Infant lung function testing - Rapid thoracic compression methods

In infancy respiratory disorders are very frequent and lung function measur ements are essential for their assessment. As infants do not cooperate with pulmonary function testing special techniques have to be developed for thi s age group. Diagnostic: Rapid thoracic compression methods have been widely adopted for quantification of actual airway caliber in healthy infants as well as in t hose with different lung diseases. The "squeeze-technique" uses an inflatab le jacket tightly surrounding chest and abdomen of the infant. Following a tidal inspiration the jacket is rapidly filled with air effecting a forced expiration by compression of chest and abdomen. Analysis for forced expirat ory flow measured by this method has been proven as useful for epidemiologi cal studies as well as for clinical purposes. Major disadvantages are the r elatively high intrasubject variability of the measured parameter and the r epresentation of only a small volume range of vital capacity as the compres sion-manoeuvre starts from end-tidal inspiration. Rapid lung inflation to a predetermined inflation pressure through a modified diaphragm pump prior t o thoracic compression allows assessment of infant lung function over an ex tended volume range. Volume-time parameters obtained from this recently int roduced new method, the so called "pump and squeeze-technique: have less in trasubject variability than the standardized flow parameter obtained from t he conventional "squeeze-technique". Further studies should evaluate the cl inical application of this new method.