Implementation of percutaneous dilation tracheotomy – value of preincisional ultrasonic examination?

BACKGROUND: In this observational study we have evaluated the implementation of percutaneous dilation tracheotomy (PDT), using the forceps dilation technique (Portex) in a multidisciplinary ICU. METHODS: We included a preincisional ultrasonic evaluation of the neck in order to visualise the isthmus glandula thyroidea and major vessels. The observational period comprised one year. PDT was performed in 28 patients. RESULTS: Implementation of PDT was uneventful. Duration of insertion was 10 min (4-40 min). Total time of tracheostomy was 8 days (1-65 days). In nine cases, the proximal end of the isthmus was overlying the space between the 1st and 2nd tracheal ring, which was considered the optimal insertion site. This resulted in seven cases of insertion between the cricoidea and the 1st tracheal ring and in two cases in a more distal insertion. Nineteen tracheotomies were performed in the interstice between the 1st and 2nd tracheal ring. In nine patients, major vessels were overlying the trachea. In none of the patients did this information result in an altered insertion site. Two cases of minor bleeding were observed; both stopped upon compression. In two patients the primary tube size (8.0) was too big and a smaller tube had to be inserted. In one patient the tube was maladapted to the stoma and had to be interchanged with an ordinary tracheostomial tube on the 5th day of tracheostomy. CONCLUSION: Based on the experience gathered in this study and information from the literature, we have abandoned the routine use of ultrasonic examination of the neck prior to PDT. In order to achieve and maintain routine, we suggest that the procedure is performed by a restricted number of doctors.     

Hypothesized neural dynamics of working memory: several chunks might be marked simultaneously by harmonic frequencies within an octave band of brain waves

The capacity of working memory (WM) for up to about seven simple items holds true both for humans and other species, and may depend upon a common characteristic of mammalian brains. This paper develops the conjecture that each WM item is represented by a different brain wave frequency. The binding-by-synchrony hypothesis, now being widely investigated, holds that the attributes of a single cognitive element cohere because electroencephalogram (EEG) synchrony temporarily unifies their substrates, which are distributed among different brain regions. However, thought requires keeping active more than one cognitive element, or WM "chunk," at a time. If there is indeed a brain wave frequency code for cognitive item-representations that are copresent within the same volume of neural tissue, the simple mathematical relationships of harmonies could provide a basis for maintaining distinctness and for orderly changes. Thus, a basic aspect of music may provide a model for an essential characteristic of WM. Music is a communicative phenomenon of "intermediate complexity," more highly organized than the firing patterns of individual neurons but simpler than language. If there is a distinct level of neural processing within which the microscopic physiological activity of neurons self-organizes into the macroscopic psychology of the organism, it might require such moderate complexity. Some of the obvious properties of music--orderly mixing and transitions among limited numbers of signal lines-are suggestive of properties that a dynamic neural process might need in order to organize and reorganize WM markers, but there are a number of additional, nonobvious advantageous properties of summating sinusoids in music-like relationships. In particular, harmonies register a stable periodic signal in the briefest possible time. Thus, the regularity of summating sinusoids whose frequencies bear harmony ratios suggests a particular kind of tradeoff between parallel and serial processing. When there are few copresent waves, at EEG frequencies, this sort of parallel coding retains behaviorally meaningful brief periods. A necessary companion hypothesis is that the brain wave frequencies underlying WM are confined to a single octave; that is, the upper and lower bounds of the band are in the ratio of 2:1. This hypothesized restriction, suggested by an empirical property of EEG bands that has been widely reported but rarely commented upon, has the important property of precluding spurious difference rhythms. A restriction to an octave, of "harmonious" frequency-markers for WM items, also seems consistent with a great deal of behavioral data suggesting that WM comprises a rapidly fading trace process in which only up to three or four item-representations are strongly activated simultaneously. There is also an additional, sequential renewal-or-revision process, within which up to another three or four items are being actively refreshed by rehearsal or replaced. Such serial processing may involve a less stringent octave band crowding problem.     

F波和面神经电图对早期周围性面瘫预后诊断的价值

目的 通过随访调查评价F波和面神经电图在早期周围性面瘫预后中的价值。方法 对发病21天内做过F波和面神经电图检查、病史已达3年的35例周围性面瘫患者进行了恢复结果随访,比较两种诊断方法预后判断的准确度。F波是否存在及面神经电图值是否大于90％分别作为两种方法的诊断界值。结果 用F波是否能引出判断周围性面瘫患者好坏的准确度为97.14％,高于面神经电图的88.57％,用F波是否消失判断患者有无并发症的准确度为94.29％,高于面神经电图的85.71％,两种方法经配对卡方检验,有显著性差异(x~2=17.72,P<0.01)。F波存在是较好预后的定性指标。结论 F波是早期周围性面瘫一种理想的判断预后的客观诊断指标。     

声测胆经体表循行线的实验研究

足少阳胆经，多弯多折，循行线长，检测难度较大。本文用低频输声的方法对３９名健康学生进行了右侧胆经的全程检测，循经性波出现率达到７２．７３％～９０．００％。再次证实了低频声波具有循本经经线传导的特异性，其传导轨迹与古典描述的胆经经线十分一致，并客观证实了胆经走行中５处弯曲的存在，同时也证实了胆经与三焦经、肝经的衔接，显示了经络是声的良导路     

超声法提取绞股蓝总皂甙的工艺研究

本实验证明，超声法可以提高绞股蓝总皂甙的提取率，最佳提取工艺为超声高频提取3次，每次80min，得率为1．226％。     

乳腺肿瘤的高频超声检查与鉴别诊断

目的对乳腺肿瘤的高频声像图特征与CDFI的表现进行探讨.方法对59例经手术、病理证实为乳腺肿瘤的高频声像图与病理进行对照.结果高频超声在肿块的物理性质诊断方面符合率达100%,在肿块良恶性鉴别诊断方面符合率为87.4%.本组的病灶好发于乳腺外上象限及内上象限,良性肿瘤彩色血流显示率低,且多位于肿瘤周边部,血流检出率为48.6%(17/35);而恶性肿瘤内部见短条状血流信号,血流检出率为91.7%(22/24),两者差异有显著性(P<0.004).结论乳腺肿瘤有明显声像特征,高频超声诊断符合率高.     

精析B超轨迹球

本文深入透彻的分析了常用轨迹球的基本构成和工作原理,设计了替换电路,并针对经常出现的故障给出了解决方法,而且就B超轨迹球的未来发展做出了展望.     

脂肪肝的超声诊断与实验室相关检查的关系分析

目的:分析脂肪肝的超声诊断与实验室相关检查的关系,以早期发现和治疗脂肪肝.方法:以超声诊断脂肪肝为标 准,结合二维声像图的检查,同时对脂肪肝患者及健康人各 100例进行血脂检测.结果:血脂的变化与脂肪肝的发生 密切相关.结论:脂肪肝与肝油三脂升高密切相关,二维超声图像结合实验室检查,可早期发现脂肪肝.     

超声医学图像灰度校正方法的改进

介绍了超声医学图像灰度校正常用方法的基本原理,这些方法主要有灰度级校正、灰度变换及直方图修正。对广泛应用且效果较好的直方图均衡化法作了较详细阐述,并针对其对于局部细节增强不显著及不具交互特征等缺点提出了改进方法,并将几种灰度校正方法级联起来对超声图像进行处理,实现了有选择地增强某个灰度值范围对比度的功能,增强了超声诊断图像的实用性。     

二尖瓣脱垂综合征163例分析

目的　了解二尖瓣脱垂综合征的临床表现。方法　对 16 3例二尖瓣脱垂综合征患者的症状、体征、心电图以及超声心动图进行分析。结果　 (1)大部分患者无症状 ,有症状的主要表现为胸痛、心悸、头晕、乏力、焦虑等。典型体征为心尖区闻及喀喇音和收缩期杂音。 (2 )心电图表现各异 ,呈非特异性。 (3)超声心动图可直接观察二尖瓣脱垂部位、程度和二尖瓣关闭不全程度。结论　典型的症状、体征对发现本病有一定价值 ,但由于部分患者缺乏症状和体征 ,心电图表现非特异性 ,故诊断有赖于超声心动图