Rhythmic electrographic discharges during deep hypothermic circulatory arrest.

Area of Science:

• Neurology
• Cardiovascular Surgery
• Neurophysiology

Background:

• Aortic arch repair often involves deep hypothermic circulatory arrest (DHCA).
• Continuous intraoperative electroencephalogram (EEG) monitoring is crucial for assessing brain activity during such procedures.

Purpose of the Study:

• To determine the prevalence and timing of rhythmic electrographic discharges and periodic sharp transients during DHCA.
• To correlate these EEG findings with patient outcomes following aortic arch repair.

Main Methods:

• Review of intraoperative EEGs and medical records of 32 patients undergoing aortic arch reconstruction with DHCA.
• Grading of EEGs based on the frequency of sharp transients and presence of rhythmic discharges.
• Analysis of preoperative, intraoperative, and postoperative data.

Main Results:

• Periodic sharp transients were observed in 30 out of 32 patients, predominantly during cooling.
• Rhythmic electrographic discharges occurred in 7 patients, mainly at temperatures below 28°C.
• No patient with these EEG discharges experienced postoperative neurologic deficits or seizures.

Conclusions:

• Periodic sharp transients are highly prevalent during deep hypothermia induction in DHCA.
• Rhythmic electrographic discharges are also common but not linked to adverse neurological events.
• Awareness of these benign EEG patterns is important for neurophysiologists, technicians, and surgeons.