Cardiovascular responses to tilting in tetraplegic man

Abstract

SUMMARY1. A study has been made of the effect of head-up tilt on blood pressure, heart rate, forearm blood flow and occluded vein pressure in the hand and foot in non-bedridden patients with chronic, closed, complete, localized traumatic transaction of the cervical spinal cord.2. In typical responses the blood pressure fell and the heart rate rose progressively for about 2 min, tending to plateau thereafter. The average falls in mean blood pressure for tilts of + 30, + 45 and + 600 were from 68 to 44, 74 to 36 and 70 to 44 mm Hg respectively, and the corresponding heart rate increases were from 67 to 85, 62 to 97 and 62 to 103 beats/min respectively. One patient lost consciousness when his blood pressure was 29/19 mm Hg and one other patient experienced symptoms suggesting cerebral ischaemia. 3. Following the return to horizontal, the blood pressure and heart rate usually returned to their previous values within 1 min and the blood pressure tended to overshoot slightly in the following few minutes. No immediate blood pressure overshoot occurred after the tilt except in association with a spasm of skeletal muscles.4. There was consistently a decrease in forearm blood flow, sometimes to unrecordably low levels and a venoconstriction with postural change and it is argued that these changes are the result of spinal cardiovascular reflexes to peripheral vessels. Following the return to the horizontal position, there was occasionally a large immediate increase in forearm blood flow. 5. Following the intravenous administration of 3 mg atropine on two occasions, head-up tilting produced further small heart rate increases.6. Spasms of skeletal muscle occur frequently in these patients and

Treatment of Orthostatic Hypotension in Cervical Cord Injury with Amezinium Metilsulfate

“…Orthostatic hypotension is a common occurrence following SCI, and in some tetraplegic patients this may significantly extend their rehabilitation periods 1) . The symptoms of hypotension are the result of inadequate perfusion of the central nervous system as a consequence of the sudden fall in BP %HR shows actual maximum heart rate as a percentage of expected maximum heart rate.…”

“…The pathogenesis of OH is complex and involve the cardiovascular, the renal, the neurological and the endocrine systems, all of which are necessary for the regulation of arterial blood pressure [1][2][3] . The symptoms associated with OH significantly interfere with the rehabilitation of patients with SCI.…”

The Sir Ludwig Guttmann Lecture 2012: the contribution of Stoke Mandeville Hospital to spinal cord injuries

“…Some of the key ones were: Johnson et al 18 on orthostatic hypotension and the renin-angiotensin system in Paraplegia, three papers in the Journal of Physiology on cardiovascular reflex response to cutaneous and visceral stimuli in spinal man, cardiovascular changes associated with skeletal muscle spasm in tetraplegic man and cardiovascular responses to tilting in tetraplegic man [19][20][21] and one in Lancet on the evidence for neurogenic control of cerebral circulation. 22 For many years we have had a close collaboration with Chris Mathias and his co-workers, key contributions being 'Blood pressure plasma catecholomines and prostaglandins during artificial erection in tetraplegic man' , 23 'Plasma prostaglandin E during neurogenic hypertension in tetraplegic man' , 24 'Enhanced pressor response to noradrenaline in patients with cervical spinal cord transection' , 25 'Renin release during head-up tilt occurs independently of sympathetic nervous activity in tetraplegic man' , 26 and a chapter in the Handbook of Clinical Neurology 'The cardiovascular system in tetraplegia and paraplegia' .…”

About orthostatic hypotension in tetraplegic individuals reflections and experience

“…(2) A modest and delayed release of catecholamines already at a low resting level 10,13,14 triggering o the renin-angiotensin system by the renal baroreceptors 11,13,14 (3) Then, in the absence of a su cient correction of the OH, a release of ADH and eventually the onset of secondary hyponatraemia. 15 ± 18,20 It has also been shown that the osmoregulatory system functions normally in spinal injured patients and that hypokalaemia, more pronounced in those who are tetraplegic, co-exists with an increase of the volume of extra-cellular¯uids and unstable hyponatraemia.…”