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Measurement of total respiratory resistance in children by a modified forced oscillation method
Insights
Total respiratory resistance (RT) measured by forced oscillation is a reliable, non-invasive alternative to body plethysmography for assessing pediatric airway resistance. This method requires less cooperation and provides reproducible results in children, including those with asthma.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
- Medical Technology
Background:
- Assessing respiratory resistance in young children is challenging due to cooperation limitations with traditional methods like body plethysmography.
- Bronchial asthma in children necessitates accurate and accessible methods for monitoring airway function.
Purpose of the Study:
- To evaluate a novel microprocessor-based forced oscillation technique for measuring total respiratory resistance (RT) in children.
- To compare this technique with body plethysmography (assessing airway resistance, Raw) in terms of baseline values and bronchodilator response.
- To assess the correlation between RT and Raw, and investigate the relationship between RT and children's height.
Main Methods:
- Total respiratory resistance (RT) was measured in 11 healthy children and 24 children with asthma (ages 2-10.5 years) using a microprocessor-driven forced oscillation technique (2-32 Hz).
- RT measurements were compared with airway resistance (Raw) obtained via body plethysmography.
- The response to aerosolized isoproterenol was assessed for both RT and Raw.
Main Results:
- A strong correlation (r=0.79) was observed between total respiratory resistance (RT) and airway resistance (Raw), although Raw values were lower (mean difference 30.3%).
- Changes in RT and Raw following bronchodilator administration were not significantly different.
- An inverse relationship between height and RT was found (r=-0.79, P<0.01).
- Resonant frequency in children ranged from 6-24 Hz (mean 16.57 Hz).
Conclusions:
- The forced oscillation method provides a rapid, reproducible, and less invasive alternative to body plethysmography for measuring respiratory resistance in children.
- This technique allows for the evaluation of respiratory resistance across a wide frequency range, including resonant frequency, with reduced patient cooperation.
- Total respiratory resistance (RT) serves as a valid approximation of airway resistance (Raw) in pediatric populations.
Abstract:
Total respiratory resistance (RT) was measured in 11 normal children, 2-5.5 years of age (mean 4.16 years), and in 24 children with bronchial asthma, 2-10.5 years of age (mean 6 years), by oscillating the respiratory system from 2-32 Hz with a new microprocessor technique. Twenty-five children were less than or equal to 5 years of age. This technique was also compared with airway resistance (Raw) by body plethysmography both in terms of baseline values and response to bronchodilators. The absolute values for Raw are lower than RT with a mean percentage difference (+/- S.E.M.) of 30.3 +/- 5.0%; however, good correlation between the two techniques was obtained (r = 0.79). The changes of RT and Raw were not significantly different after aerosolized isoproterenol (P greater than 0.05). We determined the inverse relationship between height and RT with correlation coefficient r = -0.79 (P less than 0.01). In children, resonant frequency ranged from 6-24 Hz with a mean value of 16.57 +/- 0.78 Hz. The forced oscillation method utilized clinically in this study provides an alternative to total body plethysmography or an esophageal balloon, which are technically difficult and preclude their routine use in small children. In conclusion, RT utilized in this study is a rapid and reproducible approximation of Raw. It allows evaluation of RT over a wide range of frequencies including resonant frequency and requires less cooperation than body plethysmography.(ABSTRACT TRUNCATED AT 250 WORDS)