Spatially extended versus frontal cerebral near-infrared spectroscopy during cardiac surgery: a case series...

Area of Science:

• Neurology
• Biomedical Engineering
• Cardiovascular Surgery

Background:

• Stroke is a severe complication of cardiac surgery, often caused by hypoperfusion or emboli.
• Early detection of cerebral hypoperfusion and emboli is crucial for preventing adverse postoperative outcomes.
• Transcranial Doppler (TCD) of the middle cerebral artery (MCA) can detect hypoperfusion and emboli, correlating with cerebral oxygenation measured by near-infrared spectroscopy (NIRS).

Purpose of the Study:

• To evaluate the utility of spatially extended NIRS in detecting critical cerebral perfusion events during cardiac surgery.
• To assess if whole-head NIRS can identify localized hypoperfusion or ischemic territories not detected by standard frontal monitoring.

Main Methods:

• Utilized a continuous-wave NIRS system (FOIRE-3000) with a whole-head fiber holder in three cardiac surgery patients.
• Applied principle components analysis to differentiate between global and localized hypoperfusion.
• Correlated NIRS data with TCD measurements of MCA blood flow velocity and clinical neurological assessments.

Main Results:

• Spatially extended NIRS detected critical hypoperfusion in the right MCA territory of one patient, which was not evident in frontal NIRS channels.
• This localized hypoperfusion correlated with intra- and postoperative neurological signs of ischemia.
• Standard frontal NIRS monitoring did not reveal the critical event in this specific case.

Conclusions:

• Spatially extended NIRS, covering temporal and parietal areas, shows potential for enhanced detection of critically low cerebral perfusion during cardiac surgery.
• Frontal NIRS alone may be insufficient for detecting hemispheric stroke due to potential collateral circulation via the anterior cerebral artery.