有限内固定结合负压封闭引流技术治疗严重开放性跟骨骨折的初步经验

目的 探讨有限内固定结合负压封闭引流(VSD)技术治疗严重开放性跟骨骨折的疗效.方法 2007年12月至2008月8月共收治9例严重开放性跟骨骨折患者,男8例,女1例;年龄23～55岁,平均34.5岁.按Sanders关节内跟骨骨折分型:Ⅱ型3例,Ⅲ型4例,Ⅳ型2例.开放性损伤按Gustilo分型:Ⅱ型4例,ⅢA型4例,ⅢB型1例.均使用切开复位有限内固定结合VSD技术治疗.术后观察患者软组织和骨折愈合情况,以及功能恢复情况.结果 9例患者术后获平均10个月(6～14个月)随访.2例患者手术切口切缘红肿,1例患者术后切口皮缘部分坏死,经伤口换药静脉使用抗生素后逐渐愈合.9例患者骨折均得到愈合,平均愈合时间为3.5个月.所有患者无慢性软组织感染、骨髓炎或截肢.美国足踝外科协会(AOFAS)踝与后足评分标准评分为76～93分,平均83.4分,其中优1例,良5例,中3例. 结论 有限内固定结合VSD技术治疗严重开放性跟骨骨折,骨折和软组织均得到愈合,并发症少,具有良好的早期疗效.     

改良小L形入路距下关节撑开植骨融合治疗陈旧性跟骨骨折距下关节炎

目的：观察改良跟腱旁后外侧小“L”入路距下关节撑开植骨融合治疗陈旧性跟骨骨折距下关节炎的疗效。方法：2009年3月至2012年9月,应用改良小“L”入路距下关节撑开植骨融合术治疗22例跟骨骨折伴距下关节炎患者,男13例,女9例;年龄22～49岁,平均35．3岁。病程11～32个月,平均21个月。根据Stephens-Sanders分型,Ⅱ型16例,Ⅲ型6例。通过改良AOFAS踝与后足评分标准对手术前后患足功能进行评估,比较改善程度。结果：1例出现皮缘坏死,无感染、螺钉断裂、植骨吸收及距骨坏死等情况发生。术后21例获随访,时间18～46个月,平均29个月。术后4个月融合处均获骨性愈合。末次随访时改良AOFAS评分由术前32-65分（平均50．8分）提高至末次随访66～92分（平均82．6分）,与术前比较差异有统计学意义（P〈0.01）。结论：改良小“L”入路距下关节撑开植骨融合术是治疗陈旧性跟骨骨折并发距下关节炎的一种有效方法,临床操作简单,并发症少,可矫正跟骨骨折畸形愈合的主要病理改变,恢复足部外形并改善后足功能。     

开放性跟骨骨折的手术治疗

目的:通过回顾性病例系列研究,探讨开放性跟骨骨折的临床疗效和预后相关影响因素。方法:2004年至2009年10月,共收治跟骨骨折427例,其中开放性跟骨骨折22例,有15例15足获随访,男9例,女6例;年龄18～66岁,平均34.7岁。跟骨骨折按照Sanders分型,Ⅰ型2例,Ⅱ型3例,Ⅲ型6例,Ⅳ型4例;软组织损伤Gustilo分型,Ⅰ型1例,Ⅱ型4例,ⅢA型5例,ⅢB型5例。按照OCIS分型,ⅠA型1例,ⅡA型2例,ⅡB型7例,ⅢA型2例,ⅢB型3例。所有患者急诊行伤口清创,预防性抗生素应用,根据伤口情况I期闭合或临时覆盖,患肢临时固定,根据软组织损伤情况急诊或择期行跟骨骨折复位内固定。随访是通过临床检查、影像学评估和AOFAS踝与后足评分进行预后评估。结果:15例患者均获随访,时间8～31个月,平均16.4个月,AOFAS评分(74.6±10.4)分(58～94分),有4足需要筋膜瓣或皮瓣覆盖伤口。有5例发生浅表感染,其中有4例为GustiloⅢ型,2例深部感染和1例骨髓炎,无患者需要截肢治疗。结论:开放性跟骨骨折如果早期合理清创,认真评估软组织损伤情况,把握内固定的时机和手术指征,选择恰当的固定方法,可以有效降低术后深部感染和骨髓炎发生率。另外,对于GustiloⅢ型和OCISB型骨折,应避免早期切开复位内固定。     

外侧L形切口植骨锁定钛板内固定治疗跟骨骨折

目的 探讨外侧L形切口植骨锁定钛板内固定治疗PaleyⅢ型跟骨骨折的临床疗效.方法 采用外侧L形切口植骨锁定钛板内固定治疗59例PaleyⅢ型跟骨骨折患者(73足).记录术后并发症和骨折愈合情况,测量B?hler角、Gissane角,根据AOFAS踝-后足评分系统评价疗效.结果 患者均获得随访,时间13～16个月.1例...     

V形截骨联合距下关节融合术治疗StephensⅡ、Ⅲ型跟骨骨折畸形愈合

目的 探讨跟骨V形截骨联合距下关节融合术治疗StephensⅡ、Ⅲ型跟骨骨折畸形愈合的疗效。方法 回顾分析2017年1月—2021年12月采用跟骨V形截骨联合距下关节融合术治疗的24例严重跟骨骨折畸形愈合患者临床资料。男20例，女4例；年龄33～60岁，平均42.8岁。跟骨骨折保守治疗失败19例，手术治疗失败5例。跟骨骨折畸形愈合Stephens分型：Ⅱ型14例，Ⅲ型10例。术前跟骨B?hler角4.0°～13.5°，平均8.6°；Gissane角100°～152°，平均119.3°。受伤至该次手术时间6～14个月，平均9.7个月。术前及末次随访时采用美国矫形足踝协会（AOFAS）踝与后足评分及疼痛视觉模拟评分（VAS）评价疗效；观察骨愈合情况并记录愈合时间，并测量距跟高度、距骨倾斜角、跟骨倾斜角、跟骨宽度及后足力线角。结果 术后3例出现切口皮缘坏死，经换药及口服抗生素治疗后痊愈。其余切口均Ⅰ期愈合。24例患者均获随访，随访时间12～23个月，平均17.1个月。患者足部形态均恢复良好，穿鞋恢复至伤前尺码，无前踝撞击存在。所有患者均获骨性愈合，愈合时间12～18周，平均14.1周。末次随...     

早期清创复位克氏针内固定与Ⅱ期钢板内固定治疗开放性跟骨骨折的病例对照研究

目的:比较早期清创骨折复位克氏针内固定(克氏针组)与Ⅱ期骨折复位钢板内固定(钢板组)治疗开放性跟骨骨折的临床疗效。方法:自2001年1月至2008年5月收治开放性跟骨骨折55例(58足),年龄19～65岁,平均36.8岁;伤后至就诊时间30min～7h,平均3h。克氏针组:男20例(20足),女9例(9足);软组织损伤Gustilo分型,Ⅰ型15足,Ⅱ型13足,ⅢA型1足;跟骨骨折Sanders分型,Ⅱ型9足,Ⅲ型18足,Ⅳ型2足;采用早期清创骨折复位克氏针固定治疗,软组织缺损采用VSD临时覆盖,Ⅱ期皮片或皮瓣移植术。钢板组:男18例(19足),女8例(10足);软组织损伤Gustilo分型,Ⅰ型13足,Ⅱ型14足,ⅢA型2足;跟骨骨折Sanders分型,Ⅱ型11足,Ⅲ型15足,Ⅳ型3足;采用早期清创,创面稳定后采用Ⅱ期骨折复位钢板内固定治疗。通过临床检查、影像学评估和AOFAS踝与后足评分进行预后评估。结果:克氏针组15例(23足)和钢板组13例(22足)得到随访,随访时间10～36个月,平均24个月。2组患者最后一次随访时的X线片与术前比较,跟骨高度、宽度、B觟hler角和Gissane角均有改善。根据AOFAS踝-后足评价,克氏针组优11足,良8足,可3足,差1足,术后早期伤口局部皮肤坏死2足,经换药后治愈,1足出现大面积皮肤坏死并深部感染,1足出现慢性骨髓炎,后期均行关节融合术;钢板组优7足,良4足,可4足,差7足,清创早期轻度并发症2例,慢性骨髓炎1例,Ⅱ期术后切口并发症10例,其中皮肤坏死7例,浅表感染3例。2组放射学指标和AOFAS踝-后足评分比较,差异有统计学意义;而清创术后早期并发症比较,差异无统计学意义。结论:早期清创克氏针固定治疗开放性跟骨骨折早期并发症较少,是一种简单安全有效的治疗方法。     

非植骨技术结合锁定钛板治疗跟骨粉碎性骨折的疗效观察

目的：观察锁定钛板结合非植骨手术治疗累及距下关节的跟骨骨折的疗效。方法：应用非植骨技术结合锁定钛板治疗SandersⅢ型、Ⅳ型跟骨骨折36例（41足）,采用美国足踝外科AOFAS踝-后足评分系统评价术后功能。结果：36例随访时间8-30个月,平均14个月,41足跟骨高度及宽度恢复良好,关节面复位满意;B？hler角和 Gissan角分别由术前的6.3°±9.2°、102.6°±12.11°恢复到术后的33.1°±6.5°和115.6°±12.2°;优15足,良19足,可5足,差2足,优良率为82.9％。结论：非植骨技术结合锁定钛板手术治疗跟骨骨折,可取得满意疗效。     

严重粉碎性跟骨骨折的治疗

目的 探讨严重粉碎性跟骨骨折的治疗方法。方法 45足严重粉碎性跟骨骨折给予一期植骨，解剖型钢板内固定。按Sander分型：其中Ⅲ型36足，Ⅳ型9足。结果 骨折全部愈合。随访时间8个月，3．5年，平均16．8个月。按Maryland评分系统进行术后功能评价，其中优14足，良22足，可8足，差1足，优良率80．0％。结论 一期植骨，解剖型钢板内固定是治疗严重粉碎性跟骨骨折的有效方法。     

距下关节撑开植骨融合治疗跟骨骨折畸形愈合

目的 报告并评价撑开植骨距下关节融合治疗跟骨骨折畸形的效果.方法 2004年9月至2008年1月共收治32例跟骨骨折畸形愈合患者.按照Stephens CT分型Ⅱ型畸形28例,Ⅲ型4例;术前X线及CT检查,跟骨距骨角均值18.1°,美国足踝外科协会(AOFAS)评分均值36.3.手术采用撑开植骨距下关节融合的方法治疗,术后定期随访,测量距骨跟骨角,行AOFAS评分.结果 32例患者均获随访,随访时间24-65个月,平均34个月.除1例术后创口皮缘浅表坏死经换药愈合外,切口均一期愈合,无感染发生.术后3个月融合处均获骨性愈合.末次随访时,距骨跟骨角均值22.9°,功能评分平均77.5分.与术前比较差异具有统计学意义(P<0.05).结论 撑开植骨距下关节融合及外侧骨突切除能纠正或减轻跟骨骨折畸形愈合的主要病理改变,并有效地改善症状,是治疗跟骨骨折畸形愈合较为实用的方法.     

跟骨骨折的手术治疗策略及疗效分析

目的 探讨跟骨骨折的受伤机制、临床分型、手术治疗方法及其疗效.方法 2005年6月至2009年5月共收治70例(83足)闭合性新鲜跟骨骨折患者,男45例,女25例;年龄18～62岁,平均38.3岁.骨折根据Essex-Lopresti分类:关节外骨折20足(前突骨折5足,体部骨折9足,结节部骨折3足,内外侧突骨折3足),关节内骨折63足(舌状骨折25足,关节压缩型骨折38足).63足关节内骨折根据Sanders分型:Ⅱ型30足,Ⅲ型21足,Ⅳ型12足.采用常规足外侧"L"形切开复位普通钢板或锁定钢板内固定50足,微创切开复位螺钉固定20足,撬拨复位克氏针(或加螺钉)固定13足.20足骨缺损＞2 cm3,行骨移植治疗.术后采用美国足踝外科协会(AOFAS)踝与后足评分评价患者足部功能恢复情况. 结果 70例患者术后获12～30个月(平均18个月)随访.末次随访时70例患者83足AOFAS踝与后足评分平均为(90.3±11.0)分(48～100分).20足关节外骨折患者AOFAS踝与后足评分平均为(98.1±2.6)分(90～100分),无并发症发生.63足关节内骨折患者AOFAS踝与后足评分平均为(87.8±11.4)分(48～100分).并发症包括:切口皮缘坏死2足,经换药后创面闭合;腓肠神经损伤4足;距下关节创伤性关节炎10足. 结论 对于不同类型的跟骨骨折,术前慎重评估软组织损伤和骨折类型、程度,采用适当的治疗方法,可以获得较好疗效.关节外骨折的疗效明显优于关节内骨折.     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

Intraoperative autotransfusion is associated with modest reduction of allogeneic transfusion in prosthetic hip surgery

Background: The efficacy of intraoperative salvage and washing of wound blood and the predictors of allogeneic red cell transfusions in prosthetic hip surgery are insufficiently known.
Methods: In 96 patients, undergoing primary or revision surgery, salvaged and washed red cells and, if necessary, allogeneic blood were used to keep haematocrit not lower than 33%. The bleeding of red cells during hospital stay was calculated from the red cell balance. The preoperative red cell reserve (millilitres of red cells in excess of a haematocrit of 33%) was estimated and the difference between this volume and the total bleeding of red cells was retrospectively used to classify patients with regard to the need for red cells. Stepwise regression analysis was used to define patient-related variables associated with allogeneic blood transfusion.
Results: Preoperative knowledge of the type of operation (primary, revision), the preoperative red cell reserve, and the body mass could predict roughly half of the need for banked blood (r²=0.45). Only one-third of the total bleeding of red cells was retransfused. For complete avoidance of allogeneic blood, autotransfusion was most effective in patients with a moderate need (0–4 u). However, 32% of such patients required allogeneic blood.
Conclusions: Autotransfusion has a limited efficacy to decrease the need for allogeneic blood, and other blood-saving methods should be added for this purpose. It is difficult to predict the need for allogeneic blood preoperatively.     

缺氧对肾小管上皮细胞分泌外泌体的影响

目的    观察缺氧对肾小管上皮细胞分泌外泌体的影响,探讨外泌体在缺氧致肾脏损伤中的作用及机制。 方法    （1）常氧（21% O₂）及缺氧（1% O₂）分别处理大鼠肾小管上皮细胞（NRK-52E）48 h,收集细胞上清液并使用高速梯度离心法分离外泌体。采用透射电镜、纳米示踪分析、Western印迹、蛋白浓度定量鉴定并比较两组外泌体的基本特性。（2）在共培养实验中,以不同浓度（1、10、50、100、300 mg/L）的常氧外泌体、缺氧外泌体分别干预脂多糖（LPS）诱导的大鼠原代腹腔巨噬细胞,使用实时荧光定量PCR与酶联免疫吸附试验（ELISA）法分别检测巨噬细胞白细胞介素6（IL-6）、肿瘤坏死因子α（TNF-α）、诱导型氮氧化物合酶（iNOS）水平;使用Western印迹法检测巨噬细胞磷酸化（p）STAT/STAT及细胞因子信号传导抑制蛋白1（SOCS1）的蛋白表达;最后,使用实时荧光定量PCR法检测常氧外泌体与缺氧外泌体中炎性反应相关微RNA（microRNA,miR）的表达差异。 结果    （1）离心得到的囊泡具有外泌体典型的结构,粒径小于150 nm,表达外泌体标志蛋白CD63,说明分离得到外泌体。缺氧对肾小管上皮细胞分泌的外泌体形态、粒径分布比例无明显影响,但提高了外泌体的分泌量。（2）缺氧外泌体相比于常氧外泌体促进了LPS诱导的M1型巨噬细胞IL-6、TNF-α、iNOS 的表达和分泌（均P＜0.01）,同时提高STAT的磷酸化水平并减少SOCS1的蛋白表达（均P＜0.01）;对炎性反应相关microRNA检测发现缺氧外泌体中miR-155、miR-27a表达量较常氧外泌体明显升高（P＜0.05）。 结论    缺氧可改变外泌体的生物学功能,表现为协同促进LPS诱导的M1型巨噬细胞的表型转化,这可能是慢性肾脏病微炎性反应状态持续的原因之一。     

In Vitro Function and Durability Assessment of a Novel Polyurethane Heart Valve Prosthesis

Abstract While flexible-leaflet, central-flow prosthetic heart valves promise relief from anticoagulation therapy, they continue to be restricted by inadequate durability. In consequence, a novel trileaflet valve, made entirely from polyurethane, has been developed. A batch of 6 consecutively manufactured polyurethane valves was subjected to hydrodynamic function and accelerated fatigue testing. Computerized data acquisition and control systems have been introduced to improve valve testing methodologies. In terms of hydrodynamic function, the polyurethane valve demonstrates transvalvular pressure gradients similar to those for a bioprosthetic valve (Carpentier-Edwards) and levels of retrograde flow significantly less than those for either the bioprosthetic valve or a bileaflet mechanical valve (St Jude Medical). The equivalent of 10 years of cycling without failure has been exceeded by all 6 polyurethane valves in accelerated fatigue tests with 2 valves remaining intact after 674 million cycles (equivalent to approximately 17 years) in continuing tests. Highspeed photography revealed considerable differences in leaflet motion between valves cycled at accelerated and physiological rates.     

Negative pressure ventilation vs. spontaneous assisted ventilation during rigid bronchoscopy: A controlled randomised trial

Background: Ventilation during interventional rigid bronchoscopy (IRB) under general anaesthesia (jet ventilation, positive pressure ventilation and spontaneous assisted ventilation) may offer some difficulties. This study compares the effectiveness during IRB of intermittent negative pressure ventilation (INPV) and spontaneous assisted ventilation (SAV). Methods: Thirty-eight patients submitted to IRB were randomised into two groups: SAV or INPV. All patients received a total intravenous anaesthesia; INPV patients were paralysed. Pre-and intra-operative arterial blood gases and O₂ flow through a rigid bronchoscope were assessed. The endoscopist applying a subjective score evaluated the operating conditions. Results: Patients of the INPV group, as compared to the SAV group, required a lower dosage of fentanyl (2.6 ± 1.8 (μg · kg^?1· h^?1 vs. 6.6 ± 4.8 μg · kg^?1· h^?1), a lower O₂ supply (3.3 ± 2.8 1/min vs. 11.6 ± 3.4 1/min), a shorter recovery time (5.4 ± 2.9 min vs. 9.8 ± 7.1 min) and no manually assisted ventilation (0 ± 0 vs. 1 ± 1.1 nd?/procedure). Intraoperative PaCO₂ was higher in the SAV (8.1 ± 1.3 kPa) than in the INPV group (5.0 ± 1.6 kPa) and intraoperative pH differed in the two groups (7.26 ± 0.05, SAV vs. 7.47 ± 0.08, INPV). Operating conditions, as assessed by a subjective score, were considered better with INPV than with SAV (4.9 vs. 4.3). Conclusions: As compared to SAV, INPV in paralysed patients during IRB reduces administration of opioids, shortens recovery time, prevents respiratory acidosis, excludes the need for manually assisted ventilation, reduces 02 need and affords optimal surgical conditions. INPV appears a safe, non-invasive and effective ventilatory management during IRB.