Changes in BiSpecteral Index (BiS) Values During Cardiopulmonary Bypass (CPB)

Area of Science:

• Anesthesiology
• Neuroscience
• Cardiovascular Surgery

Background:

• Bispectral Index (BiS) monitoring is a standard practice in anesthesia.
• Its application in cardiac surgery is crucial due to the high incidence of neurological injury post-cardiopulmonary bypass (CPB).
• This study retrospectively analyzed 33 cardiac surgery cases monitored with BiS.

Purpose of the Study:

• To investigate the changes in BiS values during cardiac surgery, particularly CPB.
• To explore the correlation between BiS values and neurological outcomes.
• To identify potential causes of neurological dysfunction following CPB.

Main Methods:

• Retrospective analysis of 33 cardiac surgery cases.
• Continuous BiS monitoring throughout the surgical procedure, including CPB.
• Statistical analysis of BiS value changes.

Main Results:

• BiS values, initially 40-60 post-induction, significantly decreased below 25 at the onset of CPB (p<0.05).
• Periods of hypotension correlated with low BiS values.
• The observed BiS decrease suggests potential cerebral hypo-perfusion during CPB.

Conclusions:

• The significant drop in BiS during CPB may indicate cerebral hypoxia.
• Hypo-perfusion and oxygen-poor priming fluid reaching the brain are likely causes.
• This cerebral hypoxia could contribute to the known neurological dysfunction post-CPB.