[Methacholine challenge in young children: measurement of resistance by interruption].
The aims of this study were 1. To evaluate the measurement of resistance by interruption (Rint) of bronchoconstriction induced by inhalation of methacholine and 2. To determine a threshold of increase of resistance in young children to differentiate responders from non-responders. Forty-six children (mean age 5 [4.3-6.1] years) referred for methacholine challenge were tested by measurement of Rint and transcutaneous oxygen tension. A fall of 20% or more in oxygen tension from the baseline was used to define the responders. The children studied had a baseline Rint significantly higher than normal (0.84 [0.68-1.01] vs. 0.76 [0.60-0.90] kPa L(-1)s; p < 0.03). Forty-one children were responders and had an increase in Rint significantly different from the non-responders (p < 0/04). An increase in Rint of 35% distinguished responders from non-responders in young children with chronic cough. Interrupter resistance increases significantly during bronchial provocation in responding young children and may be used to measure the degree of bronchoconstriction.
Beydon
N
N
Service de Physiologie, Hôpital, Robert Debré, Paris, France. nicole.beydon@rdb.aphp.fr
Matran
R
R
Wuyam
B
B
Amsallem
F
F
Boule
M
M
Alberti
C
C
Denjean
A
A
Gaultier
C
C
D000367:Age Factors; D000403:Airway Resistance / Q000187:drug effects* / Q000502:physiology; D001785:Blood Gas Monitoring, Transcutaneous; D001985:Bronchial Provocation Tests / Q000379:methods*; D016085:Bronchoconstrictor Agents; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D003371:Cough / Q000175:diagnosis* / Q000503:physiopathology; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D016210:Methacholine Chloride; D012129:Respiratory Function Tests / Q000379:methods*; D012680:Sensitivity and Specificity
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride