Specific airway resistance in children: Panting or tidal breathing?

SummaryBackground The measurement of specific airway resistance during tidal breathing (sRawtb) has gained popularity in children, but methodological concerns have been raised regarding the electronic compensation for the thermal artifact. The panting method (sRawp) is efficient in minimizing the latter, but may be associated with a change in end expiratory lung volume if the effort is not properly balanced. The aim of the study was to compare sRawtb with sRawp in children. Methods Fifty-five children aged 6.5–11.5 years were studied. sRawtb was measured in a commercial plethysmograph. sRawp was measured with a home made equipment that allowed breath by breath analysis (sRawp1) as well as with the commercial body box (sRawp2). Results sRawtb was significantly larger than either sRawp1 or sRawp2 (P < 0.0001). The mean (95% CI) difference sRawp1 − sRawtb was −0.374 (−0.835 to 0.088) kPa s. The difference between sRawp1 and sRawp2 was significant (P < 0.005) but not clinically relevant, and mean (95% CI) difference sRawp1 − sRawp2 was 0.115 (−0.094 to 0.324) kPa s. The breath by breath analysis showed small but significant increase in sRawp1 throughout the maneuver (P < 0.001), whatever the pattern of end expiratory level. Conclusion Tidal breathing is associated with an overestimation of sRaw compared with panting in children. Although the latter results in small increase throughout the panting maneuver, sRawp is probably more trustful than sRawtb. Pediatr Pulmonol. 2014; 49:245–251. © 2013 Wiley Periodicals, Inc.