Cutaneous vasoconstriction as a measure of incipient autonomic dysreflexia during penile vibratory stimulation in spinal cord injury

Abstract

Study design: Measurement of haemodynamic responses, cutaneous blood flow and sweat release during penile vibratory stimulation (PVS) in spinal cord-injured men. Objective: To assess the validity of using markers of sympathetic activity (cutaneous blood flow and sweat release) as a measure of incipient autonomic dysreflexia during PVS in spinal cord-injured men. Setting: Prince of Wales Medical Research Institute, Australia. Subjects: Ten spinal cord-injured men with injuries ranging from C3 to T6. Methods: Continuous arterial pressure, intermittent auscultation, heart rate (HR), respiration, cutaneous blood flow and sweat release from both finger and toe were recorded during PVS. Results: Vibration of the penis caused immediate cutaneous vasoconstriction, but negligible sweat release, in the hands and feet of the quadriplegics and the feet of the paraplegics. Systolic blood pressure (BP) increased by up to 90 mm Hg, and a compensatory vagal bradycardia was observed in five of the six quadriplegics and two of the four paraplegic subjects. Conclusion: Given that there wasFin generalFan inverse relationship between BP and skin blood flow, we conclude that continuous measurements of skin blood flow above and below the lesion can provide important information on the state of the sympathetic nervous system and early identification of reflexly evoked increases in sympathetic vasoconstrictor drive, below a spinal lesion. Coupled with a decrease in HR, this cutaneous vasoconstriction infers an increased BP.

Cardiovascular Physiology and Responses to Sexual Activity in Individuals Living with Spinal Cord Injury

“…Likewise, the studies also describe a wide variety of HR responses, ranging from a reduction of 17.5 bpm in HR below baseline during AD 84 to an increase of 13 bpm above baseline. 78 As noted earlier, individuals with an injury at or above T6 are more likely to experience more severe episodes of AD; this finding is consistent with the literature investigating the cardiovascular response to sexual activity in individuals living with SCI. 33,78,81 The variability in reported peak SBP in the literature has given rise to disagreement regarding how severe the SBP increases during PVS can be.…”

“…The mechanisms underlying of 156 mm Hg in individuals with cervical SCI. In contrast, other studies 76,78,79 that record BP continuously report a noticeably higher average peak SBP during PVS ranging from an increase of 10 mm Hg up to 107 mm Hg above baseline. The only major difference between these experimental studies was the method of BP monitoring.…”

“…Studies of PVS in individuals at risk for AD that monitor BP continuously reveal peak SBP of 65 to 107 mm Hg above baseline, occurring at or near ejaculation. 33,39,76,78,79 This is in contrast to studies that measure BP intermittently, which only report peak SBP of 40 to 50 mm Hg above baseline during procedures. [80][81][82][83] The latter estimate may be considered less accurate because SBP changes on a beat-to-beat basis 33 and intermittent monitoring can miss the peak BP depending on whether the reading was observed just before, during, or after ejaculation.…”

Prominent contribution of L-type Ca2+channels to cutaneous neurovascular transmission that is revealed after spinal cord injury augments vasoconstriction

“…In the absence of central modulation, reflexly evoked vasoconstriction elicited by distension of visceral organs, or by some other unheeded afferent input from caudal to the lesion, is exaggerated (21). In SCI patients, spinal reflex-evoked vasoconstriction is most readily studied in the skin (e.g., 7,8,34), where modified neural control of blood flow results in poor thermoregulation (21) and may contribute to increasing the risk of pressure sores and impair wound healing (11,37).…”

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

“…Indeed, we recently showed that weak electrical stimuli applied to the abdominal wall cause pronounced and prolonged cutaneous vasoconstriction and increases in blood pressure, the latter indicating that these stimuli below the lesion level caused coactivation of cutaneous, muscle and splanchnic vasoconstrictor neurones (Brown et al 2007, 2009 a ). Moreover, vibration of the penis in spinal men (a procedure performed to procure semen for fertility assessment) causes a pronounced increase in blood pressure (Sheel et al 2005) and cutaneous vasoconstriction (Brown et al 2009 b ), the latter occurring also in the absence of clinical signs of autonomic dysreflexia (Brown et al 2009 b ).…”