EXERTIONAL HYPOTENSION IN SPINAL-CORD INJURY

Study objective: To assess blood pressure (BP) response to continuous maximal arm ergometry in patients with spinal cord injury (SCI). Desig n: Cross-sectional analysis of data collected for a prospective study of functional electrical stimulation in patients with SCI. Setting: Sh ort-term rehabilitation hospital. Participants: Twenty individuals wit h SCI; 4 cervical (C6 to C8), 10 high thoracic (T1 to T6), and 6 low t horacic (T7 to T12). Measurements and results: Each subject performed continuous maximal arm ergometry with expired gas analysis. Blood pres sure was measured using a technician-assisted protocol. The BP at maxi mal exercise was compared with the highest submaximal BP reached durin g the test (triangle BP=final BP minus highest submaximal BP). All 20 subjects had a negative triangle BP(mean +/- SD; -22.8 +/- 12.1 mm Hg) for mean BP and 19 of 20 had a negative triangle BP (-25.8 +/- 14.4 m m Hg) for systolic BP. The triangle BP was not significantly related t o maximum exercise parameters, resting BP, or level of lesion. Four ab le-bodied subjects and six wheelchair-bound individuals without SCI sh owed no exertional hypotension. Repeated testing on the four able-bodi ed subjects showed excellent reproducibility for mean BP (coefficient of variation [CV]=3.6 percent; r=0.98; p<0.01) and systolic BP (CV=2.2 percent; r=0.99; p<0.01) using this protocol. Conclusions: These data describe, for the first time to our knowledge, that exertional hypote nsion is present in all individuals with SCI during continuous arm erg ometry. Further studies are needed to clarify the mechanisms responsib le for this phenomenon and to evaluate the long-term consequences for individuals with SCI.