Background. Monitoring of temperature and EEG are routine approach to assess the brain cooling

sufficiency in pts undergoing aortic arch surgery. The jugular bulb fibreoptic oxymetry is valuable

method to evaluate of brain oxygenation and metabolism (1,2).

The aim of study was to determinate efficiency of hypothermic brain protection in pts underwent aortic

arch surgery.

Methods. After local Ethic Committee approval and informed consent 35 pts 13-69 yo (44.9±10.1) were

operated on aortic arch with deep hypothermic circulatory arrest (HCA). To determinate sufficiency of

brain cooling in pts we used monitoring of temperatures (nasal+rectal) and EEG.

We studied EEG, PO2, PCO2, SO2, glucose (Glu) level in arterial and jugular bulb blood. Arteriovenous

oxygen and carbon dioxide difference (a-jbO2, jb-aCO2), oxygen extraction and arteriovenous glucose

difference (a-jbGlu) were assessed.

Results. Duration of HCA was 48.6±12.8 min. Deep depression of EEG and Tnasal 13.5±0.5 and Trectal

15.0±0.6 C° were achieved before HCA.

SjbO2 curve characterized by gradual rising during cooling and «plateau», reaching arterial oxygenation

level (98.4±0.4%).

Correlation of EEG activity and SbjO2 with core temperatures was found.

a-jbGlu decreased 4 fold before HCA.

We observed most high values of РjbО2 and SjbО2 (201.8±54.5 mmHg and 98.4±0.4% respectively),

PaO2 and SaO2 were 410.2±84.8 mmHg and 99% respectively before HCA.

Early postoperative mortality was 28.6%. None of lethality related to brain injury.

Discussion.

Brain protection with hypothermia in pts aims to reduce oxygen demand and suppress its metabolism.

The brain oxygenation and metabolism monitoring should be used to estimate adequacy of its

protection with cooling during deep HCA.

We suggest as additional metabolic criteria of brain cooling sufficiency before HCA:

1. SjbO2 curve with gradual increasing and «plateau» reaching during HCA (fibreoptic oxymetry);

2. Equalization of SbjO2 with SaO2;

3. Significant reducing of oxygen and glucose extraction by brain.

The problem is not highlighted enough yet and needs further research.

Sufficiency of brain cooling before circulatory arrest during aortic arch surgery: a combined assessment