Development and validation of a predictive model for patients with post-extubation dysphagia

BACKGROUND:Swallowing disorder is a common clinical symptom that can lead to a series of complications,including aspiration,aspiration pneumonia,and malnutrition.This study aimed to investigate risk factors of post-extubation dysphagia(PED)in intensive care unit(ICU)patients with endotracheal intubation,and to develop a risk-predictive model for PED,which could serve as an assessment tool for the prevention and control of PED.METHODS:Patients retrospectively selected from June to December 2021 in a tertiary hospital served as the derivation cohort.Patients recruited from the same hospital from March to June 2022served as the external validation cohort for the predictive model.We used a combination of variable screening and least absolute shrinkage and selection operator(LASSO)regression to select the most useful candidate predictors and checked the multicollinearity of independent variables using the variance inflation factor method.Multivariate logistic regression analysis was performed to calculate the odds ratio(OR;95%confidence interval[95%CI])and P-value for each variable to predict diagnosis.The screened risk factors were introduced into R software to build a nomogram model.The performance of the model,including discrimination ability,calibration,and clinical benefit,was evaluated by plotting the receiver operating characteristic(ROC),calibration,and decision curves.RESULTS:A total of 305 patients were included in this study.Among them,235 patients(53PED vs.182 non-PED)were enrolled in the derivation cohort,while 70 patients(17 PED vs.53 nonPED)were enrolled in the validation cohort.The independent predictors included age,pause of sedatives,level of consciousness,activities of daily living(ADL)score,nasogastric tube,sore throat,and voice disorder.These predictors were used to establish the predictive nomogram model.The model demonstrated good discriminative ability,and the area under the ROC curve(AUC)was 0.945(95%CI 0.904-0.970).Applying the predictive model to the validation cohort demonstrated good discrimination with an AUC of 0.907(95%CI 0.831-0.983)and good calibration.The decision-curve analysis of this nomogram showed a net benefit of the model.CONCLUSION:A predictive model that incorporates age,pause of sedatives,level of consciousness,ADL score,nasogastric tube,sore throat,and voice disorder may have the potential to predict PED in ICU patients.

Study on crab-cavity-based longitudinal injection scheme and prototype realization of C-band crab cavity for electron storage rings

A diffraction-limited storage ring with a multi-bend achromat lattice suffers from a small dynamic aperture for conventional off-axis injection.Thus,a longitudinal on-axis injection scheme based on a new type of crab cavity is proposed in this paper.Particle tracking simulations were performed to study the disturbance of the stored beam and the motion of the injected beam during the injection process.The possibility of multi-bunch injections was discussed.In addition,the effect of the long-range wake field induced by the stored beam was analyzed.A C-band standing-wave crab cavity was designed and produced as requested,and its field distribution was measured.The corresponding results are consistent with the simulation results.

A new imaging mode based on X-ray CT as prior image and sparsely sampled projections for rapid clinical proton CT

Proton computed tomography(CT)has a distinct practical significance in clinical applications.It eliminates 3–5%errors caused by the transformation of Hounsfield unit(HU)to relative stopping power(RSP)values when using X-ray CT for positioning and treatment planning systems(TPSs).Following the development of FLASH proton therapy,there are increased requirements for accurate and rapid positioning in TPSs.Thus,a new rapid proton CT imaging mode is proposed based on sparsely sampled projections.The proton beam was boosted to 350 MeV by a compact proton linear accelerator(LINAC).In this study,the comparisons of the proton scattering with the energy of 350 MeV and 230 MeV are conducted based on GEANT4 simulations.As the sparsely sampled information associated with beam acquisitions at 12 angles is not enough for reconstruction,X-ray CT is used as a prior image.The RSP map generated by converting the X-ray CT was constructed based on Monte Carlo simulations.Considering the estimation of the most likely path(MLP),the prior image-constrained compressed sensing(PICCS)algorithm is used to reconstruct images from two different phantoms using sparse proton projections of 350 MeV parallel proton beam.The results show that it is feasible to realize the proton image reconstruction with the rapid proton CT imaging proposed in this paper.It can produce RSP maps with much higher accuracy for TPSs and fast positioning to achieve ultra-fast imaging for real-time image-guided radiotherapy(IGRT)in clinical proton therapy applications.

羟考酮与舒芬太尼用于腹腔镜胆囊切除术麻醉诱导的效果比较

目的比较盐酸羟考酮与枸橼酸舒芬太尼用于腹腔镜胆囊切除术(LC)麻醉诱导的麻醉及镇痛效果。方法择期LC术患者60例,美国麻醉医师协会分级(ASA)Ⅰ或Ⅱ级,采用随机数字表法分为两组:羟考酮组(O组)及舒芬太尼组(S组)。麻醉诱导:O组:静脉注射丙泊酚1.0~2.0 mg/kg、羟考酮0.3 mg/kg、维库溴铵0.1 mg/kg;S组:静脉注射丙泊酚1.0~2.0 mg/kg、舒芬太尼0.3μg/kg、维库溴铵0.1 mg/kg。麻醉维持采用常用的静吸复合药物。记录入手术室后(T0)、麻醉诱导后置入喉罩前(T1)、麻醉诱导置入喉罩后1 min(T2)、建立人工气腹后(T3)、分离胆囊时(T4)、苏醒即刻(T5)和离开复苏室即刻(T6)时的心率(HR)、收缩压(SBP)、舒张压(DBP),记录苏醒即刻(T5)、离开复苏室即刻(T6)、术后4 h(T7)、术后8 h(T8)和术后第1天(T9)的疼痛数字等级评分(NRS),记录苏醒时间及术毕患者复苏过程中追加止痛药例数,观察术后患者不良反应情况。结果两组患者术中平均HR、SBP及DBP波动不超过基础值的20.0%。两组患者术毕苏醒时间无明显差异。S组苏醒后补救镇痛的比率为36.7%,较O组更多(P=0.040)。O组较S组在T5、T7、T8和T9等时间点疼痛NRS评分更低,但是差异无统计学意义。两组患者不良反应情况比较无明显差异。结论 0.3 mg/kg羟考酮与舒芬太尼0.3μg/kg用于LC手术麻醉诱导,患者麻醉及镇痛效果良好,能满足临床麻醉及术后镇痛需求。0.3 mg/kg的羟考酮有与0.3μg/kg的舒芬太尼相当或更好的镇痛作用。

Pulmonary embolism with acute pancreatitis:A case report and literature review

Acute pancreatitis is an inflammatory disease characterized by local tissue injury which can trigger a systemic inflammatory response.So vascular complications of pancreatitis are a major cause of morbidity and mortality.Pulmonary embolism in acute pancreatitis has been reported to be very rare.We reported a case of pulmonary embolism with acute pancreatitis.A 38-year-old woman broke out upper abdomen pain without definite inducement.She had no nausea and vomiting,fever,dyspnea,cough and expectoration,chest pain.The patient had been diagnosed with acute pancreatitis in local hospital.The patient was treated with antibiotics and proton pump inhibitors,and the abdomen pain was alleviated slightly.But the patient came forth cough and expectoration with a little blood,progressive dyspnea.A computed tomographic scan of the abdomen re-vealed pancreatitis.Subsequent computer tomography angiography of chest revealed pulmonary embolism(both down pulmonary arteries,left pulmonary artery and branch of right pulmonary artery).Dyspnea of the patient got well with thrombolytic treatment and anticoagulation therapy.Pulmonary embolism is a rare but potentially lethal complication of pancreatitis.Familiarity with this complication will aid in its early diagnosis,therapy and prevent pulmonary embolism,a rare but catastrophic phenomenon.

Proton linac-based therapy facility for ultra-high dose rate (FLASH) treatment

As an advanced treatment method in the past five years,ultra-high dose rate(FLASH)radiotherapy as a breakthrough and milestone in radiotherapy development has been verified to be much less harmful to healthy tissues in different experiments.FLASH treatments require an instantaneous dose rate as high as hundreds of grays per second to complete the treatment in less than 100 ms.Current proton therapy facilities with the spread-out of the Bragg peak formed by different energy layers,to our knowledge,cannot easily achieve an adequate dose rate for FLASH treatments because the energy layer switch or gantry rotation of current facilities requires a few seconds,which is relatively long.A new design for a therapy facility based on a proton linear accelerator(linac)for FLASH treatment is proposed herein.It is designed under two criteria:no mechanical motion and no magnetic field variation.The new therapy facility can achieve an ultrahigh dose rate of up to 300 Gy/s;however,it delivers an instantaneous dose of 30 Gy within 100 ms to complete a typical FLASH treatment.The design includes a compact proton linac with permanent magnets,a fast beam kicker in both azimuth and elevation angles,a fixed gantry with a static superconducting coil to steer proton bunches with all energy,a fast beam scanner using radio-frequency(RF)deflectors,and a fast low-level RF system.All relevant principles and conceptual proposals are presented herein.

Design,fabrication,and cold test of an S-band high-gradient accelerating structure for compact proton therapy facility

An S-band high-gradient accelerating structure is designed for a proton therapy linear accelerator(linac)to accommodate the new development of compact,singleroom facilities and ultra-high dose rate(FLASH)radiotherapy.To optimize the design,an efficient optimization scheme is applied to improve the simulation efficiency.An S-band accelerating structure with 2856 MHz is designed with a low beta of 0.38,which is a difficult structure to achieve for a linac accelerating proton particles from 70 to 250 MeV,as a high gradient up to 50 MV/m is required.A special design involving a dual-feed coupler eliminates the dipole field effect.This paper presents all the details pertaining to the design,fabrication,and cold test results of the S-band high-gradient accelerating structure.

Blood eosinophils and mortality in patients with acute respiratory distress syndrome: A propensity score matching analysis

BACKGROUND: The effect of blood eosinophils(EOSs) on mortality in acute respiratory distress syndrome(ARDS) patients and whether corticosteroids affect this effect are unclear.METHODS: The Medical Information Mart for Intensive Care III database(version 1.4) was used to extract data. Patients with ARDS were selected for inclusion. Cox regression models using the backward stepwise method and propensity score matching(PSM) were used to assess the relationship between blood EOS counts and 28-day mortality. RESULTS: A total of 2,567 patients with ARDS were included, and the 28-day mortality rate was 24.19%. The crude 28-day mortality was significantly lower in patients with EOS counts ≥2%(18.60% [85/457] vs. 25.40% [536/2,110], P=0.002) than in those with EOS counts <2%. In the Cox regression model, the EOS counts ≥2% showed a significant association with the decreased 28-day mortality(hazard ratio [HR] 0.731;95% confidence interval [95% CI] 0.581–0.921, P=0.008). In the corticosteroid non-use subgroup, EOS counts ≥2% was significantly related to decreased 28-day mortality(HR 0.697, 95% CI 0.535–0.909, P=0.008), but the result was not significant in the corticosteroid non-use subgroup model(P=0.860). A total of 457 well-matched pairs were obtained by a 1:1 matching algorithm after PSM. The 28-day mortality remained significantly lower in the EOS counts ≥2% group(18.60% [85/457] vs. 26.70% [122/457], P=0.003).CONCLUSIONS Higher EOS counts are related to lower 28-day mortality in ARDS patients, and this relationship can be counteracted by using corticosteroids.

Radio frequency conditioning of an S-band accelerating structure prototype for compact proton therapy facility

The development of a high-gradient accelerating structure is underway to construct a compact proton linear accelerator for cancer treatment.Extensive experiments and numerous studies are being conducted to develop compact linear accelerators for proton therapy.Optimization of the electromagnetic and mechanical design has been performed to simplify the manufacturing process and reduce costs.A novel high-gradient structure with a low relativistic proton velocity(β),v/c=0.38,was designed,fabricated,and tested at high power.The first full-scale prototype was also successfully tested with high radio frequency(RF)power,a repetition rate of 50 Hz,and pulse length of 3μs to reach a high-gradient of 46 MV/m using a 50 MW S-band klystron power supply obtained from the Shanghai Soft X-ray Free Electron Laser Facility.This is the first high-power test in China,which is in line with the expected experimental goal.This study presents preliminary high-power testing of S-band standing wave accelerating structures with 11 cells.This work aims to verify the feasibility of using a high-gradient RF accelerating structure in compact proton therapy facilities.The cold test of the prototype cavity was completed in advance.Details of the high-power RF test setup,the process of RF conditioning,and the high-power results are described.

Design optimization and cold RF test of a 2.6-cell cryogenic RF gun

To further improve the performance of acceler-ators,the first cryogenic normal-conducting RF gun in China was designed and manufactured.As a new and attractive trend,this optimized cryogenic RF gun can generate a low-emittance beam with a short-driven laser pulse because of its promising high gradient on the cath-ode.In this paper,optimization of the RF design and beam dynamics,including suppression of the peak RF field and elimination of the multipole mode,is presented.In addi-tion,the emittance growth caused by the alignment devi-ation and RF jitter is discussed.After the gun was manufactured,a cold test was conducted at both room temperature and cryogenic conditions.At room tempera-ture,the field distribution was obtained by the bead pull method.Under cryogenic conditions,the RF properties,such as the coupling coefficient and quality factor,varied with temperature.The test results agreed with the design.In the cryogenic test,vibration measurements were performed.Without vibration isolation,a maximum vibration of 50 lm was observed.These cold test results are the basis of the following high-power test.

Effectiveness of Hemorrhagic Fever with Renal Syndrome Bivalent Vaccine in China:A Metaanalysis

Objective To evaluate the effectiveness of Hemorrhagic Fever with Renal Syndrome(HFRS) bivalent vaccine in field.Methods The articles on effectiveness of HFRS bivalent vaccine were retrieved from Vip Database,China Journal Full-text Database,Wanfang database,China Hospital Knowledge Database,Chinese Biomedical Literature Database,MEDLINE and ProQuest.Two persons extracted data and evaluated the quality of data together for meta-analysis.Results Seven articles were included into the analysis,and two articles were random clinical trials,five were quasi-trials.Meta-analysis showed that the overall effectiveness of HFRS bivalent vaccine was 85%(95%confidence interval:53%-95%) within one year after vaccination,and the effectiveness in two-dose recipients and three-dose recipients was 87%(95%confidence interval:54%-96%) and 60%,respectively;it was 96%(95%confidence interval:78%-99%) within 2-5 years after vaccination,and the effectiveness in two-dose recipients and three-dose recipients was 95%(95%confidence interval:19%-100%) and 96%(95%confidence interval:70%-99%),respectively;it was 100%(only one article included) within 6-9.6 years after vaccination.The effectiveness in two-dose recipients was 88%(95%confidence interval:62%-96%) during 1-2.5 years after vaccination,and that in three-dose recipients was 94%(95%confidence interval:70%-99%) during 1-5 years after vaccination.Conclusions HFRS bivalent vaccine is effective in field,and there is no difference between two-dose recipients and three-dose recipients.We should do some further studies on the long-term effectiveness of HFRS bivalent vaccine and on the age of vaccine reception.

川西高寒草甸植物功能属性与环境因子的关系研究

作为连接植物和环境的桥梁,植物功能属性反映了植物对环境的适应以及植物内部不同功能之间的关系。本研究基于群落、植物功能属性和生境调查结果,分析了川西高寒草甸植物功能属性与环境因子的关系。研究发现:高寒草甸植物的功能属性之间主要呈现协调关系,特别是在能量、物质和生物量分配等方面。此外,根冠比(RSR)与茎比例(SMF)、繁殖器官比例(RPMF)之间存在明显的权衡关系。当面临胁迫和干扰时,高寒草甸植物可能采取将更多资源投入根部生长和发育,较少资源分配给茎和繁殖器官,但同时保证分配给叶片进行光合作用资源的策略。高寒草甸植物以矮化、减少茎、叶和繁殖器官比例(SMF、LMF和RPMF)、降低比根长(SRL),增加叶片干物质含量(LDMC)和比叶面积(SLA)、提高根冠比(RSR)、增加地下生物量(IUGB)和根干物质含量(RDMC)等一系列策略适应低温、强辐射和水分不足等环境胁迫。人为干扰会导致高寒草甸植物的高度(VH)、茎比例(SMF)、茎干物质含量(SDMC)、繁殖器官比例(RPMF)、繁殖器官干物质含量(RPDMC)、叶比例(LMF)、比根长(SRL)和地上生物量(IAGB)减小,而根冠比(RSR)增加。然而,高寒草甸植物功能属性的变化主要受环境因素影响,受人为干扰的影响相对较小。这些研究结果为理解植物如何通过调整功能属性来适应环境变化,以及制定有效的草甸保护和管理策略提供了重要的科学依据。