A Comparison of Haemodynamic Responses between Head-Up Tilt and Lower Body Negative Pressure.

Abstract

Orthostatic intolerance (OI), a disorder of the autonomic nervous system, it is the development of symptoms when standing upright which are relieved when reclining. Head-up tilt (HUT) table test is a common test for assessing orthostatic tolerance. However, HUT is limited with low sensitivity and specificity. Another approach to stimulate the changing direction and value of the gravity field vector is the lower body negative pressure (LBNP) chamber. The aims of the study is to evaluate the physiological responses of healthy subjects on HUT and LBNP, and examine the relations of two tests. A total of 19 subjects were recruited. A validated wearable device, Sotera Visi Mobile was use to collect physiological signals simultaneously throughout the experiment procedures. Each subject went through a baseline supine rest, 70o of HUT test, another round of baseline supine rest, followed by activation of LBNP test. Three level of suction were applied, i.e. -30 mmHg, -40 mmHg, and -50 mmHg. In this pilot study, healthy subjects showed significantly increased of heart rate, and decreased of systolic blood pressure and diastolic blood pressure, in both HUT and LBNP tests. Although both tests are capable of stimulating a decreased blood volume in the central circulation, but the physiological responses behaved differently and shown only very week correlation. This suggesting that a combination of LBNP test with HUT test might work the best in orthostatic intolerance assessment.

• Authors: Choon-Hian Goh, Branko G Celler, Nigel H Lovell, Einly Lim, Wei Yin Lim
• Journal: Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference (Annu Int Conf IEEE Eng Med Biol Soc) Vol. 2022 Pg. 4439-4444 (07 2022) ISSN: 2694-0604 [Electronic] United States
• PMID: 36086388 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Hemodynamics (physiology)
• Humans
• Lower Body Negative Pressure (methods)
• Orthostatic Intolerance (diagnosis)
• Pilot Projects
• Posture (physiology)