TY - JOUR T1 - How long does it take for supine gas transfer to become stable after sitting upright? JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p1220 AU - Liam O'Reilly AU - Helen Ward AU - Brendan Cooper Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p1220.abstract N2 - Introduction: We are interested in using the change in gas transfer from sitting to supine in patients with various lung diseases, but were unable to find any published studies showing how long a subject should be supine before a stable representative measurement could be made. We looked at this in healthy subjects first.Method: We measured single breath gas transfer (TLCO & KCO) using a MasterScreen lung function system (Jaeger Ltd, Hochburg, Germany) 3 times sitting at rest and then after approximately 10, 15, 20, 25 & 30 minutes respectively, lying supine in 14 healthy subjects (11F:3M; Ages: 22-51 years).Results: The results (Table 1) show that TLCO and KCO increase by about 9% and 15% respectively and VAeff decreases by 5% from sitting to supine. Stability is reached after 15 minutes.View this table:Table 1. Supine gas transferDiscussion: We have shown that changes in gas transfer when supine stabilise after 15 minutes. Unexpectedly, not all subjects showed an increase gas transfer, with 6 showing no increase or a slight decrease when supine. This result needs further explanation.Conclusion: Supine gas transfer should be measured after 15minutes lying supine. Not all subjects produced an increase in gas tarnsfer when supine. ER -