Sepsis poses a significant threat to hu-man health due to its widespread prevalence,high mortality rate,substantial treatment costs,and the absence of effective life-saving therapies.Melato-nin,a primary hormone regulating the circadian rhythm,has demonstrated potential as a promising therapeutic agent against sepsis.Its anti-inflamma-tory,antioxidant,immunomodulatory,mitochondri-al protective,and multi-organ protective effects are noteworthy.In this review,we summarize current research on the mechanisms of action and clinical efficacy of melatonin in sepsis treatment and multi-organ function preservation,aiming to offer new perspectives and support for sepsis research and therapy.

Delirium is an acute brain dysfunction syndrome,mainly manifested by cognitive impairment and mental abnormalities.It is the most common manifestation of brain dysfunction associated with severe diseases.Critically ill patients with delirium often have poor prognosis,but there is currently no"miracle drug"for the prevention and treatment of delirium in clinical practice.Melatonin is an endogenous neurohormone secreted by the pineal gland,which has the functions of regulating sleep circadian rhythm,anti-inflammatory,antioxidant,and neuroprotective.When delirium occurs in critically ill patients,the serum melatonin level often changes,indicating that melatonin may be involved in the occurrence and development of delirium.Current research suggests that exogenous supplementation of melatonin may have a preventive and therapeutic effect on delirium.This article reviews researches on the mechanism and clinical efficacy of melatonin in the prevention and treatment of delirium in critically ill patients,with the aim of providing reference for basic and clinical research on the prevention and treatment of delirium in critically ill patients.

Delirium is an acute brain dysfunction syndrome,mainly manifested by cognitive impairment and mental abnormalities.It is the most common manifestation of brain dysfunction associated with severe diseases.Critically ill patients with delirium often have poor prognosis,but there is currently no"miracle drug"for the prevention and treatment of delirium in clinical practice.Melatonin is an endogenous neurohormone secreted by the pineal gland,which has the functions of regulating sleep circadian rhythm,anti-inflammatory,antioxidant,and neuroprotective.When delirium occurs in critically ill patients,the serum melatonin level often changes,indicating that melatonin may be involved in the occurrence and development of delirium.Current research suggests that exogenous supplementation of melatonin may have a preventive and therapeutic effect on delirium.This article reviews researches on the mechanism and clinical efficacy of melatonin in the prevention and treatment of delirium in critically ill patients,with the aim of providing reference for basic and clinical research on the prevention and treatment of delirium in critically ill patients.

Sepsis poses a significant threat to hu-man health due to its widespread prevalence,high mortality rate,substantial treatment costs,and the absence of effective life-saving therapies.Melato-nin,a primary hormone regulating the circadian rhythm,has demonstrated potential as a promising therapeutic agent against sepsis.Its anti-inflamma-tory,antioxidant,immunomodulatory,mitochondri-al protective,and multi-organ protective effects are noteworthy.In this review,we summarize current research on the mechanisms of action and clinical efficacy of melatonin in sepsis treatment and multi-organ function preservation,aiming to offer new perspectives and support for sepsis research and therapy.

Objective:To construct a nomogram prediction model for predicting the risk of death in patients with sepsis-associated thrombocytopenia (SAT) in intensive care unit (ICU) for early indentification and active intervention.Methods:Clinical data of SAT patients admitted to ICU of the First Affiliated Hospital of Nanjing Medical University from December 2019 to August 2021 were retrospectively collected, including demographic data, laboratory indicators, etc. According to the prognosis at 28 days, the patients were divided into the death group and the survival group, and the differences of clinical variables between the two groups were compared. Multivariate Logistic regression analysis was performed to analyze the independent risk factors influencing mortality of patients within 28 days, then a nomogram predictive model was constructed and its performance was verified with internal data. Receiver operator characteristic curve (ROC curve) was used to evaluate the diagnostic effectiveness of the nomogram model, and the clinical applicability of this model was evaluated by clinical decision curve analysis (DCA).Results:A total of 275 patients were included, with 95 deaths at 28 days and a 28-day mortality of 34.5%. Compared with the survival group, acute physiology and chronic health evaluation Ⅱ (APACHEⅡ), sequential organ failure assessment (SOFA), lactic acid (Lac), platelet distribution width (PDW) on day 5 of ICU admission, blood urea nitrogen (BUN), total bilirubin (TBIL), aspartate aminotransferase (AST), C-reactive protein (CRP) of patients in the death group were higher, activated partial thromboplastin time (APTT) and prothrombin time (PT) were longer, platelet count (PLT) on day 3 and day 5 of ICU admission, direct bilirubin (DBIL), fibrinogen (FIB) were lower, the history of chronic lung disease, mixed site infection, lung infection, bloodstream infection, Gram-negative bacterial infection and fungal infection accounted for a higher proportion, the history of diabetes mellitus, urinary tract infection and no pathogenic microorganisms cultured accounted for a lower proportion, and the proportion of the use of vasoactive drugs, mechanical ventilation (MV), continuous renal replacement therapy (CRRT), bleeding events and platelet transfusion were higher. Multivariate Logistic regression analysis showed that APACHEⅡ score at the day of ICU admission [odds ratio ( OR) = 1.417, 95% confidence interval (95% CI) was 1.153-1.743, P = 0.001], chronic lung disease ( OR = 72.271, 95% CI was 4.475-1?167.126, P = 0.003), PLT on day 5 of ICU admission ( OR = 0.954, 95% CI was 0.922-0.987, P = 0.007), vasoactive drug ( OR = 622.943, 95% CI was 10.060-38?575.340, P = 0.002), MV ( OR = 91.818, 95% CI was 3.973-2?121.966, P = 0.005) were independent risk factors of mortality in SAT patients. The above independent risk factors were used to build a nomogram prediction model, and the area under the curve (AUC), sensitivity and specificity were 0.979, 94.7% and 91.7%, respectively, suggesting that the model had good discrimination. The Hosmer-Lemeshow goodness of fit test showed a good calibration with P > 0.05. At the same time, DCA showed that the nomogram model had good clinical applicability. Conclusions:Patients with SAT has a higher risk of death. The nomogram model based on APACHEⅡ score at the day of ICU admission, chronic lung disease, PLT on day 5 of ICU admission, the use of vasoactive drug and MV has good clinical significance for the prediction of 28-day mortality, and the discrimination and calibration are good, however, further verification is needed.

Objective:To figure out the timing of zeroing and the location of the zero line in the central venous pressure (CVP) monitoring and invasive arterial blood pressure (IBP) monitoring, and to provide scientific and accurate data for patients management.Methods:The liquid vessel models were used to simulate the pressure measurement process of the continuous pressure monitoring system. Based on the theory of fluid mechanics and the knowledge of blood pressure physiology and cardiovascular anatomy, the composition and influencing factors of the pressure in the fluid-filled catheter system during the zeroing and placing the transducer in the zero line of CVP and IBP, were analyzed.Results:The pressure in the liquid-filled catheter system was composed of atmospheric pressure, the pressure of pumping bag, the gravity of the water column (the vertical distance between the liquid level of Murphy's dropper and pressure transducer, ΔH), and the resistance of tube wall. This pressure value is set as a pressure of 0 mmHg (1 mmHg ≈ 0.133 kPa). In the process of pressure measurement, when the pressure transducer was placed at a horizontal position of 10 cm below the highest liquid level of the vessel, the pressure measured at different catheter tip positions was all 10 cmH 2O (1 cmH 2O ≈ 0.098 kPa); When the pressure transducer was placed at the horizontal position of the highest liquid level of the vessel, the measured pressure is 0 mmHg. Conclusion:Zeroing should repeatedly be performed only when one or more conditions (atmospheric pressure, pressure of pumping bag, gravity of ΔH water column and resistance of tube wall) are changed. In the measurement process, the pressure transducer should be placed at the zero line position at any time to eliminate the influence of hydrostatic pressure and to ensure the objective and accurate value.

Objective:To investigate whether myocardial inflammation and apoptosis are involved in right ventricular dysfunction (RVD) induced by injurious mechanical ventilation with high tidal volume (VT) in rats.Methods:Total 30 adult male SD rats were randomly divided into the control group (CON group), the low VT ventilation group (LVT group) and the injurious mechanical ventilation group (HVT group), with 10 rats in each group. The CON group was maintained spontaneous breathing, the LVT group and HVT group were ventilated with different VT 6 mL/kg and 20 mL/kg for 4 hours, respectively. The right jugular vein and the left carotid artery were catheterized and connected with the PowerLab biological signal acquisition and analysis system to record heart rate (HR), mean arterial pressure (MAP), right ventricular systolic pressure (RVSP), the maximum rate of rising of right ventricular pressure (+dp/dt max). Echocardiography was performed to measure left ventricular end-diastolic diameter (LVEDd), right ventricular end-diastolic diameter (RVEDd), tricuspid annulus plane systolic migration (TAPSE) and myocardial performance index (MPI). The rats were sacrified by cervical dislocation. Specimens of right ventricle tissues were taken for hematoxylin-eosin (HE) staining, and morphological changes of right ventricle tissues were observed under light microscope. Real time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to detect the mRNA and protein expressions of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), caspase-3, apoptosis-related proteins Bax and Bcl-2.Results:HR, MAP, +dp/dt max gradually decreased, while RVSP gradually increased in different group with the increase of VT ventilation. There was no significant difference between the CON group and LVT group. However, there was a statistically significant difference with respect to these index in HVT group as compared to CON group and LVT group [HR (bpm): 397.6±5.7 vs. 433.0±4.8, 441.6±7.8; MAP (mmHg, 1 mmHg≈0.133 kPa): 102.0±2.4 vs. 108.5±2.2, 110.6±2.1; +dp/dt max (mmHg/s): 2 357.65±62.80 vs. 2 661.27±55.62, 2 679.43±75.13; RVSP (mmHg): 28.8±1.0 vs. 22.6±10.8, 21.9±0.4; all P < 0.05]. Echocardiography findings showed that RVEDd/LVEDd and MPI gradually increased, TAPSE gradually decreased in different group with the increase of VT ventilation. There was no significant difference between the LVT group and CON group. However, there was a statistically significant difference with respect to these indexes in HVT group as compared to the CON group and LVT group [RVEDd/LVEDd: 0.36±0.02 vs. 0.26±0.01, 0.23±0.02; MPI: 1.23±0.03 vs. 0.84±0.04, 0.86±0.03; TAPSE (mm): 1.65±0.03 vs. 1.88±0.02, 1.91±0.04; all P < 0.05]. Histopathological observation of the right ventricle tissue showed that myocardial cells of the rats in the CON group were orderly arranged and uniformed in size. In the LVT group, there was a small amount of inflammatory cell infiltration in the myocardial interstitium, while in the HVT group, the myocardial cell arrangement was obviously disordered, the structure was obviously damaged, and more inflammatory cell infiltration was found. RT-PCR and Western blotting analysis showed that the mRNA and protein expressions of IL-6, TNF-α, caspase-3 and Bax in HVT group were significantly higher than those in the LVT group and CON group [mRNA expression (2 -ΔΔCt): IL-6 were 1.97±0.07 vs. 1.09±0.02, 1.02±0.03, TNF-α were 1.69±0.10 vs. 1.10±0.03, 1.05±0.04, caspase-3 were 1.82±0.09 vs. 1.08±0.02, 1.06±0.03, Bax were 2.19±0.14 vs. 1.07±0.03, 1.04±0.03; protein expression (gray value): IL-6 were 0.64±0.02 vs. 0.38±0.03, 0.31±0.04, TNF-α were 0.50±0.04 vs. 0.16±0.01, 0.15±0.01, caspase-3 were 0.58±0.02 vs. 0.29±0.01, 0.25±0.02, Bax were 0.50±0.03 vs. 0.21±0.01, 0.26±0.02; all P < 0.05], and the mRNA and protein expressions of Bcl-2 in the HVT group were lower than those in the LVT group and CON group [mRNA expression (2 -ΔΔCt): 1.23±0.05 vs. 1.43±0.05, 1.50±0.08; protein expression (gray value): 0.42±0.02 vs. 0.62±0.03, 0.65±0.03, all P < 0.05]. Conclusion:Myocardial inflammation and apoptosis may be involved in RVD induced by injurious mechanical ventilation.

Objective:To explore the effect of different tidal volumes (VT) on the hemodynamics of right heart in acute respiratory distress syndrome (ARDS) rats induced by oleic acid (OA).Methods:Sixty adult male Sprague-Dawley (SD) rats were divided into control group ( n = 20), ARDS model group ( n = 20), low VT (LVT) group ( n = 10) and high VT (HVT) group ( n = 10) by random number table. ARDS model was reproduced by injecting OA 0.15 mL/kg through a jugular vein. The control group was given the same amount of normal saline. The success of modeling was judged by the oxygenation index (PaO 2/FiO 2) 2 hours after modeling, at the same time, the lung tissues were collected, the wet/dry weight (W/D) ratio was determined, and the lung histopathological changes were measured by lung injury score. The rats in the LVT group and HVT group were given mechanical ventilation with VT of 6 mL/kg or 20 mL/kg for 4 hours, respectively at 2 hours after modeling. The rats in the control group and the ARDS model group maintained spontaneous breathing. After mechanical ventilation for 4 hours, the heart rate (HR), right ventricular systolic pressure (RVSP), the maximum rate of rising of right ventricular pressure (dp/dt max), and the blood pressure (BP) were measured. Meanwhile, arterial blood samples were collected for blood gas analysis, including pH value, arterial partial pressure of oxygen (PaO 2), arterial partial pressure of carbon dioxide (PaCO 2) and PaO 2/FiO 2. Results:The rats in the ARDS model group showed symptoms of respiratory distress 1 hour after modeling, and the lung tissue samples showed obvious patchy bleeding 2 hours after modeling, while the control group showed no such changes. The PaO 2/FiO 2 in the ARDS model group was significantly lower than that in the control group [mmHg (1 mmHg = 0.133 kPa): 294.3±5.9 vs. 459.0±4.4, P < 0.01], and the lung W/D ratio and lung injury score were significantly higher (lung W/D ratio: 8.24±0.25 vs. 4.48±0.13, lung injury score: 0.60±0.03 vs. 0.12±0.02, both P < 0.01). It indicated that ARDS model was successfully reproduced. The arterial blood gas analysis and hemodynamic parameters of the ARDS model group were significantly worse than those of the control group. After 4-hour mechanical ventilation, the blood gas parameters of the LVT group were better than those of the ARDS model group and the HVT group [pH value: 7.36±0.02 vs. 7.24±0.02, 7.13±0.01; PaO 2 (mmHg): 92.4±2.1 vs. 61.8±2.3, 76.6±2.2; PaCO 2 (mmHg): 49.6±1.7 vs. 61.8±1.8, 33.6±1.3; PaO 2/FiO 2 (mmHg): 440.0±10.2 vs. 274.3±21.4, 364.7±10.5; all P < 0.05]. HR, BP and dp/dt max in the LVT group were significantly higher than those in the ARDS model group and the HVT group [HR (bpm): 346.9±5.4 vs. 302.3±10.1, 265.5±12.2; BP (mmHg): 125.4±2.2 vs. 110.0±2.5, 89.2±2.8; dp/dt max (mmHg/s): 1 393.3±30.3 vs. 1 236.4±20.5, 896.1±19.5; all P < 0.05], and RVSP was significantly lower than that in the ARDS model group and the HVT group (mmHg: 31.3±0.4 vs. 34.0±1.0, 38.8±0.9, both P < 0.05). Conclusion:Mechanical ventilation with low VT can improve the hemodynamic parameters of the right ventricle and protect the function of the right heart in ARDS rats.

Objective:To investigate the correlation of monocyte/lymphocyte ratio (MLR) with the prognosis and adverse event in critically ill patients.Methods:Basic information of patients were extracted from Medical Information Mart for Intensive Care-Ⅲ (MIMIC-Ⅲ), including demographics, blood routine, biochemical indexes, systemic inflammatory response syndrome score (SIRS), sequential organ failure assessment (SOFA) score, and outcome, etc. MLR on the first day of intensive care unit (ICU) admission was calculated. The receiver operating characteristic curve (ROC curve) was applied to evaluate the prognostic value of MLR on the 30-day mortality and its cut-off value. According to the cut-off value, the patients were divided into two groups, and the differences between the groups were compared. Logistic regression model was used to analyze the relationship of MLR with 30-day mortality, continuous renal replacement therapy (CRRT), mechanical ventilation, the length of ICU stay, and total hospitalization time.Results:① A total of 43 174 critically ill patients were included. ROC curve showed that area under ROC curve (AUC) of MLR in predicting 30-day mortality was 0.655 [95% confidence interval (95% CI) was 0.632-0.687]. The cut-off value of MLR calculated according to the maximum Yoden index was 0.5. There were 16 948 patients with MLR ≥ 0.5 (high MLR group) and 26 226 patients with MLR < 0.5 (low MLR group). ② Compared with the low MLR group, the high MLR group had higher age, proportion of male, body mass index (BMI) [age (years old): 66.0 (51.7, 78.4) vs. 57.6 (27.1, 74.6), proportion of male: 57.2% vs. 52.5%, BMI (kg/m 2): 26.5 (22.5, 31.1) vs. 24.7 (14.3, 29.7)]. The high MLR group also had higher incidence of complications (hypertension: 49.2% vs. 44.6%, chronic heart failure: 32.6% vs. 21.7%, diabetes mellitus: 27.0% vs. 23.4%, chronic obstructive pulmonary disease: 21.5% vs. 16.1%, renal insufficiency: 19.3% vs. 13.1%), and higher white blood cell count (WBC), blood glucose, lactate (Lac), serum creatinine (SCr), SIRS score and SOFA score [WBC (×10 9/L): 13.8 (9.6, 19.2) vs. 11.5 (8.4, 15.6), blood glucose (mmol/L): 8.66 (6.88, 11.49) vs. 8.27 (6.55, 10.88), Lac (mmol/L): 2.2 (1.5, 3.7) vs. 2.1 (1.4, 3.3), SCr (μmol/L): 106.1 (70.7, 176.8) vs. 88.4 (70.7, 132.6), SIRS score: 3 (2, 4) vs. 2 (2, 3), SOFA score: 4 (2, 7) vs. 3 (1, 5)]. The 30-day mortality, and the proportion of patients with length of ICU stay > 5 days, total hospitalization time > 14 days, CRRT and mechanical ventilation > 5 days were significantly higher in high MLR group (30-day mortality: 20.0% vs. 8.3%, length of ICU stay > 5 days: 33.2% vs. 20.4%, total hospitalization time > 14 days: 33.7% vs. 16.2%, CRRT: 3.6% vs. 0.7%, mechanical ventilation > 5 days: 18.4% vs. 5.7%), with statistically significant differences (all P < 0.05). ③ After adjusted with the related factors, multivariate Logistic regression analysis showed that elevated MLR was an independent risk factor for increased 30-day mortality [odd ratio ( OR) = 1.54, 95% CI was 1.37-1.72, P < 0.001]. Moreover, the increased MLR was independently associated with the increased risk of usage of CRRT ( OR = 2.77, 95% CI was 2.18-3.51), mechanical ventilation > 5 days ( OR = 2.45, 95% CI was 2.21-2.72), the length of ICU stay > 5 days ( OR = 2.29, 95% CI was 2.10-2.49), and total hospitalization time > 14 days ( OR = 2.28, 95% CI was 2.08-2.49), all P < 0.001. Conclusions:Retrospective analysis of large sample shows that MLR elevation is an independent risk factor for 30-day mortality, usage of CRRT, prolonged mechanical ventilation time, prolonged hospitalization, prolonged length of ICU stay. MLR can be used for risk stratification of severe patients.

Despite the great improvements in the techniques and perioperative management of liver transplantation in recent years, there are still several perioperative complications that may lead to the poor prognosis of recipients. Prolonged mechanical ventilation (PMV) is a common complication in the early stage after surgery and may result in a high incidence rate of postoperative complications, prolonged length of stay in the intensive care unit and hospital stay, and an increase in mortality rate. In recent years, many studies have reported PMV after liver transplantation, but no summarization and statistical analysis have been performed and there are still no effective measures to prevent PMV after liver transplantation. This article summarizes the influencing factors and interventions for PMV after liver transplantation, in order to provide valuable information for reducing the duration of mechanical ventilation after liver transplantation and improving the prognosis of liver transplantation recipients.