1. Moerman A1, Van Herzeele I2, Vermassen F2, François K3, Wouters P1
Near-infrared spectroscopy for monitoring spinal cord ischaemia during endovascular thoracic aneurysm repair
Moerman A1, Van Herzeele I2, Vermassen F2, François K3, Wouters P1
1 Dept. of Anesthesiology, University Hospital Gent, Belgium
2 Thoracovascular Surgery , University Hospital Gent, Belgium
3 Cardiac Surgery , University Hospital Gent, Belgium
Introduction
During thoracic aortic surgery, spinal cord perfusion is precarious and vulnerable to haemodynamic compromise, eventually leading to neurologic injury. We report on the potential of near-infrared spectroscopy (NIRS) monitoring to detect early changes in spinal cord perfusion after endograft deployment. The importance of blood pressure maintenance to enhance spinal cord perfusion is clearly demonstrated.
Results
Fig 1. This figure demonstrates the need to maintain high systemic blood pressures to preserve adequate spinal cord perfusion after stent-graft deployment. Asterixes (*) represent deployment of stent-graft.
Fig 2. Correlation between SsO2 and mean arterial pressure (MAP) before and after stent-graft deployment, clearly showing pressure dependency of SsO2 after stent deployment, which was not present before stent deployment.
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Case report
A 53-year old man was scheduled for endovascular repair of a post-dissection aneurysm of the aortic arch and descending aorta. After total debranching of the supra-aortic vessels, endoprostheses were inserted covering the total aortic arch and descending aorta up to the level of the diaphragm. The procedure was performed under general anaesthesia with full haemodynamic monitoring and cerebrospinal fluid drainage. A NIRS sensor was placed over the tenth thoracic vertebra for continuous monitoring of spinal oxygen saturation (SsO2). There was a significant drop in mean SsO2 after stent deployment: from 76 ± 2.6% to 61 ± 5.6%. More importantly, there was a significant linear relationship between SsO2 and arterial blood pressure in the immediate postoperative period, reflecting pressure-dependency of spinal cord perfusion which was not present before stent deployment
Pre stent
Post stent
Conclusion
These data show that NIRS monitors changes in SsO2 during aortic stenting. As NIRS seems to reflect the pressure-dependence of spinal cord perfusion, it might serve as a useful non-invasive tool to optimize perioperative blood pressure management.