Respiratory function testing in early childhood: where have we come from and where are we going?

After an initially slow beginning, we are currently witnessing something of a revolution in the field of respiratory function testing during early childhood, both with respect to the number of techniques available and the applications to which they are being put. There is now an urgent need for international, collaborative efforts to develop more objective, standardized methods of assessment (including improved, properly validated equipment and software) and reliable reference data for this age group. This would improve our understanding of exactly what these tests are measuring, and facilitate the development of effective therapeutic and preventive strategies to minimize suffering from respiratory illness not only during early childhood but, hopefully, throughout life.