Boosting Carbon Dioxide Reduction in a Photocatalytic Fuel Cell with a Bubbling Fluidized Cathode: Dual Function of Titanium Carbide.

Photoelectrochemical reduction of carbon dioxide (CO2) is a promising avenue to realize resourceful utilization of carbon dioxide and mitigate the energy shortage. Herein, a photocatalytic fuel cell with a bubbling fluidized cathode (PFC-BFC) is proposed to increase the performance of the photocatalytic CO2 reduction reaction (CO2RR). Titanium carbide (Ti3C2) is first used as a fluidized cathode catalyst with the dual features of superior capacitance and high CO2RR catalytic activity. Compared with the conventional PFC system, the as-proposed PFC-BFC system exhibits a higher gas production performance. Particularly, the generation rate and Faraday efficiency for CH4 production reach to 37.2 µmol g-1 h-1 and 72%, which are 10.9 and 6.5 times higher than that of the conventional PFC system, respectively. The bubbling fluidized cathode allows a rapid electron transfer between catalysts and the current collector and an efficient diffusion of catalysts in the whole solution, thus remarkably increasing the effective reaction area of the CO2RR. In addition, the fluidized reaction mechanism of charging/discharging-coupled CO2RR is investigated. Significantly, a magnified PFC-BFC system is designed and exhibits a similar gas generation rate compared to that of the small-scale system, indicating a good potential of scaling up in the industry applications. These results demonstrated that the proposed PFC-BFC system can maximize the utilization of catalyst active sites and enhance the reaction kinetics, providing an alternative design for the application of CO2RR.

Experimental study on the flow structures and dynamics of turbulent Rayleigh-Bénard convection in an annular cell.

We conduct an experimental study on the flow structures and dynamics of turbulent Rayleigh-Bénard convection in an annular cell with radius ratio η≃0.5 and aspect ratio Γ≃4. The working fluid is water with a Prandtl number of Pr≃5.4, and the Rayleigh number (Ra) ranges from 5.05×10^{7} to 5.05×10^{8}. The multithermal-probe method and the particle image velocimetry technique are employed to measure the temperature profiles and the velocity fields, respectively. Two distinct states with multiroll standing waves are observed, which are the quadrupole state (QS) characterized by a four-roll structure and the sextupole state (SS) by a six-roll structure. The scaling exponents of Reynolds number Re with Ra are different for the two states, which are 0.56 for QS and 0.41 for SS. In addition, the standing waves become unstable upon tilting the cell by 1^{∘} in relation to the horizontal plane, and they evolve into traveling waves. At relatively high Ra, for instance, Ra⩾2.55×10^{8}, it is observed that the traveling wave state SS undergoes a transition to the traveling wave state QS. However, the opposite transition from QS to SS is not observed in our experiments. Our findings provide insights into the flow structures and dynamics in the convection flow with rotation symmetry.

Simulation of a thermo-electrochemical cell with graphite rod electrodes.

The rapid development of human society has resulted in the extensive release of waste heat. The thermo-electrochemical cell (TEC), a cutting-edge technology that converts low-grade waste heat into electricity, has garnered increasing attention. However, the complex interactions among various processes, such as fluid flow, electrochemical reactions and heat transfer, make it challenging to evaluate their effect on the overall performance of the TEC. Understanding the synergistic mechanisms and coupling effects of these processes is crucial for optimizing and implementing TECs in practical applications. In this paper, a mathematical model is developed by coupling electrochemical reactions and heat/mass transfer. The distributions of ion concentration, electrolyte velocity and temperature are analyzed under varying temperature differences and electrode distances. The results demonstrate a significant interaction between heat transfer and electrolyte flow. Higher temperatures not only improve the open circuit voltage, but also promote ion transport convection and hence enhance the current density. In addition, a higher concentration of ions or smaller electrode spacing exhibits an apparently improved performance of the TEC, due to the facilitated ion transport and reduced concentration overpotential. Notably, electrode spacing has a negligible effect on the maximum power density of the TEC under a constant heat flux, but it does enhance the current density due to the combined effect of heat and ion transfer. Overall, the proposed mathematical model provides deeper insight into the physical-chemical processes involved in TECs and offers valuable guidance for TEC design and practical applications.

Mineralogical and elemental data for soil discriminating and geolocation tracing.

One of the key tasks of soil analysis in forensic sciences is to provide information about its diversities and geolocation. In fact, soil analysis is relevant for forensic geologists. In this study, a total of 80 soil samples were collected from eight Chinese cities (10 samples per city). Different minerals and their relative percentages were analyzed by the X-ray diffraction (XRD) method. In addition, the relative amounts of montmorillonite, kaolinite, amphibole, feldspar, calcite, and dolomite provided information about the origin of a soil, either if it came from a northern or southern city of China. The oxide weight percentages of 10 elements of Al2O3, SiO2, Fe2O3, K2O, Na2O, MgO, CaO, P2O5, MnO, and TiO2 were also obtained by using X-ray fluorescence (XRF) from the 80 soil samples. Moreover, principal component analysis (PCA) and hierarchical clustering analysis (HCA) methods were performed for dimensionality reduction, elemental marker identification and soils classification to the city they came from purposes. The eighty soils analyzed in this study could be tracked correctly to their city of origin. The K-Nearest Neighbors (KNN) model was done to evaluate the prediction ability based on the soil elemental composition, and it was confirmed by cross validation methods. The results demonstrated that mineralogical and elemental composition can provide powerful information for soil discrimination and source tracing.

Early Enteral Nutrition Tolerance in Patients With Cardiogenic Shock Requiring Mechanical Circulatory Support.

Background: Enteral nutrition (EN) is recommended within the first 24-48 h for patients with hemodynamic stability, following admission to an intensive care unit (ICU). However, for patients with approximate stable hemodynamics requiring mechanical circulatory support and vasoactive drugs, the application of early EN remains controversial. We sought to evaluate the tolerance of early EN in patients with cardiogenic shock who required vasoactive drugs and mechanical circulatory support after cardiac surgery. Methods: This single-center, prospective observational study included patients with cardiogenic shock, requiring vasoactive drugs and mechanical circulatory support after cardiac surgery, undergoing EN. The primary endpoint was EN tolerance and secondary endpoints were mortality, length of mechanical ventilation, and length of ICU stay. Results: From February 2019 to December 2020, 59 patients were enrolled, of which 25 (42.37%) developed intolerance within 3 days of starting EN. Patients in the EN intolerant group had a longer median length of mechanical ventilation (380 vs. 128 h, p = 0.006), a longer median ICU stay (20 vs. 11.5 days, p = 0.03), and a higher proportion of bloodstream infections (44 vs. 14.71%, p = 0.018). The median EN calorie levels for all patients in the first 3 days of EN were 4.00, 4.13, and 4.28 kcal/kg/day, respectively. Median protein intake levels of EN in the first 3 days were 0.18, 0.17, and 0.17 g/kg/day, respectively. No significant difference was observed in the median dose of vasoactive drugs between the groups (0.035 vs. 0.05 µg/kg/min, p = 0.306). Conclusions: Patients with cardiogenic shock after cardiac surgery had a high proportion of early EN intolerance, and patients with EN intolerance had a worse prognosis, but no significant correlation was identified between EN tolerance and the dose of vasoactive drugs.

In situ identification of TATP and DADP particles collected with transparent tape by Raman spectroscopy and imaging.

Triacetone triperoxide (TATP) and its byproduct diacetone diperoxide (DADP) are commonly used home-made high explosives in bombing cases and terrorist attacks. However, these two peroxide explosives are unstable and prone to thermal decomposition, leading to challenges in sample collection and preparation in bombing cases. Therefore, there is an urgent need to develop an in situ identification method for TATP and DADP. Compared to the solvent-based swabbing methods commonly used for trace explosive collection, the tape lifting method can collect explosive particles and other potential evidence without damaging fingerprints or DNA. This study aims to develop a tape lifting method to collect trace explosive particles in bombing cases and an in situ method to identify TATP and DADP particles on the sticky side of transparent tape directly using laser confocal Raman spectroscopy. One type of fingerprint tape and two types of office tape were used to collect peroxide explosive particles followed by particle fixation on glass slides. Laser confocal Raman spectroscopy was applied to directly identify target particles, without peeling the attached tape off the glass slide. A solid-state laser emitting at 473 nm was suitable for Raman and imaging analysis of TATP and DADP. To mimic the real situation, the synthetic TATP and DADP were passed through a 100-mesh sieve, respectively. Fifty µg of each explosive powder was weighed, mixed and spread on a wooden table with dust in an area of 10 × 10 cm2. Subsequently, the samples were collected with the fingerprint tape. A targeted area of the tape with suspicious particles was imaged for analysis. Based on the difference between the characteristic Raman bands of TATP and DADP, the band ranges of 530-550 cm-1 and 750-770 cm-1 were selected, respectively, for obtaining the distribution information. The combination of Raman technology and the tape lifting method shows great potential for in situ identification of forensic samples by providing chemical and spatial information.

Veno-Arterial Extracorporeal Membrane Oxygenation for Patients Undergoing Acute Type A Aortic Dissection Surgery: A Six-Year Experience.

Objectives: Acute type A aortic dissection (aTAAD) is usually lethal without emergency surgery. Although veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is widely used in patients with cardiogenic shock following cardiac surgery, VA-ECMO support following aTAAD surgery has not been well-described. Based on our 6-year experience, we aimed to retrospectively analyze risk factors, application and timing of VA-ECMO, and outcomes in aTAAD patients. Methods: In this retrospective, single-center study, we enrolled adult patients who underwent aTAAD surgery from January 2014 to December 2019 and were supported with VA-ECMO. Patients were divided into two groups according to whether or not they were successfully weaned from VA-ECMO. Preoperative, intraoperative and postoperative variables were assessed and analyzed. Outcomes of the patients were followed up until discharge. Results: Twenty-seven patients who received aTAAD surgery with VA-ECMO support were included in the study. Nine patients (33.3%) were successfully weaned from VA-ECMO. The median VA-ECMO support time and length of hospital stay in the successfully weaned group were significantly longer than in the group could not be successfully weaned (192 [111-327] vs. 55 [23-95] h, p < 0.01; 29 [18-40] vs. 4 [3-8] days, p < 0.01). Overall in-hospital mortality was 81.5%. The main causes of death were bleeding (37%), neurological complications (15%), and multiple organ dysfunction syndrome (15%). Preoperative levels of creatine kinase-MB (CK-MB) were lower in patients who were successfully weaned from VA-ECMO than in the failed group (14 [6-30] vs. 55 [28-138] U/L, p < 0.01). Postoperative peak levels of CK-MB, cardiac troponin T, lactate dehydrogenase, and lactate were significantly lower in the successful group than in the failed group. Conclusion: Postoperative VA-ECMO support was rarely used in aTAAD patients. Our study showed that VA-ECMO can be considered as a salvage treatment in aTAAD patients, despite the high rate of complications and mortality.

Serum creatinine as a predictor of mortality in patients readmitted to the intensive care unit after cardiac surgery: a retrospective cohort study in China.

BACKGROUND: Patients readmitted to the intensive care unit (ICU) after cardiac surgery have a high mortality rate. The relationship between renal function and in-hospital mortality in readmitted patients has not been well demonstrated. METHODS: We retrospectively evaluated cardiac surgery patients who were readmitted to the ICU at least once. Data on serum creatinine levels before surgery and on the day of ICU readmission were collected. The estimated glomerular filtration rate (eGFR) was calculated according to the creatinine-based Chronic Kidney Disease-Epidemiology Collaboration equation. We used logistic regression models and restricted cubic spline curves with four knots (5%, 35%, 65%, 95%) to investigate the relationship between renal function indicators and mortality. RESULTS: Of the 184 patients evaluated, 30 patients died during hospitalization, yielding a mortality rate of 16.30%. Cardiac dysfunction (n=84, 45.65%) and respiration disorder (n=51, 27.72%) were the most common reasons for ICU readmission. Creatinine [odds ratio (OR): 1.14, 95% confidence interval (CI): 1.07-1.25] and eGFR (OR: 0.95, 95% CI: 0.93-0.98) were independently associated with in-hospital mortality after adjusting for various confounders. Both creatinine level and eGFR had a linear association with in-hospital mortality (P for non-linearity ˃0.05). CONCLUSION: Renal function is significantly associated with the in-hospital mortality of patients readmitted to the ICU after cardiac surgery, as evidenced by the independent correlation of both creatinine and eGFR with in-hospital mortality.

Forensic comparison analysis of plastic vehicle headlamp lens by gel permeation chromatography and statistical methods.

Comparison analysis of vehicle headlamp lens fragments can help establish links between the relevant vehicle with crime scenes or provide useful information to search the related vehicles. Headlamp lenses are mainly made of polycarbonate with very few signature additives, which makes them difficult to be discriminated by commonplace examination methods of infrared spectroscopy and scanning electron microscope coupled with energy dispersive X-ray spectroscopy. In this study, molecular weights (Mw) and the polydispersity index (PDI) value of 50 vehicle headlamp lens fragments from different vehicles were measured by gel permeation chromatography, and Hotelling's T2 statistical method was applied to facilitate interpretation of the data. Among the total C 50 2 = 1225 pairs of comparisons between 50 samples, 62 pairs cannot be distinguished, resulting in a discrimination rate of 94.94%. It suggested that the method of gel permeation chromatography and Hotelling's T2 statistical analysis were powerful to make further discrimination between plastic vehicle headlamp lens fragments.

Trendelenburg maneuver predicts fluid responsiveness in patients on veno-arterial extracorporeal membrane oxygenation.

BACKGROUND: Evaluation of fluid responsiveness during veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support is crucial. The aim of this study was to investigate whether changes in left ventricular outflow tract velocity-time integral (ΔVTI), induced by a Trendelenburg maneuver, could predict fluid responsiveness during VA-ECMO. METHODS: This prospective study was conducted in patients with VA-ECMO support. The protocol included four sequential steps: (1) baseline-1, a supine position with a 15° upward bed angulation; (2) Trendelenburg maneuver, 15° downward bed angulation; (3) baseline-2, the same position as baseline-1, and (4) fluid challenge, administration of 500 mL gelatin over 15 min without postural change. Hemodynamic parameters were recorded at each step. Fluid responsiveness was defined as ΔVTI of 15% or more, after volume expansion. RESULTS: From June 2018 to December 2019, 22 patients with VA-ECMO were included, and a total of 39 measurements were performed. Of these, 22 measurements (56%) met fluid responsiveness. The R2 of the linear regression was 0.76, between ΔVTIs induced by Trendelenburg maneuver and the fluid challenge. The area under the receiver operating characteristic curve of ΔVTI induced by Trendelenburg maneuver to predict fluid responsiveness was 0.93 [95% confidence interval (CI) 0.81-0.98], with a sensitivity of 82% (95% CI 60-95%), and specificity of 88% (95% CI 64-99%), at a best threshold of 10% (95% CI 6-12%). CONCLUSIONS: Changes in VTI induced by the Trendelenburg maneuver could effectively predict fluid responsiveness in VA-ECMO patients. Trial registration ClinicalTrials.gov, NCT03553459 (the TEMPLE study). Registered on May 30, 2018.

Veno-Arterial Extracorporeal Membrane Oxygenation for Patients Undergoing Heart Transplantation: A 7-Year Experience.

Objective: Primary graft dysfunction (PGD) is the leading cause of early death after heart transplantation. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can provide temporary mechanical circulatory support and time for functional recovery of the transplanted heart. The purpose of this study was to analyze the timing and prognoses of VA-ECMO in patients with severe PGD after heart transplantation. Methods: A total of 130 patients underwent heart transplantation at the Zhongshan Hospital Affiliated with Fudan University between January 2014 and December 2020. All patients received basiliximab immunoinduction and a classic double vena cava anastomosis orthotopic heart transplantation. Among them, 29 patients (22.3%) developed severe PGD in the early postoperative period. VA-ECMO was performed in patients with difficulty weaning from cardiopulmonary bypass (CPB) or postoperative refractory cardiogenic shock. Patients were divided into two groups according to whether or not they were successfully weaned from VA-ECMO (patients who survived for 48 h after weaning and did not need VA-ECMO assistance again). The perioperative clinical data were recorded, and all patients were followed up until discharge. Early outcomes were compared between groups. Results: A total of 29 patients with VA-ECMO support after heart transplantation were included in this study. The proportion of patients receiving VA-ECMO was 22.3% (29/130). Nineteen patients (65.5%) needed VA-ECMO due to difficulty with weaning from CPB, and 10 patients required VA-ECMO for postoperative cardiogenic shock. Nineteen patients (65.5%) were successfully weaned from VA-ECMO. Overall, in-hospital mortality of VA-ECMO support patients was 55.2%. The main causes of death were ventricular fibrillation (four cases), major bleeding (three cases), infection (four cases), and graft failure (five cases). Conclusion: Despite advances in heart transplantation, severe PGD remains a lethal complication after heart transplantation. At present, the treatment for severe PGD after heart transplantation is a challenge. VA-ECMO provides an effective treatment for severe PGD after heart transplantation, which can promote graft function recovery.

Stress, Burnout, and Coping Strategies of Frontline Nurses During the COVID-19 Epidemic in Wuhan and Shanghai, China.

Background: Nurses at the frontline of caring for COVID-19 patients might experience mental health challenges and supportive coping strategies are needed to reduce their stress and burnout. The aim of this study was to identify stressors and burnout among frontline nurses caring for COVID-19 patients in Wuhan and Shanghai and to explore perceived effective morale support strategies. Method: A cross-sectional survey was conducted in March 2020 among 110 nurses from Zhongshan Hospital, Shanghai, who were deployed at COVID-19 units in Wuhan and Shanghai. A COVID-19 questionnaire was adapted from the previous developed "psychological impacts of SARS" questionnaire and included stressors (31 items), coping strategies (17 items), and effective support measures (16 items). Burnout was measured with the Maslach Burnout Inventory. Results: Totally, 107 (97%) nurses responded. Participants mean age was 30.28 years and 90.7% were females. Homesickness was most frequently reported as a stressor (96.3%). Seven of the 17 items related to coping strategies were undertaken by all participants. Burnout was observed in the emotional exhaustion and depersonalization subscales, with 78.5 and 92.5% of participants presenting mild levels of burnout, respectively. However, 52 (48.6%) participants experienced a severe lack of personal accomplishment. Participants with longer working hours in COVID-19 quarantine units presented higher emotional exhaustion (OR = 2.72, 95% CI 0.02-5.42; p = 0.049) and depersonalization (OR = 1.14, 95% CI 0.10-2.19; p = 0.033). Participants with younger age experienced higher emotional exhaustion (OR = 2.96, 95% CI 0.11-5.82; p = 0.042) and less personal accomplishment (OR = 3.80, 95% CI 0.47-7.13; p = 0.033). Conclusions: Nurses in this study experienced considerable stress and the most frequently reported stressors were related to families. Nurses who were younger and those working longer shift-time tended to present higher burnout levels. Psychological support strategies need to be organized and implemented to improve mental health among nurses during the COVID-19 pandemic.

Remifentanil versus dexmedetomidine for treatment of cardiac surgery patients with moderate to severe noninvasive ventilation intolerance (REDNIVIN): a prospective, cohort study.

BACKGROUND: The use of sedation to noninvasive ventilation (NIV) patients remains controversial, however, for intolerant patients who are uncooperative, administration of analgesics and sedatives may be beneficial before resorting to intubation. The aim of this study was to evaluate the efficacy of remifentanil (REM) versus dexmedetomidine (DEX) for treatment of cardiac surgery (CS) patients with moderate to severe NIV intolerance. METHODS: This prospective cohort study of CS patients with moderate to severe NIV intolerance was conducted between January 2018 and March 2019. Patients were treated with either REM or DEX, decided by the bedside intensivist. Depending on the treatment regimen, the patients were allocated to one of two groups: the REM group or DEX group. RESULTS: A total of 90 patients were enrolled in this study (52 in the REM group and 38 in the DEX group). The mitigation rate, defined as the percentage of patients who were relieved from the initial moderate to severe intolerant status, was greater in the REM group than DEX group at 15 min and 3 h (15 min: 83% vs. 61%, P=0.029; 3 h: 92% vs. 74%, P=0.016), although the mean mitigation rate (81% vs. 85%, P=0.800) was comparable between the two groups. NIV failure, defined as reintubation or death over the course of study, was comparable between the two groups (19.2% vs. 21.1%, respectively, P=0.831). There were no significant differences between the two groups in other clinical outcomes, including tracheostomy (15.4% vs. 15.8%, P=0.958), in-hospital mortality (11.5% vs. 10.5%, P=0.880), ICU length of stay (LOS) (7 vs. 7 days, P=0.802), and in-hospital LOS (17 vs. 19 days, P=0.589). CONCLUSIONS: REM was as effective as DEX in CS patients with moderate to severe NIV intolerance. Although the effect of REM was better than that of DEX over the first 3 h, the cumulative effect was similar between the two treatments.

Prevalence, Predictors, and Early Outcomes of Post-operative Delirium in Patients With Type A Aortic Dissection During Intensive Care Unit Stay.

Objectives: The aim of this study was to investigate the prevalence and explore the predictors and early outcomes of post-operative delirium (POD) in patients with type A aortic dissection (AAD) during intensive care unit (ICU) stays. Methods: We retrospectively reviewed the records of 301 patients with AAD who underwent surgical treatment in our institution from January 2017 to December 2018. Results: Delirium developed in 73 patients (24.25%) during the ICU stay. Patients with lower estimated glomerular filtration rates [odds ratio (OR) 0.84, 95% CI 0.74-0.94, p = 0.003], post-operative midazolam use (OR 2.37, 95% CI 1.33-4.23, p = 0.004), and post-operative morphine use (OR 1.87, 95% CI 1.07-3.29, p = 0.029) were more susceptible to developing POD. Patients who developed POD had a longer ICU stay (11.52 vs. 7.22 days, p < 0.001) and hospital stay (23.99 vs. 18.91, p = 0.007) with higher hospitalization costs (48.82 vs. 37.66 thousand dollars, p < 0.001) than those without POD. The in-hospital mortality rate was higher in the delirium group, but the difference was not significant (6.85 vs. 4.82%, p = 0.502). Conclusions: The incidence of POD in patients with AAD was high and was associated with renal dysfunction and the use of midazolam and morphine. POD was associated with poor early outcomes, suggesting the importance of early screening, such as for renal dysfunction, and prevention by using sedation scales to minimize the use of midazolam and morphine in these patients.

Comparison of the proximal and distal approaches for axillary vein catheterization under ultrasound guidance (PANDA) in cardiac surgery patients susceptible to bleeding: a randomized controlled trial.

BACKGROUND: The present study aimed at comparing the success rate and safety of proximal versus distal approach for ultrasound (US)-guided axillary vein catheterization (AVC) in cardiac surgery patients susceptible to bleeding. METHODS: In this single-center randomized controlled trial, cardiac surgery patients susceptible to bleeding and requiring AVC were randomized to either the proximal or distal approach group for US-guided AVC. Patients susceptible to bleeding were defined as those who received oral antiplatelet drugs or anticoagulants for at least 3 days. Success rate, catheterization time, number of attempts, and mechanical complications within 24 h were recorded for each procedure. RESULTS: A total of 198 patients underwent randomization: 99 patients each to the proximal and distal groups. The proximal group had the higher first puncture success rate (75.8% vs. 51.5%, p < 0.001) and site success rate (93.9% vs. 83.8%, p = 0.04) than the distal group. However, the overall success rates between the two groups were similar (99.0% vs. 99.0%; p = 1.00). Moreover, the proximal group had fewer average number of attempts (p < 0.01), less access time (p < 0.001), and less successful cannulation time (p < 0.001). There was no significant difference in complications between the two groups, such as major bleeding, minor bleeding, arterial puncture, pneumothorax, nerve injuries, and catheter misplacements. CONCLUSIONS: For cardiac surgery patients susceptible to bleeding, both proximal and distal approaches for US-guided AVC can be considered as feasible and safe methods of central venous cannulation. In terms of the first puncture success rate and cannulation time, the proximal approach is superior to the distal approach. Trial registration Clinicaltrials.gov, NCT03395691. Registered January 10, 2018, https://clinicaltrials.gov/ct2/show/NCT03395691?cond=NCT03395691&draw=1&rank=1 .

Evaluation of radial artery pulse pressure effects on detection of stroke volume changes after volume loading maneuvers in cardiac surgical patients.

BACKGROUND: Fluid responsiveness is defined as an increase in cardiac output (CO) or stroke volume (SV) of >10-15% after fluid challenge (FC). However, CO or SV monitoring is often not available in clinical practice. The aim of this study was to evaluate whether changes in radial artery pulse pressure (rPP) induced by FC or passive leg raising (PLR) correlates with changes in SV in patients after cardiac surgery. METHODS: This prospective observational study included 102 patients undergoing cardiac surgery, in which rPP and SV were recorded before and immediately after a PLR test and FC with 250 mL of Gelofusine for 10 min. SV was measured using pulse contour analysis. Patients were divided into responders (≥15% increase in SV after FC) and non-responders. The hemodynamic variables between responders and non-responders were analyzed to assess the ability of rPP to track SV changes. RESULTS: A total of 52% patients were fluid responders in this study. An rPP increase induced by FC was significantly correlated with SV changes after a FC (ΔSV-FC, r=0.62, P<0.01). A fluid-induced increase in rPP (ΔrPP-FC) of >16% detected a fluid-induced increase in SV of >15%, with a sensitivity of 91% and a specificity of 73%. The area under the receiver operating characteristic curve (AUROC) for the fluid-induced changes in rPP identified fluid responsiveness was 0.881 (95% CI: 0.802-0.937). A grey zone of 16-34% included 30% of patients for ΔrPP-FC. The ΔrPP-PLR was weakly correlated with ΔSV-FC (r=0.30, P<0.01). An increase in rPP induced by PLR (ΔrPP-PLR) predicted fluid responsiveness with an AUROC of 0.734 (95% CI: 0.637-0.816). A grey zone of 10-23% included 52% of patients for ΔrPP-PLR. CONCLUSIONS: Changes in rPP might be used to detect changes in SV via FC in mechanically ventilated patients after cardiac surgery. In contrast, changes in rPP induced by PLR are unreliable predictors of fluid responsiveness.

Hemodynamic monitoring in patients with venoarterial extracorporeal membrane oxygenation.

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an effective mechanical circulatory support modality that rapidly restores systemic perfusion for circulatory failure in patients. Given the huge increase in VA-ECMO use, its optimal management depends on continuous and discrete hemodynamic monitoring. This article provides an overview of VA-ECMO pathophysiology, and the current state of the art in hemodynamic monitoring in patients with VA-ECMO.

Effect of Sequential Noninvasive Ventilation on Early Extubation After Acute Type A Aortic Dissection.

BACKGROUND: Acute type A aortic dissection (aTAAD) is associated with a high incidence of prolonged postoperative invasive mechanical ventilation. We aimed to assess whether sequential noninvasive ventilation (NIV) could facilitate early extubation postoperatively after a spontaneous breathing trial (SBT) failure among aTAAD patients. METHODS: Beginning in December 2016, we transitioned our weaning strategy from repeated SBT until success (phase 1) to extubation concomitant with sequential NIV (phase 2) for subjects who failed their first SBT. The primary outcomes were re-intubation rate, duration of invasive ventilation, and total duration of ventilation. RESULTS: During the study period, 78 subjects with aTAAD failed their first postoperative SBT (38 subjects in phase 1 and 40 subjects in phase 2). Subjects extubated with sequential NIV had shorter median (interquartile range [IQR]) duration of invasive ventilation of 39.5 (30.8-57.8) h vs 89.5 (64-112) h (P < .001) and median (IQR) length of ICU stay of 6 (4.0-7.8) d vs 7.5 (5.8-9.0) d (P = .030). There were no significant differences between the 2 phases with regard to rates of re-intubation (7.5% vs 7.89%, P = .95), tracheostomy (2.5% vs 5.26%, P = .53), and in-hospital mortality (2.5% vs 2.63%, P = .97). CONCLUSIONS: Early extubation followed by sequential NIV significantly reduced duration of invasive ventilation and length of ICU stay without increasing re-intubation rate in postoperative subjects with aTAAD who failed their first SBT.

Application of the PDCA cycle for standardized nursing management in a COVID-19 intensive care unit.

BACKGROUND: Nursing quality is an integral part of health care quality and one of key performance indicators (KPIs) for health care management. The Plan-Do-Check-Act (PDCA) cycle is a management tool for continuous improvement of a business's products or processes. It can be applied to standardize nursing management and thus improve the nursing quality and increase the survival rate of patients. This study assessed the value of the PDCA cycle in standardizing nursing management in an intensive care unit (ICU) for patients with severe coronavirus disease 2019 (COVID-19). METHODS: The status quo of the ICU was analyzed, and the relevant issues and countermeasures were proposed. The PDCA cycle was applied to standardize the nursing management in the ICU. RESULTS: Nine measures were proposed and applied to improve the management of the COVID-19 ICU: defining the clean or contaminated areas, use of self-designed shoe storage cabinets, defining staff roles and responsibilities, establishing the staffing structure, staff training, placing items at fixed locations, improving shift handover, use of bulletin boards for listing key points, and use of reserved drugs cabinets. The virus contamination awareness, professional skills, awareness of duties and responsibilities, and quality and performance of nursing were remarkably improved 2 weeks after the implementation of the above countermeasures. CONCLUSIONS: The PDCA cycle helps to standardize nursing management in COVID-19 ICU by developing and applying effective nursing management approaches.