肝外伤选择不同术式意义的探讨

目的探讨不同术式综合应用对不同程度不同类型肝外伤的治疗效果。方法分析我院1998年1月至2004年11月经手术治疗肝外伤49例的手术方式:肝缝合修补术7例;肝修补加门静脉裂口修补1例;肝动脉结扎加肝缝合修补3例;肝切开缝扎术(应用手指折断技术即FFT肝造口选择性血管胆管缝扎,缝合肝裂口)17例;清创性肝切除18例,其中5例另行肝右静脉缝扎,3例另行肝右静脉缝扎加肝后下腔静脉修补;规则性肝切除3例(右半肝2例,左外叶1例),其中2例另行肝后下腔静脉修补。结果除3例术前因重度休克,术中出现不可逆DIC,术后因MODS死亡外,其他病例均抢救成功,死亡率6.12%,无严重术后并发症。结论正确的术式选择是提高严重肝外伤疗效的关键。手术过程不能局限于肝表面止血,肝内管道处理更为重要;肝切开缝扎术及清创性肝切除术适用于大宗肝外伤病例。     

严重肝外伤伴肝周大血管破裂的手术治疗

目的 探讨严重肝外伤伴肝周大血管破裂手术治疗的临床效果.方法 总结2000年12月至2008年5月解放军一零一医院收治的12例严重肝外伤伴肝周大血管破裂的临床资料,分析治疗效果.本组全部患者病例均为急诊手术.严重肝组织毁损行肝叶切除6例,其中肝右后叶切除1例,非规则性肝右叶切除1例,左半肝切除3例,左外叶切除1例,非严重的肝破裂处均以间断缝合修补.肝周血管破裂行修补术7例,其中肝后下腔静脉破裂修补术3例(经肝正中裂劈开、肝后下腔静脉修补术2例,直接行下腔静脉破裂修补术1例),门静脉破裂行间断缝合修补术2例,肝右静脉破裂行间断缝合修补术2例.肝静脉缝扎7例,其中肝右静脉并肝中静脉缝扎术1例,肝右静脉缝扎术1例,肝中分支静脉缝扎术2例,肝左静脉缝扎术3例.肝固有动脉结扎1例.肝周纱布填塞3例.结果 本组患者治愈9例,死亡3例,其中死于术中严重创伤伴出血性休克2例,死于重型颅脑伤及出血性休克1例.结论 及时手术,确切止血及正确的手术方式是抢救成功的关键.     

严重肝外伤术后并发症防治体会

目的:总结严重肝外伤术后并发症的防治经验.方法:回顾分析近10年经手术治疗的56例严重肝外伤患者,15例伴合并伤(占26.8%),采用深层褥式缝合、大网膜填塞、选择性肝动脉结扎、肝后纱布填塞及清创性肝切除,作为处理严重肝外伤的手术方式,同时治疗合并伤.结果:术后17例发生并发症(占30.3%),9例死亡(占16.1%).因失血性休克术中死亡1例.术后并发症是死亡的主要原因,术后死亡原因:术后出血2例、MOF4例、严重腹腔感染并胆瘘1例、脑疝1例.其中伴合并伤死亡4例(占26.7%).结论:彻底止血、清创、引流,严防MOF发生,是防治严重肝外伤术后并发症的根本措施.     

严重肝外伤伴肝周大血管破裂的手术治疗

目的 探讨严重肝外伤伴肝周大血管破裂手术治疗的临床效果.方法 总结2000年12月至2008年5月解放军一零一医院收治的12例严重肝外伤伴肝周大血管破裂的临床资料,分析治疗效果.本组全部患者病例均为急诊手术.严重肝组织毁损行肝叶切除6例,其中肝右后叶切除1例,非规则性肝右叶切除1例,左半肝切除3例,左外叶切除1例,非严重的肝破裂处均以间断缝合修补.肝周血管破裂行修补术7例,其中肝后下腔静脉破裂修补术3例(经肝正中裂劈开、肝后下腔静脉修补术2例,直接行下腔静脉破裂修补术1例),门静脉破裂行间断缝合修补术2例,肝右静脉破裂行间断缝合修补术2例.肝静脉缝扎7例,其中肝右静脉并肝中静脉缝扎术1例,肝右静脉缝扎术1例,肝中分支静脉缝扎术2例,肝左静脉缝扎术3例.肝固有动脉结扎1例.肝周纱布填塞3例.结果 本组患者治愈9例,死亡3例,其中死于术中严重创伤伴出血性休克2例,死于重型颅脑伤及出血性休克1例.结论 及时手术,确切止血及正确的手术方式是抢救成功的关键.     

严重肝外伤伴肝周大血管破裂的手术治疗

目的 探讨严重肝外伤伴肝周大血管破裂手术治疗的临床效果.方法 总结2000年12月至2008年5月解放军一零一医院收治的12例严重肝外伤伴肝周大血管破裂的临床资料,分析治疗效果.本组全部患者病例均为急诊手术.严重肝组织毁损行肝叶切除6例,其中肝右后叶切除1例,非规则性肝右叶切除1例,左半肝切除3例,左外叶切除1例,非严重的肝破裂处均以间断缝合修补.肝周血管破裂行修补术7例,其中肝后下腔静脉破裂修补术3例(经肝正中裂劈开、肝后下腔静脉修补术2例,直接行下腔静脉破裂修补术1例),门静脉破裂行间断缝合修补术2例,肝右静脉破裂行间断缝合修补术2例.肝静脉缝扎7例,其中肝右静脉并肝中静脉缝扎术1例,肝右静脉缝扎术1例,肝中分支静脉缝扎术2例,肝左静脉缝扎术3例.肝固有动脉结扎1例.肝周纱布填塞3例.结果 本组患者治愈9例,死亡3例,其中死于术中严重创伤伴出血性休克2例,死于重型颅脑伤及出血性休克1例.结论 及时手术,确切止血及正确的手术方式是抢救成功的关键.     

严重肝外伤伴肝周大血管破裂的手术治疗

目的 探讨严重肝外伤伴肝周大血管破裂手术治疗的临床效果.方法 总结2000年12月至2008年5月解放军一零一医院收治的12例严重肝外伤伴肝周大血管破裂的临床资料,分析治疗效果.本组全部患者病例均为急诊手术.严重肝组织毁损行肝叶切除6例,其中肝右后叶切除1例,非规则性肝右叶切除1例,左半肝切除3例,左外叶切除1例,非严重的肝破裂处均以间断缝合修补.肝周血管破裂行修补术7例,其中肝后下腔静脉破裂修补术3例(经肝正中裂劈开、肝后下腔静脉修补术2例,直接行下腔静脉破裂修补术1例),门静脉破裂行间断缝合修补术2例,肝右静脉破裂行间断缝合修补术2例.肝静脉缝扎7例,其中肝右静脉并肝中静脉缝扎术1例,肝右静脉缝扎术1例,肝中分支静脉缝扎术2例,肝左静脉缝扎术3例.肝固有动脉结扎1例.肝周纱布填塞3例.结果 本组患者治愈9例,死亡3例,其中死于术中严重创伤伴出血性休克2例,死于重型颅脑伤及出血性休克1例.结论 及时手术,确切止血及正确的手术方式是抢救成功的关键.     

严重肝外伤伴肝周大血管破裂的手术治疗

目的 探讨严重肝外伤伴肝周大血管破裂手术治疗的临床效果.方法 总结2000年12月至2008年5月解放军一零一医院收治的12例严重肝外伤伴肝周大血管破裂的临床资料,分析治疗效果.本组全部患者病例均为急诊手术.严重肝组织毁损行肝叶切除6例,其中肝右后叶切除1例,非规则性肝右叶切除1例,左半肝切除3例,左外叶切除1例,非严重的肝破裂处均以间断缝合修补.肝周血管破裂行修补术7例,其中肝后下腔静脉破裂修补术3例(经肝正中裂劈开、肝后下腔静脉修补术2例,直接行下腔静脉破裂修补术1例),门静脉破裂行间断缝合修补术2例,肝右静脉破裂行间断缝合修补术2例.肝静脉缝扎7例,其中肝右静脉并肝中静脉缝扎术1例,肝右静脉缝扎术1例,肝中分支静脉缝扎术2例,肝左静脉缝扎术3例.肝固有动脉结扎1例.肝周纱布填塞3例.结果 本组患者治愈9例,死亡3例,其中死于术中严重创伤伴出血性休克2例,死于重型颅脑伤及出血性休克1例.结论 及时手术,确切止血及正确的手术方式是抢救成功的关键.     

严重肝外伤伴肝周大血管破裂的手术治疗

目的 探讨严重肝外伤伴肝周大血管破裂手术治疗的临床效果.方法 总结2000年12月至2008年5月解放军一零一医院收治的12例严重肝外伤伴肝周大血管破裂的临床资料,分析治疗效果.本组全部患者病例均为急诊手术.严重肝组织毁损行肝叶切除6例,其中肝右后叶切除1例,非规则性肝右叶切除1例,左半肝切除3例,左外叶切除1例,非严重的肝破裂处均以间断缝合修补.肝周血管破裂行修补术7例,其中肝后下腔静脉破裂修补术3例(经肝正中裂劈开、肝后下腔静脉修补术2例,直接行下腔静脉破裂修补术1例),门静脉破裂行间断缝合修补术2例,肝右静脉破裂行间断缝合修补术2例.肝静脉缝扎7例,其中肝右静脉并肝中静脉缝扎术1例,肝右静脉缝扎术1例,肝中分支静脉缝扎术2例,肝左静脉缝扎术3例.肝固有动脉结扎1例.肝周纱布填塞3例.结果 本组患者治愈9例,死亡3例,其中死于术中严重创伤伴出血性休克2例,死于重型颅脑伤及出血性休克1例.结论 及时手术,确切止血及正确的手术方式是抢救成功的关键.     

严重肝外伤伴肝周大血管破裂的手术治疗

目的 探讨严重肝外伤伴肝周大血管破裂手术治疗的临床效果.方法 总结2000年12月至2008年5月解放军一零一医院收治的12例严重肝外伤伴肝周大血管破裂的临床资料,分析治疗效果.本组全部患者病例均为急诊手术.严重肝组织毁损行肝叶切除6例,其中肝右后叶切除1例,非规则性肝右叶切除1例,左半肝切除3例,左外叶切除1例,非严重的肝破裂处均以间断缝合修补.肝周血管破裂行修补术7例,其中肝后下腔静脉破裂修补术3例(经肝正中裂劈开、肝后下腔静脉修补术2例,直接行下腔静脉破裂修补术1例),门静脉破裂行间断缝合修补术2例,肝右静脉破裂行间断缝合修补术2例.肝静脉缝扎7例,其中肝右静脉并肝中静脉缝扎术1例,肝右静脉缝扎术1例,肝中分支静脉缝扎术2例,肝左静脉缝扎术3例.肝固有动脉结扎1例.肝周纱布填塞3例.结果 本组患者治愈9例,死亡3例,其中死于术中严重创伤伴出血性休克2例,死于重型颅脑伤及出血性休克1例.结论 及时手术,确切止血及正确的手术方式是抢救成功的关键.     

肝门血流阻断在腹腔镜肝切除术的应用

目的探讨腹腔镜肝切除术中肝门血流阻断技术应用的技术要点及可行性。方法回顾性分析广西医科大学第一附属医院微创外科2005年5月至2011年6月期间95例行肝门血流阻断的腹腔镜肝切除术病例的临床资料。结果腹腔镜肝左外叶切除21例,左半肝切除13例,右半肝切除4例,肝段切除17例,局部性肝切除24例,血管瘤切除5例,中转开腹手术11例。39例应用间断性Pringle法行全入肝血流阻断,阻断时间为(30.84±9.51)min;56例行选择性入肝血流阻断,包括14例经Glisson鞘一并阻断肝蒂,42例打开Glisson鞘,分离并阻断鞘内动脉及门静脉。12例于断肝前阻断肝静脉,包括7例缝扎肝左静脉,4例分离肝左静脉,1例分离肝右静脉;其余病例则在断肝过程中于断面内处理肝静脉。手术时间(236.80±95.97)min,术中出血(551.55±497.41)ml,输浓缩红细胞(2.60±2.23)U,血浆(211.90±179.29)ml。术后并发症包括肝断面出血4例,胸腔积液4例,肺部感染3例,腹水7例,胆瘘2例,死亡1例。术后住院时间(12.47±4.18)d。截止2012年2月29日,72例肝癌获随访,随访时间(24.14±16.62)个月(5～81个月),1年生存率为68.4%(54/79),3年生存率为21.5%(17/79)。结论在腹腔镜肝切除术中应用肝门血流阻断技术是可行的。     

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.