Regional Cerebral Oxygen Saturation Monitoring during Spinal Surgery in Order to Identify Patients at Risk for Cerebral Desaturation

Abstract

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. Abstract: 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 ± 35 versus 200 ± 98 min, p = 0.01). Pearson'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.

Effect of Head Position on Cerebral Oxygen Saturation in Tympanoplasties Performed with Controlled Hypotensive Anesthesia

“…However, the disadvantage of that study was that there was no control group to compare the results (12). Therefore, in our study, as a control group, we also had the septoplasty group in which the head is kept in the neutral position when performing ear effect on cerebral hypoxia, but it was emphasized that the amount of blood loss was significantly effective (24). We consider that the non-significant effect of the operation time was due to the prone positioning of the patients and the neutral positioning of the head throughout the operation.…”

“…It is possible to state that there are contradictory statements on this subject in the literature. Some studies have reported that there is no correlation between c-rSO 2 and other intraoperatively monitored parameters such as MABP, SaO 2 , and EtCO 2 (24). In contrast, in another study conducted with ESS patients, it was emphasized that although controlled hypotensive anesthesia alone was a risk for cerebral desaturation, there was no risk of cerebral desaturation if MAP was >55 mmHg, EtCO 2 was 30-40, and the head was kept in the neutral position (8).…”