高频超声引导定位前臂浅静脉穿刺

目的探讨高频超声引导定位穿刺前臂浅静脉的应用价值。方法对40例常规浅静脉穿刺失败，采用高频探头在同一体表区域寻找并标记浅静脉走行及深度，确认进针方向后再次静脉穿刺，必要时采用实时引导。结果11例经高频超声标记、29例经高频超声实时引导静脉穿刺均一次成功。结论高频超声引导下静脉穿刺的成功率高，无并发症，是一种简便有效的方法，值得在临床推广应用。     

Blockade of pulmonary stretch receptors reinforces diaphragmatic activity during high-frequency oscillatory ventilation

During apneic periods elicited by high-frequency oscillatory ventilation (HFOV) a tonic diaphragmatic activity was observed, contrasting with the absence of diaphragmatic activity during apnea induced by lung inflation. To clarify the mechanism underlying the persistence of the diaphragmatic activity during HFOV-induced arrest of breathing the reflex responses to short periods of HFOV, and to periods of lung inflation with airway pressure (P _aw) equal to the meanP _aw and/or to maximalP _aw during HFOV were examined both before and after the blockade of slowly adapting stretch receptors (SR) by inhalation of sulphur dioxide (SO₂) in anaesthetized rabbits. In animals with intact SR, the HFOV-induced reflex apnea lasted longer than that induced by lung inflation, the associated diaphragmatic activity being in the most cases higher than the diaphragmatic activity during quiet expiration; inflation, however, completely inhibited diaphragmatic activity. After blockade of SR, spontaneous breathing continued during periods of lung inflation, i.e., the Hering-Breuer inflation reflex was abolished, whereas HFOV still led to a cessation of spontaneous breathing, the associated diaphragmatic activity even exceeding the level observed during quiet inspiration. From these results we conclude that only one part of the reflex response to HFOV is due to SR-stimulation and that in addition other vagal pulmonary receptors (irritant-and/or C-fibre-receptors) are involved. The stimulation of the latter counterbalances the concomitant stimulation of SR, giving rise to the tonic activity of the diaphragm.     

Numerical simulation of aerosol particle transport by oscillating flow in respiratory airways

Particle transport by oscillating flow in a tapered channel or in a tapered tube was computed from the complete equations of motion. These geometries represent a simplified model of the divergent flow field of the mammalian bronchial tree. The computed deformation profile of a line of particles, transported by the oscillatory motion, was compared with prior experimental results and analytical calculations. All three methods agree that there is transport in the divergent direction of the tube by an axial stream of steady drift in the core for moderately high frequency of oscillation (Womersley parameter in the range of 1 to 10). Bidirectional flow is established by an annular stream in the convergent direction, with no net flow on integral cycles of the oscillating fluid. At higher frequency, however, the steady stream transforms to a different shape in the tapered tube, with transport in the divergent direction nearer the walls of the tube, rather than in the core. Transport by the continuing streams with oscillatory ventilation of the respiratory tract should deliver medicinal aerosols of low intrinsic particle mobility to the peripheral regions of the lungs.     

高频重复经颅磁刺激联合认知行为治疗对脑卒中后焦虑和抑郁共病状态患者的影响

目的观察高频重复经颅磁刺激(rTMS)联合认知行为治疗对脑卒中后焦虑(PSA)、脑卒中后抑郁(PSD)共病状态患者的影响。 方法采用随机数字表法将160例脑卒中后焦虑抑郁状态患者分为对照组和观察组。两组患者均给予脑卒中常规治疗、抗抑郁药物治疗和认知行为治疗,对照组同时给予高频rTMS假刺激治疗,观察组则给予高频rTMS真刺激治疗。观察4周后2组患者抑郁症状、焦虑症状、睡眠质量、日常生活能力改善情况。 结果两组患者汉密尔顿抑郁量表(HAMD)评分、汉密尔顿焦虑量表(HAMA)评分、匹兹堡睡眠指数量表(PSQI)、改良Barthel指数(MBI)在治疗前差异无统计学意义(P均>0.05)。治疗4周后,对照组和观察组的HAMD评分、HAMA评分、PSQI较治疗前下降,差异有统计学意义(P均<0.05),其中观察组下降更为明显,与对照组相比,差异有统计学意义(P<0.05)。对照组和观察组MBI与治疗前相比,均有明显提高,差异有统计学意义(P<0.05),而观察组和对照组相比,观察组分数提高更显著,差异有统计学意义(P<0.05)。观察组治疗有效率为87.50%,高于对照组的71.25%。两组之间差异有统计学意义(Uc＝－3.45,P<0.001)。 结论高频rTMS治疗联合认知行为治疗和认知行为治疗均能有效改善PSA+PSD患者的焦虑抑郁症状、睡眠质量及日常生活能力,但高频rTMS治疗联合认知行为治疗的效果更加明显。     

High-frequency ventilation and conventional mechanical ventilation in newborn babies with respiratory distress syndrome: A prospective,randomized trial

Objective Morbidity and mortality remain high amongst babies ventilated for a respiratory distress syndrome (RDS). Whether newly developed ventilators allowing high frequency ventilation such as high frequency flow interrupted ventilation (HFFIV) could decrease the morbidity and the mortality was investigated in a randomized study.Design Preterm babies weighing 1800g suffering from RDS and ventilated by conventional mechanical ventilation (CMV) were randomized to be further ventilated either by CMV (group CMV) or by HFFIV (group HFFIV) when peak inspiratory pressure (PIP) on CMV was 20cmH₂O.Setting The study was undertaken in the neonatal intensive care unit of the Erasmus Hospital.Patients 24 patients entered into the investigation and were randomized but 2 patients were removed from the study because the switch over to HFFIV failed. Eight of the 12 CMV patients and 5 of the 10 HFFIV patients completed the study.Measurements and results Clinical variables, blood gas analysis and ventilatory variables were looked at. There were no differences in mortality, in incidence of air leaks and pulmonary complications or in blood gas analysis. Bronchopulmonary dysplasia was not decreased by the use of HFFIV.Conclusion It is concluded that HFFIV is safe although it offers no concrete advantages over CMV when applied as we did in a low pressure approach.     

Evaluation of high-frequency jet ventilation in oxygenation through an artificial membrane lung

The membrane oxygenator often develops impaired gas exchange after prolonged use because plasma proteins adhere to the membrane's surface and leak through its micropores. This study was performed to examine the efficacy of high-frequency jet ventilation (HFJV) in minimizing these problems in a "flat plate" type of membrane oxygenator. We first vibrated the membrane of the oxygenator by HFJV from 1 to 10 Hz to find the frequency most effective for optimal gas exchange in animals with partial extracorporeal circulation. These studies suggested that 6 Hz HFJV was preferable in our model. We subsequently performed in vivo extracorporeal oxygenation in dogs for 8 h using the membrane oxygenator with or without 6 Hz HFJV. Although the gas exchange capacity within the first 8 h was similar in the two groups, after 6 h a significant decrease in the red blood cell count and in the hematocrit was found in the group not receiving HFJV. Scanning electron microscopic examination of the membranes after 8 h of use disclosed that the membrane from the group receiving HFJV had less plasma protein and fibrin adhesion than that from the group not receiving HFJV. Moreover, it appears that with prolonged extracorporeal oxygenation, 6 Hz HFJV also protects against a decrease in the hematocrit of the passed blood and might lead to enhanced gas exchange. Our data suggest that good gas exchange can be maintained for periods even longer than 8 h if HFJV is used in conjunction with the membrane oxygenator.     

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.     

Multisim 2001在高频电路中的应用

介绍一个优秀的电路设计与仿真软件Multisim 2001的功能特点，并通过几个高频电路的仿真分析实例，说明该软件在高频电路中的应用，具有方便、经济、高效等优点。     

高频振荡通气联合肺表面活性物质治疗新生儿胎粪吸入综合征的效果

目的 探讨高频振荡通气联合肺表面活性物质( pulmonary surfactant,PS)治疗新生儿胎粪吸入综合征(meconium aspiration syndrome,MAS)的临床疗效.方法 回顾性分析2008年6月至2011年6月本院新生儿重症监护病房收治的53例MAS患儿的临床资料,根据治疗措施不同分为常频通气组23例,高频通气组18例,高频通气+PS组12例.方差分析及卡方检验比较3组通气治疗2、12、24、48 h后肺氧合功能指标和呼吸机参数指标如氧合指数、动脉/肺泡氧分压比值(arterial oxygen/alveolar oxygen ratio,a/ApO2)和吸入氧浓度(inspired oxygen fraction,FiO2)的变化,以及患儿的呼吸机使用时间、住院时间、症状变化及转归情况.结果 3组患儿机械通气前氧合指数、a/ApO2和FiO2差异无统计学意义.机械通气治疗2和48 h后,常频通气组氧合指数分别为(23.79±7.27)和(15.04±4.76)mm Hg;a/ApO2分别为0.11±0.04和0.31±0.07;FiO2分别为0.74±0.16和0.47±0.21.高频通气组氧合指数分别为(21.13±6.29)和(11.73±4.54) mm Hg;a/ApO2分别为0.14±0.06和0.35±0.06;FiO2分别为0.68±0.14和0.41±0.11.高频通气+PS组氧合指数分别为(18.35±5.68)和(7.85±5.06)mm Hg; a/ApO2分别为0.17±0.03和0.40±0.02;FiO2分别为0.59±0.13和0.29±0.16.与常频通气组比较,高频通气组治疗后氧合指数、a/ApO2和FiO2有所好转,高频通气+PS组在时限和程度上比高频通气组好转更明显,差异均有统计学意义(P均＜0.05).常频通气组患儿机械通气时间为(7.2±0.6)d,住院时间为(22.2±4.5)d,氧疗时间为(15.4±2.4)d;高频通气组较之缩短,分别为(4.2±1.4)、(15.6±3.4)和(11.8±5.3)d;高频通气+ PS组最短,分别为(2.9±0.5)、(11.8±4.3)和(7.4±2.2)d,差异均有统计学意义(P均＜0.05).结论 早期高频振荡通气联合PS治疗新生儿MAS的效果好于单纯的常频或高频通气.     

高频超声诊断下咽鳞癌淋巴结转移的临床研究

目的 探讨高频超声在诊断下咽鳞癌颈淋巴结转移的应用价值。方法 收集于耳鼻咽喉科接受颈淋巴结清扫术的47例下咽鳞状细胞癌患者的临床资料,以病理检查结果为金标准,对颈部触诊、颈部强化CT、高频超声检查结果,以kappa值反映三种方法结果与金标准的一致程度,以灵敏度、特异度评价三种检查方法的诊断效果;用Pearson χ²检验比较三种方法的灵敏度和特异度。结果 研究纳入下咽癌患者47例,所有患者均无远处转移病灶。三种检查方法,超声检查与病理检查的一致性最好(Kappa=0.718)。以术后病理检查结果为准,对于下咽癌颈淋巴结转移,超声诊断的灵敏度最高(91.9%)、高于触诊,差异有统计学意义;超声灵敏度也有高于强化CT(78.9%)的趋势,但差异无统计学意义。在特异度方面,触诊最高(94.74%)、超声(78.95%)次之、强化CT(61.11%)最低,三者的差异均无统计学意义。结论 对于诊断下咽癌颈淋巴结转移,高频超声检查具有较高的灵敏度及特异度,可为临床诊断及所采用的手术方式提供重要信息,因其无创、便携、可重复等优点,可作为监测下咽癌颈部淋巴结转移的重要辅助手段。