Christian Riberholt1, Niels Olesen2,3, Peter Hovind4, Jesper Mehlsen5, Tue Hvass Petersen1. 1. a Research Unit on Brain Injury Rehabilitation , Department of Neurorehabilitation/TBI Unit , Rigshospitalet, Copenhagen , Denmark. 2. b Department of Anaesthesia , Rigshospitalet, Copenhagen , Denmark. 3. c Department of Neuroscience and Pharmacology , University of Copenhagen , Copenhagen , Denmark. 4. d Department of Clinical Physiology , Nuclear Medicine and PET , Rigshospitalet, Copenhagen , Denmark. 5. e Coordinating Research Centre , Bispebjerg & Frederiksberg Hospital, Frederiksberg , Denmark.
Abstract
PRIMARY OBJECTIVE: This study aimed to investigate the effect of intravenous saline administration on orthostatic hypotension (OH) during head up tilt (HUT) and the change in the renin-angiotensin-aldosterone system before and after HUT in patients with severe acquired brain injury (ABI). RESEARCH DESIGN: The study is designed as an observational study. METHODS AND PROCEDURES: Fourteen patients with ABI, low level of consciousness and OH were monitored before, during and after HUT with non-invasive beat-to-beat blood pressure measurement, and transcranial Doppler determination of middle cerebral artery blood flow velocity. Blood samples were collected before and after two HUT sessions separated by 1 hour and saline was administered in between. MAIN OUTCOMES AND RESULTS: Patients' ability to stand upright did not change after saline administration due to OH. The patients showed signs of reduced cerebral autoregulation at both HUT sessions. The patients had a significant lower level of renin and angiotensin II but not aldosterone. CONCLUSIONS: Patients with severe ABI and OH demonstrate no improvement in standing time with reduced plasma renin and angiotensin II after two HUT sessions and 1 hour fluid administration. Research focusing on the ability to retain fluid after bed rest is warranted.
PRIMARY OBJECTIVE: This study aimed to investigate the effect of intravenous saline administration on orthostatic hypotension (OH) during head up tilt (HUT) and the change in the renin-angiotensin-aldosterone system before and after HUT in patients with severe acquired brain injury (ABI). RESEARCH DESIGN: The study is designed as an observational study. METHODS AND PROCEDURES: Fourteen patients with ABI, low level of consciousness and OH were monitored before, during and after HUT with non-invasive beat-to-beat blood pressure measurement, and transcranial Doppler determination of middle cerebral artery blood flow velocity. Blood samples were collected before and after two HUT sessions separated by 1 hour and saline was administered in between. MAIN OUTCOMES AND RESULTS:Patients' ability to stand upright did not change after saline administration due to OH. The patients showed signs of reduced cerebral autoregulation at both HUT sessions. The patients had a significant lower level of renin and angiotensin II but not aldosterone. CONCLUSIONS:Patients with severe ABI and OH demonstrate no improvement in standing time with reduced plasma renin and angiotensin II after two HUT sessions and 1 hour fluid administration. Research focusing on the ability to retain fluid after bed rest is warranted.
Entities:
Keywords:
Cerebral autoregulation; head up tilt; rehabilitation; renin–angiotensin–aldosterone system
Authors: Christian Gunge Riberholt; Markus Harboe Olsen; Christian Baastrup Søndergaard; Christian Gluud; Christian Ovesen; Janus Christian Jakobsen; Jesper Mehlsen; Kirsten Møller Journal: Front Neurol Date: 2021-04-14 Impact factor: 4.003