Noninvasive Monitoring of Dynamic Cerebrovascular Autoregulation and ‘Optimal Blood Pressure’ in Normal Adult Subjects

• Published in: Neurocritical care Vol. 30; no. 1; pp. 201 - 206
• Main Authors: Pham, Paul, Bindra, Jessica, Aneman, Anders, Chuan, Alwin, Worthington, John M., Jaeger, Matthias
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.02.2019; Springer Nature B.V
• Subjects: Adult; Arterial Pressure - physiology; Blood pressure; Cerebrovascular Circulation - physiology; Critical Care Medicine; Female; Head injuries; Healthy Volunteers; Hemorrhage; Homeostasis - physiology; Humans; Intensive; Internal Medicine; Male; Medicine; Medicine & Public Health; Middle Aged; Neurology; Neurophysiological Monitoring - methods; Original Article; Oxygen saturation; Photoplethysmography; Physiology; Spectroscopy, Near-Infrared; Young Adult; United States > US; Optimal cerebral perfusion pressure; Cerebral autoregulation; Neuromonitoring; Near-infrared spectroscopy
• ISSN: 1541-6933; 1556-0961; 1556-0961
• DOI: 10.1007/s12028-018-0600-2

Background Cerebrovascular autoregulation can be continuously monitored from slow fluctuations of arterial blood pressure (ABP) and regional cerebral oxygen saturation (rSO 2 ). The purpose of this study was to evaluate the index of dynamic cerebrovascular autoregulation (TOx) and the associated ‘optimal’ ABP in normal adult healthy subjects. Methods Twenty-eight healthy volunteers were studied. TOx was calculated as the moving correlation coefficient between spontaneous fluctuations of ABP and rSO 2 . ABP was measured with the Finometer photoplethysmograph. The ABP with optimal autoregulation (ABP OPT ) was also determined as the ABP level with the lowest associated TOx (opt-TOx). Results Average rSO 2 and TOx was 72.3 ± 2.9% and 0.05 ± 0.18, respectively. Two subjects had impaired autoregulation with a TOx > 0.3. The opt-TOx was − 0.1 ± 0.26. ABP OPT was 87.0 ± 16.7 mmHg. The difference between ABP and ABP OPT was − 0.3 ± 7.5 mmHg. In total, 44% of subjects had a deviation of ABP from ABP OPT exceeding 5 mmHg. ABP OPT ranged from 57 to 117 mmHg. Conclusions TOx in healthy volunteers on average displays intact autoregulation and ABP close to ABP OPT . However, some subjects have possible autoregulatory dysfunction or a significant deviation of ABP from ABP OPT , which may confer a susceptibility to neurological injury.