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Objective To investigate the effectiveness of pulse pressure variability (PPV) measured by continuous non-invasive arterial pressure (CNAP) monitor in guidance of fluid resuscitation in postoperative hypovolemic patients. Methods A prospective randomized controlled trial was conducted on the postoperative hypovolemic patients admitted to Department of Intensive Care Unit of Fujian Provincial Hospital from August 2018 to August 2020. They were randomly divided into PPV group and central venous pressure (CVP) group, and fluid resuscitation targeted by PPV < 10% (measured by CNAP) and CVP 8~12 mmHg were performed respectively. The main outcomes included fluid resuscitation time, duration of mechanical ventilation, cumulative fluid balance and incidence of cardiopulmonary complications. The secondary outcomes included hemodynamics [heart rate (HR), mean arterial pressure (MAP), CVP, cardiac index (CI), and PPV] and tissue oxygen metabolism [central venous oxygen saturation (ScvO2), arterial lactic acid (Lac), oxygen delivery index (DO2I), oxygen consumption index (VO2I), and oxygen uptake rate (ERO2)] as the goal of fluid resuscitation was arrived. Results A total of 78 patients were enrolled, including 38 in PPV group and 40 in CVP group. There were no significant differences in the baseline, hemodynamic and tissue oxygen metabolism parameters between the 2 groups (all P>0.05). The hemodynamic and tissue oxygen metabolism parameters were significantly improved as the goal of fluid resuscitation was arrived. No significant differences were seen in MAP, CI and PPV between the 2 groups after fluid resuscitation (all P>0.05), while CVP in the PPV group was significantly lower than that of the CVP group (P < 0.05). Compared with the CVP group, the ScvO2, DO2I, VO2I and ERO2 were increased significantly after fluid resuscitation in the PPV group (all P < 0.05), while Lac was decreased obviously in the PPV group (P < 0.05). Furthermore, the fluid resuscitation time and duration of mechanical ventilation were notably shortened, the cumulative fluid balance was remarkably decreased, and the incidence of cardiopulmonary complications was statistically reduced in the PPV group than the CVP group (all P < 0.05). Conclusion PPV measured by CNAP monitor can be used to guide the early fluid resuscitation in postoperative hypovolemic patients, which contributes to stabilizing the hemodynamic state more timely, improving the tissue oxygen metabolism, shortening the duration of mechanical ventilation, and reducing the risk of cardiopulmonary complications.

Introduction: Left ventricular diastolic dysfunction (LVDD) adversely impacts renal function, and E/e′ is a significant predictor of adverse kidney events under different clinical conditions. However, no studies have evaluated the association between LVDD and septic acute kidney injury (AKI) among patients with severe sepsis and septic shock. Methods: This multicenter retrospective study evaluated adult patients with severe sepsis or septic shock between January 1, 2013, and December 31, 2019, who underwent echocardiography within 24 hours after admission to an intensive care unit. Results: A total of 495 adult patients were enrolled in the study. LVDD grades II and III were associated with severe (stage 3) AKI (p < 0.001, p for trend < 0.001). E/e′ and e′ were risk factors for septic AKI (OR, 1.155; 95% CI, 1.088–1.226, p < 0.001; and OR, 7.218; 95% CI, 2.942–17.712, p < 0.001, respectively) in the multivariate logistic regression analysis. The area under the receiver operating characteristic curve of E/e′ and e′ was 0.728 (95% CI, 0.680–0.777, p < 0.001) and 0.715 (95% CI, 0.665–0.764, p < 0.001), respectively. Conclusions: LVDD was associated with septic AKI, and E/e′ and e′ are useful predictors of septic AKI among patients with severe sepsis or septic shock. Trial registration: The study was registered at the Chinese Clinical Trial Registry (Protocol No. ChiCTR2000033083). [ABSTRACT FROM AUTHOR]

Finally, both Newtonian and viscoelastic RPCF (see inset Graph $K$ of figure 2) fully relaminarize at Graph $Ro=1$ with two slightly different drag values because of their different viscosity, i.e. Graph $Re {\tau 0}=36.1$ and Graph $Re {\tau }=36.0$. Commensurate with above-mentioned vortical changes (see figures 2 and 3), Graph $W {x,p}$, is enhanced when Graph $Ro\leqslant 0.2$ and it diminishes for Graph $Ro>0.2$. For Graph $Ro=0.3 - 0.7$, Graph $W {x,C}$ monotonically increases as Graph $Ro$ is enhanced; hence, it becomes the dominant production term for Graph $\langle \omega ^2 x\rangle$ in the buffer layer. When Graph $J^u$ is recast in wall units, i.e. Graph $J^u={Re^2 \tau }/{Re^2}$, polymer-induced DM can be directly related to the changes of Graph $J^u$ through variation of its components in the core flow region, i.e. Graph $J^u R$ and Graph $J^u p$. [Extracted from the article]

The elastic-plastic Richtmyer-Meshkov instability of multiple interfaces is investigated by numerical simulation using a multimaterial solid mechanics algorithm based on an Eulerian framework. This Richtmyer-Meshkov instability problem is realized by a copper layer that is flanked by vacuum and a copper block of different material strength. The research efforts are directed to reveal the influence of the layer thickness and material strength on the deformation of the perturbed solid-vacuum interface impacted by an initial shock. By varying the initial thickness (x&#95;{I}) of the copper layer and the yield stress (σ&#95;{Y2}) of the copper block, two deformation modes, which have been identified as the broken mode and the stable mode, are closely scrutinized. For a fixed x&#95;{I} and a decreasing σ&#95;{Y2}, the reflected rarefaction waves (RRWs), developing after the initial shock impacts the perturbed interface 1 (I1) between vacuum and the copper layer, become stronger after traveling across the interface 2 (I2). Subsequently, the velocity of I2 becomes larger, causing the width of I1 to grow larger. This width growth of I1 leads to a final separation of the spike from I1 and, consequently, the deformation mode changes from the stable mode to the broken mode. For a fixed σ&#95;{Y2} and a decreasing x&#95;{I}, the RRWs impact I2 at an earlier moment with a greater strength and thus the deformation mode changes from the stable mode to the broken mode. Meanwhile, the comparison of the spike width of cases whose deformation mode is the broken mode shows that there exists a maximum value of rescaled spike width, at which the deformation mode changes from the stable mode to the broken mode.

This retrospective aims to present a coherent history of important findings in direct numerical simulations and experiments in turbulent Taylor-Couette (TC) flow of dilute polymeric solutions in the last decade. Specifically, the sequence of flow transitions due to a continuous increase of fluid elasticity from classical Newtonian, to inertially and in turn to elastically dominated, and finally to the inertialess purely elastic turbulence, is presented. In each elastically modified flow state, the drag modification, coherent flow structures, velocity and elastic stress statistics, mechanism of turbulent kinetic energy production, spectral features as well as the self-sustaining cycles of turbulence, are discussed. Finally, to provide a broader perspective, an overview of important similarities and differences between elastically induced turbulence in prototypical curvilinear and rectilinear shear flows including the curvature-free limit of TC flow, namely, the spanwise-rotating plane Couette flow, is presented. This article is part of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper (part 1)'.

Objective: To investigate the value of pulse indicator continuous cardiac output (PiCCO) monitoring in the treatment management of patients with severe heart failure., Methods: Sixty patients of severe heart failure admitted to intensive care unit (ICU) of Fujian Provincial Hospital from August 2017 to February 2019 were enrolled, and they were divided into control group and treatment group according to random number table method, with 30 in each group. The treatment group used bedside PiCCO to carry out minimally invasive hemodynamics monitoring, according to the monitoring data target guidance for vasoactive drugs and liquid management. The control group was based only on traditional electrocardiogram (ECG) monitoring and lung sound, urine volume of vasoactive drugs and liquid management. The changes of cardiac index (CI), global end diastolic volume index (GEDVI), extravascular lung water index (EVLWI), systemic vascular resistance index (SVRI), invasive mean arterial pressure (MAP) and central venous pressure (CVP) were observed before and 72 hours after treatment in the treatment group. The 7-day total effective rate, the length of ICU stay and 28-day mortality were compared between the two groups., Results: Compared with before treatment, CI and MAP in the treatment group were significantly increased after treatment [CI (mL×s -1 ×m -2 ): 53.34±16.67 vs. 35.01±13.34, MAP (mmHg, 1 mmHg = 0.133 kPa): 72.6±10.6 vs. 62.5±10.3, both P < 0.05], GEDVI, EVLWI, SVRI, CVP were significantly decreased [GEDVI (mL/m 2 ): 760.3±90.2 vs. 960.2±110.3, EVLWI (mL/kg): 6.5±1.3 vs. 12.5±6.2, SVRI (kPa×s×L -1 ×m -2 ): 297.3±35.1 vs. 434.1±58.8, CVP (mmHg): 10.1±2.6 vs. 12.2±3.4, all P < 0.05]. Compared with the control group, the 7-day total effective rate of the treatment group was significantly higher (90.0% vs. 80.0%), the length of ICU stay was significantly shorter (days: 8.2±4.5 vs. 10.3±2.5), and the 28-day mortality was significantly lower, with statistically significant difference (all P < 0.05)., Conclusions: PiCCO monitoring is a goal-oriented treatment management for patients with severe heart failure, which is helpful to individualized accurate treatment, shorten the length of ICU stay and improve short-term prognosis.

Objective: To evaluate the difference and correlation between continuous non-invasive arterial pressure (CNAP) monitor and pulse indicated continuous cardiac output (PiCCO) monitor on determination of hemodynamic parameters in mechanically ventilated critically ill patients, and to assess the feasibility of non-invasive monitoring of hemodynamics with CNAP., Methods: A prospective observation self-control study was conducted.The critically ill patients with mechanical ventilation who needed hemodynamics monitoring, and admitted to the fourth department of intensive care unit (ICU) of Fujian Provincial Hospital from June 2018 to March 2019 were enrolled. PiCCO catheter were inserted immediately after admission, the hemodynamic indexes were measured by thermodilution method, and mean arterial pressure (MAP PiCCO ), cardiac index (CI PiCCO ), pulse pressure variation rate (PPV PiCCO ) and systemic vascular resistance index (SVRI PiCCO ) were obtained at 0 hour and 24 hours respectively. Meanwhile, the above indexes (MAP CNAP , CI CNAP , PPV CNAP and SVRI CNAP ) were measured with CNAP. All measurements were repeated thrice and average values were reported. The differences in above parameters between the two methods were evaluated. Pearson test was used for the correlation analysis and Bland-Altman analysis method was used for consistency test., Results: Thirty-eight patients were enrolled into this study. One patient died within 24 hours was excluded, 2 patients were excluded due to withdrawing treatment within 24 hours, 2 patients were excluded because of atrial fibrillation, and 1 patient's data was lost due to technical problems. Thus, data from 32 patients were available for final analysis. There were 12 females and 20 males, aging 26-84 years old with the mean of (66.8±19.1) years old, body mass index (BMI) of (23.7±3.9) kg/m 2 , acute physiology and chronic health evaluation II (APACHE II) score of 19.5±5.3, sepsis-related organ failure assessment (SOFA) score of 9.7±4.1. There were no significant differences in CI or PPV between CNAP and PiCCO groups [CI (mL×s -1 ×m -2 ): 59.8±12.6 vs. 58.5±14.2, PPV: (14.7±6.8)% vs. (14.0±6.8)%, both P > 0.05]. MAP and SVRI measured by CNAP were significantly higher than those measured by PiCCO [MAP (mmHg, 1 mmHg = 0.133 kPa): 65.6±9.4 vs. 60.1±9.2, SVRI (kPa×s×L -1 ×m -2 ): 206.2±53.9 vs. 179.5±57.8, both P < 0.01]. The correlation analysis showed that MAP, CI, PPV and SVRI measured by the two methods were significantly positively correlated (r value was 0.624, 0.864, 0.835 and 0.655 respectively, all P < 0.05). Bland-Altman analysis showed that CNAP and PiCCO had a good consistency for the measurement of CI and PPV, the average differences were 1.2 mL×s -1 ×m -2 and 0.5% respectively, while the 95% confidence interval (95%CI) were -12.8-15.3 mL×s -1 ×m -2 and -7.1%-8.2% respectively. However, the consistency of MAP and SVRI measured by those two methods was poor, the average differences were 5.5 mmHg and 26.8 kPa×s×L -1 ×m -2 respectively, while the 95%CI was -10.4-21.3 mmHg and -64.5-118.0 kPa×s×L -1 ×m -2 respectively., Conclusions: CNAP was comparable with PiCCO when monitoring CI and PPV in mechanically ventilated critically ill patients; while the results of MAP and SVRI might be inaccurate, which should be interpreted correctly and carefully.