Reversibility prediction of chronic airways flow limitation by a new simple spirometric parameter.

A new simple spirometric parameter for predicting the reversibility of bronchial obstruction is evaluated in two homogeneous groups of severe COLD patients. By combining FEV1 and MMEF, this index is practically the product of the volume expired in 1s and the corresponding flow at 50% of FVC which characterizes the emptying pattern. The parameter provides a useful method for verifying the patient's responsiveness to beta 2-bronchodilator drugs. The bronchial flow limitation depends more on the airways obstruction present than on the characteristics of the drugs administered. A threshold level for the new parameter was defined (1000 l/s); beneath this value responsiveness to beta 2 drugs must be considered practically negligible.