Cold air challenge and specific airway resistance in preschool children

Important asthma outcomes such as lung function and bronchial hyperresponsiveness are probably determined in early childhood. Early and longitudinal objective assessment of lung function and bronchial hyperresponsiveness is necessary to enable early diagnosis, monitor intervention and improve prognosis in preschool children. Cold air challenge and plethysmographic measurement of specific airway resistance (sRaw) are feasible candidate methods for diagnosis, clinical monitoring and research during this critical period of lung growth and development. Methodology and practical aspects of cold air challenge and assessment of sRaw in preschool children are reviewed. Reference values are provided for sRaw and have allowed discrimination between health and respiratory disease, both in cross-sectional and longitudinal studies. Bronchial hyperresponsiveness can be determined with acceptable repeatability and provides good discrimination between asthmatics and healthy. The effects of classic anti-asthmatic therapies have also been documented with these techniques. The need for further standardisation and improvement of these methods and future perspectives are outlined.