Effect of changes in cerebral oximeter values during cardiac surgery on the incidence of postoperative neurocognitive deficits (POND): A retrospective study based on propensity score–matched analysis

Objectives The occurrence of postoperative neurocognitive deficits(POND)after major cardiac surgery is associated with an increase in perioperative mortality and morbidity. Oxidative stress caused by oxygen can affect neuronal damage, which can lead to POND. Whether the intraoperative rSO2 value reflects oxidative stress and the associated incidence of POND is unknown. Methods Among 3482 patients undergoing cardiac surgery, 976 patients were allocated for this retrospective study. Of these, 230 patients (32.5%) were observed to have postoperative neurologic symptoms. After propensity score 1:2 ratio matching, a total of 690 patients were included in the analysis. Recorded data on the occurrence of POND from the postoperative period to predischarge were collected from the electronic records. Results The mean baseline rSO2 value was higher in the POND (–) group than in the POND (+) group. The mean overall minimum rSO2 value was lower in the POND (+) group (52.2 ± 8.3 vs 48.3 ± 10.5, P < 0.001). The mean overall maximum rSO2 values were not significantly different between the two groups (72.7 ± 8.3 vs 73.2 ± 9.2, P = 0.526). However, there was a greater increase in the overall maximum rSO2 values as compared with baseline in the POND (+) group (10.9 ± 8.2 vs 17.9 ± 10.2, P < 0.001). The degree of increase in the maximum rSO2 value was a risk factor affecting the occurrence of POND (adjusted odds ratio, 1.08; 95% confidence interval [CI], 1.04–1.11; P < 0.001). The areas under the receiver-operating characteristic curve for delta values of minimal and maximal compared with baseline values were 0.60 and 0.71, respectively. Conclusions Increased cerebral oximeter levels during cardiac surgery may also be a risk factor for POND. This is considered to reflect the possibility of oxidative neuronal damage, and further studies are needed in the future.

Cerebral Oximetry Measurements Results Depending on a Preclinical Skull Phantom Model

It is more common to perform non-invasive examination during general anaesthesia to ensure effective perioperative patient care. To achieve these results, researchers and clinicians are seeking out different technologies and developing new equipment. One such apparatus is a cerebral oximeter, which is used during cardiac surgery with cardiopulmonary bypass for neuroprotection management for reducing risk of postoperative neurological injury (cerebral stroke, neurocognitive dysfunction, and cerebral haemorrhage). A cerebral oximeter performs non-invasive transcutaneous measurements using near infrared radiation to assess the oxygenation of tissues. The objective of the study was to determine if the angle and thickness of a patient’s skull affects measurements. Intralipid water solution, gelatine, and ink were used to make six phantoms with skull thickness ranging from 6 to 11 mm. All phantoms were bent froma0to20 degrees angle. The cerebral oximeter SOMETICS INVOS 5100C was used to perform regional oximetry measurements. For skull thickness of 11 mm, the rSO2 was 45.8% (SD 0.96); for skull thickness of 10 mm, the rSO2 was 45.25% (SD 2.22); for skull thickness of 9 mm, the rSO2 was 32% (SD 1.63); for skull thickness of 8 mm, the rSO2 was 17% (SD 1.83); for skull thickness of 7 mm, the rSO2 was 15% (SD 0); for skull thickness of 6 mm, the rSO2 was 15% (SD 0). No significant changes were observed regarding the angle of the skull phantom. The thickness of the bone layer of the skull phantom affected the regional oximetry results, whereas the angle of the skull did not affect it.

The Effect of Changes in Cerebral Oximeter Values During Cardiac Surgery on the Incidence of Postoperative Cognitive Dysfunction (POCD): a Retrospective Study Based on Propensity Score Matched Analysis

Background The occurrence of postoperative cognitive dysfunction(POCD) after major cardiac surgery is associated with an increase in perioperative mortality and morbidity. The increased regional cerebral oxygen saturation(rSO2) value is likely related to increased POCD due to oxidative stress. The incidence of POCD in relation to an increase in rSO2 values is not clinically known yet.Methods Among 3482 patients underwent cardiac surgery, 976 patients were allocated for this retrospective study. Of these, 230 patients (32.5%) were observed to have postoperative neurologic symptoms. After propensity score 1:2 ratio matching, a total of 690 patients were included in the analysis. Recorded data on occurrence of POCD from the postoperative period to predischarge were collected from the electronic records. Results The mean baseline rSO2 value was higher in the POCD (–) group than in the POCD (+) group (61.9 ± 9.6 vs 55.3 ± 11.4; P < 0.001). The mean overall minimum rSO2 value was lower in the POCD (+) group (52.2 ± 8.3 vs 48.3 ±10.5, P < 0.001). As compared with baseline, the POCD (+) group had significantly higher values in the CPB preweaning and CPB post-weaning periods (P < 0.001, respectively). There was a greater decrease in the overall minimum rSO2 values compared with baseline in the POCD (–) group (P < 0.001). The maximum mean rSO2 changes compared with baseline were higher in the POCD (+) group (adjusted odds ratio, 1.08; 95% confidence interval [CI], 1.04–1.11; P < 0.001). The AUROC for delta values of minimal compared with baseline values was 0.62 and the AUROC for the delta values of maximal compared with baseline values was 0.72.Conclusions Increased cerebral oximeter levels relative to baseline values has an effect on the development of POCD. Intraoperative oxidative damage was associated with increased POCD, and increased cerebral oximeter levels during cardiac surgery can also be a risk factor for POCD.

Association of biomarker S100B and cerebral oximetry with neurological changes during carotid endarterectomy performed in awake patients

Summary. Background: This study attempted to correlate neurological symptoms in awake patients undergoing carotid endarterectomy (CEA) under local anaesthesia (LA) with serum concentration of S100B protein and measurement of cerebral oximetry with near-infrared spectroscopy (NIRS). Patients and methods: A total of 64 consecutive CEAs in 60 patients operated under LA during an 18-month period were prospectively evaluated. A cerebral oximeter was used to measure cerebral oxygen saturation (rSO2) before and after cross-clamping along with serum concentration of the S100B protein. Selective shunting was performed when neurological changes occurred, regardless of NIRS. Neurological deterioration occurred (neurological symptoms group) in 7 (10.9 %) operations. In 57 (89.1 %) operations, the patients were neurologically stable (no neurological symptoms group). Results: The neurological symptoms that occurred after clamping correlated with an increase in the serum level of S100B ( P = .040). The cut-off of 22.5 % of S100B increase was determined to be optimal for identifying patients with neurological symptoms. There was no correlation between rSO2 decline and neurological symptoms ( P = .675). Two (3.1 %) perioperative strokes occurred. Conclusions: We found a correlation between neurological symptoms and serum S100B protein increase. However, because of the long evaluation time of serum S100B, this monitoring technique cannot be performed during CEA.