经尿道双极等离子电切术治疗良性前列腺增生症

目的 探讨经尿道前列腺等离子双极电切术治疗良性前列腺增生的临床疗效.方法 选取2014年5月至2015年5月收入本科室治疗的良性前列腺增生症(BPH)患者44例,随机分为观察组和对照组,每组22例.观察组采用经尿道前列腺等离子双极电切术(TUPKP)治疗,对照组采用经尿道前列腺电切术(TURP)治疗.对比两组手术时间、术中出血量、术后膀胱冲洗时间、留置导管时间、住院时间,并发症发生率、IPSS评分、QOL评分、Qmax和RVU等指标.结果 观察组术中出血量、术后膀胱冲洗时间、留置导管时间低于对照组,差异具有统计学意义(P＜0.05);两组手术时间、住院时间差异无统计学意义(P＞0.05).两组患者治疗后症状均明显改善,IPSS评分、QOL评分、残余尿RVU较治疗前明显下降(P＜0.05);最大尿流率Qmax较治疗前明显升高(P＜0.05);术前和术后3个月IPSS评分、QOL评分、Qmax、RVU比较,组间差异无统计学意义(P＞0.05).观察组患者并发症发生率(18.18％)明显低于对照组(59.09％),差异具有统计学意义(P＜0.05).结论 TUPKP治疗BPH具有更好的安全性,值得临床推广应用.     

TUERP与TKRP治疗大体积BPH的安全性和疗效比较

目的:比较经尿道双极等离子前列腺剜除术(transurethral enucleative resection of prostate,TUERP)与经尿道双极等离子前列腺电切术(transurethral plasma kinetic resection of the prostate,TKRP)治疗大体积BPH的安全性和疗效。方法:回顾性分析96例大体积BPH(前列腺体积70ml)患者的临床资料:60例行TUERP,36例行TKRP。所有患者手术前均行直肠指诊、经直肠前列腺彩超、尿流动力学检查及相关实验室检查,进行IPSS及QOL评分,就两种手术方式中前列腺切除重量、手术时间、术中出血量、留置导尿管时间、并发症、术后住院时间进行对比,同时就两组患者术前和术后IPSS、生活质量评分(quality of life score,QOL)、术后1个月的最大尿流率(Qmax)进行对比。结果:术前两组患者一般情况比较差异无统计学意义(P0.05);术后两组患者IPSS、QOL、Qmax(术后1个月)明显改善,与术前比较差异有统计学意义(P0.01),但组间比较差异无统计学意义(P0.05)。TUERP组术中出血量较少,其手术时间、留置导尿管时间、术后住院时间明显小于TKRP组(P0.05),前列腺切除重量,TUERP组明显高于TKRP组(P0.05)。结论:TUERP组与TKRP组对治疗大体积BPH疗效相同,TUERP对大体积BPH患者更安全。     

小功率钬激光前列腺剜除术在良性前列腺增生治疗中的临床价值

目的 评价小功率钬激光前列腺剜除术用于良性前列腺增生治疗中的临床价值.方法 选择2012年1月至2015年6月本院收治的良性前列腺增生患者312例,将患者随机分为两组,观察组为行小功率钬激光前列腺剜除术组,对照组为行经尿道前列腺电切术组,每组156例.比较两组手术时间、切除增生重量、术后血清Na+、血Hb、并发症、导尿管留置时间、住院时间以及术后最大尿流率(Qmax)、国际前列腺症状评分(IPSS)、生活质量评分(QOL)、血清前列腺特异性抗原(PSA).结果 两组患者围手术期指标结果显示,观察组切除标本重量、血清Na+、Hb、术后冲洗时间、尿管留置时间、术后住院时间及并发症等与对照组相比较,差异有统计学意义(P＜0.05);两组患者术后随访结果显示,观察组3、6及12个月的Qmax、IPSS、QOL及PSA与对照组相比较,差异均无统计学意义(P＞0.05).结论 小功率钬激光前列腺剜除术与经尿道前列腺电切术用于治疗良性前列腺增生疗效相当,且具有并发症发生率低的优点,值得在临床上推广应用.     

前列腺等离子电切剜除术治疗良性前列腺增生的疗效观察

目的探讨前列腺等离子电切剜除术(PKEP)与经尿道前列腺等离子双极汽化电切术(PKRP)治疗良性前列腺增生(BPH)的效果。方法选择2014-01—2017-01间中山市火炬开发区医院收治的61例BPH患者。将行PKEP的21例患者纳入观察组,行PKRP的40例患者纳入对照组。比较2组的疗效。结果观察组手术时间、术中出血量、膀胱冲洗时间、切除前列腺质量及并发症发生率均优于对照组。差异均有统计学意义(P0.05)。2组术后3个月的QOL评分、IPSS评分、PRV及Qmax均优于术前(P0.05),但组间差异无统计学意义(P0.05)。结论与PKRP比较,采用PKEP治疗BPH,可缩短手术时间和术后膀胱冲洗时间,减少术中出血量,且术后并发症发生率低。     

经尿道前列腺等离子双极电切剜除术治疗良性前列腺增生效果分析

目的探讨经尿道前列腺等离子双极电切剜除术(TUPKEP)和经尿道前列腺电切术(TURP)治疗良性前列腺增生(BPH)的效果及安全性。方法将80例BPH患者根据不同手术方法分为2组,每组40例,分别实施TUPKEP(研究组)和TURP(对照组)。比较2组手术时间、术中出血量、术后膀胱冲洗时间、住院时间、并发症发生率及手术前后最大尿流率(Qmax)、残余尿量(RUV)、国际前列腺症状评分(IPSS)和生活质量(QOL)。结果研究组手术时间、术中出血量、术后膀胱冲洗时间、住院时间均优于对照组,术后尿道狭窄、继发性出血、电切综合征等并发症发生率均低于对照组,差异均有统计学意义(P<0.05)。2组患者术前Qmax、RUV、IPSS以及QOL评分差异均无统计学意义(P>0.05)。术后3个月2组患者Qmax、RUV、IPSS以及QOL评分均优于术前,差异有统计学意义(P<0.05);但2组间比较,差异无统计学意义(P>0.05)。结论 TUPKEP和TURP治疗BPH,均具有显著效果,但TUPKEP创伤小,术后并发症少,恢复时间短,安全性高。     

剥离式经尿道前列腺切除术与经尿道前列腺电切术治疗良性前列腺增生的比较研究

目的:比较经尿道前列腺电切术(TURP)与使用专用前列腺增生腺体剥离器行剥离式经尿道前列腺切除术(剥离式TURP,TUERP)治疗良性前列腺增生(BPH)的疗效与安全性。方法:BPH患者630例,均具备手术指征,随机分为TURP组(305例)和剥离式TURP组(325例)。术前两组年龄、前列腺体积、国际前列腺症状评分(IPSS)、最大尿流率(Qmax)数值比较,差异无统计学意义(P均0.05)。记录两组手术时间、手术切除率、术后需要持续膀胱冲洗时间、术后生活质量评分(QOL)、手术并发症数据,进行统计学分析。结果:手术后的资料分析显示,TUERP手术切除率优于TURP组的手术切除率[(60.1±12.3)%vs(47.0±13.3)%,P0.05)];TUERP组平均手术时间比TURP组短[(40.4±14.2)min vs(57.9±15.9)min,P0.05];术后冲洗时间较短[(2.2±1.1)d vs(2.7±0.6)d,P0.05]。TUERP组手术前后血清Na+和血红蛋白浓度变化无统计学意义,TURP组血清Na+和血红蛋白浓度变化有统计学意义[血Na+:(141.2±3.5)mmol/L vs(136.9±4.7)mmol/L,P0.01,血红蛋白:(137.6±8.8)g/L vs(124.8±9.6)g/L,P0.01]。术后3个月,两组的IPSS评分、QOL评分、Qmax评分均较术前有显著改善(P均0.01),组间比较无显著性差异。(P0.05)。结论:剥离式TURP治疗BPH和TURP比较,具有手术时间短、手术切除率高、术中出血少、术后恢复快、并发症少等优点,在临床上有良好的应用前景。     

经尿道双极等离子电切术治疗良性前列腺增生效果观察

目的比较经尿道前列腺双极等离子电切术(TPKR)及经尿道前列腺电切术(TURP)治疗良性前列腺增生(BPH)的效果。方法随机将130例BPH患者分为2组,每组65例。对照组给予TURP,观察组实施TPKR。比较分析2组治疗效果。结果观察组手术时间和术中出血量及术后并发症均少于对照组,差异有统计学意义(P0.05)。术后膀胱冲洗时间、留置尿管时间及住院时间,2组差异无统计学意义(P0.05)。术后2组患者IPSS、QOL和Qmax改善程度均优于术前,差异有统计学意义(P0.05),但组间比较差异无统计学意义(P0.05)。结论 TURP和TPKR治疗BPH均有良好的治疗效果,但TPKR出血量少及并发症发生率低。     

经尿道等离子前列腺剜除术治疗高龄高危前列腺增生症

目的 探讨经尿道等离子前列腺剜除术治疗高龄高危良性前列腺增生(BPH)患者的安全性及疗效.方法 将70例高龄高危BPH患者随机分为两组,每组35例,分别行经尿道等离子前列腺剜除术(TUPKEP)和传统的经尿道前列腺电切术(TURP).比较两组患者的手术时间、出血量、前列腺腺体切除重量、术后膀胱冲洗时间、术后住院天数、术后国际前列腺症状评分(IPSS)、生活质量评分(QOL)、残余尿量(PVR)、最大尿流率(Qmax)等指标.对两组指标进行统计学分析.结果 TUPKEP组在手术的出血量、手术时间、术后膀胱冲洗时间以及术后的住院时间要明显小于TURP组(P＜0.05);TUPKEP组前列腺腺体切除重量大于TURP组(P＜0.05);两组患者术后随访3个月,残余尿、国际前列腺症状评分、生活质量评分差异均无显著性意义(P ＜0.05);TUPKEP组术后最大尿流率大于TURP组,两组比较有显著性差异(P＜0.05).结论 TUPKEP治疗BPH疗效确切,且安全性较好,特别适用于高龄高危的患者.     

经尿道等离子前列腺剜除术与电切术治疗前列腺增生的疗效分析

目的比较经尿道等离子前列腺剜除术(TUERP)和等离子前列腺电切术(PKRP)治疗前列腺增生患者的临床疗效,为基层医院前列腺增生的手术方式的选择提供参考。方法选取自2014年9月到2016年9月期间我院泌尿外科收治的前列腺增生患者68例,将患者随机分为TUERP组34例和PKRP组34例。分析两组手术时间、术中出血量、切除组织量、有无包膜穿孔以及术后3个月的国际前列腺症状评分(IPSS)、生活质量评分(QOL)、残余尿量(PVR)、最大尿流率(Qmax)等指标。结果与PKRP相比,TUERP手术时间更短,出血量更少,包膜穿孔例数少,切除组织量多、术后冲洗时间更短(P0.05)。此外,TUERP组无输血病例,PKRP组有1例患者由于出血严重而输注2个单位的红细胞悬液。术后随访3个月,我们发现两组患者术后3个月的PVR、Qmax、IPSS、QOL均较术前有明显改善(P0.05),术后3个月两组间PVR、Qmax、IPSS、QOL差异无统计学意义(P0.05)。结论 TUERP近期手术疗效不差于PKRP术,但与PKRP术相比,切除组织更完全,出血量少,手术时间更短,值得在基层医院推广应用。远期效果仍有待长期随访的大样本随机对照研究进一步证实。     

腹腔镜下耻骨后保留尿道前列腺切除术与经尿道前列腺电切术的比较

目的:比较腹腔镜下耻骨后保留尿道前列腺切除术与经尿道前列腺电切术(transurethral resection of prostate,TURP)治疗大体积前列腺的手术效果。方法:将2013年12月至2014年12月入院的40例前列腺体积大于80 ml的患者按计算机随机数字法分为两组,20例接受腹腔镜下耻骨后保留尿道前列腺切除术,20例接受TURP,应用独立样本t检验方法对比两组患者年龄、术前前列腺体积、国际前列腺症状评分(international prostate symptom score,IPSS)、生活质量指数评分(quality of life score,QOL)、最大尿流率(maximum flow rate,Qmax)、残余尿、血红蛋白、手术时间、术中出血量、术后冲洗时间、留置尿管时间、术后住院时间、术后3个月IPSS、QOL、Qmax、残余尿的差异。结果:两组年龄、术前前列腺体积、IPSS、QOL、Qmax、残余尿、术前血红蛋白、术后3个月IPSS、QOL、Qmax差异无统计学意义(P0.05),手术时间、术中出血量、术后冲洗时间、拔除尿管时间、术后住院时间两组相比差异有统计学意义(P0.05)。结论:腹腔镜下耻骨后保留尿道前列腺切除术治疗大体积前列腺较TURP具有优势,表现为手术时间短、出血量少、术后冲洗时间短、留置尿管时间短等。     

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.