Objective Patients with chronic liver diseases often exhibit unique hemodynamic abnormalities and metabolic disorders.Postoperative fluid management presents numerous challenges,especially for critically ill patients admitted to the intensive care unit(ICU)after surgery.This study aimed at exploring the relationship between postoperative fluid therapy and prognosis.Methods Based on 2 414 patients with chronic liver diseases who underwent surgical treatment and were subsequently transferred to the ICU in the MIMIC-IV database,a retrospective cohort study was conducted on the final 2 143 patients after our inclusion and exclusion criteria.Multivariate adjusted logistic regression model was used to analyze the association between fluid therapeutic regimens on the first day after ICU admission and the risk of 7-day death after surgery.Restricted cubic spline(RCS)was applied to analyze the dose-response relationship.Results Multivariate analysis indicated that restrictive fluid resuscitation was an independent protective factor.Compared with the non-restrictive fluid resuscitation group,restrictive fluid resuscitation significantly reduced the 7-day postoperative mortality rate(6.4％vs 12.4％,OR=0.44,95％CI:0.22～0.88,P=0.021),decreased the use of mechanical ventilation(42.9％vs 72.3％,OR=0.29,95％CI:0.24～0.35,P<0.001),and shortened the ICU stay(1.86 vs 3.47 d,OR=0.81,95％CI:0.78～0.84,P<0.001).RCS curve showed that the fluid intake on the first postoperative day and the 7-day postoperative mortality risk presented a J-shaped curve relationship,with an inflection point at 1 850 mL.Beyond this threshold,the 7-day postoperative mortality risk was increased.Subgroup analysis results indicated that the protective effect of restrictive fluid resuscitation was consistent across different age and comorbidity groups.Conclusion For patients with chronic liver diseases,adopting a restrictive fluid therapy on the first day after surgery can effectively reduce the risk of short-term death.Moreover,there is a non-linear dose-effect relationship between the fluid intake and the 7-day mortality risk.When the fluid intake exceeds 1 850 mL,the risk of death significantly increases.

Objective To identify risk factors for postoperative respiratory failure(PORF)in cardiovascular surgery patients using machine learning algorithms and to construct a specific risk prediction model.Methods A retrospective cohort was conducted on 1 623 patients undergoing cardiovascular surgery between 2011 and 2020 from the INSPIRE database.Following data quality analysis,multiple imputation was employed to handle missing data,and the Boruta algorithm was used for feature selection.Eight machine learning models were constructed based on the selected features,including Gradient Boosting Machine(GBM),Generalized Linear Model(GLM),Extreme Gradient Boosting(XGBoost),K-Nearest Neighbors(KNN),Neural Network(NNET),Naive Bayes(NB),Support Vector Machine(SVM),and Random Forest(RF).Model performance was evaluated using metrics including the area under the curve(AUC),sensitivity,and specificity.Variables significantly influencing PORF were identified using the permutation importance algorithm.Results The overall incidence of PORF was 27.05％(439/1 623).The in-hospital mortality rate was significantly higher in the PORF group than the non-PORF group(12.98％vs 1.60％,P<0.001).Among the developed models,the SVM model demonstrated the best performance,achieving an AUC of 0.705 in the testing set,with a sensitivity,specificity,positive predictive value(PPV),and negative predictive value(NPV)of 0.481,0.825,0.504,and 0.812,respectively.Based on feature importance analysis,the top 10 variables most predictive of PORF were anesthesia duration,arterial partial pressure of carbon dioxide(PaCO?),calcium level,lymphocyte percentage,cardiopulmonary bypass duration,intraoperative blood loss,age,creatinine level,aspartate aminotransferase(AST)level,and activated partial thromboplastin time(aPTT).Conclusion A predictieon model for PORF following cardiovascular surgery is successfully developed.This model can identify high-risk patients and estimate their probability of developing respiratory failure,thereby facilitating data-driven clinical decision-making.

Objective:To evaluate the effects of biorhythm factors on the occurrence of acute kidney injury (AKI) after cardiac surgery using cardiopulmonary bypass.Methods:This was a retrospective cohort study. Data from patients undergoing heart surgery involving cardiopulmonary bypass from June 2018 to December 2019 were collected and divided into 2 groups ( n=125 each) based on the time of anesthesia operation: morning rhythm group (group Ⅰ) and afternoon rhythm group (group Ⅱ). Anesthesia operation was performed from 8: 00 to 12: 00 in group Ⅰ. Anesthesia was performed from 14: 00 to 18: 00 in group Ⅱ. The occurrence of postoperative AKI and other postoperative complications (pulmonary infection, sepsis, cerebral infarction) was recorded. Results:Compared with group Ⅱ, the incidence of postoperative AKI was significantly increased, the relative risk was 3.2 (95% confidence interval 1.31-7.70), and no significant change was found in the incidence of pulmonary infection, sepsis and cerebral infarction in group Ⅰ ( P>0.05). Conclusions:Biorhythm factors affect the development of AKI after cardiac surgery using cardiopulmonary bypass, and performing surgeries in the afternoon rather than the morning helps reduce the risk of postoperative AKI.

Objective:To evaluate the effect of melatonin on prefrontal cortex ischemia-induced cognitive impairment in rats and to investigate the receptor mechanism.Methods:Clean-grade adult male Sprague-Dawley rats, weighing 300 g, were selected, and a catheter was implanted into the prefrontal cortex.The experiment was performed in two parts.Experiment Ⅰ Twenty-four rats, in which catheters were successfully inserted into the prefrontal cortex, were assigned into 3 groups ( n=8 each) using a random number table method: control group (group C), model group (group M) and melatonin group (group ME). Normal saline 0.5 μl was injected into the prefrontal cortex in group C, 1 μmol/L endothelin 0.5 μl was microinjected into the prefrontal cortex in group M, and 1 μmol/L endothelin and 1 μmol/L melatonin 0.5 μl were injected into the prefrontal cortex in group ME.Experiment Ⅱ Forty-four rats, in which catheters were successfully inserted into the prefrontal cortex, were assigned into 4 groups ( n=11 each) using a random number table method: model group (group M), melatonin group (group ME), MT 1/2R antagonist luzindole + melatonin group (group L + ME) and MT 2R antagonist 4p-pdot + melatonin group (group P + ME). In group M, 1 μmol/l endothelin 0.5 μl was microinjected into the prefrontal cortex.In group ME, 1 μmol/L endothelin + 1 μmol/L melatonin 0.5 μl was injected into the prefrontal cortex.In group L + ME, 1 μmol/L endothelin + 1 μmol/L MT 1/2R antagonist + 1 μmol/L melatonin 0.5 μl was injected into the prefrontal cortex.In group P + ME, 1 μmol/L endothelin + 1 μmol/L MT 2R antagonist + 1 μmol/L melatonin 0.5 μl was injected into the prefrontal cortex.T-maze and the open field tests were performed at 1 week after administration. Results:Experiment Ⅰ There was no significant difference in the locomotor speed in open field test among C, M and ME groups ( P>0.05). The rate of correct selection in T-maze test was significantly lower in M and ME groups than in group C and higher in group ME than in group M( P<0.05). Experiment Ⅱ There was no significant difference in the locomotor speed in open field test among the four groups( P>0.05). Compared with group M, the rate of correct selection in open field test was significantly increased in ME and P+ ME groups ( P<0.05), and no significant change was found in group L+ ME ( P>0.05). Compared with group ME, the rate of correct selection in open field test was significantly decreased in group L+ ME ( P<0.05), and no significant change was found in group P+ ME( P>0.05). Conclusion:Melatonin can attenuate prefrontal cortex ischemia-induced cognitive impairment in the rats, and the mechanism is related to activation of MT 1R.

Objective:To investigate the relationship between lateral hypothalamus and melatonin-induced reduction of wakefulness in rats and the receptor mechanism.Methods:Forty clean-grade adult male Sprague-Dawley rats, weighing 250-300 g, were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), melatonin group (group M), melatonin type-1/2 receptor (MT 1R) antagonist luzindole plus melatonin group (group L+ M), and melatonin type-2 receptor (MT 2R) antagonist 4P-PDOT plus melatonin group (P+ M group). In group C, 0.5 μl of 0.9% NaCl solution was microinjected into the lateral hypothalamus.In group M, 1 μmol/L melatonin 0.5 μl was microinjected into the lateral hypothalamus.In group L+ M, 1 μmol/L MT 1/2R and 1 μmol/L melatonin (0.5 μl in total) was microinjected into the lateral hypothalamus.The microinjection time was from 19: 30 to 20: 00.The changes in sleep-wake duration and the oscillating energy in different frequency bands of electroencephalogram were detected by using electroencephalogram and electromyogram recording technology. Results:Compared with group C, the percentage of wakefulness time was significantly decreased, the percentage of non-rapid eye movement sleep and rapid eye movement sleep time was increased, the energy for delta oscillation was increased, the energy for theta oscillation was decreased, and no significant change was found in the energy for alpha oscillation in M and P+ M groups ( P<0.01), and no significant change was found in the parameters mentioned above in group L+ M ( P>0.05). Compared with group M, the percentage of wakefulness time was significantly increased, the percentage of non-rapid eye movement sleep and rapid eye movement sleep time was decreased, the energy for delta oscillation was decreased, and the energy for theta oscillation was increased in group L+ M ( P<0.01), and no significant change was found in the parameters mentioned above in group P+ M ( P>0.05). Conclusion:The lateral hypothalamus may be involved in melatonin-induced reduction of wakefulness in rats, and the mechanism may be related to activating MT 1R in the lateral hypothalamus.

Objective:To evaluate the relationship between degrees of biliary obstruction and levels of lipid peroxidation in patients.Methods:A total of 140 patients of both sexes, with biliary obstruction, without biliary puncture and drainage, aged 40-64 yr, with body mass index of 18.5-23.9 kg/m 2, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, were selected.The patients with different degrees of biliary obstruction were divided into 4 groups ( n=35 each) according to Child-Pugh grade total bilirubin (TBIL) concentrations: group A (TBIL<17 μmol/L), group B (17 μmol/L≤TBIL<34 μmol/L), group C (34 μmol/L≤TBIL<51 μmol/L) and group D (TBIL≥51 μmol/L). The serum TBIL, direct bilirubin (DBIL), indirect bilirubin (IBIL), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bile acid (TBA) and malondialdehyde (MDA) concentrations were measured.The correlation between serum MDA concentration and degree of biliary obstruction was tested by Spearman correlation analysis. Results:Compared with group A and group B, the serum DBIL, IBIL, ALT, AST, TBA and MDA concentrations were significantly increased in group C and group D ( P<0.05), and there was no significant difference in the parameters mentioned above between group A and group B ( P>0.05). Compared with group C, the serum DBIL, IBIL, ALT, AST, TBA and MDA concentrations were significantly increased in group D ( P<0.05). Serum MDA concentration was positively correlated with degree of biliary obstruction ( r=0.54, P<0.05). Conclusion:The degree of biliary obstruction can reflect the level of lipid peroxidation in patients.

Objective:To evaluate the effect of propofol on excitability of pyramidal neurons in orbitofrontal cortex of mice and the underlying ion channel mechanism.Methods:Brain slices of 400 μm thickness from healthy male C57 mice (aged 8-12 weeks)were prepared.This experiment was performed in two parts.Part Ⅰ The brain slices were divided into 2 groups ( n=7 each) based on the random number table method: control group (C group) and propofol group (P group). Cells were perfused with vehicle in group C and with 10 μmol/L propofol in group P. Part Ⅱ The brain slices were divided into 5 groups ( n=8 each) using the random number table method: propofol group (P group), hyperpolarization-activated non-selective cation channel antagonist ZD7288 plus propofol group (Z + P group), inward rectifier potassium channel antagonist topiramate plus propofol group(T + P group), transient activation of voltage-gated potassium channel antagonist 4-aminopyridine (4AP) plus propofol group (A + P group), and delayed activation of voltage-gated potassium channel antagonist tetraethylammonium (TEA) plus propofol group (TEA + P group). Cells were perfused with 10 μmol/L propofol for 2 min in P group, with 5 μmol/L ZD7288 and 10 μmol/L melatonin for 2 min in Z+ P group, with 5 μmol/L topiramate and 10 μmol/L propofol for 2 min in T + P group, with 10 μ mol/L 4-aminopyridine and 10 μmol/L propofol for 2 min in A+ P group, and with 10 μmol/L TEA and 10 μmol/L propofol for 2 min in TEA+ P group.The whole-cell currents, membrane potential and discharge frequency of pyramidal neurons in the orbitofrontal cortex were recorded by whole-cell patch-clamp. Results:Part Ⅰ Compared with C group, whole-cell currents were significantly increased, and the membrane potential and discharge frequency were decreased in P group ( P<0.01). Part Ⅱ Compared with P group, no significant change was found in the whole-cell currents, membrane potentials and discharge frequency in Z+ P group, T+ P group and A+ P group ( P>0.05), and the whole-cell currents were significantly decreased, and the membrane potentials and discharge frequency were increased in TEA+ P group ( P<0.05). Conclusion:Propofol can inhibit the excitability of pyramidal neurons in the orbitofrontal cortex, and the mechanism is related to activating delayed activation of voltage-gated potassium channels in mice.

Objective: To preliminarily investigate the effect of intraoperative goal-directed fluid management (GDFM) on pulmonary function and oxygen dynamics in patients with severe burns. Methods: From February 2017 to May 2018, 30 patients admitted to Burn Department of our hospital with severe burns who met the criteria for inclusion and needed escharectomy and skin grafting were enrolled in this prospective randomized controlled trial. The patients were divided into group GDFM of 15 cases [14 males and 1 female, (45±14) years old] and conventional liquid management group of 15 cases [12 males and 3 females, (42±10) years old] according to the random number table. During escharectomy and skin grafting, volume of patients in group GDFM was managed according to the GDFM scheme, based on cardiac output index, stroke volume variation, stroke volume index, hemoglobin, central venous oxygen saturation (ScvO₂), and other parameters; volume of patients in conventional liquid management group was managed according to clinical experience and conventional liquid management scheme, based on mean arterial pressure, central venous pressure, urine output, hemoglobin, and other parameters. At post operation hour (POH) 1, 6, 12, and 24, arterial and venous blood was collected from patients of the two groups to determine the levels of extravascular lung water index (ELWI), global end-diastolic volume index (GEDI), oxygenation index, ScvO₂, central venous-to-arterial blood carbon dioxide partial pressure difference (Pcv-aCO₂), lactic acid, pH value, bicarbonate ion, and base excess routinely. Data were processed with Fisher′s exact probability test, t test, analysis of variance for repeated measurement, and least significant difference test. Results: (1) The ELWI of patients in group GDFM was (4.3±1.1) mL/kg at POH 1, which was significantly lower than (6.5±3.6) mL/kg in conventional liquid management group (t=2.26, P<0.05). The ELWI levels of patients in group GDFM at POH 6, 12, and 24 were (6.8±2.2), (6.6±2.0), and (6.9±1.6) mL/kg, respectively, significantly higher than the level at POH 1 within the same group (P<0.01), and similar to (8.5±3.1), (7.8±2.3), and (8.0±3.5) mL/kg in conventional liquid management group (t=1.73, 1.53, 1.10, P>0.05). The GEDI levels between patients of the two groups were similar, and there was no significantly statistical difference between the two groups as a whole (treatment factor main effect F=2.35, time factor main effect F=0.44, interaction F=0.07, P>0.05). (2) The oxygenation index of patients in group GDFM was (350±78) mL/kg at POH 1, which was significantly higher than (259±109) mL/kg in conventional liquid management group (t=2.63, P<0.05). In conventional liquid management group, the oxygenation index of patients at POH 6 was significantly higher than that at POH 1, 12, or 24 (P<0.01). The ScvO₂ levels of patients in group GDFM at POH 1, 6, and 12 were 0.516±0.105, 0.679±0.121, and 0.713±0.104, respectively, which were significantly higher than 0.382±0.194, 0.545±0.194, and 0.595±0.191 in conventional liquid management group (t=2.35, 2.27, 2.10, P<0.05). The ScvO₂ levels of patients in the two groups at POH 6, 12, and 24 were significantly higher than those levels at POH 1 within the same group (P<0.01), and the ScvO₂ of patients in conventional liquid management group at POH 24 was significantly higher than that at POH 6 or 12 within the same group (P<0.05 or P<0.01). The Pcv-aCO₂ levels of patients in group GDFM were significantly lower than those in conventional liquid management group at POH 1 and 6 (t=2.55, 2.71, P<0.05). The Pcv-aCO₂ of patients in group GDFM at POH 12 was significantly lower than that at POH 6 or 24 within the same group (P<0.05). (3) The blood lactic acid levels and pH values between patients of the two groups were similar at POH 1, 6, 12, and 24 (t=0.89, 0.19, 0.26, 0.23; 1.55, 0.71, 0.77, 0.77, P>0.05). In conventional liquid management group, the blood lactic acid levels of patients at POH 6, 12, and 24 were significantly lower than the level at POH 1 within the same group (P<0.05), and the pH values of patients at POH 6, 12, and 24 were significantly higher than the value at POH 1 within the same group (P<0.05). The levels of bicarbonate ion and base excess between patients of the two groups were similar, and there were no significantly statistical differences between the two groups as a whole (treatment factor main effect F=0.06, 0.11, time factor main effect F=2.07, 1.59, interaction F=1.45, 0.91, P>0.05). Conclusions GDFM is helpful to improve the pulmonary function and oxygen dynamics in patients with severe burns in the short term after escharectomy and skin grafting. It has certain significance in preventing and reducing pulmonary edema and pulmonary complications in patients with severe burn after operation.

Clinical teaching round is one of main teaching methods during standardized training for residents. However, the particularity of standardized resident training in clinical anesthesia determines that it is difficult to apply the teaching round model of other disciplines. In this study, seven core contents of Mini-Clinical Evaluation Exercise (Mini-CEX) were modified after considering the characteristics of anesthesia specialty and applied to the teaching rounds of standardized training for residents of anesthesia , thus promoting the standardization and improving the quality of anesthesia teaching rounds.

Objective To evaluate the effects of melatonin on the excitability of pyramidal neurons in the prefrontal cortex and the role of melatonin receptor 1 (MT1 R)-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) signaling pathway.Methods Brains were obtained from male SpragueDawley rats between 14 and 21 days after birth.The brain slices of 350-μm thick were prepared and placed in artificial cerebrospinal fluid.The brain slices were divided into 5 groups (n =6 each) using a random number table method:control group (C group),melatonin group (M group),MT1/2R antagonist luzindole plus melatonin group (L+M group),MT2R antagonist 4P-PDOT plus melatonin group (P+M group) and PKA inhibitor Rp-cAMPS plus melatonin group (R+M group).Cells were perfused for 2 min with artificial cerebrospinal fluid in group C.Cells were perfused for 2 min with 1 μmol/L melatonin in group M.Cells were perfused for 2 min with the mixture of 1 μmol/L MT1/2R antagonist luzindole and 1 μmol/L melatonin in group L+M.Cells were perfused for 2 min with the mixture of 1 μmol/L MT2R antagonist 4P-PDOT and 1 μmol/L melatonin in group P+M.In group R+M,1 mmol/L PKA inhibitor Rp-cAMPS was continuously added to the pipette solution,and cells were perfused for 2 min with 1 μmol/L melatonin.The whole-cell patch-clamp technique was used to record the membrane potential and clamp current of pyramidal neurons in the prefrontal cortex.Results Compared with group C,the clamp current was significantly increased,and the membrane potential was decreased in group M (P＜0.05).Compared with group M,the clamp current was significantly decreased,and the membrane potential was increased in L + M and R + M groups (P＜0.05),and no significant change was found in the clamp current or membrane potential in group P+M (P＞0.05).Conclusion Melatonin inhibits the excitability of pyramidal neutrons in the prefrontal cortex,and the mechanism is related to activating MT1 R-cAMP-PKA signaling pathway.