“He’s Dizzy When He Stands Up”: An Introduction to Initial Orthostatic Hypotension

Abstract

Introduction to the patient and the most frequent orthostatic complaintThe most frequent orthostatic complaint in young people is lightheadedness or dizziness on rapid standing, sometimes from a seated position, most often from a supine position after hours of recumbency(1,2). The most common complainant is an adolescent in the middle of a growth spurt. Often the patient is already tall or is growing rapidly. Similar complaints are seen among young people of both sexes, particularly in patients of slender build and reduced blood volume (3). The complaints relate to normal physiology shared by people of all ages and have been identified by students of orthostasis in the past (1,2,4-6). Typically, there is transient pallor, perhaps some loss of postural tone, blurred vision or even loss of vision (black out, white out, spots), and less commonly, loss of consciousness. Symptoms instantly disappear with recumbency and are reduced or even abolished by standing up more slowly or in stages (7). Symptoms and signs peak soon after standing, in synchrony with a transient and substantial decrease in blood pressure which has its nadir at approximately 8-15 seconds after standing as shown in Figure 1. Heart rate increases as BP falls. These findings can be demonstrated using beat-to-beat finger arterial photoplethysmography (Finapres, Finometer, TNO Amsterdam) (2,8,9) or other means for beat-to-beat assessment. The BP decrements are usually not apparent by auscultatory or oscillometric blood pressure measurement, having a far too rapid and fleeting time course to be detected by these methods (10).Thus, the clinician needs to rely on clinical history and perhaps observation of the patient. The history is that of rapid-onset, short-lived dizziness and other symptoms on rapidly standing upright. If the patient can remain upright or can be held upright, all symptoms abate and disappear within 60 seconds and usually within less than 30 seconds (11). After recovery, the patient is usually entirely well and is free of subsequent fainting and of Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.The authors declare no conflicts of interest. . These studies should be cautiously interpreted because they excluded subjects with known OI. However, they do demonstrate that IOH need not cause more pernicious forms of OI. This short-lived hypotension is different from simple faint, in which maintaining the patient in the upright position makes the faint persistent and the patient often becomes much worse, clinically (12). NIH Public AccessCan it occur on a tilt table? We often observe the phenomenon as t...

Squatting maneuver - an easy and efficient method to evaluate postural effect on human arterial blood pressure regulation

“…suggested that healthy teenagers and young adult subjects using the beat-to-beat measurement of stroke volume with calculation of CO and systemic vascular resistance (SVR) have established that CO actually increases with the onset of standing up, whereas SVR falls markedly. [31][32][33][34] This study confirms the findings suggested by Tschakovsky et al and Rossberg and Penaz that the fall in BP after arising from squatting is based primarily on a fall in SVR. [35,36] In accordance with the previous studies in healthy young adults, the CO at the moment of the nadir was increased, however, for the large initial fall in BP on standing after supine rest, the hemodynamic mechanism can be either a large fall in CO or in SVR.…”

Reduced Cerebral Blood Flow With Orthostasis Precedes Hypocapnic Hyperpnea, Sympathetic Activation, and Postural Tachycardia Syndrome

“…The decrease in arterial BP with initial orthostatic hypotension is larger during standing than during HUT, although present in both 20 . Nevertheless, these patients uniformly identified their symptoms including dyspnea during tilt with symptoms that occur during “real world” orthostasis.…”

“…Changing from supine to standing transfers >500ml of central BV caudally, initially decreasing central BV and increasing BV within the splanchnic vasculature and lower extremites 20, 21, 24 . There is often a period of IOH during which BP and CBF transiently decrease, sometimes markedly, reaching their nadir 10-20 s after standing 25 , A reflex tachycardia results, and BP and CBFv are restored within 30-60 s. IOH results from the normal delay of arterial baroreflex detection and autonomic response to gravitational BV redistribution.…”

“…The first minute of active standing or HUT often includes a period of hemodynamic instability known as “initial orthostatic hypotension” (IOH) characterized by translocation of blood from cephalic towards the caudal portion of the body causing a fall in central BV and BP and concomitant rise in HR attributed to a lag in compensatory adrenergic vasoconstriction 20, 21 . Often the first minute of tilting is not used for analysis.…”

Speed of Heart Rate Recovery in Response to Orthostatic Challenge

“…Orthostasis evokes a rapid physiological response involving the coordinated action of several systems, including the skeletal-muscle pump and arterial and cardiopulmonary baroreflexes. 11 The orthostatic response reflects a balance between cardiac output and total peripheral resistance modulated by the autonomic nervous system and baroreflexes and most commonly measured using changes in heart rate and blood pressure. When resting in the supine position, venous and arterial reservoirs are at the same height, but standing up reduces venous return by displacing ≈500/700 mL (10 mL/kg) of central blood into the peripheral system.…”