue N<sub>2</sub> to LCI<sub>N2</sub> and length of washout calculated at a) the traditional 2.5% washout cut-off and b) the 5% washout cut-off.</b> The contribution of tissue N<sub>2</sub> to LCI<sub>N2</sub> calculated at the 2.5% cut-off (LCI<sub>uncorr</sub>−LCI<sub>Cournand</sub>) increased as washout time increased. However, this relationship was no longer observed at the earlier 5% cut-off.</p
Summary of tissue nitrogen correction equations.
<p>Summary of tissue nitrogen correction equations.</p
Relationship between the contribution of tissue N<sub>2</sub> to FRC<sub>N2</sub> and the difference between FRC as measured by MBW<sub>N2</sub> and MBW<sub>SF6</sub>.
<p>FRC<sub>N2</sub> became disproportionately greater than FRC<sub>SF6</sub> as the contribution of tissue N<sub>2</sub> estimated by the within-subject difference FRC<sub>N2</sub>—FRC<sub>Cournand</sub> increased.</p
Average slopes of the second half of all uncorrected, Lundin-corrected and Cournand-corrected FRC<sub>N2</sub>/breath number curves (depicted graphically in Fig 4) for healthy subjects and those with CF.
<p>Average paired difference (uncorrected-corrected) in absolute and relative (percent of uncorrected slope) terms are shown. Data are expressed as mean 95% confidence interval) unless otherwise stated.</p
Effect of applying Lundin and Cournand correction equations to previously published observational MBW data.
<p>Data are shown as pre-treatment and post-treatment LCI with paired treatment effect. Values are presented as mean (SD) unless otherwise indicated.</p
Within-subject difference between uncorrected LCI<sub>N2</sub> and LCI<sub>N2</sub> corrected for tissue N<sub>2</sub> excretion (LCI<sub>Cournand</sub>) at different washout cut-offs.
<p>The difference was progressively smaller when calculated at earlier cut-offs of the washout in both health and CF.</p
Estimates of tissue N<sub>2</sub> contribution to MBW outcomes at the 2.5% washout cut-off.
<p>Values are presented as the mean within-subject difference (95% CI) of the uncorrected–corrected MBW<sub>N2</sub> outcome. Outcomes were corrected by applying either the Cournand or Lundin tissue N<sub>2</sub> excretion equations.</p
Tissue N<sub>2</sub> excretion equations used for correction of MBW<sub>N2</sub> measurements.
<p>The three equations used to estimate the volume of N<sub>2</sub> excreted from the body tissues are plotted over a 7 minute time period. The Cournand 1941 equation was adjusted for a constant excretion rate and plotted for a subject with the average body size of the subjects measured in the Lundin 1953 study. The ATS/ERS equation calculates the volume of tissue N<sub>2</sub> excreted using Cournand’s 1941 equation standardized to a 7 minute washout for all subjects.</p