Objective

Without surgical repair thoracoabdominal aneurysms carries a lethal prognosis. Aside from the significant risk of mortality this type of surgery carries, the most feared post-operative complication is that of spinal cord ischaemia. This risk has been reduced with adjuncts including cerebrospinal fluid (CSF) drainage. We are developing a novel low power multipurpose electromagnetic sensor platform for the real time detection of biomarkers in the CSF to alert the surgeon of impending ischaemia.

Methods

Serial dilution of lactic acid, albumin and 8-isoprostane were prepared in water, synthetic CSF, and human CSF and placed on the microwave sensor. Acquisition measurement was performed with a ZVL-6 Rohde and Schwarz Vector Network Analyser. Once calibrated, this sensor will be tested clinically both intra-operatively and post-operatively during thoraco-abdominal aneurysm repair. Major medical databases were searched to identify papers related to CSF biomarkers measured during TAAAR.

Results

The work uses an interdigitated electrode and shows it is capable of detecting various concentrations of albumin (from 0 to 100 g/L) with a high degree of repeatability at 200MHz (R2 = 0.991) and 4GHz R2 = (0.975). A linear relationship is observed between concentration of 8-isoprostane and S11 magnitude where R2=0.9996 to a concentration of 2.0pg/ml. From our systematic review potential biomarker candidates include GFPa, HSP70 and 27 and our future studies will utilise these biomarkers.

Conclusion

To date, we have demonstrated accurate and real time detection, of lactate in both experimental set up and human CSF with good sensitivity and resolution. Furthermore, we have shown that protein detection is possible with our sensor. Future experiments is focusing on calibrating the sensor to detect novel biomarkers that indicate spinal cord ischaemia in human CSF. With our current results we intend to move this technology from bench-side to bedside and begin clinical testing quickly.