Haemodynamic, hormonal and urinary responses to postural change in tetraplegic and paraplegic man.

We have studied the haemodynamic, hormonal and urinary effects of postural change in 6 tetraplegic patients, 6 paraplegic patients and 6 normal subjects. Measurements of blood pressure and heart rate, plasma renin activity, plasma aldosterone, urine volume and electrolyte excretion were made for 60 minutes while sitting and 60 minutes while recumbent. In tetraplegics the blood pressure was lower when sitting and rose during recumbency, unlike paraplegics and normal subjects.