Background: Cerebrovascular autoregulation can be continuously monitored from slow fluctuations of arterial blood pressure (ABP) and regional cerebral oxygen saturation (rSO2). 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 rSO2. ABP was measured with the Finometer photoplethysmograph. The ABP with optimal autoregulation (ABPOPT) was also determined as the ABP level with the lowest associated TOx (opt-TOx). Results: Average rSO2 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. ABPOPT was 87.0 ± 16.7 mmHg. The difference between ABP and ABPOPT was − 0.3 ± 7.5 mmHg. In total, 44% of subjects had a deviation of ABP from ABPOPT exceeding 5 mmHg. ABPOPT ranged from 57 to 117 mmHg. Conclusions: TOx in healthy volunteers on average displays intact autoregulation and ABP close to ABPOPT. However, some subjects have possible autoregulatory dysfunction or a significant deviation of ABP from ABPOPT, which may confer a susceptibility to neurological injury.
- Cerebral autoregulation
- Near-infrared spectroscopy
- Optimal cerebral perfusion pressure