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Respiratory resistance and transcutaneous PO2 during histamine provocation in children with bronchial asthma
D Holmgren1, I Engström, J Bjure
1Department of Pediatrics I, University of Göteborg, East Hospital, Sweden.
Insights
Histamine provocation tests effectively identify bronchial asthma severity in children. The forced oscillation technique and transcutaneous oxygen monitoring show significant differences in bronchial reactivity between asthmatic and healthy children, and among asthma severity levels.
Area of Science:
- Pediatric Pulmonology
- Respiratory Medicine
- Clinical Allergy
Background:
- Bronchial asthma is a common chronic respiratory disease in children, characterized by airway hyperresponsiveness.
- Assessing bronchial reactivity is crucial for diagnosing and managing pediatric asthma.
- Current methods for assessing bronchial reactivity in children can be challenging.
Purpose of the Study:
- To evaluate the efficacy of histamine provocation tests using the forced oscillation technique (FOT) to assess bronchial reactivity in children with asthma.
- To determine if FOT can differentiate between asthmatic and healthy children and correlate with asthma severity.
- To assess the utility of transcutaneous PO2 (PtcO2) monitoring during histamine challenge.
Main Methods:
- Sixty-six children with asthma (aged 8-15 years) underwent histamine provocation testing with FOT during a symptom-free period.
- A significant bronchial reaction was defined as a 50% increase in respiratory system resistance (Rrs).
- The provocative dose causing a 50% increase in Rrs (PD50Rrs) was calculated, and PtcO2 was monitored in a subset of patients.
Main Results:
- Children with asthma had significantly lower mean PD50Rrs (0.22 mg/mL) compared to healthy children (1.55 mg/mL).
- Mean PD50Rrs was significantly lower in severe asthma (0.13 mg/mL) than in mild asthma (0.34 mg/mL).
- Histamine challenge caused a significant fall in PtcO2 (average 29%) in asthmatic children, with 88% experiencing a ≥20% decrease.
Conclusions:
- Histamine provocation tests using FOT are effective in assessing bronchial reactivity in children with asthma.
- This method demonstrates good discriminatory capacity for different degrees of asthma severity.
- Combined use of FOT and PtcO2 monitoring provides a valuable tool for evaluating bronchial reactions in pediatric asthma.
Abstract:
Bronchial reactivity was assessed in 66 children with bronchial asthma (aged 8-15 years) by provocation with histamine-HCl during a symptom-free period. A significant bronchial reaction to histamine was defined as a 50% increase in the resistance of the respiratory system (Rrs) determined by the forced oscillation technique. The provocative dose causing a 50% increase in the Rrs (PD50Rrs) was interpolated from the log dose-response curve. The mean PD50Rrs was significantly lower in children with asthma (0.22 mg/mL) compared with a group of healthy children in the same age range (1.55 mg/mL) (P < 0.001). In children with clinically severe asthma, the mean PD50Rrs was lower (0.13 mg/mL) than in children with mild asthma (0.34 mg/mL) (P < 0.001). Transcutaneous PO2 (PtcO2) was monitored in 25 of the children with asthma. In this group the proportion of mild and severe asthma, the baseline lung function variables, and the PD50Rrs were not significantly different from those of the whole group of children. During the reaction, the PtcO2 fell on average by 29% of the baseline value (P < 0.001); in 88% of the children, the fall in PtcO2 was 20% or more of the baseline value. We conclude that histamine provocation tests using the forced oscillation technique and transcutaneous PO2 to assess a bronchial reaction have a good discriminatory capacity for different degrees of clinical severity of asthma in children.