Objective:To analyze the application of functional residual capacity (FRC)-guided optimal positive end-expiratory pressure (PEEP) in pulmonary retention in patients with acute respiratory distress syndrome (ARDS), and to explore the correlation between FRC and trans-pulmonary pressure and their predictive value for prognosis.Methods:Seventy-eight ARDS patients on mechanical ventilation admitted to department of critical care medicine of the First Affiliated Hospital of Jinzhou Medical University from March 2018 to May 2019 were enrolled. According to random number table method, the patients were divided into experimental group and the control group. PEEP of all patients were gradually increased in recruitment after fully sedation and analgesia. The best PEEP was set by monitoring FRC in the experimental group, and by monitoring maximum oxygen in the control group set. The differences before and after 30 minutes and 2 hours recruitment manoeuvres in dynamic compliance (Cdyn), oxygenation index (PaO 2/FiO 2), and mechanical power (MP) were compared between the two groups. Pearson method was used to analyze the correlation between FRC and trans-pulmonary pressure. The predictive value of FRC and trans-pulmonary pressure for 28-day mortality in patients with ARDS was analyzed by receiver operating characteristic (ROC) curve. Results:The optimal PEEP was (16.24±1.57) cmH 2O (1 cmH 2O = 0.098 kPa) in the experimental group and (14.11±1.15) cmH 2O in the control group in recruitment maneuvres, with statistically significant difference between the two groups ( t = 5.678, P = 0.000). Pearson correlation analysis showed that there was a significant correlation between FRC and trans-pulmonary pressure in ARDS patients ( r = 0.759, P = 0.000). Cdyn and PaO 2/FiO 2 in the experimental group were higher than the control group at 30 minutes and 2 hours after recruitment maneuvres [Cdyn (mL/cmH 2O): 61.16±3.55 vs. 58.54±5.25, 58.59±2.82 vs. 56.86±3.40; PaO 2/FiO 2 (mmHg, 1 mmHg = 0.133 kPa): 245.27±14.86 vs. 239.00±5.34, 192.25±5.11 vs. 188.86±5.07], MP was lower than the control group (J/min: 16.32±1.11 vs. 17.05±1.22, 15.22±1.25 vs. 17.03±1.50), the difference was statistically significant (all P < 0.05). The ROC curve analysis showed that both FRC and trans-pulmonary pressure had predictive value for the 28-day mortality of ARDS patients, and the area under the ROC curve (AUC) was 0.868, and 0.828 respectively (both P < 0.01). Conclusions:Measuring FRC in patients with ARDS during recruitment maneuvres can guide optimal PEEP. FRC was significantly correlated with trans-pulmonary pressure, and both of them had predictive value for 28-day mortality in ARDS patients.

Objective:To verify the clinical safety and efficacy of new intelligent ventilation mode adaptive minute ventilation (AMV)+IntelliCycle ventilation in patients with mild-to-moderate acute respiratory distress syndrome (ARDS).Methods:The patients with mild-to-moderate ARDS, admitted to intensive care unit (ICU) of the First Affiliated Hospital of Jinzhou Medical University from February 2018 to February 2019, were enrolled in the study. The patients were divided into synchronous intermittent mandatory ventilation+pressure support ventilation (SIMV+PSV) group and AMV+IntelliCycle group according to the random number table method. All patients were given mechanical ventilation, anti-infection, analgesia and sedation, nutritional support and symptomatic treatment of primary disease after admission. SV800 ventilator was used for mechanical ventilation. In the AMV+IntelliCycle group, after setting the minute ventilation volume (VE), inhaled oxygen concentration (FiO 2) and positive end expiratory pressure (PEEP), the ventilator was turned on the full-automatic mode, and the preset value of VE percentage was 120%. In the SIMV+PSV group, the ventilator parameters were set as follows: the ventilation frequency was 12-20 times/min, the inspiratory expiratory ratio was 1∶1-2, the peak inspiratory pressure (PIP) limit level was 35-45 cmH 2O (1 cmH 2O = 0.098 kPa), and the setting of FiO 2 and PEEP was as the same as that of AMV+IntelliCycle group, the triggering flow was set to 2 L/min. All of the clinical parameters between the two groups were compared. The main outcomes were duration of mechanical ventilation, ventilator alarm times, manual operation times, and the mechanical power; the secondary outcomes were respiratory rate (RR), VE, tidal volume (VT), PIP, mouth occlusion pressure (P0.1), static compliance (Cst), work of breathing (WOB), and time constant at 0, 6, 12, 24, 48, 72, and 120 hours; and the blood gas analysis parameters of patients before and after ventilation were recorded. Results:A total of 92 patients with mild-to-moderate ARDS were admitted during the study period, excluding those who quit the study due to death, abandonment of treatment, accidental extubation of tracheal intubation and so on. Eighty patients were finally enrolled in the analysis, with 40 patients in SIMV+PSV group and AMV+IntelliCycle group respectively. ① Results of main outcomes: compared with the SIMV+PSV mode, AMV+IntelliCycle ventilation mode could shorten the duration of mechanical ventilation (hours: 106.35±55.03 vs. 136.50±73.78), reduce ventilator alarm times (times: 10.35±5.87 vs. 13.93±6.87) and the manual operations times (times: 4.25±2.01 vs. 6.83±3.75), and decrease the mechanical power (J/min: 12.88±4.67 vs. 16.35±5.04, all P < 0.05). But the arterial partial pressure of carbon dioxide (PaCO 2) of AMV+IntelliCycle group was significantly higher than that of SIMV+PSV group [mmHg (1 mmHg = 0.133 kPa): 41.58±6.81 vs. 38.45±5.77, P < 0.05]. ② Results of secondary outcomes: the RR of both groups was improved significantly with the prolongation of ventilation time which showed a time effect ( F = 4.131, P = 0.005). Moreover, compared with SIMV+PSV mode, AMV+IntelliCycle mode could maintain a better level of RR, with intervention effect ( F = 5.008, P = 0.031), but no interaction effect was found ( F = 2.489, P = 0.055). There was no significant difference in VE, PIP, P0.1 or Cst between the two groups, without intervention effect ( F values were 3.343, 2.047, 0.496, 1.456, respectively, all P > 0.05), but they were significantly improved with the prolongation of ventilation time in both groups, with time effect ( F values were 2.923, 12.870, 23.120, 7.851, respectively, all P < 0.05), but no interaction effect was found ( F values were 1.571, 1.291, 0.300, 0.354, respectively, all P > 0.05). The VT, WOB or time constant in both groups showed no significant changes with the prolongation of ventilation time, and no significant difference was found between the two groups, there was neither time effect ( F values were 0.613, 1.049, 2.087, respectively, all P > 0.05) nor intervention effect ( F values were 1.459, 0.514, 0.923, respectively, all P > 0.05). Conclusion:AMV+IntelliCycle ventilation mode can shorten the ventilation time of patients with mild-to-moderate ARDS, reduce mechanical power, and reduce the workload of medical care, but PaCO 2 in the patients with AMV+IntelliCycle mode is higher than that in the patients with SIMV+PSV mode.

Objective:To establish a risk prediction model dominated by diaphragm thickening fraction (DTF) and intra-abdominal pressure (IAP) monitoring, and to explore the predictive value of the model for weaning failure in patients with severe acute pancreatitis (SAP).Methods:A prospective research was conducted. Sixty-three patients undergoing invasive mechanical ventilation treatment who diagnosed with SAP admitted to intensive care unit of the First Affiliated Hospital of Jinzhou Medical University from August 2020 to October 2021 were enrolled. The spontaneous breathing trial (SBT) was carried out when the clinical weaning criteria was met. The stable cardiovascular status, good pulmonary function, no chest and abdominal contradictory movement, and adequate oxygenation were defined as successful weaning. Otherwise, it was defined as failure weaning. The clinical indicators such as SBT 30-minure DTF, IAP, tidal volume (VT), respiratory rate (RR), body mass index (BMI), and blood lactic acid (Lac) were compared between the weaning success group and the weaning failure group. The indicators with statistically significant differences in the single-factor analysis were included in the secondary multivariable Logistic regression analysis to establish a risk prediction model. The correlation between the DTF and IAP at 30 minutes of SBT was analyzed. Receiver operator characteristic curve (ROC curve) was drawn to analyze the predictive value of the risk prediction model for SAP patient withdrawal failure at 30 minutes of SBT.Results:Finally, 63 patients with SAP were enrolled. Among the 63 patients, 42 were successfully weaned and 21 failed. There were no significant differences in age, gender, and oxygenation index (PaO 2/FiO 2), sequential organ failure assessment (SOFA) score, acute physiology and chronic health evaluation Ⅱ (APACHEⅡ) score at admission between the two groups, indicating that the data in the two groups were comparable. Compared with the weaning success group, IAP, RR, BMI and Lac at 30 minutes of SBT in the weaning failure group were significantly increased [IAP (mmHg, 1 mmHg≈0.133 kPa): 14.05±3.79 vs. 12.12±3.36, RR (times/min): 25.43±8.10 vs. 22.02±5.05, BMI (kg/m 2): 23.71±2.80 vs. 21.74±3.79, Lac (mmol/L): 5.27±1.69 vs. 4.55±1.09, all P < 0.05], while DTF and VT were significantly decreased [DTF: (29.76±3.45)% vs. (31.86±3.67)%, VT (mL): 379.00±98.74 vs. 413.60±33.68, both P < 0.05]. Secondary multivariable Logistic regression analysis showed that DTF [odds ratio ( OR) = 0.758, 95% confidence interval (95% CI) was 0.584-0.983, P = 0.037], IAP ( OR = 1.276, 95% CI was 1.025-1.582, P = 0.029), and RR ( OR = 1.145, 95% CI was 1.014-1.294, P = 0.029) were independent risk factors for SBT withdrawal failure in 30 minutes in SAP patients. The above risk factors were used to establish the risk prediction model of aircraft withdrawal failure at 30 minutes of SBT: Logit P = -0.237-0.277×DTF+0.242×IAP+0.136×RR. Pearson correlation analysis showed that SBT 30-minute DTF was significantly correlated with IAP in SAP patients, and showed a significant positive correlation ( r = 0.313, P = 0.012). The ROC curve analysis results showed that area under the ROC curve (AUC) of the risk prediction model for SAP patient withdrawal failure at 30 minutes of SBT was 0.716, 95% CI was 0.559-0.873, P = 0.003, with the sensitivity of 85.7% and the specificity of 78.6%. Conclusions:DTF, IAP and RR were independent risk factors for SBT withdrawal failure in 30 minutes in SAP patients. The DTF and IAP monitoring-oriented risk prediction model based on the above three variables has a good predictive value for weaning failure in patients with SAP.

Biometrics plays an important role in information society. As a new type of biometrics, electroencephalogram (EEG) signals have special advantages in terms of versatility, durability, and safety. At present, the researches on individual identification approaches based on EEG signals draw lots of attention. Identity feature extraction is an important step to achieve good identification performance. How to combine the characteristics of EEG data to better extract the difference information in EEG signals is a research hotspots in the field of identity identification based on EEG in recent years. This article reviewed the commonly used identity feature extraction methods based on EEG signals, including single-channel features, inter-channel features, deep learning methods and spatial filter-based feature extraction methods, etc. and explained the basic principles application methods and related achievements of various feature extraction methods. Finally, we summarized the current problems and forecast the development trend.
Electroencephalography