RT Journal Article
SR Electronic
T1 How does variation of the bag volume in inert gas rebreathing cardiac output measurements influence the reproducibility in patients with pulmonary diseases?
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP p1526
VO 38
IS Suppl 55
A1 Frederik Trinkmann
A1 Franziska Kraus
A1 Martin Borggrefe
A1 Jens J. Kaden
A1 Joachim Saur
YR 2011
UL http://erj.ersjournals.com/content/38/Suppl_55/p1526.abstract
AB Background: Cardiac output (CO) is an important hemodynamic parameter, however its determination is difficult in daily clinical routine. Non-invasive inert gas rebreathing (IGR) showed promising results in recent investigations with the volume of the rebreathing bag (Vb) being an important factor. The aim of our study therefore was to evaluate the influence of different Vb on the reproducibility of IGR.Methods: The collective consisted of 45 patients (age 26 to 88 years). The CO was determined in patients with obstruction (group A), restriction (group B) and pulmonary healthy controls (group C). For Vb of 2200 ml, 1700 ml and 1200 ml two repeated measurements were taken each. The determination of lung function was performed using bodyplethysmography.Results: Pulmonary obstruction was diagnosed in 12 patients (FEV1 52±21%) and restriction in 11 patients (VC 61±16%). The mean CO did neither differ between the groups (p=0.1) nor for the different Vb (p=0.2). The mean bias between the repeated measurements was 0.2±0.9l/min for Vb=2200ml, 0±0.7l/min for Vb=1700ml and 0.3±0.7l/min for Vb=1200ml. There was no statistically significant difference between the groups for the different Vb=2200ml (p=0.7), 1700ml (p=0.4) und 1200ml (p=0.2).Conclusion: The reproducibility of IGR is not negatively affected by Vb, so that it can be varied between 1200 und 2200 ml. This is especially important when Vb has to be reduced due to incomplete inspiration. The trend to a worse reproducibility at extreme volumes at rest should be further investigated. For now, measurements should only be compared directly when identical Vb were used.