THE VENTILATORY RESPONSE TO ARM ELEVATION OF PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

Although arm activity is poorly tolerated by patients with COPD, the v entilatory response to arm elevation alone is not well understood. We therefore studied the ventilatory response to arm elevation using a cu stomized arm support sling to eliminate the effect of an increase in m etabolic activity that might be attributable to independent arm elevat ion and used leg exercise to increase metabolic activity. During arm e levation at rest, there was a significant decrease in vital capacity ( 180 ml) and a small decrease in functional residual capacity (120 ml) as measured by body plethysmography. Minute ventilation was unchanged. When supported arm elevation (SAE) was compared with the control arm position (CAP), minute ventilation was unchanged although the pattern of breathing became more rapid and shallow (mean +/- SD, SAE vs CAP: f (b) = 17.9 +/- 5.3 vs 16.2 +/- 4. 8 breaths . min-1; VT = 533 +/- t26 vs 579 +/- 142 ml; p<0.05). During steady-state leg exercise, the incr ease in VO2, VCO2 and VE did not differ between SAE and CAP; however, both f(b) and V(T) changed toward a more rapid, shallow pattern of bre athing (SAE vs CAP: f(b) = 24.3 +/- 3.0 vs 22.8 +/- 3.5 breaths-min-1; VT = 990 +/- 293 vs 1,081 +/- 309 ml; p<0.05). During unsupported arm elevation VO2, VCO2, and VE, and f(b) were significantly greater than during the CAP. Approaches that train arm muscles and strategies that either support arm muscles or allow for frequent rests during upper a rm activity may improve the endurance and the quality of life for COPD patients.