Novel predictors of permanent pacemaker implantation following transcatheter aortic valve replacement

BACKGROUND Conduction and rhythm abnormalities requiring permanent pacemakers(PPM)are short-term complications following transcatheter aortic valve replacement(TAVR),and their clinical outcomes remain conflicting.Potential novel predictors of post-TAVR PPM,like QRS duration,QTc prolongation,and supraventricular arrhythmias,have been poorly studied.AIM To evaluate the effects of baseline nonspecific interventricular conduction delay and supraventricular arrhythmia on post-TAVR PPM requirement and determine the impact of PPM implantation on clinical outcomes.METHODS RESULTS Out of the 357 patients that met inclusion criteria,the mean age was 80 years,188(52.7%)were male,and 57(16%)had a PPM implantation.Baseline demographics,valve type,and cardiovascular risk factors were similar except for type II diabetes mellitus(DM),which was more prevalent in the PPM cohort(59.6%vs 40.7%;P=0.009).The PPM cohort had a significantly higher rate of pre-procedure right bundle branch block,prolonged QRS>120 ms,prolonged QTc>470 ms,and supraventricular arrhythmias.There was a consistently significant increase in the odds ratio(OR)of PPM implantation for every 20 ms increase in the QRS duration above 100 ms:QRS 101-120[OR:2.44;confidence intervals(CI):1.14-5.25;P=0.022],QRS 121-140(OR:3.25;CI:1.32-7.98;P=0.010),QRS 141-160(OR:6.98;CI:3.10-15.61;P<0.001).After model adjustment for baseline risk factors,the OR remained significant for type II DM(aOR:2.16;CI:1.18-3.94;P=0.012),QRS>120(aOR:2.18;CI:1.02-4.66;P=0.045)and marginally significant for supraventricular arrhythmias(aOR:1.82;CI:0.97-3.42;P=0.062).The PPM cohort had a higher adjusted OR of heart failure(HF)hospitalization(aOR:2.2;CI:1.1-4.3;P=0.022)and nonfatal myocardial infarction(MI)(aOR:3.9;CI:1.1-14;P=0.031)without any difference in mortality(aOR:1.1;CI:0.5-2.7;P=0.796)at one year.CONCLUSION Pre-TAVR type II DM and QRS duration>120,regardless of the presence of bundle branch blocks,are predictors of post-TAVR PPM.At 1-year post-TAVR,patients with PPM have higher odds of HF hospitalization and MI.

Effects of Budesonide Aerosol Inhalation on Perioperative Lung Function in Patients Undergoing Cardiopulmonary Bypass Valve Replacement

[Objectives]To explore the effects of budesonide aerosol inhalation on the perioperative pulmonary function of patients undergoing cardiopulmonary bypass valve replacement.[Methods]A total of 82 patients who underwent cardiopulmonary bypass valve replacement during January 2018 and May 2019 in the Affiliated Hospital of Chengde Medical College were selected.They were divided into blank control group(group A,n=28),aerosol control group(group B,n=27,normal saline aerosol treatment),and experimental group(group C,n=27,budesonide aerosol treatment)by the random number table method.Corresponding treatments were given 5 d before surgery and 5 d after surgery,and the treatment effects of the 3 groups were compared.[Results]The clinical symptom scores of the patients in the experimental group were significantly lower than those in the blank control group and the aerosol control group,and the total effective rate of treatment was significantly higher than that in the blank control group.[Conclusions]Perioperative application of budesonide aerosol inhalation can effectively improve the clinical symptoms,treatment effect,and clinical prognosis of patients undergoing cardiopulmonary bypass valve replacement.

Effect of thyroid hormone on myocardial and cerebral ischemia reperfusion injury in valve replacement under cardiopulmonary bypass

Objective:To study the effect of thyroid hormone (euthyrox) on myocardial and cerebral ischemia reperfusion injury in valve replacement under cardiopulmonary bypass.Methods:A total of 76 patients who received valve replacement under cardiopulmonary bypass in our hospital between January 2013 and December 2016 were collected and divided into control group (n=38) and observation group (n=38) according to random number table. Observation group took euthyrox orally 1 week before surgery, control group took vitamin C tablets orally at the same point in time, and both therapies lasted for 1 week. Before taking medicine and after cardiopulmonary bypass (before end of surgery), serum levels of myocardial enzyme spectrum indexes and nerve injury indexes were compared between the two groups of patients. Results: Before taking medicine, differences in the serum levels of myocardial enzyme spectrum indexes and nerve injury indexes were not statistically significant between the two groups of patients. After cardiopulmonary bypass, serum myocardial enzyme spectrum indexes cTnT, CK-MB,α-HBD and LDH levels in observation group were lower than those in control group;serum nerve injury indexes NSE, S100B and GFAP levels were lower than those in control group while bFGF level was higher than that in control group.Conclusion: Euthyrox intervention in valve replacement under cardiopulmonary bypass can effectively reduce the myocardial and cerebral ischemia reperfusion injury.

Surgical management of moderate ischemic mitral valve regurgitation: Where do we stand?

Ischemic mitral regurgitation(IMR) represents a common complication after myocardial infarction. The valve is anatomically normal and the incompetence is the result of papillary muscles displacement and annular dilatation, causing leaflets tethering. Functionally the leaflets present a restricted systolic motion due to tethering forces that displaces the coaptation surface toward the left ventricle apex. The patients present poor left ventricular function at the time of surgery and the severity of the mitral regurgitation increases the risk of mortality. Currently there is general agreement to treat surgically severe IMR nevertheless strong evidences for patient with moderate insufficiency remains poor and proper treatment debated. The most effectivesurgical approach for the treatment of IMR remains debated. Some authors demonstrated that coronary artery bypass graft(CABG) alone is beneficial in patients with IMR. Conversely, in most patients, moderate IMR will persist or worsen after CABG alone which translate in higher long-term mortality as a function of residual mitral regurgitation severity. A probable reason for this unclear surgical management of functional MR is due to the contemporary suboptimal results of reparative techniques. The standard surgical treatment of chronic IMR is CABG associated with undersized annuloplasty using complete ring. Though, the recurrence of mitral regurgitation remains high(> 30%) because of continous left ventricle remodeling. To get better long term results, in the last decade, several subvalvular procedures in adjunct to mitral anuloplasty have been developed. Among them, surgical papillary muscle relocation represents the most appreciated option capable to restore normal left ventricle geometry. In the next future new preoperative predictors of increased mitral regurgitation recurrence are certainly needed to find an individual time period of treatment in each patient with moderate IMR.

Risk profile and outcomes of aortic valve replacement in octogenarians

AIM: To investigate the patient characteristics, relationship between the Logistic EuroSCORE (LES) and the observed outcomes in octogenarians who underwent surgical aortic valve replacement (AVR). METHODS: Two hundred and seventy three octogenarians underwent AVR between 1996 and 2008 at Bristol Royal Inf irmary. Demographics, acute outcomes,length of hospital stay and mortality were obtained. The LES was calculated to characterize the predicted operative risk. Two groups were def ined: LES ≥ 15 (n = 80) and LES < 15 (n = 193). RESULTS: In patients with LES ≥ 15, 30 d mortality was 14% (95% CI: 7%-23%) compared with 4% (95% CI: 2%-8%) in the LES < 15 group (P < 0.007). Despite the increase in number of operations from 1996 to 2008, the average LES did not change. Only 5% of patients had prior bypass surgery. The LES identifi ed a low risk quartile of patients with a very low mortality (4%, n = 8, P < 0.007) at 30 d. The overall surgical results for octogenarians were excellent. The low risk group had an excellent outcome and the high risk group had a poor outcome after surgical AVR. CONCLUSION: It may be better treated with transcatheter aortic valve implantation.

Combined Surgical Treatment of Atherosclerotic Coronary Artery Disease and Moderate Aortic Valve Stenosis in Patient with Concomitant Lipton’s R-III Type of Single Coronary Artery Anomaly

A single coronary artery is a very rare condition,commonly associated with other congenital anomalies.It could be generally considered as neither benign nor malignant form of congenital coronary artery anomalies since its pathophysiological and clinical implications grossly depend on different anatomical patterns defined by the site of origin and distribution of the branches.By presenting the patient who underwent successful coronary artery bypass grafting and aortic valve replacement surgery in a presence of isolated single coronary artery,we intend to emphasize natural and procedural risks and distinguish casual from causal in this extremely rare clinical and surgical scenario.

MINIMALLY INVASIVE ACCESS FOR AORTIC VALVE OPERATION:A LIMITED SUPERIOR MEDIAN STERNOTOMY

Minimath mvasive curdiac surgerv has been developed to offer pauents the benefitsal’open heart operationas with decrreascd pain and limited skin incision A limitedsuperior median sternotomy has been shown to provide a good exposure for aorticvalve replacement(AVR:and good results In this study we report the results ofminimaly AVR compared standard sternotomy AVR performed in the same period.I rom Muv 1996 to January 1998.86 patients received isolated aortic valvereplacement by the hmited stiperior median sternotom\(group 1).As a control groupreplacement by standard sternotomy in the same period.Surgical procedure.A midline skin mcision from the first to the first to the third intercostalspace and a median stemolomy from jugular notch to the fourth intercostal space areperformed.The pericardium is incised.e\posing the ascending sorta and rightatrium Aortic and right atrial cannulation are performed as usual Cardiopulmonarybypass and cardioplegia are applied by the usual technique.After opening the aorta.three traction sutures at the tip of the commissures ate placed elevating the valvefor better exposure.After being weaned from cardiopulmonary bypass,oneretrosternal tube is placed and the sternotomy is closed with one metal band and twoMedian ischemic time and median bypass time between the two groups showed nosignificant difference(p】0.05)Median entire operation time in group I wasobviously shorter than that in group 2(p【0.01).Median postoperative dramagewas 229ml in group one.369ml in group 2.The difference between the two groups(p【0.05)was significant.Median postoperative respiratory support time was 743hours(h)in group one.11.26h in group 2.with signifieant difference(p【0.05).Median duration of hospital stay were 6.2 days(d)in group 1.94d in group 2.withsignificant difference(p【0.01).Reoperntions for bleeding were 2 in group 1.4 ingroup 2.sternum infection or disruption one in group 1 and 3 in group 2 There weretwo hospital deaths respeclively in the two group(not procedure related,The limited superior median sternotomy provides good exposure to the leftventricular outflow tract aortie valve aseending norta.and even to the mitral valvethrough the roof of the left atrium Therefore it seems to be suitable for all kinds ofaortic valve operations Besides less pain.shorter skin incision.shorter respiratorysupport time and lower blood loss.it has more advantages as opening and elosure ofthe sternum is fuster.decreasing infection and disruption of the sternum.and linallydecreasing the time required for hospitah/ation and recovery.

Experimental Observation on Antithrombotic Property of A New Bileaflet Mechanical Heart Valve in Sheep

Objective:To observe the antithrombotic property of a new all-pyrolytic carbon bileaflet mechanical heart valve so as to provide evidence for clinical practice. Methods:15 sheep underwent mitral valve replacement(MVR) with this new mechanical valve. Each animal was placed on cardiopulmonary bypass. All of the sheep were given in an anticoagulation protocol and followed for three months. Final studies were performed on all animals surviving for more than 12 weeks. Results:10 sheep died within 48 h after operation,5 sheep survived. The long-term survivors were killed for autopsies,2 sheep were killed after 1 week,1 after 12 weeks and 2 after two and half years. Pathological examination of 10 sheep which died early after operation revealed that there was neither evidence of thrombosis nor any failure of the mechanical valve. Autopsy studies in the 5 long-term survivors revealed that the sewing ring was covered by a thin layer of microthrombi consisted most of platelets and fibrin after 1 week. The sewing ring was covered by a tissue layer,with partial organized microthrombi and endothelialization after 12 weeks. Two and half years after operation,the complete endothelialization presented around the sewing ring without restriction of bileaflet motion. The tissue ingrowth tends to stop at the pyrolytic carbon-fabric interface on both surfaces of left atrium and ventricle. This study demonstrated that the new prosthetic heart valve had not promoted thrombosis and thrombembolism.

丙泊酚镇静体外循环下心脏瓣膜置换术后谵妄发生的影响因素分析

目的探讨丙泊酚镇静体外循环(CPB)下心脏瓣膜置换术后谵妄发生的影响因素。方法选择2020年1月至2022年12月于南阳市中心医院行CPB下心脏瓣膜置换术患者152例为研究对象,依据丙泊酚镇静深度将患者分为观察A组[50≤脑电双频指数(BIS)<60]和观察B组(35≤BIS<45),每组76例。收集患者的年龄、性别、体质量指数(BMI)、糖尿病、高血压、冠状动脉性心脏病、慢性阻塞性肺疾病、睡眠障碍、营养障碍、焦虑、抑郁、吸烟史、饮酒史、术前心功能不全、术中低氧血症、术中低蛋白血症、术后急性肾损伤、二次插管、大量输血、过度疼痛、术后左心室射血分数(LVEF)、手术方式、CPB时间等临床资料,采用重症监护病房(ICU)患者意识模糊评估法(CAM-ICU)评估患者术后谵妄发生情况。比较观察A组和观察B组患者术后谵妄发生情况;应用单因素和多因素logistic回归分析术后谵妄发生的影响因素。结果152例心脏瓣膜置换术患者有36例发生术后谵妄,发生率为23.68%。观察A组和观察B组患者术后谵妄发生率分别为38.16%(29/76)、9.21%(7/76),观察A组患者术后谵妄发生率显著高于观察B组(χ^(2)=17.617,P<0.05)。性别、BMI、合并糖尿病、合并高血压、合并冠状动脉性心脏病、合并认知障碍、合并睡眠障碍、合并营养障碍、合并焦虑、合并抑郁、吸烟史、饮酒史、术中低氧血症、术中低蛋白血症、术后急性肾损伤、二次插管、大量输血、手术方式与患者术后谵妄发生无关(P>0.05);年龄、慢性阻塞性肺疾病、术前心功能不全、过度疼痛、术后LVEF、CPB时间与患者术后谵妄发生相关(P<0.05)。多因素logistic回归分析显示,年龄≥60岁、术前心功能不全、过度疼痛、CPB时间≥100 min是患者术后谵妄发生的危险因素(P<0.05),术后LVEF≥50%、丙泊酚镇静深度35≤BIS<45是患者术后谵妄发生的保护因素(P<0.05)。结论丙泊酚镇静深度为35≤BIS<45、术后LVEF≥50%可有效降低患者CPB下心脏瓣膜置换术后谵妄的发生风险,年龄≥60岁、术前心功能不全、过度疼痛、CPB时间≥100 min会增加患者术后谵妄的发生风险。

经导管主动脉瓣植入术中心肺转流辅助效果分析

目的回顾本中心近些年经导管主动脉瓣植入(TAVI)和经心尖主动脉瓣置换(TAVR)术中接受心肺转流(CPB)的情况,以期为患者的救治提供经验。方法收集本中心自2019年1月至2021年12月TAVI和TAVR手术患者的资料,按结局把CPB患者分成死亡组和存活组。结果共收集348例TAVI和TAVR患者,男性占60.9%,平均年龄为(72±9)岁,总住院死亡率为13.5%。19例(5.5%)术中接受CPB辅助,其住院死亡率明显高于非CPB患者(42.1%vs.11.9%,P<0.05),术中心脏骤停并发症是主要原因;死亡组CPB建立时间明显长于生存组[(28±6)min vs.(21±3)min,P<0.01]。Logistic二元回归分析结果表明经心尖手术入路是术中接受CPB辅助的高风险因素;CPB建立时间的长短影响患者的结局。结论TAVI和TAVR中经心尖手术入路是术中接受CPB辅助的高风险因素,CPB患者具有更高的住院死亡率;完善的CPB策略可缩短CPB建立的时间从而降低住院死亡率。

心脏不停跳冠脉搭桥术同期行瓣膜置换术对冠心病合并心脏瓣膜病患者预后的影响

目的分析心脏不停跳冠脉搭桥术同期行瓣膜置换术治疗冠心病(CHD)合并心脏瓣膜病患者的效果。方法回顾性收集2021年8月至2023年8月河南省胸科医院接收的CHD合并心脏瓣膜病患者92例为研究对象,依据1∶1配对原则进行分组,其中接受心脏不停跳冠脉搭桥术同期行瓣膜置换术46例纳入不停组,接受停跳体外循环下冠脉搭桥术同期行瓣膜置换术46例纳入停跳组。对比两组手术指标、并发症状况、心功能分级状况、心脏超声指标[左室射血分数(LVEF)、左房舒张末前后径(LAEDD)、左室舒张末期内径(LVEDD)]、心肌受损指标[心肌肌钙蛋白Ⅰ(cTnⅠ)、肌酸激酶同工酶(CK-MB)]。结果不停组手术时间、住院时间、ICU入住时间短于停跳,24 h引流量少于停跳组(P<0.05)。不停组术后3个月心功能分级优于停跳组(P<0.05),LAEDD、LVEDD小于停跳组,LVEF高于停跳组(P<0.05)。术后7 d不停组血清CK-MB、cTnⅠ水平低于停跳组(P<0.05)。结论心脏不停跳冠脉搭桥术同期行瓣膜置换术治疗CHD合并心脏瓣膜病患者效果确切,可有效缩短康复进程,改善心功能,减轻心肌损伤,且安全性高。

河北省心血管外科围手术期用血现状的多中心回顾性研究

目的分析心血管外科围手术期用血现状及异体输血的影响因素,为围手术期血液管理提供参考。方法选取2019年-2020年河北省102家医院共772例主动脉瓣置换术(AVR)和冠状动脉旁路移植术(CABG)患者的临床资料,比较围手术期关键指标、不同血液成分、不同等级医院输血率和输血量的差异,并采用多元线性逐步回归模型分析围手术期异体输血的影响因素。结果2019年-2020年,河北省医院AVR患者异体输血率分别为93.3%和100.0%,CABG患者异体输血率分别为89.4%和90.2%,异体输血率普遍较高。输血概率与医院等级相关,围手术期出血量、手术时长等是影响输血总需求的主要风险因素。结论河北省各医院应建立多学科协同血液管理模式,实施患者血液管理策略,积极推进自体输血技术应用,改良手术方式;相关管理部门应开展临床用血评价与公示,促进各医院严格落实临床用血审核制度,为患者制订合理、科学的输血方案,以降低出血量和异体输血率,进而保障输血安全。

房颤射频消融术对心脏搭桥合并心脏瓣膜手术患者心功能、心肌损伤及预后的影响

目的探究房颤射频消融术(RA)对心脏搭桥合并心脏瓣膜手术患者心功能、心肌损伤及预后的影响。方法选取我院2022年2月至2023年3月接受心脏搭桥合并心脏瓣膜手术患者50例,随机数字表法将其分为观察组25例(房颤RA治疗)与对照组25例(保守药物治疗)。对比两组手术相关指标、不同时间点心肌损伤[肌酸激酶同工酶(CK-MB)、肌钙蛋白I(cTnI)、N末端脑钠肽前体(NT-proBNP)]及心功能[左心室射血分数(LVEF)、左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)]指标,术后随访3个月,统计患者窦性心律转复及心脑血管不良事件(MACCE)发生率。结果观察组体外循环时间比对照组长,总住院时间比对照组短,差异均有统计学意义(P<0.05)。两组术后血清CK-MB、cTnI、NT-proBNP水平均呈现先上升、后下降趋势(P<0.05);观察组术后2 h血清CK-MB、cTnI、NT-proBNP水平均显著高于对照组(P<0.05),但两组间术后48 h上述指标差异均无统计学意义(P>0.05)。术后3个月,观察组比对照组LVEF[(49.78±2.35)%vs.(45.03±2.17)%]显著上升,LVEDD[(54.93±4.30)mm vs.(57.38±4.16)mm]、LVESD[(39.62±4.37)mm vs.(46.15±5.23)mm]显著下降(P<0.05)。观察组术后第1天、出院时及术后3个月窦性心律转复率均显著高于对照组(P<0.05),术后3个月内MACCE两组对比差异无统计学意义(P>0.05)。结论房颤RA能有效改善心脏搭桥合并心脏瓣膜手术患者心功能,提高窦性心律转复率,短期预后好,但可能引发一过性心肌酶上升。

旁通阀结构对燃料电池系统阴极压力控制效果的分析

为减小压力波动对燃料电池寿命的不利影响,通过仿真及对比试验,探究增加旁通阀对阴极供给系统压力波动的改善效果。根据对燃料电池输出特性与各组件工作原理的分析,建立机理与控制模型;采用基于自抗扰的反向解耦方法实现流量与压力的解耦控制;运用模糊PI方法实现压力波动控制。通过Matlab/Simulink仿真验证了解耦方法在该系统结构下的控制效果,在对比试验中,压力波动峰值分别为无旁通阀1.82kPa与有旁通阀1.09kPa,旁通阀的增加减小了压力波动,使阴极流道压力的稳定性得到了更有效的控制,对提升燃料电池寿命有重要意义。

调节套筒节流孔倒角对高旁阀流场及结构的影响

为了研究高旁阀内部流场和结构可靠性受调节套筒节流孔倒角深度和角度的影响,开展了高旁阀内部流场的数值计算和单向热-流-固耦合分析.通过分析倒角前阀门内的流场得出以下结论:节流后蒸汽会形成激波和一系列激波串并消失于二级节流筒底盖板处,环形调节套筒密封面处出现应力集中现象,密封面内外较大的压差是造成密封面发生形变的主要原因.以降低调节套筒密封面形变量为目标,研究了调节套筒节流孔倒角的角度和深度对流场和密封面形变量的影响,结果表明:在研究选取的全范围内,倒角角度和深度的增加均能降低调节套筒密封面处的压差和形变量,当倒角角度为72.5°时,调节套筒两侧的形变量降幅分别为17.06%和15.72%,研究结果可为进一步优化阀门流动特性,降低阀门结构形变量提供依据.

体外循环下瓣膜置换术患者右美托咪定用量及对患者微循环和血流动力学的影响

目的:探讨体外循环(CPB)期间右美托咪定(Dex)用量对瓣膜置换术患者血流动力学的影响。方法:选取2020-06-2022-12于本院接受择期CPB瓣膜置换术患者85例作为研究对象,随机分为低剂量组(n=28)、高剂量组(n=28)和对照组(n=29),在麻醉诱导前10min分别输注0.2μg/kg·h^(-1)Dex、0.4μg/kg·h^(-1)Dex、生理盐水至术毕。比较麻醉诱导后(T1)、CPB转机开始前(T2)、CPB转机后1h(T3)、CPB转机停止时(T4)、术毕4h(T5)、术毕24h(T6)的各组血流动力学指标;分析Dex输注时长对脑电双频谱指数(BIS)的影响及术后恢复情况。结果:低剂量组和高剂量组给药12min、给药15min、插管后1min的BIS值均低于对照组(P<0.05);低剂量组T2-T4时HR、T2-T5时MAP、T2-T6时LA和cTnI、术后心血管不良事件、鼻温肛温复温时间、术后24h N端脑钠肽前体(NT-proBNP)水平低于对照组,而T2-T6时ScvO_(2)和尿量、心脏自动复跳率高于对照组(P<0.05);高剂量组T2时HR和MAP低于低剂量组,而鼻温肛温复温时间、术后24h NT-proBNP高于低剂量组(P<0.05)。结论:低剂量的Dex即可取得良好的麻醉镇静效果,维持血流动力学的相对稳定,在麻醉诱导开始前10min时输注0.2μg/kg·h^(-1)Dex可有效改善CPB下瓣膜置换术对微循环的影响,降低LA和cTnI水平、提高ScvO_(2)和尿量、缩短鼻温肛温的复温时间。

两种进口停搏液在心脏瓣膜置换术中的临床效果比较

目的本文旨在对del Nido心肌停搏液(DN)与组氨酸-色氨酸-酮戊二酸停搏液(HTK)在心脏瓣膜置换术中的临床效果进行回顾性分析,以期为其临床应用提供参考。方法回顾性分析2018年1月1日至2023年9月10日期间496例在本院心血管外科就诊的患者资料。按照排除标准剔除部分资料,并使用SPSS 22.0统计软件包对两组患者的部分特征进行倾向性评分匹配,最终纳入102例患者,其中DN组51例,HTK组51例。记录两组患者术中特征,并对比术后两组患者不同时间血清肌酸激酶同工酶(CKMB)、心肌肌钙蛋白I(cTnI)、血气分析和并发症情况。取入ICU时间点的心肌损伤标志物与主动脉阻闭时间进行相关性分析。最后将主动脉阻闭时间分为<90 min与90~120 min两组进行亚组分析。结果两组患者基本特征在倾向性匹配前与匹配后均无统计学意义。术中DN组与HTK组的停搏液+总量、K浓度、心肺转流时间与主动脉夹闭时间在倾向性匹配前后差异均具有统计学意义(P<0.05)。DN组(R=0.878,R=0.758,P<0.001)与HTK组(R=0.951,R=0.925,P<0.001)的主动脉夹闭时间与CKMB、cTnI具有一定的相关性。亚组分析显示在90~120 min内DN组与HTK组的CKMB、cTnI值差异具有统计学意义(P<0.05)。结论两种停搏液均具有较高的安全性。在主动脉阻断时间<90 min时的两组心肌保护效果无明显差异,90~120 min时DN可能具有更好的心肌保护效果。

加料泵旁通阀PID自动控制系统

作为烟丝生产工艺中的重要环节,添加香糖料可对烟丝质量起到关键性作用。为了保证生产中香糖料的流量控制精度,在加料管路中使用旁通阀PID自动控制。通过实际生产跟踪,加料泵旁通阀PID自动控制系统与电动调节针形阀的配合调控,使料液流量具有更快速、灵敏的调控反应,提高了对加料环节的流量控制。

常规岛汽机旁路调节阀抗震性能研究

为防止常规岛汽机旁路调节阀在地震期间发生共振,致使调节阀与连接管道受到破坏,使用ANSYS软件中Modal模块,对DN 300 Class900汽机旁路调节阀进行模态分析,得到调节阀各阶自振频率。当调节阀的基频高于33 Hz时,使用等效静力法。对调节阀进行抗震分析,得到阀门整体及各部件的等效应力和变形。根据ASME BPVC-Ⅲ中对核级设备抗震的规定,对调节阀在承受地震载荷时的应力强度进行评定,结果表明:阀体、阀盖、阀杆、支架最大应力分别为133.63、77.52、29.46、71.54 MPa,中法兰螺栓最大拉应力为183.23 MPa,最大剪应力为15.36 MPa,均满足抗震强度要求。

不同剂量右美托咪定对CPB心脏瓣膜置换术患者手术结局及心肌损伤情况的影响

目的分析行体外循环(CPB)心脏瓣膜置换术患者采用不同剂量右美托咪定对手术结局及心肌损伤情况的影响。方法选取我院2021年1月至12月收治的202例行CPB心脏瓣膜置换术患者作为研究对象,并以右美托咪定使用剂量将其分为0.2μg组(101例,0.2μg右美托咪定)和0.4μg组(101例,0.4μg右美托咪定)。比较两组的麻醉效果。结果两组患者的CPB时长、主动脉阻断时长和心脏自动复跳率比较,差异无统计学意义(P>0.05)。术前及术后,两组的脑利钠肽(BNP)、肌酸激酶同工酶(CK-MB)、心肌肌钙蛋白T(cTnT)、可溶性生长刺激表达基因2蛋白(sST2)、心型脂肪酸结合蛋白(hFABP)水平比较,差异均无统计学意义(P>0.05)。两组患者的术中心动过缓、低血压、呼吸抑制和术后头晕发生率比较,差异无统计学意义(P>0.05);0.4μg组的术后恶心呕吐、认知障碍发生率显著高于0.2μg组(P<0.05)。结论对行CPB心脏瓣膜置换术患者采用0.2μg右美托咪定进行手术麻醉可取得更佳的手术预后保障。