Objectives: Deep hypothermic circulatory arrest (DHCA) is commonly used during thoracic aortic surgery, and is initiated only after a sufficient degree of cerebral hypothermia is induced. The criteria for initiating DHCA vary among institutions: most centers use temperature criteria, some use electroencephalography, and a minority use jugular bulb oxyhemoglobin saturation SjO2 criteria. The purpose of this study was to determine whether the use of SjO2 monitoring to guide the onset of DHCA was associated with better post-operative neuropsychological outcome. Methods: Sixty-one thoracic aortic surgical patients underwent both pre- and post-operative neuropsychological testing. Patients were divided into three groups: (1) those with SjO2≥95% at DHCA onset; (2) those with SjO2<95% at DHCA onset; and (3) those without SjO2 monitoring. Results: There were no statistically significant differences in the incidence of post-operative decline in neuropsychological function among the three groups of patients. Patients in whom SjO2 data were used to guide onset of DHCA had lower esophageal and bladder temperatures at that time compared with patients without SjO2 monitoring. Conclusions: Monitoring of SjO2 had no apparent effect upon post-operative neuropsychological outcome, and there were no trends in our small patient cohort suggesting differences that our study was not adequately powered to detect. Use of SjO2 monitoring was associated with more profound hypothermia prior to DHCA due to more prolonged cooling in attempts to bring the SjO2 above the 95% threshold. Using our institutional cooling protocol, SjO2 monitoring does not appear to increase neuroprotection in patients undergoing DHCA for thoracic aortic repairs.
- Aortic aneurysm
- Hypothermic circulatory arrest
- Jugular bulb oxyhemoglobin saturation
- Outcome study
- Thoracic surgery