THEORETICAL BASIS FOR IMPROVEMENT FOLLOWING REDUCTION PNEUMOPLASTY INEMPHYSEMA

Reduction pneumoplasty may improve flow rates, comfort, and exercise t olerance in severe emphysema. The basis for improvement has not been s ystematically addressed. The major disability of emphysema stems from impairment of maximal expiratory flow-volume performance of the lung ( MEFV). This requires the chest wall to operate at high volumes, which in turn severely compromises inspiratory muscle function. Clinical ben efit, then, requires that MEW performance improve so that the operatin g lung volume is reduced. This study presents theory and illustrative calculations. Removing nonventilating sung (e.g., bullae) simply displ aces the MEN curve down the volume axis. Removing ventilating parenchy ma reduces both volume and maximal expiratory now at iso-lung recoil p ressure, and shortens the curve an the volume axis. The critical benef icial effect in both cases is reduction of the volume for a given limi ting flow VL (V-max). Removing a given fraction of lung from the venti lating compartment is nearly as effective as removing it from the nonv entilating compartment. Lowering of operating volumes benefits the str ength, efficiency, endurance, and reserve of the Inspiratory muscles a nd thus extends the metabolic scope of the emphysematous patient.