Cardiovascular Responses to Bladder and Bowel Distension after Human Spinal Cord Injury

Bladder and bowel distention are primary triggers of autonomic dysreflexia in individuals with spinal cord injury (SCI), with reports of systolic blood pressure (SBP) rising by more than 20 mmHg and remaining elevated, with intolerable symptoms. The goal of the current study was to quantify the degree of cardiovascular changes, as well as the presence/absence and type of symptomatic indices, in a controlled laboratory setting during bladder filling (urodynamics) and bowel distention (anorectal manometry [ARM]). A total of 56 individuals (35 males and 21 females) with SCI participated in the study, with injury levels ranging from C2 to L3 and American Spinal Injury Association Impairment Scale grades A-D. Filling cystometry (CMG) and ARM were conducted on separate days, and continuous arterial blood pressure (BP) was acquired throughout. International SCI datasets for bladder and bowel function were also completed. The data indicate that 90.9% of individuals had a maximum change in SBP above 20 mmHg during CMG (group mean of 45 mmHg) and 85.4% of individuals had a maximum change in SBP above 20 mmHg during ARM (group mean of 37 mmHg). One or two symptoms (goosebumps, sweating, flushing, chills, tingling, and headache) occurred in 43.6% of participants during CMG and 23.6% during ARM, with higher rates reported in the dataset questionnaires. The maximum changes in SBP typically occurred at maximum vesicle pressure and/or at first sensation during CMG, and during balloon catheter insertion or withdrawal during the ARM procedure. These data, taken together, indicate that urodynamic and bowel assessments in individuals with SCI should include measures of BP and be considered in daily management practices, as the frequent triggering of cardiovascular changes likely impacts health and well-being.