不同肺复张模式对ARDS患者呼吸力学及呼出气冷凝液炎症因子的影响

目的：比较控制性肺膨胀（SI）和压力控制（PCV）两种肺复张模式对急性呼吸窘迫综合征（ARDS）患者肺氧合功能、呼吸力学、呼出气冷凝液炎症因子及血流动力学的影响。方法45例ARDS患者随机分为对照组、SI组和PCV组。对照组使用保护性肺通气治疗;S I组在保护性肺通气基础上使用控制性肺膨胀治疗;PC V组联合压控法肺复张治疗。每12 h重复1次RM ,连续3 d。观察各组患者治疗前、治疗12、24、48、72 h各时间点氧合指数（PaO2／FiO2）、气道峰压（PIP ）、气道平台压（Pplat）、静态肺顺应性（Cst）。检测治疗前、治疗24、72 h呼出气冷凝液（EBC）中 TNF‐α、IL‐6、IL‐10水平,监测SI组与PCV组RM前后血流动力学变化。结果①三组患者治疗12、24、48、72 h各时间点PaO2／FiO2、Cst均呈上升趋势,PIP、Pplat呈下降趋势,与治疗前比较均有统计学意义;同时间点RM组（SI组和PCV组）PaO2／FiO2、Cst高于对照组,PIP、Pplat低于对照组,比较有统计学意义,但上述指标SI组与PCV组比较无统计学意义。②SI组与PCV组患者治疗后呼出气冷凝液（EBC ）中TNF‐α、IL‐6、IL‐10水平均呈下降趋势,在治疗后24、72 h与治疗前比较均有统计学意义,但SI组与PCV组比较差异无统计学意义。③SI组与PCV组在肺复张时MAP下降,HR、CVP升高,与复张前比较差异显著,PCV组上述指标波动幅度及持续时间均低于SI组,在肺复张时、复张后60、120、300 s两组上述指标比较差异有统计学意义。结论 SI与 PCV两种肺复张均能改善ARDS患者肺氧合功能、增加肺顺应性,降低平台压,减轻肺部炎症反应;PCV肺复张对血流动力学影响低于SI。     

颈动脉支架植入术中低血流动力学紊乱相关危险因素

目的分析颈动脉支架植入(CAS)术中低血流动力学紊乱(HD)的危险因素。方法回顾性分析121例接受CAS患者,根据CAS术中血压和心率变化评估有无HD;以单因素及多因素logistic回归分析筛选CAS中发生HD的危险因素。结果共42例发生HD(HD组),其中27例见于球囊扩张时,14例见于植入支架时,1例见于以封堵器封堵血管时;79例未见HD(非HD组)。单因素分析显示,组间患者年龄、颈动脉狭窄程度和部位(有无累及球部或分叉部)、血管斑块性质及球囊后扩张差异均有统计学意义(P均<0.05);多元logistic回归结果显示,年龄、狭窄部位、血管斑块性质及球囊后扩张均为HD的独立危险因素(P均<0.05)。结论CAS术中发生HD与患者年龄、颈动脉狭窄部位、血管斑块性质及有无球囊后扩张有关。     

Hemodynamic Responses to Rapid Pacing: A Model for Tachycardia Differentiation

The hemodynamic responses to rapid atrial and ventricular pacing were examined in 10 closed-chest anesthetized dogs in an attempt to distinguish hemodynamically stable from unstable tachycardias. Pressure monitoring catheters were placed in the femoral artery, right atrium, and right ventricle to measure mean arterial pressure, mean right atrial pressure, and mean right ventricular pressure at baseline heart rate and after rapid high right atrial and right ventricular apex pacing. Pressures recorded during rapid pacing (average of the pressures at 30 and 60 seconds of pacing) at pacing rates of 180, 250, and 280/minute were compared to those recorded initially at baseline heart rates. Rapid right ventricular apex pacing resulted in significant increases in mean right atrial pressure (from 6 ± 1 mmHg (mean ± standard error) to 12 ± 1 mmHg, a 100% increase, P < 0.001) and mean right ventricular pressure (from 11 ±1 mmHg to 16 ± 1 mmHg, a 45% increase, p < 0.02) with marked hemodynamic compromise (mean arterial pressure decreased from 85 ± 6 mmHg to 50 ± 6 mmHg, a 41% decrease, P < 0.01). These parameters remained stable (no statistically significant difference from baseline) during high right atrial pacing. In half of the dogs high right atrial pacing at rates 250 resulted in atrioventricular Wenckebach. Thus, it is concluded that mean right atrial pressure and mean right ventricular pressure may be useful in distinguishing hemodynamically significant tachycardias, and in the future design of antitachycardia devices.     

Effects of hemodynamic conditions and valve sizing on leaflet bending stress in self-expanding transcatheter aortic valve: An in vitro study

Transcatheter aortic valve (TAV) replacement has become a viable alternative to surgery for high and intermediate risk patients with severe aortic stenosis. This technology may extend to the younger and lower risk patients. In this population, long-term durability of the TAV is key. Increased leaflet mechanical stress is one of the main determinants of valve structural deterioration. This in vitro study aims at evaluating leaflet bending stress (LBS) in the self-expanding TAV for different valve sizes, stroke volumes (SV), and degrees of valve oversizing (OS). Three different sizes (23, 26, and 29 mm) of CoreValve (CV) were tested on a pulse duplicator in annulus size ranging from 17 to 26 mm. Leaflet bending stress and bending of the leaflet coaptation line in diastole pinwheeling index (PI) were measured using high-speed camera imaging (1000 images/s). For each given CV and annulus size, geometric orifice area (GOA) increased significantly with OS (P < .001) and SV (P = .001). LBS decreased with increasing prosthesis size and aortic annulus (AA) size while increasing with SV (P < .03). The largest value of peak LBS (3.79 MPa) was obtained with the CV 23 mm in AA of 17 mm (%OS = 35%), SV 90 mL and the smallest value (0.99 MPa) for the CV 29 mm in AA of 26 mm (%OS = 12%), SV 30 mL. On multivariable analysis, LBS increased independently with larger OS, smaller AA size and higher SV. The PI increased with decreasing AA size and increasing OS. Moderate valve OS, such as generally used for transcatheter aortic valve implantation, is associated with increased LBS during valve opening and closing, especially in small annuli. Hence, TAV OS may negatively impact long-term valve durability.     

Use of the GlideScope does not lower the hemodynamic response to tracheal intubation more than the Macintosh laryngoscope: a systematic review and meta-analysis

Background:It is presently unclear whether the hemodynamic response to intubation is less marked with indirect laryngoscopy using the GlideScope (GlideScope) than with direct laryngoscopy using the Macintosh laryngoscope. Thus, the aim of this study was to determine whether using the GlideScope lowers the hemodynamic response to tracheal intubation more than using the Macintosh laryngoscope.Methods:We performed a comprehensive literature search of electronic databases for clinical trials comparing hemodynamic response to tracheal intubation. The primary aim was to determine whether the heart rate (HR) and mean blood pressure (MBP) 60 s after tracheal intubation with the GlideScope were lower than after intubation with the Macintosh laryngoscope. We expressed pooled differences in HR and MBP between the devices as the weighted mean difference with 95% confidence interval and also performed trial sequential analysis (TSA). Second, we examined whether use of the GlideScope resulted in lower post-intubation hemodynamic responses at 120, 180, and 300 s compared with use of the Macintosh laryngoscope. For sensitivity analysis, we used a multivariate random effects model that accounted for within-study correlation of the longitudinal data.Results:The literature search identified 13 articles. HR and MBP at 60 seconds post-intubation was not significantly lower with the GlideScope than with the Macintosh (HR vs MBP: weighted mean difference = 0.22 vs 2.56; 95% confidence interval −3.43 to 3.88 vs −0.82 to 5.93; P = .90 vs 0.14; I² = 77% vs 63%: Cochran Q, 52.7 vs 27.2). Use of the GlideScope was not associated with a significantly lower HR or MBP at 120, 180, or 300 s post-intubation. TSA indicated that the total sample size was over the futility boundary for HR and MBP. Sensitivity analysis indicated no significant association between use of the GlideScope and a lower HR or MBP at any measurement point.Conclusions:Compared with the Macintosh laryngoscope, the GlideScope did not lower the hemodynamic response after tracheal intubation. Sensitivity analysis results supported this finding, and the results of TSA suggest that the total sample size exceeded the TSA monitoring boundary for HR and MBP.     

分水岭脑梗死的危险因素及病因分析

目的：分析分水岭脑梗死（ WSI）的危险因素及病因。方法2012年10月～2014年5月连续收集入住航天中心医院神经内科的WSI患者86例（ WSI组）,同期选择年龄、性别相匹配的非WSI的脑梗死患者86例（非WSI组）,比较两组临床资料及影像学特点。结果 WSI组糖尿病、低灌注比例高于非WSI组（P＝0．024、0．043）,收缩压、平均动脉压水平均低于非WSI组（P＝0．016、0．030）;WSI组皮层小梗死发生比例、大脑中动脉及颈内动脉中重度狭窄或闭塞比例、前/后交通动脉均不开放比例均高于非WSI组（ P＝0．000、0．016、0．007、0．021）;前/后交通动脉均开放比例低于非WSI组（ P＝0．033）。结论 WSI发生的危险因素有糖尿病、低灌注及低血压,发病原因为脑动脉中重度狭窄或闭塞和低灌注事件所致的血流动力学障碍、微栓塞、Willis环血流代偿。     

盐酸右美托咪定对老年患者术后早期认知功能的影响

目的观察盐酸右美托咪定（DEX）对老年患者术后早期认知功能（POCD）的影响。方法选择择期在全麻下手术的老年患者60例,随机分为2组,观察组（D组）和对照组（C组）,每组30例。D组全麻诱导前静脉微泵注DEX 4μg/ml,用量为0.4μg/kg,输注时间10 min;C组以相同方法输注等量0.9%氯化钠溶液。2组分别于术前1 d、术后1 d、术后3 d进行简易精神状态量表（mini-mental state examination,MMSE）评分,并观察记录药物输注时（T0）、输注后5 min（T1）、插管时（T2）、插管后1 min（T3）、插管后5 min（T4）的收缩压（SBP）、舒张压（DBP）及心率（HR）。结果 2组术前MMSE评分比较差异无统计学意义,2组术后各时点评分均低于术前（P〈0.05）。术后1 d D组的MMSE评分高于C组（P〈0.05）,D组和C组术后1 d分别有4例（14.8%）和12例（42.9%）发生认知功能下降,差异有统计学意义（P〈0.05）;术后3 d分别有3例（11.1%）和5例（17.6%）发生认知功能下降,术后3 d 2组的MMSE评分和认知功能下降发生率均无统计学差异（P〉0.05）。D组在T1、T3、T4时间点的SBP、DBP、HR均低于C组（P〈0.05）。结论老年患者全麻诱导前预输注DEX对术后早期的认知功能下降有一定的预防作用,且不影响诱导期血流动力学的稳定,方法安全。     

Cerebral hemodynamic and ventilatory responses to hypoxia,hypercapnia, and hypocapnia during 5 days at 4,350?m

This study investigated the changes in cerebral near-infrared spectroscopy (NIRS) signals, cerebrovascular and ventilatory responses to hypoxia and CO₂ during altitude exposure. At sea level (SL), after 24 hours and 5 days at 4,350 m, 11 healthy subjects were exposed to normoxia, isocapnic hypoxia, hypercapnia, and hypocapnia. The following parameters were measured: prefrontal tissue oxygenation index (TOI), oxy- (HbO₂), deoxy- and total hemoglobin (HbTot) concentrations with NIRS, blood velocity in the middle cerebral artery (MCAv) with transcranial Doppler and ventilation. Smaller prefrontal deoxygenation and larger ΔHbTot in response to hypoxia were observed at altitude compared with SL (day 5: ΔHbO₂−0.6±1.1 versus −1.8±1.3 μmol/cmper mm Hg and ΔHbTot 1.4±1.3 versus 0.7±1.1 μmol/cm per mm Hg). The hypoxic MCAv and ventilatory responses were enhanced at altitude. Prefrontal oxygenation increased less in response to hypercapnia at altitude compared with SL (day 5: ΔTOI 0.3±0.2 versus 0.5±0.3% mm Hg). The hypercapnic MCAv and ventilatory responses were decreased and increased, respectively, at altitude. Hemodynamic responses to hypocapnia did not change at altitude. Short-term altitude exposure improves cerebral oxygenation in response to hypoxia but decreases it during hypercapnia. Although these changes may be relevant for conditions such as exercise or sleep at altitude, they were not associated with symptoms of acute mountain sickness.     

彩色多普勒超声评价桡动脉血管条件对自体动静脉造瘘术的临床价值

目的探讨彩色多普勒超声评价桡动脉血管条件对自体动静脉造瘘术的临床价值。方法利用彩色多普勒超声对拟行自体动静脉造瘘的133例终末期肾病患者桡动脉血管情况进行检测,与术后内瘘血管参数进行对比分析。结果 133例患者中术前桡动脉正常者95例,异常者38例;进行造瘘手术者131例,因桡动脉血管条件差放弃手术者2例,内瘘失败13例,桡动脉正常组术后成功率(95.8%)高于桡动脉异常组(75%)。桡动脉正常组各血流参数均明显优于异常组,且术后4周吻合口的血流量、血管内径优于术后1周及术前。结论彩色多普勒超声既可以提供术前桡动脉血管条件的多项数据,预测术后内瘘血管功能状态,又可以在术后动态监测内瘘血管情况,具有较好的临床应用价值。