Viscerosympathetic reflexes in human spinal cord injury: relationships between detrusor pressure, blood pressure and skin blood flow during bladder distension

Abstract

New Findings r What is the central question of this study?Dangerous increases in blood pressure (autonomic dysreflexia) can be caused by visceral stimuli in spinal cord injury, but it is not known how cutaneous vasoconstriction is related to increases in bladder and blood pressures during bladder distension. r What is the main finding and its importance?We show that an increase in bladder pressure causes cutaneous vasoconstriction in the fingers that is inversely related to the bladder pressure. Skin blood flow was inversely related to the increase in blood pressure in nine of 15 patients. Monitoring finger blood flow therefore provides a useful, supplementary, non-invasive means of assessing sympathetic outflow below the lesion in high thoracic or cervical spinal cord injury.Autonomic dysreflexia, a dangerous and sustained increase in blood pressure brought about by widespread, reflexly generated vasoconstriction, can be induced by visceral or somatic sensory inputs originating below the lesion following spinal cord injury (SCI). We assessed whether cutaneous vasoconstriction below the lesion could serve as a proxy marker of incipient autonomic dysreflexia during bladder distension. Skin blood flow (pulse plethysmography), sweat release, blood pressure, heart rate, bladder and rectal pressures were recorded during routine cystometry (urodynamics) in 16 patients with SCI. Eight urological patients without SCI served as control subjects. In all SCI patients, who had sustained injuries 2 months to 44 years previously at levels C3-T3, bladder filling (mean ± SD, 339 ± 132 ml) induced increases in detrusor (bladder-rectal) pressure (52 ± 25 cmH 2 O) and cutaneous vasoconstriction in the fingers, but no consistent increases in sweat release. This occurred irrespective of whether the spinal lesions were complete [American Spinal Injury Association (ASIA) grade A, n = 6] or incomplete (ASIA B-D; n = 10). Group mean blood pressure for the SCI patients increased by 17 ± 15 mmHg, but in four patients the pressure decreased or did not change. Despite similar bladder volumes (423 ± 126 ml) in the control patients, the increases in detrusor pressure (14 ± 8 cmH 2 O) and blood pressure (9 ± 12 mmHg) were significantly smaller than in the SCI patients; moreover, there were no consistent changes in skin blood flow in the control subjects. In all SCI patients, changes in finger pulse amplitudes were inversely correlated to changes in detrusor pressure (mean r = −0.62 ± 0.17). Changes in finger pulse amplitudes correlated inversely to changes in blood pressure in nine of 15 patients. It is concluded that cystometry in SCI patients is associated

Autonomic dysreflexia severity during urodynamics and cystoscopy in individuals with spinal cord injury

“…However, we can infer from the cystoscopy that gravity filling of the bladder resulted in only 150 ml of bladder volume filling, much lower than the volume (up to 500 ml) instilled by continuous pump during urodynamics. In our 21 subjects, the bladder filling during urodynamics induced detrusor pressure (average 44.1±29.8 cm H 2 O), which was consistent with the study by Wallin et al 17 However, in this study investigators reported a positive correlation (r ¼ 0.52, Po0.05) between the maximal detrusor pressure and the maximal increase in BP. This correlation was not present in our study.…”

Risk factors to develop autonomic dysreflexia during urodynamic examinations in patients with spinal cord injury

“…Detrusor pressure seems to be a trigger for AD in patients with bladder distension (not the bladder volume). Wallin et al have shown that in patients with SCI above T4, changes in bladder pressure correlate positively with changes in blood pressure and inversely with changes in pulse rate, whereas in control subjects without SCI, these changes are not shown. Furthermore, Yoshizawa et al used an experimental model in rats with SCI above Th5.…”

Autonomic Dysreflexia following Spinal Cord Injury

“…So, if the patient has not an indwelling catheter, the catheterization of the urinary bladder is indicated. 34 40 Because any manipulation with a urinary catheter can start an AD reaction, it should be performed in local anesthesia utilizing 2 to 3 minutes instillation of trimecaine hydrochloride or lidocaine hydrochloride lubricating jelly into the urethra 40 71 72 If the urinary bladder is empty, but symptoms of AD persist, the fecal impaction of the distal colon must be suspected. The complete bowel evacuation after mucosal anesthesia should, therefore, follow.…”

“…The complete bowel evacuation after mucosal anesthesia should, therefore, follow. 67 69 71 If the aforementioned measures do not alleviate symptoms and reduce blood pressure sufficiently, pharmacological management must be initiated. 39 40 Because the administration of antihypertensive drugs in patients with unstable cardiovascular functions may lead to sudden hypotension, the selection of medicaments, as well as their initial dosage should be cautious and attended by monitoring blood pressure every 2 to 5 minutes for at least 2 hours after resolution of AD episode.…”