| Autor: |
Dummer JF; Respiratory Services, Christchurch Hospital, Christchurch, New Zealand. jack.dummer@otago.ac.nz, Storer MK, Hu WP, Swanney MP, Milne GJ, Frampton CM, Scotter JM, Prisk GK, Epton MJ |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of breath research [J Breath Res] 2010 Dec; Vol. 4 (4), pp. 046001. Date of Electronic Publication: 2010 Nov 15. |
| DOI: |
10.1088/1752-7155/4/4/046001 |
| Abstrakt: |
Using selected ion flow tube-mass spectrometry (SIFT-MS) for on-line analysis, we aimed to define the optimal single-exhalation breathing manoeuvre from which a measure of expired acetone concentration could be obtained. Using known acetone concentrations in vitro, we determined the instrument's accuracy, inter-measurement variability and dynamic response time. Further, we determined the effects of expiratory flow and volume on acetone concentration in the breath of 12 volunteers and calculated intra-individual coefficients of variation (CVs). At acetone concentrations of 600-3000 ppb on 30 days over 2 months there was an instrument measurement bias of 8% that did not change over time, inter-day and intra-day CVs were 5.6% and 0.0%, respectively, and the 10-90% response time was 500 ± 50 ms (mean ± SE). Acetone concentrations at exhalation flows of 193 ± 18 (mean ± SD) and 313 ± 32 ml s(-1) were 619 ± 1.83 (geometric mean ± logSD) and 618 ± 1.82 ppb in the fraction 70-85% by volume of exhaled vital capacity (V(70-85%)) and 636 ± 1.82 (geometric mean ± logSD) and 631 ± 1.83 ppb in V(85-100%). A difference was observed between acetone concentrations in the V(70-85%) and V(85-100%) fractions (p < 0.01), but flow had no effect. Median intra-individual CVs were 1.6-2.6%. On-line SIFT-MS measurement of acetone concentration in a single exhalation requires control of exhaled volume but not flow, and yields low intra-individual CVs and is potentially useful in approximating blood glucose and monitoring metabolic stress. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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