Effect of leak around the endotracheal tube on measurements of pulmonary compliance and resistance during mechanical ventilation: A lung model study

We studied the effect of leaks around the endotracheal tube (ETT) on the measurement of pulmonary mechanics during mechanical ventilation. We also evaluated the influence of different ventilator settings on the magnitude of leak. An adjustable leak was created at the end of the ETT in a lung model with constant compliance. Flow, tidal volume, and pressure changes were measured above and below the leak. Compliance (C_i) and resistance (R_i) during inspiration were determined by linear regression analysis (LRA) using the equation of motion and the Mead and Wittenberger method (MWM). The ventilatory change that influenced the degree of leak most was prolongation of inspiratory time (T_i). The presence of a leak around the ETT resulted in an overestimation of the C_i and R_i values, which was proportional to the size of the leak. This overestimation was also influenced by the method used to determine C_i and R_i. Because the contribution of the leak to the tidal volume progressively increased as inspiration continued, methods of analysis that depended mainly on measurement points at the end of inspiration showed a larger deviation from the true C_i and R_i values than methods mainly influenced by measurement points at the beginning of inspiration. Because of this, shortening of inspiration, or analysis of points at the beginning of inspiration reduces the error in the measurements of C_i and R_i when a leak is present. Breaths with a large leak should be excluded from any analysis of pulmonary mechanics. Pediatr Pulmonol. 1996; 22:35–43. © 1996 Wiley-Liss, Inc.     

儿童癌症幸存者成年后的慢性疾病

由于治疗方法的进步,近80%的儿童和青少年癌症患者能够长期生存。在美国,约有270000例儿童癌症的幸存者,即每640名20至39岁成年人中就有一名幸存者。大量的幸存者有利于儿童癌症治疗后长期健康结果的研究。现在可以明确的是,化疗和放疗所致的儿童各器官系统损害在临床上可能潜伏多年。为了全面了解治疗儿童癌症而继发的健康问题,重要的是衡量三项长期结果:健康状况、死亡率和患病率。这三项中,关于前两项已有相当好的研究报道。在一项对20227例癌症5年生存者的回顾性分析中,Mertens等发现以下原因导致的超额死亡率具有统计学意义:继发癌症(…     

腹腔镜外科和妇科联合手术的临床应用

目的：探讨腹腔镜技术在外科和妇科疾病治疗中联合应用的临床价值。　
方法：总结近7年来施行腹腔镜联合手术治疗妇、外科疾病229例的临床资料,其中腹腔镜胆囊切除术(laparoscopic cholecystectomy,LC)联合输卵管造口术5例,LC联合卵巢囊肿剥除术28例,LC联合子宫肌瘤剔除术25例,LC联合子宫次全切除术39例,LC联合子宫全切除术26例,LC联合子宫内膜异位症手术6例;腹腔镜阑尾切除术(laparoscopicappendectomy,LA)联合输卵管手术38例,LA联合卵巢囊肿切除术32例,LA联合子宫全切除术或子宫次全切除术24例,腹腔镜肝囊肿开窗引流术联合卵巢囊肿切除术6例。
结果：229例妇、外科联合腹腔镜手术均获成功,无中转开腹手术。手术时间40~220 min,平均120 min;住院1~6 d,平均3.4 d。仅1例术后10 d阴道残端出血非手术疗法治愈。175例随访3~24个(平均19.5)月,1例术后2个月发现阴道残端息肉,经手术切除治愈。　
结论：严格掌握联合手术指征,充分术前准备,多科室良好配合,腹腔镜联合手术能够有效地同时处理外科和妇科并存疾病,在基层医院具有良好的应用前景。     

Characterization of the techniques of pressure ejection and microiontophoresis using in vivo electrochemistry

Catecholamine levels in frontal cortex were determined in vivo by electrochemical detection after the local application of dopamine (DA) from multibarrel micropipettes by pressure ejection or microiontophoresis. Tissue DA levels were linearly related to microapplication doses with either technique and reached steady state with longer application times. Furthermore, the plateau DA tissue concentrations were clearly related to ejection pressure or iontophoretic current. Using either microapplication technique, the tissue DA levels decreased as distance between the recording electrode and the tip of the drug pipette increased. However, pressure ejected and iontophoretically applied drug differed in their concentration versus time dynamics. Thus, although similar tissue concentrations of drug can be generated by the two techniques, the time dynamics of the drug effects may not be comparable. The quantitative use of these drug application techniques requires a minimal amount of variance in release between pipettes in order to effectively measure small sensitivity differences. Although the 10-fold variance with microiontophoresis does not appear resolvable at present, improved pipette construction techniques permit the variability in dosage to be limited to a maximum of 3-fold with pressure ejection. In addition, the present data also suggest that this variance can be further minimized by holding either ejection duration or ejection pressure constant when establishing dose-response relationships.     

牙列缺损的计算机三维建模

目的 建立牙列缺损的计算机三维模型。方法 采用表面绘制法,依据CT扫描头颅骨标本获得的二维断层图像数据在3D Studio Max中沿牙体长轴放样、微调并赋以材质,得到牙列缺损的计算机三维模型。结果 能在计算机中方便快速地模拟任意类型的牙列缺损,并可全方位地旋转、放大和缩小。结论 提供了一种牙列缺损三维建模的新方法,有利于三维义齿专家系统的开发和计算机辅助教学。     

经关节入路微创钢板固定技术治疗股骨远端C型骨折

目的探讨经关节入路微创钢板固定(MIPPO)技术治疗股骨远端C型骨折的临床疗效。方法2002年4月～2005年2月,应用MIPPO技术治疗股骨远端C型骨折14例,按AO/ASIF分类：C1型3例,C2型6例,C3型5例。先行关节内骨折切开复位、松质骨螺钉固定,再行髁上部分骨折间接复位、经关节内切口插入髁支撑钢板或LISS钢板桥接固定骨折。结果12例患者获得10～32个月(平均18．4个月)随访,骨折均获愈合,愈合时间10周～12个月,平均4．6个月。按Kolmert和Wulff的评价标准：优4例,良5例,可2例,差1例,优良率为75%。结论应用MIPPO技术治疗股骨远端C型骨折实现了微创操作,具有创伤小、软组织干扰少、骨折愈合快等优点,疗效满意。     

Continued anti-VEGF treatment does not prevent recurrences in eyes with stable neovascular age-related macular degeneration using a treat-and-extend regimen: a retrospective case series

BackgroundThe continuation of anti-vascular endothelial growth factor (anti-VEGF) treatment after achieving stability in patients with neovascular age-related macular degeneration has generally been advocated. In our own patients, we thought to assess whether continued anti-VEGF treatment is capable of preventing recurrences.MethodsIn this retrospective observational case series, patients with stable disease either opted to continue treatment every 12–14 weeks (Group 1) or stopped treatment with subsequent follow-up visits every 8–12 weeks (Group 2).ResultsOf the 103 eyes of 103 patients achieving stability, 49 eyes continued treatment (Group 1), whereas treatment was stopped in 54 eyes undergoing regular follow-up (Group 2). Recurrent disease was observed in 21 (42.9%) and 33 (61.1%) cases in Group 1 and Group 2, respectively (p = 0.08). Time between achieving stable disease and recurrence was comparable between Group 1 and Group 2 (11.1 ± 8.2 months vs. 9.2 ± 6.7 months; p = 0.43). The number of visits between achieving stability and disease recurrence was similar, but not the number of injections (3.5 ± 2.0 vs. 0.2 ± 0.4; p < 0.001).ConclusionsContinuing anti-VEGF therapy after achieving functional and morphological stability every 12–14 weeks does not prevent recurrences. Patients deserve to be informed of a potential lifetime risk of recurrences, even under continued therapy.Subject terms: Macular degeneration, Retinal diseases     

Alterations in endogenous pain modulation in endurance athletes: An experimental study using quantitative sensory testing and the cold-pressor task

There is evidence for long-term alterations in pain tolerance among athletes compared with normally active controls. However, scientific data on pain thresholds in this population are inconsistent, and the underlying mechanisms for the differences remain unclear. Therefore, we assessed differences and similarities in pain perception and conditioned pain modulation (CPM) at rest in endurance athletes and normally active controls.