高速磨钻在侵袭性骨肿瘤治疗中的应用

目的：探讨高速磨钻在治疗侵袭性骨肿瘤治疗中的作用。方法：2000年4月～2001年9月收治长骨侵袭性骨肿瘤病例28例，采用高速磨钻方法治疗17例。首先，开窗刮除瘤腔内肿瘤组织，然后直视下应用高速磨钻沿各个方向仔细磨除瘤腔内壁表面骨嵴，尤其是瘤腔顶部，额外磨除瘤腔皮质骨下1～5mm的骨组织，直到显露正常骨质。必要时也磨除部分软骨下骨，部分病变区域需至关节软骨平面。即使病变部位骨皮质因侵蚀破坏后变薄或已经穿破，应用高速磨钻可能钻破骨皮质，也应继续磨除残留骨皮质，达到磨除干净为止。选择非结构性移植物，包括自体髂骨或同种异体骨、碳酸化羟基磷灰石，填充骨缺损。结果：术后平均随访时间16个月(7～24个月)。无局部复发及远处脏器转移。术后关节功能轻度受限1例；切口早期炎性反应2例；深部感染1例；病变部位远侧肿胀1例。未发生继发性病理骨折。结论：侵袭性骨肿瘤腔壁在肉眼和显微镜下均可见凸凹不平的骨嵴，常刮匙并不能刮除骨嵴间的肿瘤细胞。高速磨钻对骨组织具有较强的切割作用，能较易磨平凸出的骨嵴，虽然仍为病灶内手术，但应用高速磨钻后扩大了手术切除的范围，可以达到边缘切除的效果，保证手术的彻底性。高速磨钻的应用是减少侵袭性骨肿瘤复发的有效手段，值得普及、推广。     

微波原位灭活联合人工关节假体置换治疗四肢恶性骨肿瘤的疗效分析

 目的 探讨微波原位灭活联合人工假体置换术治疗四肢恶性骨肿瘤（侵袭范围超过骨全长2/3）的可行性。方法 2001年6月至2012年4月对19例侵袭范围超过骨全长2/3的原发恶性骨肿瘤及转移瘤患者采用微波灭活联合假体置换术进行治疗。男12例, 女7例;年龄11~65岁, 平均47岁。原发恶性骨肿瘤11例,转移瘤8例。股骨远端8例、胫骨近端6例、肱骨近端3例、股骨近端2例。术前X线、CT显示骨干皮质破坏小于骨全长的1/3,而MRI显示肿瘤侵袭范围超过骨全长2/3。依据MRI确定截骨范围,定制肿瘤型人工假体。采用常规肿瘤假体置换入路,按广泛切除原则充分显露瘤段骨及软组织肿块。使用铜网保护瘤段骨周围软组织,用2 450 MHz微波将瘤段骨内部加热到50 ℃,持续20 min,按术前测量长度进行截骨,人工关节假体重建,逐层缝合组织及皮肤。结果 手术时间平均100 min,术中失血量平均600 ml。随访10个月~5年,平均2.7年。原发恶性骨肿瘤患者中1例术后出现复发,带瘤生存;2例术后其他部位转移,死亡;余8例随访期间未出现复发或转移。6例转移瘤患者分别于术后5~20个月出现其他部位转移,死亡;2例随访期间未出现原位复发或转移。3例肱骨近端肿瘤患者术后肩关节外展、上举功能受限,其余患者无关节功能受限。结论 微波灭活联合人工假体置换术治疗髓腔内广泛受累的四肢恶性骨肿瘤,能最大限度地保留术后患者的肢体功能。     

冷冻外科治疗肢体恶性骨肿瘤

总结和评估液氮冷冻治疗肢体恶性骨肿瘤的价值。方法：对５４例肢体性骨肿瘤采用瘤骨液氮浸泡法，杀灭恶性肿瘤细胞，保留骨的原来结构，采用内固定术，恢复患者肢体的完整结构和功能。结果：经过平均５年随访，本组病例按Ｅｎｎｅｋｉｎｇ’ｓ肢体功能评价优良率６８．５％；局部肿瘤复发率在１１．１％，并发症为１８．５％，并节退变为２２．２％，肿瘤坏死率评价发现冷冻后肿瘤细胞完全坏死。结论：液氮瘤骨灭活法是肢体恶生骨肿     

冷冻外科治疗肢体恶性骨肿瘤△

目的总结和评估液氮冷冻治疗肢体恶性骨肿瘤的价值。方法对54例肢体恶性骨肿瘤采用瘤骨液氮浸泡法,杀灭恶性肿瘤细胞,保留骨的原来结构,采用内固定术,恢复患者肢体的完整结构和功能。结果经过平均5年随访,本组病例按Enneking's肢体功能评价优良率68.5%;局部肿瘤复发率在11.1%,并发症为18.5%,关节退变为22.2%。肿瘤坏死率评价发现冷冻后肿瘤细胞完全坏死。结论液氮瘤骨灭活法是肢体恶性骨肿瘤保肢术的有效方法。     

瘤段灭活再植治疗股骨皮质旁骨肉瘤1例(并文献复习)

皮质旁骨肉瘤占全身恶性骨肿瘤的0.6％～1％,临床少见,长管状骨好发.其治疗方式以手术为主,保肢治疗是医患双方的共同目标,符合现代肿瘤治疗发展趋势,主要方式有:肿瘤部分切除原位灭活、瘤段截除灭活再植、瘤段截除后异体半关节移植、肿瘤型人工关节置换.     

四肢骨骼系统恶性肿瘤保肢治疗的组织修复及功能重建

[目的]探讨恶性骨肿瘤切除后,采用同种异体骨移植和自体瘤段骨灭活再植进行保肢治疗的过程中组织修复及功能重建的重要性.[方法]回顾性研究本院收治的56例恶性骨肿瘤患者,其中男35例,女21例;年龄9～60岁,平均19岁.位于肱骨近段者9例,股骨远端30例,胫骨近段17例.成骨肉瘤32例,软骨肉瘤17例,恶性骨巨细胞瘤3例,转移瘤4例.采用同种异体骨移植和自体瘤段骨灭活再植修复肿瘤切除后骨缺损的同时行软组织修复和功能重建,按Mankin分级法评价保肢术后功能恢复情况,骨愈合情况及并发症等. [结果]本组优20例占35.7%,良11例占19.6%,可8例占14.3%,差17例占30%,治疗满意率70%.56例中无瘤存活38例,死亡12例,5年生存30例,生存率55%.其中51例随访时间超过10个月,均骨性愈合,无骨不连.除局部肿瘤复发以外,常见并发症有感染4例,骨折3例,关节面塌陷1例,关节强直5例,感染率仅7%.无内固定折断.[结论]采用同种异体骨移植和自体瘤段骨灭活再植对四肢恶性骨肿瘤行有效的组织修复和功能重建,不但可以保留肢体,且保留的肢体具有良好的功能,为四肢骨骼系统恶性肿瘤患者开辟了有效的治疗途径.     

活骨移植治疗四肢骨肿瘤切除后长段骨与关节缺损

目的:探讨四肢骨肿瘤的广泛或边缘切除后,长段骨关节缺损的修复方法及其疗效。方法:四肢骨肿瘤切除术后骨缺损14例,男10例,女4例;年龄4~37岁。骨巨细胞瘤4例,骨化性纤维瘤1例,非骨化性纤维瘤2例,韧带样纤维瘤1例,骨纤维结构不良3例,侵袭性骨母细胞瘤1例,软骨母细胞瘤1例,瘤样病损致骨溶解1例。14例四肢侵袭性良性骨肿瘤行肿瘤广泛或边缘切除,应用吻合血管的腓骨、带腓骨头腓骨近端和带旋髂深血管的髂骨瓣移植修复骨缺损、重建桡腕关节和重建肩关节。移植体行简单内固定加外固定。术后定期复查X线片、多普勒血管超声,其中3例行ECT核素骨扫描,并作关节功能评定。结果:随访3个月~5年,13例均于手术后3个月后达Ⅰ期愈合,其中1例因内固定松动再次手术而愈合。1例肿瘤局部复发,再次行肿瘤切刮与植骨术后愈合;2例畸形愈合行截骨矫形后愈合。关节功能评定:优9例,良3例,差2例。结论:骨肿瘤切除后行骨移植修复骨缺损、重建关节,手术切除彻底,复发率低,植骨愈合可靠,重建后的关节功能良好。     

复合移植重建恶性骨肿瘤切除后骨缺损

目的将切除的肿瘤骨去除瘤组织、经灭活处理后植回原位．重建骨骼的缺损。方法1997年7月～2000年12月．对24例长骨恶性骨肿瘤患者施行了广泛切除加灭活骨移植物复合假体重建骨缺损的治疗．其中成骨肉瘤17例，骨转移癌7例。肿瘤广泛切除后．清除瘤骨上所有的肿瘤组织，开槽打通髓腔，再经200g／L高渗盐水浸泡30mm．体积分数95％的酒精浸泡20min．然后植回原位。13例采用灭活肿瘤骨结合人工关节复台重建骨缺损．11例采用灭活肿瘤骨结合交锁髓内钉重建骨干缺损。所有成骨肉瘤患者术前均行两个周期的规范化疗。结果所有患者均获随访，中位随访时问为2.5年。术后1例患者发生灭活骨与宿主骨接合处的连接失败。2例患者在术后6个月～2年内局部复发，1例接受了肿瘤再切除治疗、另1例接受了截肢手术。无一例发生灭活骨的疲劳性骨折。术后6个月时重建关节的功能评分均在25分以上。结论应用自体灭活骨代替同种异体移植物进行复合移植重建骨缺损的优点包括：(1)相对于同种异体骨，降低了骨连接部的不愈台率；(2)降低了局部感染率；（3)造价低；(4)经过平均2．5年的随访，来发现灭活骨有异体骨移植常见的骨吸收现象。体外实验证实200g/G高渗盐水对骨的渗透力较强．具有良好的灭活效果。与酒精联合应用进一步降低了局部复发率。全部病例中只有2例局部复发．占9％．达到国际上对保肢术规定的局部复发率的要求。     

侵袭性骨肿瘤骨质破坏的开矿学观察和图像分析

将整个骨肿瘤制成组织大切片，通过光镜观察和图像分析，对１０例侵袭性骨肿瘤的骨质破坏机制进行研究，其中骨肉瘤２例，纤维肉瘤３例，骨巨细胞瘤，软骨母细胞瘤淋巴瘤，骨髓瘤和骨旁骨肉瘤各１例。结果表明：肿瘤中心区的骨质破坏程度明显高于肿瘤边缘区和外围区，同时未见到破骨细胞被激活致溶骨增强的现象，这些都是支持侵袭性骨钟瘤的骨质破坏机制，主要是肿瘤细胞直接溶骨的学说。     

带血供腓骨移植重建股骨近端溶骨性病变致骨缺损

[目的]评价带血供游离腓骨移植重建股骨近端侵袭性良性溶骨性病变所致骨缺损的临床疗效。[方法]总结自2008年4月~2013年3月收治股骨近端良性侵袭性肿瘤或肿瘤样病变共14例,采用病灶内扩大刮除、氯化锌烧灼瘤壁,吻合血管腓骨移植,支持钢板内固定等方法手术治疗,影像学随访评价病变转归、植骨愈合;采用改良肌肉骨髂系统肿瘤学会(Musculoskeletal Tumor Society,MSTS)肢体功能评价表随访肿瘤切除术后患者肢体功能。[结果]随访18~67个月,平均(35.71±15.80)个月。其中1例骨巨细胞瘤患者于术后12个月复发。其余13例患者随访期间均未见病变复发表现,钢板固定无松动、断裂,无术后病理性骨折,未见股骨头缺血性坏死等其他并发症。移植腓骨无缺血坏死表现、与受区2~7个月骨性愈合,平均愈合时间(4.54±1.27)个月。术后3、6个月MSTS功能评分依次为(25.57±4.27),(27.07±6.53)分。[结论]病灶刮除,氯化锌烧灼瘤壁,吻合血管腓骨移植填充重建,结合支持钢板内固定是股骨近端侵袭性良性肿瘤及瘤样病变的有效外科治疗方法。中期随访表现为病变复发率低,破坏骨结构得以重建,髋关节功能良好。     

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.