[Body plethysmography in infants and small children. Respiratory function diagnosis using a special baby plethysmograph].

Successful body plethysmographic examination of infants and toddlers can now be performed by means of a special baby plethysmograph which is commercially available (Fa. Jaeger, Würzburg, Fed. Rep. of Germany). The apparatus is equipped with a heated rebreathing system and manipulation ports. Examinations require paying attention to certain potential sources of error: the consequences of necessary sedation; possible undefined leaks due to non-airtight manipulation ports; the influence of irregular breathing or increasing hyperventilation; the effect of nasal resistance; the large variation in total airway resistance; problems in the quantitative evaluation of box pressure/flow curves and curve form analysis. Careful handling can overcome all these difficulties. From the clinical point of view, body plethysmographic examination is just as important for infants and toddlers as for schoolchildren and adults.