Correlation of continuously monitored regional cerebral blood flow and brain tissue oxygen

Acta Neurochir (Wien). 2005 Jan;147(1):51-6; discussion 56. doi: 10.1007/s00701-004-0408-z.


Background: The purpose of this study was to investigate the relationship between continuously monitored regional cerebral blood flow (CBF) and brain tissue oxygen (PtiO2).

Methods: Continuous advanced multimodal neuromonitoring including monitoring of PtiO2 (Licox, GMS) and CBF (QFlow, Hemedex) was performed in eight patients after severe subarachnoid haemorrhage (n=5) and traumatic brain injury (n=3) for an average of 9.6 days. Parameters were measured using a flexible polarographic PtiO2-probe and a thermal diffusion CBF-microprobe.

Findings: Regarding the whole monitoring period in all patients, the data indicated a significant correlation between CBF and PtiO2 (r=0.36). In 72% of 400 analysed intervals of 30 minutes duration with PtiO2 changes larger than 5 mmHg, a strong correlation between CBF and PtiO2 existed (r>0.6). In 19% of intervals a still statistically significant correlation was observed (0.3<r<0.6). During the remaining 9% no correlation was found (r<0.3). Regarding the clinical stability of the monitoring devices, the CBF monitoring system allowed monitoring of CBF in 64% of the time when PtiO2 monitoring was possible only. Phases of non-monitoring were mostly due to fever of the patient, when the system does not allow monitoring to avoid overheating of the cerebral tissue.

Conclusions: This study suggests a correlation between CBF and PtiO2. The level of PtiO2 seems to be predominately determined by regional CBF, since changes in PtiO2 were correlated in 90% of episodes to simultaneous changes of CBF.

MeSH terms

  • Brain / physiopathology*
  • Brain Injuries / physiopathology*
  • Cerebrovascular Circulation / physiology*
  • Humans
  • Intracranial Pressure / physiology
  • Monitoring, Physiologic / instrumentation*
  • Oxygen / physiology*
  • Partial Pressure
  • Point-of-Care Systems
  • Prospective Studies
  • Subarachnoid Hemorrhage / physiopathology*


  • Oxygen