Bronchial challenge with carbachol in 3-6-year-old children: Body plethysmography assessments

Abstract

Several studies of airway responsiveness in young children (3–6 years old) have been reported, but few have attempted measurements of airway resistance by body plethysmography. Therefore, we decided to study nonspecific bronchial responsiveness following cumulative doses of inhaled carbachol in 44 children with clinical asthma (CA group), 44 children with chronic cough (CC group), 38 children with wheezy bronchitis in the first 2 years of life (WB group), and 40 controls. Specific airway resistance (sRaw) was measured in a body plethysmograph, and specific airway conductance (sGaw=1/sRaw) was calculated. Two parameters were used to assess individual bronchial responses: 1) PD100 (the dose of carbachol which induced a 100% increase in sRaw), and 2) bronchial reactivity (BR), i.e., the slope of the log‐dose sGaw response to carbachol. Significant differences were observed in PD100 and BR between the control group and the three groups of young patients (P < 0.001). Moreover, PD100 of the CA group was significantly lower than in the CC group (83.1 ± 7.8 μg vs. 108.0 ± 10.2 μg, respectively, P < 0.05), but was similar to the WB group PD100 (94.4 ± 8.5 μg). BR in the CA group was significantly higher than in both the CC and WB groups (0.127 ± 0.009 cm H2O‐L.sec−1 · log μg−1 vs. 0.073 ± 0.006 cm H2O−1 · sec−1 · log μ−1 and 0.082 ± 0.006 cm H2O−1 · sec−1 · log μg−1, respectively, P < 0.001). Repeatability and coefficients of variation were always acceptable. Continuous SaO2 monitoring in some children of the CA group demonstrated the safety of the method, which is proposed as a technique in future studies. Pediatr Pulmonol. 1999; 27:117–123. © 1999 Wiley‐Liss, Inc.

An Official American Thoracic Society/European Respiratory Society Statement: Pulmonary Function Testing in Preschool Children

“…Auscultation of the trachea or of the chest may reveal wheezing during BC and has been reported in six studies in preschool children (see Table E1) (150,265,269,271,273,274). Wheezing was detected in 8 to 78% of sick, responsive children and in 8% of responsive, but asymptomatic, children; it was not observed in nonresponsive children.…”

“…Short-and long-term reproducibility of BC in preschool children has been reported in three studies in groups of 21 to 40 children (see details in the online supplement) (265,267,270). The reproducibility of BC in preschool children has been found acceptable and further studies on reproducibility in BC tests are needed to confirm these encouraging data.…”

“…Drugs. Although methacholine (acetyl-␤-methylcholine chloride) is the most commonly used drug, some investigators prefer to assess bronchial responsiveness with histamine (263,264) or carbachol (265), and more recently with adenosine 5Ј-monophosphate (AMP) (266). Methacholine, histamine, and carbachol are bronchoconstrictors acting directly on the smooth muscle where AMP is believed to act via stimulating the release of constrictor mediators from mast cells.…”

Relationship between bronchial hyperresponsiveness and lung function in children age 5 and 6 with and without asthma

“…Badier et al . also reported that the BHR of asthmatic preschool children was similar to that of wheezy bronchitis . Our findings correlated with their results that wheezy bronchitis, as well as asthma, is associated with BHR.…”

Relationship between bronchial hyperresponsiveness and development of asthma in children with chronic cough

“…By using the tcPO 2 method to study BHR in children with chronic cough, we have shown that Dmin-PO 2 values in the chronic cough group were lower than those in the age-matched control group, and higher than those in the age-matched asthmatic group; these results are similar to another recent report. 23 Long-term follow-up has shown a statistical difference in Dmin-PO 2 between patients with chronic cough in early life who developed asthma, and those who did not.…”