Predictors of 30-day readmission following pancreatic surgery:A retrospective review

Background： Pancreatectomies have been identified as procedures with an increased risk of readmission.In surgical patients, readmissions within 30 days of discharge are usually procedure-related. We sought to determine predictors of 30-day readmission following pancreatic resections in a large healthcare system.Methods： We retrospectively collected information from the records of 383 patients who underwent pancreaticresections from 2004–2013. To find the predictors of readmission in the 30 days after discharge,we performed a univariate screen of possible variables using the Fisher’s exact test for categorical variables and the Mann–Whitney U test for continuous variables. Multivariate analysis was used to determinethe independent factors.

The 20―30-day oscillation of the global circulation and heavy precipitation over the lower reaches of the Yangtze River valley

Based on the observational data in summer, the variations of intraseasonal oscillation (ISO) of the daily rainfall over the lower reaches of the Yangtze River valley (LYRV) were studied by using the non-integer spectrum analysis. The NCEP/NCAR reanalysis data for the period of 1979―2005 were analyzed by principal oscillation pattern analysis (POP) to investigate the spatial and temporal characteristics of principal ISO patterns of the global circulation. The relationships of these ISO patterns to the rainfall ISO and the heavy precipitation process over LYRV were also discussed. It is found that the rainfall over LYRV in May―August is mainly of periodic oscillations of 10―20, 20―30 and 60―70 days, and the interannual variation of the intensity of its 20―30-day oscillation has a strongly positive correlation with the number of the heavy precipitation process. Two modes (POP1, POP2) are revealed by POP for the 20―30-day oscillation of the global 850 hPa geopotential height. One is a circumglobal telecon-nection wave train in the middle latitude of the Southern Hemisphere (SCGT) with an eastward propagation, and the other is the southward propagation pattern in the tropical western Pacific (TWP). The POP modes explain 7.72% and 7.66% of the variance, respectively. These two principal ISO patterns are closely linked to the low frequency rainfall and heavy precipitation process over LYRV, in which the probability for the heavy precipitation process over LYRV is 54.9% and 60.4% for the positive phase of the imaginary part of POP1 and real part of POP2, respectively. Furthermore, the models of the global atmospheric circulation for the 20―30-day oscillation in association with or without the heavy pre-cipitation process over LYRV during the Northern Hemisphere summer are set up by means of the composite analysis method. Most of the heavy precipitation processes over LYRV appear in Phase 4 of SCGT or Phase 6 of TWP. When the positive phases of 20―30-day oscillations for the rainfall over LYRV are associated with (without) the heavy precipitation process, a strong westerly stream appears (disappears) from the Arabian Sea via India and Bay of Bengal (BOB) to southern China and LYRV for the global 850 hPa filtered wind field during Phase 4 of SCGT. This situation is favorable (unfavorable) for the forming of the heavy precipitation process over LYRV. Similarly, a strong (weak) western wind belt forms from India through BOB to southern China and LYRV and the subtropical northwestern Pacific and central and eastern equatorial Pacific during Phase 6 of TWP for the cases with (without) the heavy precipitation process. The evolutions of these ISO patterns related to the 20―30-day oscillation are excited by either the interaction of extratropical circulation in both hemispheres or the heat source forcing in Asia monsoon domain and internal interaction of circulation in East Asia. These two global circulation models might therefore provide valuable information for the extended-range forecast of the heavy precipitation process over LYRV during the 10―30 days.

Extended-Range Forecasts of the Principal 20-30-Day Oscillation of the Circulation over East Asia During the Summer of 2002

Daily 850-hPa meridional wind fields in East Asia from March to September 2002 were used to establish a model of the principal oscillation pattern （POP）. This model was then used to conduct independent extended-range forecasts of the principal temporal and spatial variations in the low-frequency meridional wind field on a time scale of 20-30 days. These variations affect the occurrence of heavy precipitation events in the lower reaches of the Yangtze River valley （LYRV）. The results of 135 forecast experiments during the summer half year show that the predicted and observed anomalies are strongly correlated at a lead time of 20 days （mean correlation greater than 0.50）. This strong correlation indicates that the model is capable of accurately forecasting the low-frequency variations in meridional wind that corresponded to the 3 heavy precipitation events in the LYRV during the summer of 2002. Further forecast experiments based on data from multiple years with significant 20-30-day oscillations show that these prediction modes are effective tools for forecasting the space-time evolution of the low-frequency circulation. These findings offer potential for improving the accuracy of forecasts of heavy precipitation over the LYRV at lead times of 3-4 weeks.

Head and neck cancer readmission reduction(HANCARRE)project:Reducing 30-day readmissions

Objective:Unplanned 30-day readmissions result in increased costs and decreased patient satisfaction.The objective of this study was to compare readmission rates before and after a multidisciplinary quality improvement initiative that focused on patient and staff education,use of targeted skilled nursing facilities,and appropriate use of patient observation status.Methods:This was a quality improvement study of all unplanned admissions to the Head and Neck Oncology service at a tertiary care facility during a 3-year period between October 2015 and September 2018.In October 2016,the Head and Neck Oncology service revised its discharge practices for patients undergoing extirpative and/or reconstructive surgery.These changes included enhancing patient education,increasing the use of a skilled nursing facility with directed staff education and patient handoffs by advanced practice nurses,and appropriate utilization of 23-h observation status for returning patients.The readmission rate from the pre-intervention era(October 2015 through September 2016)was compared to the readmission rate from the post-intervention era(October 2016 through September 2018).Secondary outcomes were the rates of 23-h observation within 30 days of the discharge as well as emergency room visits within 30 days of discharge.Results:In this sample of 449 patients,161(35.9%)were observed before the change-in-practice(before October 2016),and 288(64.1%)were observed following the change-in-practice(after September 2016).On univariable analysis,the risk of readmission declined by approximately 41.4%from the pre-intervention era,though this conclusion was not statistically significant(P=0.06).On multivariable analysis,patients at moderate or high risk of death were 2.31 times more likely than those at minor risk of death to readmit within 30 days(P=0.03).Similarly,those with recurrent or persistent cancer were 3.33 times more likely than those undergoing initial curative surgical management of cancer to readmit within 30 days(P=0.001).No patient characteristics were associated with a 23-h observation following discharge(allP>0.05).Conclusions were similar for emergency room visits following discharge.Conclusions:A three-part quality improvement strategy resulted in a clinically important decrease in 30-day readmissions,though the decline was not statistically significant.There were no significant changes in 23-h observation within 30 days of discharge or emergency room visits within 30 days of discharge.

30-60-day Oscillations of Convection and Circulation Associated with the Thermal State of the Western Pacific Warm Pool during Boreal Summer

This study focuses on the characteristics of the 30 60-day oscillation (MJO) associated with the interannual variability of the thermal state in the western Pacific warm pool. The composite results show that, the amplitude of MJO convection over the tropical western Pacific tends to intensify (reduce) in the WARM (COLD) case. The negative correlations between MJO convection in the WARM and in the COLD cases are examined to be significant over most of the Asian-Pacific region. The evolutions of MJO convection and lower circulation, on the one hand, exhibit larger differences between the WARM and COLD cases, but on the other hand, display a unique feature in that a well-developed MJO cyclone (anticyclone) is anchored over the Asian-Western Pacific domain at the peak enhanced (suppressed) MJO convection phase over the western Pacific warm pool, either in the WARM or in the COLD case. This unique feature of MJO shows a Gill-type response of lower circulation to the convection and is inferred to be an inherent appearance of MJO. The context in the paper suggests there may exist interactions between MJO and the interannual variability of the thermal state in the western Pacific warm pool.

The 30–60-day Intraseasonal Variability of Sea Surface Temperature in the South China Sea during May–September

This study investigates the structure and propagation of intraseasonal sea surface temperature（SST） variability in the South China Sea（SCS） on the 30-60-day timescale during boreal summer（May-September）. TRMM-based SST, GODAS oceanic reanalysis and ERA-Interim atmospheric reanalysis datasets from 1998 to 2013 are used to examine quantitatively the atmospheric thermodynamic and oceanic dynamic mechanisms responsible for its formation. Power spectra show that the 30-60-day SST variability is predominant, accounting for 60% of the variance of the 10-90-day variability over most of the SCS. Composite analyses demonstrate that the 30-60-day SST variability is characterized by the alternate occurrence of basin-wide positive and negative SST anomalies in the SCS, with positive（negative） SST anomalies accompanied by anomalous northeasterlies（southwesterlies）. The transition and expansion of SST anomalies are driven by the monsoonal trough-ridge seesaw pattern that migrates northward from the equator to the northern SCS. Quantitative diagnosis of the composite mixed-layer heat budgets shows that, within a strong 30-60-day cycle, the atmospheric thermal forcing is indeed a dominant factor, with the mixed-layer net heat flux（MNHF） contributing around 60% of the total SST tendency, while vertical entrainment contributes more than 30%. However, the entrainment-induced SST tendency is sometimes as large as the MNHF-induced component, implying that ocean processes are sometimes as important as surface fluxes in generating the30-60-day SST variability in the SCS.

Bifurcation of Nonlinear Kelvin Wave-CISK with ConditionalHeating in a Truncated Spectral Model: A PossibleMechanism of 30-60-Day Oscillation at the Equator

In this paper, the nonlinear Kelvin wave equations with 'positive-only' nonlinear (conditional) heating at the equator are reduced to a sixth-order nonlinear ordinary differential equation by using the Galerkin spectral truncated method. The stability analysis indicates that when the heating parameter increases, the supercritical pitchfork and Hopf bifurcations can occur for the prescribed three heating profiles. Numerical calculations are made with the help of the fourth-order Rung-Kutta method. It is found that the convection heating-related Hopf bifurcation can lead to limit cycle and chaotic solutions. In a wide range of heating parameter, the solutions possess 30-60-day periods, and are dominated by wavenumbers one and two, especially by wavenumber-one. In addition, the zonal winds of the low-frequency solutions have a phase reversal between the upper and lower tropospheres. Thus, it appears that the convection heating-related Hopf bifurcation might be a possible mechanism of 30-60-day oscillation in the tropical atmosphere.

The Anzhen Risk Scoring System for Acute Type A Aortic Dissection:A Prospective Observational Study Protocol

Introduction:Acute type A aortic dissection(ATAAD)is a catastrophic disease with fatal outcomes.Malperfusion syndrome(MPS)is a serious complication of ATAAD,with an incidence of 20–40%.Many studies have shown that MPS is the main risk factor for poor ATAAD prognosis.However,a risk scoring system for ATAAD based on MPS is lacking.Here,we designed a risk scoring system for ATAAD to assess mortality through quantitative assessment of relevant organ malperfusion and subsequently develop rational treatment strategies.Methods and analysis:This was a prospective observational study.Patients’perioperative clinical data were col-lected to establish a database of ATAAD(N≥3000)and determine whether these patients had malperfusion complica-tions.The Anzhen risk scoring system was established on the basis of organ malperfusion by using a random forest survival model and a logistics model.The better method was then chosen to establish a revised risk scoring system.Ethics and dissemination:This study received ethical approval from the Ethics Committees of Beijing Anzhen Hospital,Capital Medical University(KS2019034-1).Patient consent was waived because biological samples were not collected,and no patient rights were violated.Findings will be disseminated at scientific conferences and in peer-reviewed publications.

Exploratory COVID-19 death risk score based on basic laboratory tests and physiological clinical measurements

BACKGROUND:In the event of a sudden shortage of medical resources,a rapid,simple,and accurate prediction model is essential for the 30-day mortality rate of patients with COVID-19.METHODS:This retrospective study compared the characteristics of the survivals and non-survivals of 278 patients with COVID-19.Logistic regression analysis was performed to obtain the“COVID-19 death risk score”(CDRS)model.Using the area under the receiver operating characteristic(AUROC)curve and Hosmer-Lemeshow goodness-of-fit test,discrimination and calibration were assessed.Internal validation was conducted using a regular bootstrap method.RESULTS:A total of 63(22.66%)of 278 included patients died.The logistic regression analysis revealed that high-sensitivity C-reactive protein(hsCRP;odds ratio[OR]=1.018),D-dimer(OR=1.101),and respiratory rate(RR;OR=1.185)were independently associated with 30-day mortality.CDRS was calculated as follows:CDRS=−10.245+(0.022×hsCRP)+(0.172×D-dimer)+(0.203×RR).CDRS had the same predictive effect as the sequential organ failure assessment(SOFA)and“confusion,uremia,respiratory rate,blood pressure,and age over 65 years”(CURB-65)scores,with AUROCs of 0.984 for CDRS,0.975 for SOFA,and 0.971 for CURB-65,respectively.And CDRS showed good calibration.The AUROC through internal validations was 0.980(95%confidence interval[CI]:0.965-0.995).Regarding the clinical value,the decision curve analysis of CDRS showed a net value similar to that of CURB-65 in this cohort.CONCLUSION:CDRS is a novel,efficient and accurate prediction model for the early identification of COVID-19 patients with poor outcomes.Although it is not as advanced as the other models,CDRS had a similar performance to that of SOFA and CURB-65.

Effects of Intraseasonal Oscillation on the Anomalous East Asian Summer Monsoon During 1999

The 1999 East Asian summer monsoon was very unusual for its weak northward advance and remarkably anomalous climate conditions. The monsoonal southwesterly airflow and related rain belt in East Asia were blocked south of the Yangtze River Valley. The monsoonal airflow and major moisture transport conduct shifted eastward and turned northward to Japan from the tropical western Pacific rather than to East China from the South China Sea （SCS） as in normal years. Severe and prolonged drought occurred over extensive areas of North China and heavy precipitation in South China and Japan. The investigation on the possible intrinsic mechanisms related to such an anomalous monsoon year has shown that the unique behavior of intraseasonal oscillation may play an essential role during this process. During this year, the northward propagation of 30-60-day anomalous low-level cyclone/anticyclone collapsed in the region around 20°N and did not extend beyond the latitudes of the Yangtze River basin due to the barrier of strong cold air intrusion from the mid-latitudes. The southwesterly moisture flux on the northwestern flank of the anticyclonic moisture transport system in the western North Pacific, which was regulated by the northward shift of 30-60-day cyclonic/anticyclonic moisture transport, also did not reach the region north of 30°N as well. Under this circumstance, the weak northward advance of the monsoon westerlies and associated northward moisture transport could not arrive in North China and led to the severe droughts there in 1999. The SCS and South China were mostly affected by the airflow in the southern and northern flanks of the same 30-60-day cyclones or anticyclones, respectively, and thus controlled by the nearly reverse zonal wind and moisture convergent/divergent conditions. The rainfall in the SCS and South China showed out-of-phase oscillation through the transient local Hadley circulation, with the rainfall maximum occurring in the SCS （South China） when the 30-60-day anticyclone （cyclone） reached its peak phase.

Nonlinear Three-Wave Interaction among Barotropic Rossby Waves in a Large-scale Forced Barotropic Flow

In this paper. the coupling equations describing nonlinear three-wave interaction amongRossby waves including the forcing of an external vorticity source are obtained. Under certainconditions, the coupling equations with a constant amplitude forcing, the stability analysis indicates that when the amplitude of the external forcing increases to a certain extent, a pitchforkbifurcation occurs. Also. it is shown fi-o m numerical results that the bifurcation can lead to chaoticbehavior of' strange' attractor. For the obtained three-variable equation, when the amplitude ofmodulated external forcing gradually increases, a Period-doubling bifurcation is found to lead tochaotic behavior. Thus, in a nonlinear three-wave coupling model in the large-scale forcedbarotropic atmospheric flow, chaotic behavior can be observed. This chaotic behavior can explainin part 30-60-day low-flequency oscillations observed in mid-high latitudes.

ZONALLY SYMMETRICAL EKMAN-CISK MECHANISM AND 30—60-DAY LOW FREQUENCY OSCILLATION NEAR THE EQUATOR

Based on the baroclinic semi-geostrophic model,the effects of zonally symmetrical Ekman- CISK mechanism on the characteristics of 30—60-day low frequency oscillation(LFO)near the equator are investigated.It is found that the theoretical results are in good agreement with the observational features of LFO.Besides,the planetary-scale LFO with the period of 30—60 d could be triggered by the Ekman-CISK mechanism,and the growth rate of perturbation with wave number 1 is in order of O (10^(-6)s^(-1)).The zonal propagation of LFO and the corresponding longitudinal-height structure of physical quantities are also discussed in detail.

COMPARISON STUDY ON THE INTRASEASONAL VARIATIONS IN CIRCULATIONS AND PRECIPITATION MODULATED BY THE TROPICAL CYCLOGENESIS OVER SOUTH CHINA SEA-WESTERN PACIFIC DURING GUANGDONG FLOODING PERIOD

Based on tropical cyclone datasets from Shanghai Typhoon Institute of China Meteorological Administration,the National Centers for Environmental Prediction (NCEP,USA) reanalysis data and the rainfall records from 743 stations in China,the impacts of cyclogenesis number over the South China Sea and the western Pacific are studied on the 30-60-day oscillations in the precipitation of Guangdong during the flooding period.The year with more-than-normal (less-than-normal) tropical cyclogenesis is defined as a 'high year' ('low year').In light of the irregular periodic oscillations,the method used to construct the composite life cycle is based on nine consecutive phases in each of the cycles.Phases 1,3,5,and 7 correspond to,respectively,the time when precipitation anomalies reach theminimum,a positive transition (negative-turning-to-positive) phase,the maximum,and a negative transition phase.The results showed that the precipitation of the 30-60-day oscillations is associated with the interaction between a well-organized eastward propagation system from the Arabian Sea/Bay of Bengal and a westward-propagating system (with cyclonic and anticyclonic anomalies in the northwest-southeast direction) from the South China Sea to western Pacific during the high years,whereas the precipitation is affected during a low year by the circulation over the South China Sea and western Pacific (with cyclonic and anticyclonic anomalies in the northeast-southwest direction).During the high year,the warm and wet air mass from the ocean to the west and south are transported to Guangdong by westerly anomalies and an enclosed latitudinal cell,which ascends in the Northern Hemisphere low latitudes and descends in the Southern Hemisphere low latitudes.During the low year,the warm and wet air mass from the ocean to the south is transported to Guangdong by southwesterly wind anomalies and local ascending movements.Because the kinetic energy,westerly,easterly shift,vertical velocity and vapor transportation averaged over (109-119° E,10-20° N) is stronger in high years than those in low years,the precipitation of the 30-60-day oscillations in Guangdong is higher in high years than that in low years.

Impact of Multi-Scale Oscillations at High and Low Latitudes on Two Persistent Heavy Rainfall Events in the Middle and Lower Reaches of the Yangtze River

To investigate the multi-scale features in two persistent heavy rainfall （PHR） events in the middle and lower reaches of the Yangtze River （MLRYR） in June of 1982 and 1998, this study examines the impact of multi-scale oscillations in the north and south of 30°N on the PHR events by performing sensitivity experiments with the Weather Research and Forecast （WRF） model. It is found that the 60-day low- pass perturbation made a trivial contribution to the MLRYR precipitation during the PHR event in 1982. This PHR event resulted mainly from the combined effects of 30-60-day oscillation at low latitudes and 10-30-day oscillation at both high and low latitudes. The southwesterly anomalies associated with the 30- 60-day anticyclonic anomaly over the northwestern Pacific facilitated moisture transport from the ocean to the MLRYR and enhanced the low-level convergence and ascending motion in the MLRYR. This similarly occurred in the 10-30-day oscillation as well. Moreover, the 10 30-day anomalies at high latitudes played a role in strengthening the large-scale low-level convergence over the MLRYR. The PHR event in 1998 was mainly related to the 60-day oscillation at both high and low latitudes and 30-60-day oscillation at low latitudes. The 60-day low-pass filtered anomalous cyclone at high latitudes in the north of 30°N contributed to the development of low-level convergence and ascending motion in northern MLRYR while the anomalous anticyclone at low latitudes in the south of 30°N not only increased the moisture in the MLRYR but also preconditioned the dynamical factors favorable for PHR over the whole area. The 30-60-day perturbations located north and south of 30°N worked together producing positive moisture anomaly in the MLRYR. In addition, the anomalous circulation in the south of 30°N tended to favor the development of ascending motion and low-level convergence in the MLRYR.

Comparison of the Multi-Scale Features in Two Persistent Heavy Rainfall Events in the Middle and Lower Reaches of Yangtze River

Two persistent heavy rainfall（PHR） events in the middle and lower reaches of Yangtze River（MLYR）occurring in June 1982 and 1998 are studied in this paper.Though both events happened in the Meiyu season,their large-scale background and developing processes were quite different.During the PHR event in 1982,the Lake Baikal area was occupied by a strong westerly trough and the western Pacific subtropical high（WPSH） was stronger and more westward-extending than the normal years.Under such a condition,the cold dry air and warm moist air were continuously transported to the MLYR and favored the PHR there.For the event in 1998,the WPSH was similar to that in 1982,while the westerly trough in the Lake Baikal area was comparatively weak and a shortwave trough situating in East China contributed to advect cold dry air to the MLYR.It is found that the high-latitude trough was closely related to the 1030-day low-frequency oscillation while the anomaly of WPSH was linked with the combined effect of both30 60- and 10 30-day low-frequency oscillations in the PHR event in 1982.By contrast,the 60-day low-pass perturbation demonstrated positive impact on the westward extension of WPSH and development of the Baikal trough while the 30 60-day oscillation played a role in strengthening the shortwave trough in East China and the WPSH in the case of 1998.Though the low-latitude 30 60-day oscillations contributed to the intensification and westward extension of the WPSH in both PHR events,their evolution exhibited evident differences.In the 1982 case,the 30 60-day anomalies originated from the western Indian Ocean were much more like the Madden Julian Oscillation,while its counterpart in the 1998 case was much more similar to the first mode of the boreal summer intraseasonal oscillation.

A Study of the Characteristics of the Low-Frequency Circulation over the Tibetan Plateau and its Association with Precipitation in the Yangtze River Valley in 1998

The propagation characteristics of the atmospheric low frequency （LF, 30-60 days） oscillation （LFO） around the Tibetan Plateau from troposphere to stratosphere and its relationship with the floods over the mid-lower reaches of the Yangtze River in the summer of 1998 are studied, based on the GAME dataset from Meteorological Research Institute （MRI）/Japan Meteorological Agency, the TRMM satellite rainfall and the 730-station precipitation over China. The results show that the zonal propagation direction of LFOs in horizontal winds varies with seasons in the troposphere during May to August in 1998. The eastward propagation of LFOs is remarkable before the start of the rainy season in the Tibetan Plateau and the eastern Asian continent, while the westward propagation is significant after the start date. The northward LFOs from the south side of the plateau and the southward LFOs from the north are both significant before and after the start date. The plateau is a LFO sink in the meridional and zonal directions, but the west part of it is an intensifying area for the continual westward LFOs only after the start of the rainy season. Besides, the strongest LFOs occur at the tropopause （100 hPa） and rapidly decay after entering the stratosphere. The rainfall over the mid-low reaches of Yangtze River in the summer of 1998 exhibits two LFO cycles. According to the phases of the two rainfall LFO cycles, the composite analyses of precipitation distribution, LF circulations at 500 and 100 hPa, and LF vertical motion along 30°N are performed. It is the joint effect of the mid-upper tropospheric strong 30-60-day filtered cyclone （anticyclone） over the eastern plateau and the LFO anticyclone （cyclone） over the west subtropical Pacific that induces the whole layer LF descending （ascending） motion over the mid-lower reaches of Yangtze River, which provides the favorable condition for the break （maintenance） of precipitation.