Hemodynamic Response to the Upright Posture

Journal of Clinical Pharmacology - Tập 34 Số 5 - Trang 375-386 - 1994
James J. Smith1, Carol Porth1, Molly Erickson1
1Department of Physiology, Medical College of Wisconsin, The University of Wisconsin‐Milwaukee School of Nursing, and the Zablocki Veterans Administration Medical Center, Milwaukee, Wisconsin.

Tóm tắt

The authors' objective was to review previous studies of immediate (first 30 seconds) and stabilized (30 seconds to 20 minutes) hemodynamic responses of healthy adults to the head‐up posture, with particular reference to alteration of such responses in the elderly and the usefulness of such data in the diagnosis of orthostatic hypotension. The immediate response in healthy young adults is characterized by a prompt rise in heart rate, which peaks at about 8 to 15 seconds and then tapers; the arterial pressure and total vascular resistance decrease sharply at 5 to 10 seconds, followed by a rapid rebound and overshoot. Over the first 30 seconds there is a steady parallel decline of thoracic blood volume and stroke volume; there is also an initial surge of cardiac output followed by a steady decrease. During the stabilized response (30 seconds to 20 minutes), the hemodynamic variables are relatively steady, showing average increases in heart rate of about 15 to 30%, in diastolic pressure of 10 to 15%, and in total vascular resistance of 30 to 40%; during the 5th to 20th minutes there are also decreases in thoracic blood volume averaging about 25 to 30%, in cardiac output 15 to 30%, and in pulse pressure about 5 to 10%. It is evident that in normal human subjects, assumption of the upright posture results in profound hemodynamic changes, most of them occurring during the first 30 seconds. In elderly subjects (aged 60–69 years), there are, in the upright posture, lesser increments of heart rate and diastolic pressure, but no significant differences from younger age groups in the response of thoracic blood volume, cardiac output or total vascular resistance. However, beginning at about age 75, there is an increasing incidence of orthostatic hypotension, which averages about 14 to 20% at age 75 and older. The tendency toward orthostatic hypotension in the elderly is due (1) to the structural and functional changes in the circulation itself, (2) to a decline in autonomic function, and (3) to a probable functional deficiency of the skeletal muscle pump. The authors believe that closer hemodynamic monitoring of orthostatic hypotension patients would considerably increase our understanding and aid in the diagnosis of this condition.

Từ khóa


Tài liệu tham khảo

Harkel ADJ, 1990, Assessment of cardiovascular reflexes: Influence of posture and period of preceding rest, J Appl Physiol, 68, 147, 10.1152/jappl.1990.68.1.147

10.1136/bmj.1.6106.145

10.1152/ajpheart.1982.243.5.H676

Smith JJ, 1984, Transient hemodynamic responses to circulatory stress in normal male subjects of different ages, Physiologist, 27, 210

10.1152/jappl.1991.70.2.523

10.1016/0002-8703(73)90529-2

Patterson RP, 1973, Studies on the effect of controlled volume change on thoracic electrical impedance, Chest, 64, 597

10.1152/jappl.1975.38.5.851

Ramos MU, 1975, Transthoracic electric impedance: A clinical guide for pulmonary fluid accumulation, Minn Med, 58, 671

10.1378/chest.64.5.597

Ebert TJ, 1986, The use of thoracic impedance for determining thoracic blood volume in man, Aviat Space Environ Med, 57, 49

10.1152/jappl.1970.29.1.133

Lakatta EG, 1986, Hemodynamic adaptations to stress with advancing age, Acta Med Scand Suppl, 711, 39, 10.1111/j.0954-6820.1986.tb08930.x

Brauer G, 1975, Zum verhalten des Menschen bei unterschiedlicher Geschwindigkeit des Übergangs vom leigen zur Kopf aufwartsposition, Acta Biol Med Germ, 34, 1153

Ewing DJ, 1980, Autonomic mechanisms in the initial heart rate response to standing, J Appl Physiol, 49, 809, 10.1152/jappl.1980.49.5.809

10.1152/physrev.1953.33.2.202

Rowell LD, 1986, Human Circulation During Physical Stress.

Gauer ON, 1965, Handbook of Physiology, Sect. 2, Circulation, 2409

Blomqvist CG, 1982, Handbook of Physiology, 1025

Smith JJ, 1990, Circulatory Response to Upright Posture, 1

10.1007/BF00587518

10.1093/geronj/42.4.406

Hagen RD, 1978, Plasma volume changes with movement to the upright position, J Appl Physiol, 45, 414, 10.1152/jappl.1978.45.3.414

Hinghofer‐Szalkay H, 1986, Fluid and protein shifts after positional changes in humans, Am J Physiol, 250, 1168

10.1111/j.1748-1716.1964.tb02940.x

Duprez DP, 1987, Postural cardiovascular reflexes: Comparison of forearm and calf vessels, J Appl Physiol, 63, 1801, 10.1152/jappl.1987.63.5.1801

10.1016/0531-5565(91)90007-9

Hellebrandt FA, 1943, Physiological study of vertical stance in man, Physiol Rev, 23, 220, 10.1152/physrev.1943.23.3.220

Strandell T, 1964, Circulatory studies in healthy old men, Acta Med Scand, 175, 1

Weisfeldt ML, 1980, The Aging Heart.

Smith JJ, 1990, Circulatory Response to the Upright Posture., 121

10.1042/cs0720335

10.1093/geronj/45.1.M20

10.3181/00379727-156-39884

Harris T, 1986, Is age or level of systolic blood pressure related to positional blood pressure change?, Gerontologist, 26, 59A

Porth CM, 1993, Minute‐lyminate hemodynamic responses of community dwelling elders to a 5‐minute free stand, FASEB J

Docherty JR, 1990, Cardiovascular responses in aging: A review, Pharmacol Rev, 42, 103

Hajduczok G, 1991, Increase in sympathetic activity with age: Role of impairment of cardiopulmonary baroreflexes, Am J Physiol, 260, H1121

Loeppky JP, 1975, Cardiorespiratory responses to orthostasis and the effects of propranolol, Aviat Space Environ Med, 46, 1164

Tyden G, 1977, Aspects of cardiovascular reflex in man, Acta Physiol Scand Suppl, 468, 7

10.1113/jphysiol.1983.sp014647

10.1093/cvr/16.11.663

10.1042/cs0680503

10.1113/jphysiol.1978.sp012170

Joyner MJ, 1988, Temporal dissociation of vascular resistance and sympathetic neural discharge in humans, Physiologist, 31, 112

Lipsitz LA, 1986, Effect of advanced age on cardiovascular responses to orthostatic stress, Gerontologist, 26, 58a

10.1111/j.1532-5415.1989.tb05871.x

10.1002/j.1552-4604.1991.tb03645.x

10.1152/jappl.1990.68.4.1458

10.1002/j.1552-4604.1991.tb03655.x

Wieling W, 1988, Standing, Orthostatic Stress and Autonomic Function in Autonomic Failure., 309

Thông tin
Thông tin xuất bản

Journal of Clinical Pharmacology

Tập 34 Số 5

375-386

Thông tin tác giả