A comparative study of various methods for estimating the residual volume in childhood
Petro, W.; Wiesemann, H.G.; Pirrone, P.; Korn, V.
Praxis und Klinik der Pneumologie 35(3): 144-148
1981
ISSN/ISBN: 0342-7498 PMID: 7232287 Document Number: 175525
Residual volume was estimated in 61 children (15 with obstructive airways disease) by spirometric He gas mixing procedure, body plethysmography and a new modified He rebreathing technique. The new technique is based on oscillatory measurements of the density of an He-O2 mixture (He concentration over 70%). The gas is mixed by forced rebreathing and therefore reaches underventilated lung areas. The correlation with the spirographic He gas mixing method and body plethysmography is close (r = 0.82 and = 0.85, respectively). Wash-in time is reduced to about 1 min without signs of hypercapnia. CO2 absorption and O2 stabilization is not needed. The time of wash-in in the oscillatory technique is independent of the functional residual capacity. In the presence of airways obstruction, the oscillatory technique produces higher values compared to spirographic measurements. Results agree with literature values. Advantages of the method are low cost, ease of application, technical and methodical superiority and the possibility of simultaneous measurement of respiratory impedance.