Expiratory flow limitation during exercise in COPD: detection by manual compression of the abdominal wall

Manual compression of the abdomen (MCA) during spontaneous expiration is a simple method for the detection of flow limitation in the chronic obstructive pulmonary disease (COPD) patients during resting breathing, based on comparison of flow/volume curves obtained during MCA with that of the preceding control breath. It was assessed whether this nonstandardized technique is also feasible during exercise. MCA was performed during resting breathing and constant-exercise work at one- and two-thirds maximal mechanical power output (W'max) in six normal subjects and 12 COPD patients. Changes in end-expiratory lung volume (EELV) were also studied. With the aid of inspection, abdominal palpation and lung auscultation, MCA could always be applied during expiration. Flow limitation was never detected in the six normal subjects, whereas four of the COPD patients were flow limited at rest, seven during exercise at one-third W'max and nine during exercise at two-thirds W'max. Expiratory flow limitation detected by MCA was always associated with an increase in EELV during exercise, indicating dynamic hyperinflation occurrence or increase. It is concluded that manual compression of the abdomen is a very simple and reliable method for the detection of flow limitation during exercise.