Incidence Of Orthostatic Hypotension Research Articles

Compression Garments as Countermeasures to Orthostatic Intolerance

All astronauts experience some degree of orthostatic intolerance following spaceflight, ranging from tachycardia to orthostatic hypotension and syncope. The purpose of this study was to evaluate the ability of two compression garments, the National Aeronautics and Space Administration's inflatable antigravity suit (AGS) and the Russian Federal Space Agency's non-inflatable compression garment (Kentavr), to prevent hypovolemia-related orthostatic intolerance. To mimic the plasma volume loss experienced by astronauts during spaceflight 19 healthy subjects received an intravenous dose of a diuretic, furosemide (0.5 mg x kg(-1)), and then consumed a low-salt diet for 36 h. Thereafter, subjects participated in a 15-min 80 degrees head-up tilt test wearing either the AGS (N = 9) or Kentavr (N = 10). Compression garments were used in the fashion recommended by the respective agencies, delivering approximately 78 mmHg and approximately 30 mmHg of compression in the AGS and Kentavr, respectively. Incidence of presyncope and hemodynamic responses during upright tilt were compared to a separate group of hypovolemic control subjects (N = 16). Subjects wearing the AGS or Kentavr completed the full 15 min of upright tilt without incidence of orthostatic hypotension or presyncope. In contrast, only 9 control subjects (56%) were able to complete the tilt test. In addition, both types of compression garments maintained systolic blood pressure and significantly reduced tilt-induced tachycardia and reductions in stroke volume. Although both garments successfully countered hypovolemia-induced orthostatic intolerance, the Kentavr provided protection by using lower levels of compression. Determining the optimal compression level required for protection of intolerance may improve crewmember comfort and decrease restrictions on physical activities after spaceflight.

Poster 197: Hypotension in poststroke patients: effects on outcome.

Objectives: To evaluate (1) the incidence of orthostatic hypotension and hypotension without documented orthostatic blood pressures in poststroke patients who participate in inpatient rehabilitation, and (2) whether hypotension increases length of stay (LOS) or FIM™ instrument changes compare with stroke patients who do not have hypotension. Design: Retrospective study. Setting: Veterans Affairs inpatient rehabilitation ward. Participants: 75 subjects (74 men, 1 women) with first-time acute cerebrovascular accident admitted to rehabilitation floor. Interventions: Not applicable. Main Outcome Measures: Acute and rehabilitation LOS, admission and discharge FIM scores, FIM change, and FIM efficiency (FIM change/rehabilitation LOS). Results: 25 subjects had hypotension, 7 of 25 subjects had orthostatic hypotension, and 18 of 25 had hypotension (at least >20mmHg decrease in blood pressure from the baseline with or without dizziness) without documented orthostatic blood pressures. 50 subjects had no hypotension. Hypotension subjects had a mean age of 72.0±10.7 years compared with the nonhypotensive subjects, who had a mean age of 66.8±12.0 years ( P<.05). Hypotensive subjects had a rehabilitation LOS of 29.0±11.8 days compared with nonhypotensive subjects at 21.6±10.2 days ( P<.01). Hypotensive subjects had a FIM efficiency score of .94±.47 compared with nonhypotensive subjects at 1.2±0.5 ( P<.05). There was no significant correlation between rehabilitation LOS and age. No significant differences were found in acute LOS, admission FIM scores, discharge FIM scores, or FIM change ( P<.05). Conclusions: There is a high prevalence (33%) of hypotension in our study patients who were admitted to the rehabilitation floor. Hypotension adversely effected the LOS and FIM efficency. Hypotension needs to be aggressively taken into consideration by the rehabilitation team early to improve the efficiency of care.

Efficacy and safety of once-daily alfuzosin in the treatment of lower urinary tract symptoms and clinical benign prostatic hyperplasia: a randomized, placebo-controlled trial

Objectives. To assess the efficacy and safety, and determine the optimal dosage, of a once-daily (OD) formulation of the clinically uroselective alpha 1-blocker, alfuzosin, in patients with lower urinary tract symptoms and symptomatic benign prostatic hyperplasia. Methods. Five hundred thirty-six patients were randomized to receive alfuzosin (10 mg OD or 15 mg OD), without initial dose titration, or placebo in a 3-month double-blind trial conducted in North America. The primary efficacy criteria were improvement in symptoms (International Prostate Symptom Score) and peak urinary flow rate. Results. Alfuzosin was significantly more effective than placebo in improving the symptoms and peak urinary flow rate from the first follow-up visit (day 28). The mean change in the International Prostate Symptom Score from baseline at endpoint was −3.6 and −3.4 with alfuzosin 10 mg and 15 mg, respectively, compared with −1.6 with placebo (alfuzosin 10 mg versus placebo, P = 0.001; alfuzosin 15 mg versus placebo, P = 0.004). The median increase in the peak urinary flow rate was +1.1 mL/s and +1.0 mL/s with alfuzosin 10 mg and 15 mg, respectively, compared with 0.0 mL/s with placebo ( P = 0.0006 versus placebo for both dose groups). The patients’ quality of life also significantly improved with both alfuzosin doses. Overall, alfuzosin at both doses was well tolerated. The incidence of orthostatic hypotension as determined by systematic blood pressure measurements with both doses of alfuzosin was similar to placebo. No clinically relevant ejaculation disorders were observed with alfuzosin. Conclusions. Alfuzosin 10 mg OD, administered without dose titration, provides effective relief from the symptoms of benign prostatic hyperplasia with no additional benefit from a 15-mg dose. It is well tolerated from a cardiovascular viewpoint and is not associated with abnormal ejaculation.

Differential effects of fosinopril and enalapril in patients with mild to moderate chronic heart failure

Objectives To investigate the efficacy and safety of fosinopril in the treatment of chronic heart failure (CHF), patients with mild to moderate CHF and left ventricular ejection fractions <40% were randomly assigned in a double-blind manner to receive fosinopril 5 to 20 mg every day ( n = 122) or enalapril 5 to 20 mg every day ( n = 132) for 1 year. Results The event-free survival time was longer (1.6 vs 1.0 months, P = .032) and the total rate of hospitalizations plus deaths was smaller with fosinopril than with enalapril (19.7% vs 25.0%, P = .028). There was consistently better symptom improvement with fosinopril ( P < .05). The incidence of orthostatic hypotension was lower in the fosinopril group (1.6 % vs 7.6 %, P < .05). Conclusions Fosinopril 5 to 20 mg every day was more effective in improving symptoms and delaying events related to worsening of CHF and produced less orthostatic hypotension than enalapril 5 to 20 mg every day. (Am Heart J 1998;136:672-80.)

Orthostatic hypotension during postoperative continuous thoracic epidural bupivacaine-morphine in patients undergoing abdominal surgery.

Fifty patients undergoing colonic surgery received combined thoracic epidural and general anesthesia followed by continuous epidural bupivacaine 0.25% and morphine 0.05 mg/mL, 4 mL/h, for 96 h postoperatively plus oral tenoxicam 20 mg daily. Heart rate (HR) and arterial blood pressure (BP) were measured at supine rest, during orthostatic stress, and after walking prior to and 24, 48, and 72 h and 48 h postoperatively compared to preoperatively (P < or = 0.008); 16 vs 6 patients presented resting systolic BP values < 100 mm Hg (lower range, 70 mm Hg) post- versus preoperatively (P = 0.048). During orthostatic stress the decrease in systolic BP and concomitant increase in HR was similar post- versus preoperatively (BP, P > 0.3; HR, P > 0.34) and 12 vs 8 patient; (P = 0.45) experienced a systolic BP decrease > 20 mm Hg post- versus preoperatively. After walking, systolic BP was significantly lower postoperatively compared with preoperatively (P < or = 0.01). Epidural infusion was discontinued in three patients due to either persisting resting or orthostatic hypotension. There was no correlation between ASA classification, intraoperative bleeding, or postoperative dizziness and incidence of orthostatic hypotension. The results suggest that patients undergoing abdominal surgery and treated with continuous small-dose thoracic epidural bupivacaine-morphine are subjected to a decrease of BP at rest and during mobilization, but not to an extent that seriously impairs ambulation in most patients.

Impairment of carotid-cardiac vagal baroreflex in wheelchair-dependent quadriplegics

The incidence of orthostatic hypotension can increase after prolonged exposure to chair rest and bedrest and is associated with post-bed rest impairment of the carotid-cardiac baroreflex response. We therefore hypothesized that the hypotension observed in humans confined to wheelchairs may be manifested by a reduced baroreflex sensitivity. We compared baroreflex responses of 16 wheelchair-dependent (WCD) quadriplegics with those of 15 able-bodied subjects (ABS) matched for age, height, and weight. Beat-to-beat R-R intervals were measured during application of graded pressures from 40 to -65 mmHg using a neck chamber for noninvasive stimulation of the carotid baroreceptors. Changes of R-R intervals were plotted against carotid distending pressures. The maximum slope of the stimulus-response relationship was greater (P less than 0.0001) in ABS (6.1 +/- 0.6 ms/mmHg) than in WCD (2.6 +/- 0.4 ms/mmHg). The range of the R-R interval response, i.e., the capacity to buffer blood pressure changes, was only 138 +/- 19 ms in WCD compared with 253 +/- 19 ms in ABS (P less than 0.001). Mean sitting systolic-to-diastolic blood pressures in WCD (92/60 mmHg) were less (P less than 0.0001) than in ABS (120/77 mmHg), although there were no significant differences between groups in supine resting blood pressures. Chronic loss of stimulation to carotid baroreceptors by routine standing posture is associated with attenuated sensitivity and reduced buffer capacity of the arterial baroreflex and hypotension during sitting in WCD patients.

Blood Pressure Abnormalities as Background Roles for Vertigo, Dizziness and Disequilibrium

In 3 years, a total of 1,291 patients have undergone equilibrium examinations because of vertigo, dizziness and disequilibrium in the Otoneurological Division of Toyama Medical and Pharmaceutical University. Abnormal blood pressures (hypertension, hypotension and orthostatic hypotension) were found in 18.67% (241 patients). Hypotension was found significantly more often in peripheral vestibular disorders and hypertension in central nervous system disorders. Furthermore, the incidence of orthostatic hypotension was statistically higher in hypertensive patients than in hypotensive patients. Therefore, we conclude that blood pressure measurement by the Schellong test method in patients with vertigo, dizziness and disequilibrium is very important.

Incidence of orthostatic hypotension in patients with primary affective disorders treated with tricyclic antidepressants

Previous studies have indicated that postural hypotension is an uncommon event when tricyclic antidepressants are used in the treatment of depression, and other studies have indicated that postural hypotension is a possible predictor of positive therapeutic response to antidepressant therapy. In this study, 20 depressed patients with the diagnosis of primary affective disorders were hospitalized and treated with tricyclic antidepressants. All patients had been without medication for at least 2 weeks before the study began. Blood pressure recordings were made after a 5-minute resting period and then followed by another reading after the patient had been standing for 2 minutes. Our findings indicate that these patients with primary affective disorders developed significant orthostatic hypotension. It is our belief that orthostatic hypotension is a significant event in patients who have primary affective disorders treated with tricyclic antidepressants, and this sign should be looked for in all patients regardless of age or the presence of significant cardiovascular disease.