主动脉出口血压对左心室血流特性的影响

采用Mimics对心脏进行三维重构，用3-matic进行模型优化以及模型误差分析，对左心室室壁运动做速度分布假设，基于UDF宏文件对左心室室壁运动编写程序，将血液视为非牛顿流体，采用动网格技术研究不同血压对左心室血液流动的影响。模拟发现当左心室收缩时，压力梯度明显，内部压力减小。当左心室舒张时，内部压力逐渐增高。二尖瓣口处的速率先增大后减小。血压升高，左心室内剪切应力持续增大，极易破坏红细胞结构，产生溶血现象，导致心脏功能紊乱。     

Microspheres of essential oil in polylactic acid and poly(methyl methacrylate) matrices and their blends

This study is focussed on micro-encapsulation of essential oils in polylactic acid (PLA) and a poly(methyl methacrylate) (PMMA) matrix as well as blends of the same. Microspheres were prepared by the solvent evaporation technique and characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR). The encapsulation efficiencies and release profiles of the essential oils were studied by gas chromatography mass spectrometry (GC-MS) and head-space solid-phase microextraction GC-MS, respectively. Furthermore, the microspheres were tested for antibacterial activity against both Gram-negative and Gram-positive bacterial strains.

The results showed that the microspheres compositions (PLA/PMMA ratio) have significant effect on their characteristics. The process adopted for preparing the microspheres promoted formation of spherical particles at the sizes of 1.5–9.5?µm. The highest encapsulation efficiency of the prepared microspheres was observed in systems consisting of linalool (81.10?±?10.0?wt. % for PLA system and 76.0?±?3.3?wt. % for PMMA system). Confirmation was also made that the release rate of the microspheres was affected by the size of the same.     

Ventilatory support in the intensive care unit

This article focuses on the functional features of positive-pressure ventilators, the modes of invasive and non-invasive mechanical ventilation, and the main ventilator settings. It also highlights the potential complications of mechanical ventilation, the basic principles of weaning, and the pathophysiological basis of patient-ventilator dyssynchrony.     

DHS和PFNA固定治疗老年股骨粗隆间骨折的疗效

目的对比动力髋螺钉(dynamic hip screw,DHS)治疗和股骨近端抗旋髓内钉(proximal femoral nail anti-rotation,PFNA)固定治疗老年股骨粗隆间骨折疗效。方法纳入本院收治的45例采用PFNA固定治疗的老年股骨粗隆间骨折患者作为研究组,研究时间为2017年11月-2018年11月;回顾性分析2016年11月-2017年11月在我院采用DHS治疗的45例老年股骨粗隆间骨折患者的临床资料,作为对照组。记录两组的相关手术指标,观察手术并发症情况。结果研究组的手术时间和骨折愈合时间均短于对照组,术中出血量明显少于对照组,术后疼痛VAS评分均明显低于对照组(P<0.05)。对照组的并发症发生率高于研究组(P<0.05)。结论PFNA固定治疗比DHS治疗老年股骨粗隆间骨折更加安全有效,值得临床借鉴和应用。     

运动学对线应用于全膝关节置换术的研究进展

全膝关节置换术是目前治疗终末期膝关节骨性关节炎最有效的方法之一，全膝关节置换术后膝关节功能、术后膝关节疼痛与术后下肢力线有着密切的关系。目前膝关节置换术下肢对线方式主要采用机械力学对线方法，该方法可以改善膝关节功能，但是有部分患者也会产生术后膝关节的疼痛、活动受限等并发症，导致术后患者满意度较差。近些年越来越多的研究开始关注运动力学对线技术并应用于临床。运动学对线技术旨在重建患者的解剖结构，将膝关节假体运动轴与膝关节生理性运动轴保持一致，减少膝关节周围软组织和韧带的松解，实现膝关节生理性运动。该文就运动力学对线方法在全膝关节置换术中的应用进展作一综述。     

右美托咪啶与芬太尼联合对ICU 腹部外科术后机械通气患者镇静镇痛的效果比较

目的:探讨右美托咪啶与芬太尼联合在ICU腹部外科术后机械通气患者中的应用效果及对镇静、镇痛作用的影响。方法:选择2018年5月—2019年6月ICU腹部外科术后机械通气患者62例,随机分为对照组(n=31例)和观察组(n=31例)。两组均采用芬太尼持续静脉泵入,对照组采用咪达唑仑镇静镇痛,观察组采用右美托咪啶镇静镇痛,比较两组镇痛镇静效果、镇静剂使用剂量、苏醒及达到镇静所需时间、血流动力学水平及安全性。结果:两组T2、T3时间点VAS评分分别为(2.40±0.31 vs 2.43±0.32和2.01±0.12 vs 2.05±0.15)、Ramsay量表评分分别(3.21±0.35 vs 3.20±0.33和3.01±0.25vs 3.00±0.24)均低于T1时间点(VAS评分2.94±0.69 vs 2.96±0.71;Ramsay量表评分3.57±0.61 vs 3.58±0.62)(P0.05);观察组右美托咪啶联合芬太尼镇痛镇静达到镇静所需时间(34.29±3.56) min长于对照组(23.63±3.21)(t=5.535,P=0.043);观察组镇静剂使用剂量(220.59±15.25)μg、苏醒时间(3.29±0.69)min均少(短)于对照组镇静剂使用剂量(386.44±18.92)μg、苏醒时间(7.56±1.21)min(t=6.294、6.092,P=0.023、0.025);两组T1、T2时间点心率[观察组T1(88.47±9.76)次/min、T2(86.41±9.43)次/min;对照组T1(89.53±10.41)次/min、T2(87.46±9.58)次/min]均高于T0时间点[观察组(78.78±4.35)次/min、对照组(79.12±4.41)次/min](P0.05);观察组T1、T2时间点MVP(79.58±5.71、87.53±6.76)mmHg高于对照组(74.12±4.69、75.26±5.61)mmHg(t=9.613、7.223,P=0.011、0.016);观察组的不良反应发生率为6.45%,与对照组的12.90%差异无统计学意义(χ~2=1.214, P=0.643)。结论:将右美托咪啶联合芬太尼用于ICU腹部外科术后机械通气患者中能获得良好的镇痛、镇静效果,缩短苏醒及达到镇静所需时间,血流动力学相对稳定,药物安全性较高,值得推广应用。     

A modality-specific somatosensory evoked potential test protocol for clinical evaluation: A feasibility study

ObjectiveWe aimed to establish an objective neurophysiological test protocol that can be used to assess the somatosensory nervous system.MethodsIn order to assess most fiber subtypes of the somatosensory nervous system, repetitive stimuli of seven different modalities (touch, vibration, pinprick, cold, contact heat, laser, and warmth) were synchronized with the electroencephalogram (EEG) and applied on the cheek and dorsum of the hand and dorsum of the foot in 21 healthy subjects and three polyneuropathy (PNP) patients. Latencies and amplitudes of the modalities were assessed and compared. Patients received quantitative sensory testing (QST) as reference.ResultsWe found reproducible evoked potentials recordings for touch, vibration, pinprick, contact-heat, and laser stimuli. The recording of warm-evoked potentials was challenging in young healthy subjects and not applicable in patients. Latencies were shortest within Aβ-fiber-mediated signals and longest within C-fibers. The test protocol detected function loss within the Aβ-fiber and Aδ-fiber-range in PNP patients. This function loss corresponded with QST findings.ConclusionIn this pilot study, we developed a neurophysiological test protocol that can specifically assess most of the somatosensory modalities. Despite technical challenges, initial patient data appear promising regarding a possible future clinical application.SignificanceEstablished and custom-made stimulators were combined to assess different fiber subtypes of the somatosensory nervous system using modality-specific evoked potentials.