Unstable baseline blood pressure in chronic tetraplegia

Abstract

Study design: Case-control.

Objective: Tetraplegic patients are subject to episodes of autonomic dysreflexia and postural hypotension. It is suggested that these patients sustain, in addition, unstable baseline blood pressure (BP) that is independent of symptoms and body position.

Methods: BP monitoring was conducted in 10 tetraplegic patients, motor and sensory complete (American Spinal Injury Association (ASIA) A) (Group A), and five paraplegic at T8-T10 levels, ASIA A (Group B). A SpaceLabs automatically inflating pneumatic cuff recorded arm pressures at 10-30 min intervals in the daytime, sitting position and at 30 min intervals in the night-time, recumbent position. Group mean arterial pressure (MAP) and MAP standard deviation (MAP variation) for sitting and recumbent positions were compared.

Results: Sitting the MAP for Group A was less than that of Group B; 87+/-9 versus 108+/-7 mmHg, P<0.01. However, MAP variability for Group A was greater than for Group B; 17+/-4 (20% of MAP) versus 13+/-2 mmHg (12% of MAP), P=0.04. In the recumbent position, the MAP for Group A was similar to that for Group B; 87+/-13 versus 97+/-7 mmHg, P=0.16. However, MAP variability for Group A remained higher than for Group B; 13+/-3 (20% of MAP) versus 8+/-2 mmHg (8% of MAP), P=0.02.

Conclusion: Tetraplegic patients demonstrate unstable BP in either the sitting or recumbent position compared with low thoracic paraplegic patients.