_Applied_  
_sciences_  
_Article_  
**Regional Cerebral Oxygen Saturation Monitoring**  
**during Spinal Surgery in Order to Identify Patients at Risk for Cerebral Desaturation**  
**[PERSON] 1,2,*, [PERSON] 3, [PERSON] 2,4 and [PERSON] 1,2**  
1 Department of Anesthesiology, Riga East Clinical University Hospital, Hipokrata Street 2, LV1038 Riga, Latvia; [EMAIL_ADDRESS]  
2 Department of doctoral studies, Riga Stradins University, Dzirciema Street 16, LV1007 Riga, Latvia; [PERSON]]  
3 Department of Anesthesiology, University Hospital of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany; [PERSON]S]  
4 Department of Anesthesiology, Paul Stradins Clinical University Hospital, Plisonu Street 13, LV1002 Riga, Latvia  
* Correspondence: [EMAIL_ADDRESS]  
Received: 16 February 2020; Accepted: 17 March 2020; Published: 19 March 2020  
**Featured Application: The aim of our study was to evaluate the usefulness of intraoperative cerebral oxygenation monitoring during spinal surgery. Study includes specifically spinal neurosurgical patients, as spinal surgery, being performed in prone position, carries a certain risk for altered cerebral blood perfusion and oxygen supply. As a result, we show a benefit of cerebral oxygen saturation non-invasive intraoperative monitoring using Near infrared spectroscopy devices cerebral oximeters as in couple of patients we saw cerebral oxygen saturation drop below threshold values that would otherwise stay unrecognized as other intraoperative measurements stayed stable during cerebral oxygen desaturation.**  
Background: Near infrared spectroscopy (NIRS) devices are non-invasive and monitor cerebral oxygen saturation (rSCo\({}_{2}\)) continuously. NIRS interventional protocol is available in order to avoid hypoxic brain injury. Methods: We recruited patients scheduled for spinal surgery (\(n=44\)). rSCo\({}_{2}\) was monitored throughout the surgery using INVOS 4100 cerebral oximeter. If the rSCo\({}_{2}\) values dropped more than 20% below baseline, or there was an absolute drop to below 50%, NIRS interventional protocol was followed. Results: In two patients rSCo\({}_{2}\) decreased by more than 20% from baseline values. In one patient rSCo\({}_{2}\) decreased to below 50%. NIRS protocol was initiated. As the first step, correct head position was verified-in one patient rSCo\({}_{2}\) increased above the threshold value. In the two remaining patients, mean arterial pressure was raised by injecting Ephedrin boluses as the next step. rSCo\({}_{2}\) raised above threshold. Patients with desaturation episodes had longer medium time of the operation (\(114\pm 35\) versus \(200\pm 98\) min, \(p=0.01\)). [PERSON]'s correlation showed a negative correlation between rSCo\({}_{2}\) and duration of operation (r \(=-0.9\), \(p=0.2\)). Receiver operating characteristic curve analysis showed blood loss to be a strong predictor for possible cerebral desaturation (Area under the curve (AUC): 0.947, 95%CI: 0.836-1.000, \(p=0.04\)). Conclusion: Patients with higher blood loss might experience cerebral desaturation more often than spinal surgery patients without significant blood loss.  
**Keywords: cerebral oxygen saturation; near infrared spectroscopy; cerebral oximeter; spinal surgery**