Postural Fall In Blood Pressure Research Articles

Delayed symptoms and orthostatic intolerance following peanut challenge.

Clinical reactions to Oral Food Challenge (OFC) in peanut-allergic individuals have been well-characterised, but rates and phenotypes of symptom recurrence beyond the first hour after objective symptoms are less well-characterised. To evaluate the rate of new-onset symptoms occurring at least 1h after stopping OFC in peanut-allergic children and adults undergoing peanut-OFC. We prospectively collected data relating to adverse events following positive reactions at double-blind, placebo-controlled food challenges (DBPCFC) to peanut in children and adults evaluated for eligibility to participate in two clinical trials (NCT02149719, NCT02665793). The trials included people aged 8 to 45 with primary, IgE-mediated peanut allergy at DBPCFC. The challenge protocol included consumption of a light meal 1h after reaction. A total of 121 participants (64 children, 57 adults) had immediate, objective symptoms at DBPCFC, 25 (17 children, 8 adults) with anaphylaxis. Thirty-three (27%) had progression or recurrence of symptoms ≥1 h after objective clinical reaction, of whom 8 developed anaphylaxis. In 23 cases, the onset of new symptoms was associated with consumption of a light meal. In eight cases, symptoms were limited to a symptomatic postural fall in blood pressure noted in preparation for discharge, without any other new features of an allergic reaction. Progressive or new-onset symptoms ≥1h following initial allergic reaction at OFC are common and can include orthostatic hypotension. Recurrent symptoms may be temporally associated with food consumption.

Cardiac Autonomic Neuropathy in Patients with Type 2 Diabetes Mellitus at High Risk for Foot Ulcers.

Aim:To study the prevalence of cardiac autonomic neuropathy (CAN) in patients with Type 2 diabetes mellitus at high risk for foot ulcers.Materials and Methods:We screened patients attending diabetic clinic for identifying patients at high risk for foot ulcers. Those with foot risk category 1, 2 and 3 as per criteria of Foot Care Interest Group were subjected to battery of cardiovascular autonomic reflex tests. Those with one abnormal test were termed as probable CAN and those with two abnormal tests as definite CAN. Those with postural fall in blood pressure with one other abnormal test were termed to have advanced CAN.Results:A total of 74 patients were recruited in the study. The prevalence of abnormal cardiovascular autonomic reflex test was sustained hand grip 81%, E/I ratio 66.2%, 30:15 ratio 28.3% and orthostatic hypotension 13.5%. The prevalence of possible CAN was 31.0% (23/74) and definite CAN was 66.2% (49/74). Ten patients had advanced CAN. There was no observable difference in presence of probable or definite CAN in three risk category for foot ulcers.Conclusion:We found a high prevalence of CAN in subgroup of diabetic patients at increased risk for foot ulcer.

Vestibular Stimulation for Stress Management in Students.

Although several methods are developed to alleviate stress among college students, logistic limitations in adopting them have limited their utility. Hence, we aimed to test a very practical approach to alleviate stress among college students by achieving vestibular stimulation using swings. In this study 60 male and female participants were randomly assigned into vestibular stimulation or control groups. Depression, anxiety, stress scores, sleep quality, heart rate, blood pressure, Autonomic functions, respiratory, haematological, cognitive function, Quality of life were recorded before and after 1(st), 7(th), 14(th), 21(st), 28(th) days of vestibular stimulation. STAI S and STAI T scores were significantly improved on day 28(th) following vestibular stimulation. Diastolic and mean arterial blood pressure were significantly decreased and remained within normal limits in vestibular group on day 28(th) following vestibular stimulation. Postural fall in blood pressure was significantly improved on day 14 onwards, following vestibular stimulation. Respiratory rate was significantly improved on day 7 onwards, following vestibular stimulation. PSQI sleep disturbance, PSQI sleep latency, PSQI total score and bleeding time was significantly improved following vestibular stimulation. Our study supports the adoption of vestibular stimulation for stress management. Hence, placement of swings in college campuses must be considered, which may be a simple approach to alleviate stress among college students.

A rare cause of upper gastrointestinal bleeding: Posttraumatic pseudoaneurysm

Introduction: Hemobilia is a rare cause of upper gastrointestinal bleeding. It needs prompt diagnosis and immediate management to safe the life. Posttraumatic pseudoaneurysm of hepatic artery is seen mostly after abdominal trauma causing liver injury or interventions on hepatobiliary system. On esophagogastroduodenoscopy active bleeding without apparent source is clue to the diagnosis. case report: A 27-year-old male presented with history of one episode of hematemesis and melena. there was history of roadside accident one and a half months before and he had liver injury which was revealed on computed tomography of the abdomen. Patient was managed conservatively and discharged. On examination, patients was anemic and had postural fall in blood pressure. Emergency esophagogastroduodenoscopy revealed blood coming from ampulla. computed tomography angiography (ctA) revealed pseudoaneurysm in segmental branches of right hepatic artery with active bleeding. conclusion: Hemobilia is defined as bleeding into the biliary tree from abnormal communication between blood vessel and bile duct. the most common cause of posttraumatic hemobilia is pseudoaneurysm. the classic triad of hemobilia is absent in 70% of cases and in such cases clinical diagnosis is difficult. the ctA is the investigation of choice and embolization is the treatment option. surgery should be done in cases refractory to embolization.

Quick and Simple Evaluation of Sudomotor Function for Screening of Diabetic Neuropathy

Objective. The aim of this study was to compare SUDOSCAN, a new device to evaluate sweat function (reflecting peripheral small C-fiber status), with conventional measures of peripheral and cardiac neuropathy in patients with type 2 diabetes. Methods. 265 diabetic patients were tested for symptoms and clinical signs of neuropathy using Michigan Neuropathy Screening Instrument (MNSI), vibration perception threshold (VPT) using biothesiometer, and cardiac autonomic neuropathy (CAN) using Ewing's protocol. Sudomotor function was investigated with SUDOSCAN through measurement of electrochemical skin conductance (ESC) of hands and feet. Lower ESC is suggestive of sudomotor dysfunction. Results. Lower ESC at feet was significantly associated both with increasing symptoms (MNSI A) and increasing score on physical abnormalities (MNSI B). Lower ESC at feet was also significantly associated with increasing VPT by biothesiometry (P < 0.01), and with higher number of abnormal CAN results (P < 0.05). ESC was associated with postural fall in blood pressure (sympathetic abnormality) (P < 0.05), but not with heart rate variability (HRV) tests (parasympathetic abnormalities). Conclusions. Sudomotor dysfunction testing may be a simple test to alert physicians to peripheral nerve and cardiac sympathetic dysfunction. Ease of performance could make it useful in a busy diabetic clinic. Further studies with hard clinical outcomes are indicated.

Risk Factors for Hemodynamic Instability during Surgery for Pheochromocytoma

Surgery on pheochromocytoma carries a risk for hemodynamic (HD) instability. The aim of this study was to identify preoperative risk factors for intraoperative HD instability. In addition, efficacy of pretreatment with the alpha-adrenergic receptor (alpha) antagonists phenoxybenzamine (PXB) and doxazosin (DOX) was compared with respect to reduction of intraoperative HD instability. Seventy-three patients operated in Erasmus Medical Center between 1995 and 2007 were included. Parameters studied were catecholamine type and concentration, tumor diameter, mean arterial pressure (MAP) before and after (MAP(alpha)) pretreatment with alpha-antagonist, postural fall in blood pressure (BP) after pretreatment, type of alpha-blockade, type of operation, and presence of a familial polytumor syndrome. HD instability was assessed by measuring the number and time period MAP was below 60 mm Hg and systolic BP (SBP) was above 160 mm Hg. A correlation was found between the intraoperative time periods of SBP above 160 mm Hg and plasma norepinephrine levels (r = 0.23; P < 0.05), tumor diameter (r = 0.36; P < 0.01), and postural BP fall (r = 0.30; P < 0.05). MAP at presentation and after alpha-blockade above 100 mm Hg (BP, 130/85 mm Hg) was related to more and longer episodes with a SBP above 160 mm Hg (P < 0.01). Type of operation or alpha-blockade and presence of a familial polytumor syndrome were not related to intraoperative HD instability. Postoperative MAP was lower in the DOX group than in the PXB group (P < 0.05). Risk factors for HD instability during surgery for pheochromocytoma include a high plasma NE concentration, larger tumor size, more profound postural BP fall after alpha-blockade, and a MAP above 100 mm Hg (130/85 mm Hg). Efficacy for preventing HD instability was identical for PXB and DOX.

Seating-Induced Postural Hypotension Is Common in Older Patients with Decompensated Heart Failure and May Be Prevented by Lower Limb Compression Bandaging

Background: Postural hypotension induced by transition from supine to sitting position and measures for its prevention in heart failure has not been investigated. Objective: Our purpose was to evaluate the prevalence of postural hypotension and associated clinical manifestations as well as the contribution of various risk factors for postural hypotension on transition from lying to sitting in older patients with decompensated heart failure, and to study the eventual preventive effect of leg bandaging. Methods: Seating-induced postural hypotension (≥20 mm Hg systolic and/or ≥10 mm Hg diastolic blood pressure fall) was assessed on the first study day in 108 patients aged ≥60 years, hospitalized for acutely decompensated heart failure. On the next day, in patients manifesting postural hypotension, compression bandages were applied along both legs before seating. Blood pressure, heart rate, O₂ saturation, and the occurrence of dizziness or palpitations were recorded prior to and 1, 3 and 5 min following seating. Results: Postural hypotension occurred in 49.1% of patients. Dizziness and/or palpitations manifested in 25%. Diastolic (36.1%) versus systolic (23.1%) postural hypotension prevailed (p = 0.05). On univariate analysis, postural hypotension was associated with female sex (p = 0.03), more severe heart failure (p = 0.05), longer bedrest (p = 0.04), higher supine systolic (p = 0.01) or diastolic (p = 0.002) blood pressure, nonischemic heart failure (p = 0.002), and not using nitrates (p = 0.01). On multivariate analysis, longer bedrest (OR = 1.58, 95% CI = 1.13–2.2, p < 0.001), higher supine diastolic blood pressure (OR = 1.33, 95% CI = 1.1–1.61, p = 0.001), and nonischemic heart failure (OR = 3.48, 95% CI = 1.4–8.63, p = 0.009) were the most predictive of postural hypotension. Compression bandages prevented postural hypotension in 21 of 49 patients and decreased the degree of postural blood pressure fall (p < 0.001). Conclusion: Seating-induced postural hypotension is common among older inpatients with decompensated heart failure, especially with longer bedrest, higher supine diastolic blood pressure and non-ischemic etiology. Leg compression bandaging may be useful for the prevention of postural hypotension in these patients.

Childhood Sporadic Pheochromocytoma: Clinical Profile and Outcome in 19 Patients

Sporadic pheochromocytoma is a rare tumor of childhood and accounts for less than 1% of cases of hypertension. We describe the presentation and outcome of 19 adolescents with sporadic pheochromocytoma seen over past 10 years at a tertiary care center in north India. The mean age (+/- SD) at presentation was 15.1 +/- 2.4 years with range from 9-18 years. The male to female ratio was 12:7. The lag time between onset of symptoms to diagnosis ranged from 1 month to 5 years with mean (+/- SD) of 1.09 +/- 1.02 years. The majority of children presented with hypertension and paroxysms. Paroxysms, characterized by the triad of headache, palpitations and sweating, was present in 13 (68%) of these patients. Twelve (63%) patients had postural fall in blood pressure, ten (53%) had abdominal pain, four (21%) had visual blurring, and three (16%) each had palpable abdominal mass and significant weight loss at presentation. Nausea and vomiting are common symptoms in children with pheochromocytoma and were present in six (32%) and three (16%) patients, respectively. Café-au-lait macule was present in only two (11%) patients. Urinary vanilyl mandelic acid (VMA) was found to be significantly high in ten (53%) patients, and urinary epinephrine and norepinephrine in eight (42%). Six (32%) patients had both VMA and urinary epinephrine and norepinephrine within normal limits and five (26%) had significant elevation of both. The tumor was localized by ultrasonography in 17 (89%) patients and by computed tomography in 18 (95%), and in one patient it was localized by 131I-MIBG scan. Sixteen (84%) patients had adrenal pheochromocytoma (including four with bilateral masses), while the remaining three (16%) had abdominal extra-adrenal pheochromocytoma originating from sympathetic ganglions. The mean (+/- SD) diameter of the tumor was 4.4 +/- 1.7 cm, ranging from 2.2-7.5 cm. Pre-operatively, hypertension was managed by phenoxybenzamine in six (32%), sustained release prazosin in 12 (63%), beta-blockers in 14 (74%), calcium channel blockers in 12 (63%), and angiotensin converting enzyme inhibitors and diuretics in only two (11%) patients. Eighteen (85%) patients underwent exploratory laparotomy for removal of the tumor. On follow-up, 13 (72%) patients became normotensive, while six (32%) patients continued to have hypertension. In conclusion, childhood pheochromocytoma is characterized by atypical symptomatology; ultrasonography is a useful modality in localizing the lesions in the majority of patients; surgery is rewarding in most patients.

Cutaneous sympathetic function in patients with multiple system atrophy.

Some procedures increase the sweat output (SSwR; sympathetic sweat response) and reduce the cutaneous blood flow (SVR; skin vasomotor reflex) in the hand. We evaluated SSwRs and SVRs to deep inspiration, mental arithmetic, exercise, and tactile stimulation in 40 MSA patients and 15 healthy controls. We also conducted head-up tilt tests and R-R interval variation tests (CV(R-R)). SSwRs were present in all controls, but absent in 19 (47.5 %) of the MSA patients. The mean SSwR amplitudes in the MSA group were significantly lower than those in the control group. SVRs were evoked in all subjects except 3 MSA patients. There were no marked differences in SVR amplitudes between the two groups. Orthostatic hypotension and low CV(R-R) values were seen in 18 (45 %) and 13 (32.5 %) of the MSA patients, respectively. SSwR amplitudes correlated significantly with postural fall in blood pressure and CV(R-R) values in the MSA group. SSwRs were absent in about half of the MSA patients, and the SSwR results correlated with those of the cardiovascular autonomic tests. The SVRs were not severely disturbed in the MSA patients. We considered SSwR a useful index for the detection of autonomic dysfunction in MSA.

Effects of long-term exercise training on cardiac autonomic nervous activities and baroreflex sensitivity

Reductions in tonic vagal controls of the heart and depressed baroreflex sensitivity (BRS) have been associated with a postural fall in blood pressure (BP) and the incidence of cardiac events among older people. We examined the hypothesis that BP regulation during orthostatic challenge as well as heart rate variability (HRV) at rest can be better maintained in long-term exercise-trained, healthy, older men (aged 60-70 years). Subjects were classified into two groups; long-term exercise-trained (LTET, n=14) and sedentary (SED, n=10) according to their history of physical activity. Prior to the dynamic BRS assessment, supine resting autonomic cardiac modulation was assessed by means of time domain HRV [standard deviation of ECG R-R interval (RRISD) and the coefficient of variation (CV)]. The BRS was assessed during 60 degrees head-up tilting by simultaneously measuring beat-by-beat systolic blood pressure (SBP) and ECG R-R interval changes. The BRS gain was determined by the regression slope coefficient based on the extent of the SBP fall and the corresponding ECG R-R shortening during the orthostatic challenge. The results indicated that the LTET group manifested greater ECG R-R interval fluctuations with significantly higher resting RRISD and CV, compared with the SED group [59.5 (10.4) versus 27.7 (7.8) ms, p<0.05; 5.5 (0.8) versus 2.8 (0.7)%, p<0.05], respectively. Using dynamic BRS testing during the acute orthostatic challenge, the LTET group showed a significantly higher BRS gain than the SED [6.4 (0.8) versus 3.8 (0.6) ms x mmHg(-1), p<0.017] group. These results indicate that CV and BRS are well maintained in healthy, LTET older individuals when compared with their sedentary peers. Our data suggest that this augmented autonomic cardiac modulation reflects better parasympathetic responsiveness in LTET individuals. Data provide further support for long-term exercise training as another possible cardioprotective factor that might decrease susceptibility to ventricular fibrillation as well as assist arterial BP at the onset of an orthostatic challenge in older men.

Treatment of erectile dysfunction with sildenafil citrate (Viagra) in parkinsonism due to Parkinson's disease or multiple system atrophy with observations on orthostatic hypotension

OBJECTIVESTo assess the efficacy and safety of sildenafil citrate (Viagra) in men with erectile dysfunction and parkinsonism due either to Parkinson's disease or multiple system atrophy.METHODSTwenty four patients with erectile...

Abstracts of literature

Abstracts of literature

Cardiovascular, autonomic, and plasma catecholamine responses in unilateral and bilateral carotid artery stenosis

OBJECTIVETo determine impairment of baroreceptor afferent activity, which may affect cardiovascular autonomic function in patients with unilateral and bilateral carotid artery stenosis. Comparison was made with normal subjects and hypertensive...

Orthostatic blood pressure changes and arterial baroreflex sensitivity in elderly subjects.

orthostatic hypotension in elderly people is often attributed to diminished afferent baroreflex sensitivity, but this has not been demonstrated. We examined the hypothesis that postural change in blood pressure is related to baroreflex sensitivity, independent of the confounding effect of baseline blood pressure. we studied 25 active, untreated elderly subjects free of postural symptoms (mean age 70 +/- 1 years): 16 with hypertension (clinic blood pressure 194 +/- 6/98 + 3 mmHg) and nine normotensive controls (clinic blood pressure 134 + 3/77 + 3 mmHg). We assessed baroreflex sensitivity from the heart rate and blood pressure responses to the Valsalva manoeuvre and a pressor and depressor stimulus (bolus phenylephrine injection or sodium nitroprusside infusion respectively). Subjects were then passively tilted to 60 degrees and maximum changes in systolic blood pressure, heart rate, forearm blood flow and forearm vascular resistance recorded. maximum change in systolic blood pressure with head-up tilt was correlated with supine systolic blood pressure (r = 0.60, P = 0.001). Maximum change in systolic blood pressure with orthostasis was greater in the hypertensive subjects (45 +/- 4 mmHg versus 29 +/- 6, P = 0.04) and the heart rate increment was less (16 +/- 2 bpm versus 24 +/- 4, P = 0.02). The increase in forearm vascular resistance with tilt was similar in the two groups (47 +/- 11 versus 38 +/- 7 units, P = 0.52). All three methods of assessing baroreflex sensitivity showed a reduction in the hypertensive subjects (all P < or = 0.02). Lower values of baroreflex sensitivity were related to greater falls in systolic blood pressure with tilt, after adjustment for the baseline level of systolic blood pressure. we found a relationship between baroreflex sensitivity and the systolic blood pressure fall with orthostasis, even after adjustment for prevailing systolic blood pressure. Despite equivalent changes in forearm vascular resistance with tilt, greater falls in systolic blood pressure were seen in hypertensive subjects than in normotensive controls, due in part to an inadequate baroreflex-mediated heart rate response. The postural fall in blood pressure often observed in elderly hypertensive subjects may be related to the reduced baroreflex sensitivity seen in this condition.

Neck and other muscle pains in autonomic failure: their association with orthostatic hypotension.

Neck pain in the suboccipital and paracervical region ('coathanger' configuration) is often reported by patients with autonomic failure and orthostatic hypotension. The frequency of this pain, along with pains in the buttock and calf regions, was determined by questionnaire in two major groups with primary chronic autonomic failure--pure autonomic failure (PAF) and multiple system atrophy (MSA). Comparisons were made with Parkinson's disease, cerebellar degeneration and other disorders in which neurological symptoms overlap but in which there was neither autonomic failure nor orthostatic hypotension. Neck pain was present in 93% of patients with PAF, 51% of patients with MSA and 38-47% of the non-autonomic groups. Buttock pain was present in smaller but similar proportions (8-19%) of each group, like calf pain (23-37%). Neck pain in PAF and MSA differed from that in the other groups in being relieved by sitting or lying flat and in being associated with factors that lower blood pressure in these patients. Buttock pain was posturally related in PAF and MSA; for calf pain there was no difference between groups. Neck pain was related to the degree of orthostatic hypotension; in PAF patients, whose postural blood-pressure fall was greater than that in MSA, there was a greater frequency of neck pain.

Cardiovascular and catecholamine changes induced by supine exercise and upright posture in vasovagal syncope. Comparisons with normal subjects and subjects with sympathetic denervation.

The haemodynamic and catecholamine responses to supine leg exercise were studied in vasovagal syncope (n = 10), pure autonomic failure (n = 10) and in control (n = 10) subjects. With exercise, blood pressure increased in controls; with a smaller rise in vasovagal syncope, and a substantial fall in pure autonomic failure. Heart rate increased similarly in controls and vasovagal syncope, but less in pure autonomic failure. The increase in cardiac index was less in controls and pure autonomic failure than vasovagal syncope; the fall in systemic vascular resistance was greatest in pure autonomic failure, but also fell more in vasovagal syncope than controls. Plasma noradrenaline levels increased in controls; with a smaller rise in vasovagal syncope and no increase in pure autonomic failure. Plasma adrenaline levels increased in vasovagal syncope only. The blood pressure responses to standing before and after exercise were similar in controls and vasovagal syncope, with no postural blood pressure fall; in pure autonomic failure there was a greater postural blood pressure fall post exercise. In conclusion, with supine exercise, blood pressure rose in controls and vasovagal syncope, and fell in pure autonomic failure. Systemic vascular resistance fell more in vasovagal syncope and pure autonomic failure, than controls. Noradrenaline responses differed and adrenaline rose in vasovagal syncope only. Standing post exercise did not induce syncope in vasovagal syncope, but increased postural hypotension in pure autonomic failure. There are clear differences in response to exercise in vasovagal syncope and pure autonomic failure. The differences between vasovagal syncope and control subjects suggest an underlying abnormality which may predispose to vasodepression in subjects with vasovagal syncope.

Spectral analysis of blood pressure and heart rate, catecholamine and neuropeptide Y plasma levels in a new model of neurogenic orthostatic hypotension in dog.

The aim of the study was to compare changes in blood pressure (BP) and heart rate (HR) variability, catecholamine and neuropeptide Y (NPY) plasma levels induced by passive head-up tilt in normal and sino-aortic denervated (SAD) chloralose-anaesthetized dogs. In controls, 80 degrees head-up tilt test failed to change BP and increased HR. Plasma noradrenaline and NPY levels (but not adrenaline) significantly rose. In SAD dogs, head-up tilt test induced a marked and reproducible decrease in BP without any change in HR or noradrenaline and NPY plasma levels. In SAD dogs, spectral analysis in supine position was characterized by reduced variability in the high frequency (HF) band of the HR spectrum without changes in low frequency (LF) bands of both HR and systolic blood pressure (SBP). Head-up tilt test increased the LF component of SBP variability and decreased the HF component of HR variability in controls but failed to modify HR and BP variabilities in SAD dogs. In conclusion, sino-aortic denervation in dogs elicits a reproducible postural fall in BP with impaired adaptation of sympathetic nervous system activity. This model may be of value in evaluating the pharmacological effects of drugs for the management of orthostatic hypotension.

Oedema in patients with Addison's disease on replacement therapy: glcocorticoid excess and mineralocorticoid deficiency?

Steroid hormones influence mechanisms related to oedema formation, including postural vasoconstriction and vascular tone. We studied fifteen patients (7 male, 8 female) with primary adrenal failure on clinically optimal replacement therapy. Five patients, all female, had clinically detectable oedema. Patients with oedema had evidence of mineralocorticoid deficiency, with increased supine and erect plasma renin activity and greater postural fall in blood pressure. Mean morning plasma cortisol levels were significantly higher in the group with oedema, suggesting they were receiving insufficient mineralocorticoid and a possible relative excess of glucocorticoid. There were no significant differences between patients with and without oedema in lower-limb cutaneous blood flow or in postural vasoconstrictor responses measured by laser Doppler flowmetry. The mechanism of oedema formation is unclear, but appears not to be modulated by haemodynamic mechanisms with expansion of intravascular volume or, in contrast to the known effects of sex hormones, by impairment of postural vasoconstriction. Theoretically, excess glucocorticoid replacement may result in oedema formation, by direct action on vascular tone, by altering capillary permeability, or by influencing other factors such as atrial natriuretic peptide. Measurement of plasma renin activity in conjunction with plasma cortisol profiles may be useful in adjusting replacement therapy in patients with Addison's disease and oedema.

Postural Fall in Blood Pressure in the Elderly in Relation to Drug Treatment and Other Lifestyle Factors

In a study of 843 independent-living men and women aged between 60 and 87 in Perth, Western Australia, stepwise multiple regression, after correction for initial levels of systolic blood pressure, showed that postural fall in systolic blood pressure was positively related to alcohol intake of more than 20 ml/day, the use of sleeping tablets and higher levels of anxiety on the Spielberger state-trait scale, and negatively related to body mass index. Postural fall in blood pressure was not significantly related to treatment for hypertension, age, sex, patterns of usual physical activity, tea or coffee drinking, or the diagnosis of diabetes mellitus. This analysis is the first to examine the relationship between lifestyle factors and the magnitude of the fall in systolic blood pressure on standing after adjustment for the association between the change in a variable and its initial level. Our analysis suggests the need for further study of the possible role of lifestyle factors such as the use of sleeping tablets and alcohol in postural hypotension in the elderly.

Plasma norepinephrine responses to head-up tilt are misleading in autonomic failure.

The failure of plasma norepinephrine to rise during upright posture is accepted as a diagnostic sign of autonomic nervous failure in patients with postural hypotension. Our clinical experience has been that this test is misleading, with an increase in plasma norepinephrine commonly occurring. To test whether this might result from absent reflex postural venous constriction lowering cardiac output and plasma norepinephrine clearance, we measured norepinephrine plasma kinetics during recumbency and 30 degrees head-up tilting in six patients with pure autonomic failure and eight healthy subjects. Mean arterial pressure fell by 54 +/- 8 mm Hg with head-up tilt in the patients with pure autonomic failure. The plasma norepinephrine concentration (arterial sampling) increased 73 +/- 29 pg/ml (mean difference +/- SED, p less than 0.02), solely because of a 36% reduction in the clearance of norepinephrine from plasma (0.78 +/- 0.09 l/min, p less than 0.0001). In normal subjects, plasma norepinephrine concentration rose by 112 +/- 20 pg/ml (p less than 0.001), largely because of a 24% increase in norepinephrine spillover to plasma (190 +/- 20 ng/min, p less than 0.005). When the postural fall in blood pressure and cardiac output in the pure autonomic failure patients was prevented by the selective venoconstrictor dihydroergotamine (10 micrograms/kg i.v.), no fall in plasma clearance or rise in plasma concentration of norepinephrine occurred. Measurement of the change in plasma norepinephrine with postural stimulation in patients with orthostatic hypotension is not a reliable diagnostic test for autonomic failure because elevations can occur in the plasma concentration that are entirely attributable to reduced plasma norepinephrine clearance.