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Backgrounds Hyperlactatemia is a common metabolic disorder after cardiac surgery with cardiopulmonary bypass. Epinephrine use has been identified as a potential cause of increased lactate levels after cardiac surgery. Stress can lead to an increase in catecholamines, mainly epinephrine, in the body. Exogenous epinephrine causes hyperlactatemia, whereas endogenous epinephrine released by stress may have the same effect. Opioids are the most effective anesthetics to suppress the stress response in the body. The authors sought to provide evidence through a retrospective data analysis that helps investigate the relationship between intraoperative opioid dosage and postoperative lactic acidosis after cardiac surgery. Methods The clinical data of 215 patients who underwent valvular heart surgery with cardiopulmonary bypass from July 2016 to July 2019 were analyzed retrospectively. Blood lactate levels were measured at 0.1 h, 2 h, 4 h, and 8 h after surgery. Patients with continuous increases in lactate levels and lactate levels exceeding 5 mmol/L at two or more time points were included in the lactic acidosis group, whereas the other patients were included in the control group. First, univariate correlation analysis was used to identify parameters that were significantly different between the two groups, and then multivariate regression analysis was conducted to elucidate the independent risk factors for lactic acidosis. Fifty-one pairs of patients were screened by propensity score matching analysis (PSM). Then, lactic acid levels at four time points in both groups were analyzed by repeated measures ANOVA. Results he EF (heart ejection fraction) (OR = 0.94, P = 0.003), aortic occlusion time (OR = 10.17, P P = 0.01) of sufentanil was an independent risk factor for lactic acidosis after valvular heart surgery. The patients were further divided into two groups with the mean sufentanil infusion rate as the reference point. The data were filtered with PSM (Propensity Score Matching). Lactic acid values in both groups peaked at 4 h after surgery and then declined. The rate of lactic acid decline was significantly faster in the group with a higher sufentanil dosage than in the lower group. The difference was statistically significant (P P Conclusion The inadequate intraoperative infusion rate of sufentanil is an independent risk factor for lactic acidosis after heart valve surgery. The possibility of lactic acidosis caused by this factor after cardiac surgery should be considered, which is helpful for postoperative patient management.

Objective To explore the feasibility and effect of electrocorticography (ECoG) for intraoperative mapping of motor cortex. Methods Eight patients with brain lesions near motor areas were operated under awake craniotomy from June 2017 to June 2019. The motor⁃related cortices were detected by intraoperative direct electrical stimulation (DES). The ECoG signals including μ rhythm and slow cortical potential (SCP) were collected intraoperatively and analyzed by wavelet analysis from patients at rest and hand⁃moving state (grasp and extension motion). The changes of event⁃related desynchronization (ERD) of different rhythms were analyzed by wavelet analysis before and after hand grasping. The threshold values of μ rhythm, SCP and different pattern recognition in combination were compared by using DES as "gold standard". The receiver operating characteristic (ROC) area under the curve (AUC) and the sensitivity and specificity were evaluated. Results When the threshold of ERD of the μ rhythm was chosen as 40%, the sensitivity and specificity of ECoG mapping of motor cortex were 81.08% (30/37) and 83.33% (25/30). The ERD threshold of the SCP was chosen as 1.6, the sensitivity and specificity were 83.78% (31/37) and 80% (24/30) respectively. Combined μ rhythm with SCP mapping revealed high sensitivity (97.29%, 36/37) and moderate specificity (80%, 24/30) as compared with DES when D mode (sensitive priority mode) was chosen, that was either μ rhythm or SCP positive was defined as the motor cortex. Conclusions The ECoG analysis has a higher sensitivity to locate the motor cortex without stimulating the brain. It is expected as a new adjuvant to DES for intraoperative mapping of eloquent cortex. DOI:10.3969/j.issn.1672⁃6731.2020.11.005