The Importance of Venous Return in Starling‐Like Control of Rotary Ventricular Assist Devices

Rotary ventricular assist devices (VADs) are less sensitive to preload than the healthy heart, resulting in inadequate flow regulation in response to changes in patient cardiac demand. Starling‐like physiological controllers (SLCs) have been developed to automatically regulate VAD flow based on ventricular preload. An SLC consists of a cardiac response curve (CRC) which imposes a nonlinear relationship between VAD flow and ventricular preload, and a venous return line (VRL) which determines the return path of the controller. This study investigates the importance of a physiological VRL in SLC of dual rotary blood pumps for biventricular support. Two experiments were conducted on a physical mock circulation loop (MCL); the first compared an SLC with an angled physiological VRL (SLC‐P) against an SLC with a vertical VRL (SLC‐V). The second experiment quantified the benefit of a dynamic VRL, represented by a series of specific VRLs, which could adapt to different circulatory states including changes in pulmonary (PVR) and systemic (SVR) vascular resistance versus a fixed physiological VRL which was calculated at rest. In both sets of experiments, the transient controller responses were evaluated through reductions in preload caused by the removal of fluid from the MCL. The SLC‐P produced no overshoot or oscillations following step changes in preload, whereas SLC‐V produced 0.4 L/min (12.5%) overshoot for both left and right VADs. Additionally, the SLC‐V had increased settling time and reduced controller stability as evidenced by transient controller oscillations. The transient results comparing the specific and standard VRLs demonstrated that specific VRL rise times were improved by between 1.2 and 4.7 s ( = 3.05 s), while specific VRL settling times were improved by between 2.8 and 16.1 seconds ( = 8.38 s) over the standard VRL. This suggests only a minor improvement in controller response time from a dynamic VRL compared to the fixed VRL. These results indicate that the use of a fixed physiologically representative VRL is adequate over a wide variety of physiological conditions.     

烧伤后早期准确削痂治疗深Ⅱ度创面的临床研究

目的探讨烧伤后早期在深Ⅱ度创面削痂手术中使用电动取皮刀准确削痂，对创面进程和愈合质量的影响。方法选择62例深Ⅱ度烧伤患，随机分为二组，均在伤后72h内进行创面削痂手术。术中分别使用电动取皮刀和滚轴取皮刀削痂，观察术中削痂创面出血量、手术所需时间、创面愈合时间及残留肉芽创面的发生事。结果早期对深Ⅱ度创面削痂能降低局部炎症反应。与滚轴取皮刀削痂相比较，用电动取皮刀削痂可降低残留创面的发生率22．6％，缩短病程3．5d。结论电动取皮刀削痂可尽量保存残存的皮肤附件，避免使用滚轴取皮刀削痴过程中经常出现的削痂创面边缘锯齿样切口，也可以避免因术经验、技术的不足所导致的削痴过浅或过深的问题，促进创面愈合和缩短病程，是一种简单易行的削痂方法。     

开放性眼外伤玻璃体积血的手术治疗

①目的 探讨现代玻璃体手术对开放性眼外伤玻璃体积血的治疗效果。②方法 对108例开放性眼外伤玻璃体积血的病人，于伤后2～4周施行玻璃体切割置换术(单纯玻璃体切割术24例，联合晶体切割84例，联合视网膜手术76例)。③结果 术后经随访2周～18个月，48例达功能治愈，36例达解剖治愈，总治愈率达77．7％。24例继发青光眼者眼压控制在1．37～2．24kPa。④结论 适时地施行玻璃体切割置换术，可很大程度地改善开放性眼外伤玻璃体积血病人的预后，对有效防治外伤性玻璃体视网膜病变以及牵引性视网膜脱离等具有重要作用。     

超声手术刀组织切割的实验研究

用国产超声手术刀，在大白兔活体上进行切割实验．并与普通手术刀和高频电刀进行了比较．结果显示超声手术刀的组织切割速度和切缘整齐情况不及普通手术刀，但有一定的止血功能，组织损伤不如高额电刀大，也不引起肌肉收缩，无组织烧焦气味；术后切缘愈合良好．认为超声手术刀更适合于肝、脾等实质性组织的切割．如在操作柄、刀具、仪器性能等方面能进一步改进，应用效果会更好。     

旋转叶轮血泵的发展与展望

主要从结构设计、轴承密封设计、控制系统设计三个方面介绍了旋转叶轮血泵技术的最新发展 ,并对其发展趋势做出了展望。     

基于趁鲜切制与传统切制工艺的人参饮片质量评价分析

目的 优选人参Panax ginseng趁鲜切制饮片工艺,比较分析趁鲜切制与传统切制人参饮片的质量,为人参趁鲜切制的合理性提供数据支持。方法 考察切片厚度、烘干温度、烘干时间等因素优选人参趁鲜切制饮片最佳制备工艺;建立指纹图谱结合化学计量法评价2种炮制工艺人参饮片质量差异性;并定量分析2种人参饮片中指标性成分人参皂苷含量差异。结果 人参趁鲜切制饮片的最佳制备工艺为人参鲜药材含水量65%,烘干温度50℃、烘干时间8 h、切片厚度1.5 mm;指纹图谱分别确定了人参趁鲜切制饮片和传统切制工艺饮片22个共有峰,指认了其中7个共有峰,2种炮制工艺所得人参饮片指纹图谱相似度分别在0.983～0.992、0.948～0.996。趁鲜切制与传统切制工艺饮片之间的指纹图谱相似度为0.960～0.993,相似度良好;主成分分析（principal component analysis,PCA）将人参趁鲜切制饮片和传统切制饮片归为2类,正交偏最小二乘法-判别分析（orthogonal partial least squares-discriminant analysis,OPLS-DA）确定2种炮制工艺项...     

肛门括约肌间切开术治疗高位肛瘘的临床研究

目的:研究肛门括约肌间切开术治疗高位肛瘘之临床疗效。方法:将72例高位肛瘘患者按随机数字表法随机分为对照组(切开挂线术组)和试验组(括约肌间切开术组),各36例。比较两组手术基本情况、临床疗效、肛门功能、创面面积、局部疼痛及并发症等方面的差异。结果:试验组住院时间(8.22±2.10)d,短于对照组的(14.17±2.83)d;试验组创面愈合时间(35.75±11.15)d,短于对照组的(55.69±13.42)d;术后3个月试验组肛管静息压、肛管最大收缩压分别为(58.39±6.72)mmHg、(143.72±8.24)mmHg,均高于对照组的(51.25±4.33)mmHg、(126.75±11.49)mmHg;术后3个月试验组Wexner大便失禁评分(0.56±0.61)分,低于对照组的(3.25±0.81)分;在手术当天、术后第7天换药时、术后第14天这3个时间点试验组创面面积分别为(10.70±1.67)cm^2、(8.34±1.18)cm^2、(6.25±1.13)cm^2,均小于对照组的(20.52±1.58)cm^2、(16.26±2.37)cm^2、(13.98±2.24)cm^2;在术后第7 h、术后首次排便时、术后第7天排便时这3个时间点试验组疼痛指数分别为(3.44±0.91)分、(4.17±0.77)分、(2.64±0.82)分,均低于对照组的(6.25±0.73)分、(7.22±1.20)分、(5.28±1.49)分;试验组术后并发症发生率为17%,低于对照组的53%(均P<0.05)。两组手术在复发率、临床疗效方面无显著性差异(均P>0.05)。结论:相比于切开挂线术,括约肌间切开术治疗高位肛瘘具有更好地维护肛门功能、创伤小、康复快、疼痛轻、并发症少等显著优势。     

Cutting oil dermatitis on guinea pig skin

The effect of repeated exposure of cutting oil on 8 guinea pigs' skin was evaluated by visual scoring for erythema and skin water vapour loss (SVL) measurement over a 6-week period. The visual scores (measuring severity of erythema) and SVL values were significantly higher on skin treated with cutting oils (positive control) compared to untreated skin (negative control) throughout the study period. The scores and SVL values returned to near-baseline values when cutting oil application was stopped. In addition, the effect of 2 "after-work" emollient creams on 8 guinea pigs' skin repeatedly treated with a cutting oil was assessed by similar methods. The visual scores and SVL values of guinea pig skin that was repeatedly treated with the cutting oil and moisturized with "after-work" emollient creams, were significantly higher than negative and positive control guinea pig skin. It appeared that the 2 "after-work" emollient creams do not alleviate the irritant effect of the cutting oil on guinea pig skin. They appeared to aggravate the irritant effect of the cutting oil.     

Magnetically suspended rotary blood pump with radial type combined motor-bearing

A magnetically suspended centrifugal blood pump is being developed with a combined motor-bearing for long-term ventricular assist systems. The combined motor-bearing actively suspends a rotor in a radial direction to deal with radial force unbalance in the pump and rotates the rotor by using the electric magnetic field. Therefore, the pump has no mechanical parts such as bearings of the motor and has a long lifetime. The developed pump consists of a thin rotor with a semi open-type 6 vane impeller and a stator to suspend and rotate the rotor. The rotor has 4-pole permanent magnets on the circumferential surface. The outer diameter and the thickness of the rotor are 60 mm and 8 mm, respectively. Axial movement and tilt of the rotor are restricted by passive stability based on the thin rotor structure. Radial movements of the rotor, such as levitation in radial direction and rotation, are controlled actively by using electric magnets of the stator. The electric magnet coils to produce levitation and rotation forces are constructed on the periphery stator. The p +/- 2-pole algorithm and the synchronous motor mechanism are adopted to levitate and rotate the rotor. The radial gap between the rotor and the stator is 1 mm. A closed-loop circuit filled with water was connected to the developed pump to examine the basic performance of the pump and the magnetic suspension system. Maximum rotational speed, flow rate, and head were 2,800 rpm, 11 L/min, and 270 mm Hg, respectively. The rotor with the impeller could be suspended completely during the entire pumping process. We conclude the pump with the combined motor-bearing has sufficient performance for the blood pump.