抑肽酶对心瓣膜置换术患者围术期IL—6，IL—8释放的影响

目的：了解抑肽酶对心瓣膜置换术患者围术期全身炎症应答的影响,方法：将接受心瓣膜置换术的16例患者随机分为：对照组(n=8),不用抑肽酶,治疗组（n=8),于预冲液中加入抑肽酶300万单位,分别于术前,停机,停机后1小时和术后1天抽取外周血2ml,收集血清用酶联免疫吸附测定（ELISA）双抗夹心法检测白细胞介素－6（IL－6）和白细胞介素－8（IL－8）,。结果：体外循环术后患者血清IL－6和IL－8水平升高（P＜0．05）,术后1天仍高于术前,停机后1小时治疗组IL－6水平和停机量IL－8水平低于对照组,但判别均无显著性意义＊（P＞0．05）,结论：尽管抑肽酶有抗炎症效应,但仅预冲液中加入抑肽酶300万单位无法有效抑制心瓣膜置换术患者围术期促炎性细胞因子IL－6和IL－8的释放。     

小剂量抑肽酶用于体外循环肺保护的临床研究

目的：探讨小剂量抑肽酶对体外循环（CPB）所致急性损伤的保护作用。方法：28例首次择期心脏瓣膜置换术患者随机分为抑肽酶组和对照组，各14例。于麻醉诱导前，CPB前，CPB结束后1h及24h测定TNF－α和IL－10血浆水平，于CPB前，CPB结束后10min,1h测定呼吸指数（RI）。结果：CPB结束后1h及24h，对照组TNF－α明显高于诱导前及相同时点抑肽酶组的水平（P＜0．05），CPB结束后1h，两组IL－10均明显增加，但抑肽酶组明显高于对照组（P＜0．05）；CPB结束后10min及1h，对照组RI较基础值及抑肽酶组明显增高（P＜0．05）。结论：小剂量抑肽酶具有抗炎及肺保护作用。     

术前应用抑肽酶对脑膜瘤切除术患者围术期凝血功能的影响

目的 评价术前应用小剂量抑肽酶对脑膜瘤切除术患者围术期凝血功能的影响。方法60例择期行脑膜瘤切除术患者，年龄18～60岁，ASAⅠ或Ⅱ级，随机分为对照组（Ⅰ组）、抑肽酶50万KIU组（Ⅱ组）、100万KIU组（Ⅲ组）和200万KIU组（Ⅳ组），每组15例。Ⅱ～Ⅳ组以100ml／h的速率于麻醉诱导后持续输注相应剂量抑肽酶（溶于50ml生理盐水中）。分别在入室后（基础值）、抑肽酶输注完成时、取瘤时、术毕、术后24h测定血常规和凝血功能各指标。结果各组一般资料、手术时间、尿量、输液量、出血量、肿瘤体积比较差异无统计学意义（P〉0．05）。与基础值比较，四组术中及术后红细胞计数、血红蛋白、红细胞压积、血小板计数均降低，术后白细胞计数升高，术中血浆凝血酶原时间、纤维蛋白原、凝血速率均延长或降低，Ⅲ、Ⅳ组术中活化凝血活酶时间延长，Ⅳ组术中血小板功能增强（P〈0．05）；与Ⅰ组比较，Ⅲ、Ⅳ组术毕及术后时白细胞升高，Ⅱ～Ⅳ组术中活化部分凝血活酶时间延长，Ⅳ组术中血小板功能增强（P〈0．05）。结论脑膜瘤切除术患者术前应用100万和200万KIU抑肽酶可使APTT延长，200万KIU抑肽酶对血小板功能有保护作用。     

不同剂量抑肽酶对非体外循环下冠状动脉搭桥术病人围术期炎性反应的影响

目的比较两种剂量抑肽酶对非体外循环下冠状动脉搭桥术(OPCAB)病人围术期白细胞介素-6(IL-6)、白细胞介素-10(IL-10)和肌钙蛋白I(TnI)的影响。方法39例OPCAB病人随机分为对照组(C组)、全量抑肽酶组(AH组)、半量抑肽酶组(AL组),每组13例。AH组:抑肽酶2．0×106 KIU溶于100 ml生理盐水中,于麻醉诱导后经30min恒速静脉输注完毕,然后以0．5×106 KIU／h速率静脉输注抑肽酶至手术结束;AL组:给药方法同上,抑肽酶剂量为AH组的一半。C组:输注同等容量生理盐水。分别在麻醉诱导后即刻(基础值)、冠状动脉血管吻合结束后0．5 h、术后2 h、6 h、18 h采集中心静脉血,测定IL-6、IL-10和TnI。结果与基础值相比,血浆IL-6、IL-10和TnI术后均升高(P<0．05)。与C组相比,两用药组血浆IL-6、IL-10和TnI水平术后降低,术后18 h胸液引流量减少(P<0．05);但两用药组间差异均无统计学意义。结论全量和半量抑肽酶均能抑制OPCAB病人围术期炎性反应,减轻心肌损伤,减少术后失血。对OPCAB病人半量抑肽酶为推荐剂量。     

国产抗纤溶药用前列腺电切术中对血小板保护作用的研究

目的：探讨经尿道前列腺电切术中分别应用三种国产抗纤溶药——氨甲环酸、抑肽酶和止血芳酸对血小板的保护作用，以及对术后止血的功效．方法：选择60例良性前列腺增生手术患者，随机分为3组，即氨甲环酸组、抑肽酶组和止血芳酸组，测定术后12h，24h和48h的血小板计数、出血量、血浆纤溶酶活性和D-二聚体浓度。结果：术后血小板计数在氨甲环酸组和抑肽酶组相接近，在止血芳酸组则显着性下降。出血量在氨甲环酸组和抑肽酶组无显着性差异，在止血芳酸组显着性增高（P〈0．05）。血浆纤溶酶活性在氨甲环酸组和抑肽酶组显着性高于基础值，但仍有所降低；在止血芳酸组则显着性高于前二组。D-二聚体含量在三组间无显着性差异。结论．氨甲环酸和抑肽酶通过抑制纤溶亢进，均能确切减少前列腺电切术后的出血量，但抑肽酶存在潜在的过敏反应，且价格较贵，故以氨甲环酸更适宜於经尿道前腺电切术后止血。     

冠状动脉搭桥术后血浆可溶性Fas及其配体的变化

目的比较在心肺转流（CPB）或非CPB下冠状动脉搭桥术（cABG）后可溶性Fas（sFas）和可溶性Fas配体（sFasL）的血浆浓度变化。方法19例病人分别在CPB（CPB组，n=9）或非CPB（非CPB组，n=10）下行择期cABG。术前、术毕和术后取血测定白细胞介素-6（IL-6）、中性粒细胞弹性蛋白酶、sFas、sFasL血浆浓度。结果术毕、术后4h的IL-6和术毕、术后4、12h的中性粒细胞弹性蛋白酶非CPB组明显低于CPB组（P〈0．05或P〈0．01）。CPB组的sFas在术后4、12h明显升高（P〈0．05或P〈0．01），非CPB组在术后12h明显升高（P〈0．01），术后24h恢复至术前水平。两组的sFasL在术毕和术后4、12h均明显升高（P〈0．05或P〈0．01），术后24h恢复至术前水平；其中术后12h非CPB组明显低于CPB组（P〈0．05）。结论CPB或非CPB下行cABG均导致sFas和sFasL血浆浓度升高，但CPB的应用使sFasL血浆浓度升高得更多。sFasL血浆浓度可反映机体炎性反应的程度。     

氨基己酸对体外循环下心脏直视手术患者纤溶系统的影响

目的探讨氨基己酸对体外循环(CPB)下心脏直视手术患者纤溶系统的影响。方法40例心脏直视手术患者随机分为二组:氨基己酸组(A组)和对照组(B组),每组20例。A组在CPB 预充液中单次加入氨基己酸200 mg/kg,B组在CPB预充液中加入等量生理盐水。分别于切皮前即刻(T0)、CPB 8min(T1)、30min(T2)、鱼精蛋白中和肝素后10min(T3)、术后2 h(T4)时采集静脉血,测定血浆组织型纤溶酶原激活物(t-PA)、纤溶酶原激活物抑制剂(PAI)、纤溶酶(Plm)活性及D-二聚体(D- dimer)浓度,同时记录术后24 h内出血量及输库血量。结果与T0比较,B组血浆t-PA、t-PA/PAI活性在T1-3、Plm活性在T1,2、D-dimer浓度在T1-4时升高(P<0.05或0.01)。与B组比较,A组血浆t-PA活性、t-PA/PAI在T1-3、Plm活性在,T1,3、D-dimer浓度在T2-4时降低(P<0.05或0.01)。术后24 h出血量及输库血量A组少于B组(P<0.05)。结论CPB可激活纤溶系统;氨基己酸可抑制CPB引起的纤溶系统激活,减少术后出血和输库血量。     

肝癌常规切除术中抑肽酶的血液保护作用

目的 探讨抑肽酶在常规肝癌切除术中的价值。方法 82例常规肝癌切除手术病例，随机分为两组，试验组(A组，40例)在麻醉诱导后静注抑肽酶1 112EPU后持续泵注抑肽酶278EPU／h，直至手术后2h停药；对照组(B组，42例)持续泵注生理盐水。在诱导前、手术开始O．5h、2h、4h、术后6h、12h抽血检测血常规、血栓弹性描记图(TEG)、凝血四项指标。观察两组围术期的’lEG和凝血功能检查变化情况以及术中出血量、围术期输血率和平均输血量。结果 使用抑肽酶之后，试验组的术前高凝状态缓解，术中凝血功能状态保持相对的稳定。而对照组在手术后高凝状态进一步加重，部分病例手术后期及术后呈现低凝状态。试验组在术中出血量、围术期输血率和平均输血量都明显少于对照组。结论 常规肝癌切除手术中抑肽酶可稳定凝血功能状态；减少围手术期出血及输血。     

体外循环术中小剂量抑肽酶对急性炎性反应的作用

目的 探讨体外循环（ECC）术中小剂量抑肽酶是否能减轻ECC所致的急性炎性反应。方法 将28例首次心瓣膜置换术患者随机分为抑肽酶组和对照组,各14例。于麻醉诱导前、ECC前、ECC后1小时和24小时测定血浆中白细胞介素－10（IL－10）、肿瘤坏死因子－α（TNF-α）和白细胞计数。结果 两组IL－10ECC后1小时比麻醉诱导前明显升高（P＜0．01）,且抑肽酶组明显高于对照组（P＜0．01）;对照组TNF－α和白细胞计数在ECC后1小时和24小时较麻醉诱导前明显升高,且高于抑肽酶组（P＜0．05）。结论 小剂量抑肽酶可抑制ECC所致的炎性反应。     

术后镇痛对冠心病患者心肌缺血的影响

目的通过观察冠心病患者术后血浆内皮素（ET-1）、一氧化氮（NO）、6-酮前列腺素F1α（6-Keto-PGF1α）浓度及血压的变化，探讨术后镇痛与心肌缺血的关系。方法胆囊结石合并冠心病患者40例，随机分为A、B两组，硬膜外麻醉复合气管插管全麻，术毕A组接电子镇痛泵，配方为0．125％布比卡因＋芬太尼0．01mg／kg＋格拉司琼3mg，行硬膜外自控镇痛（PCEA）；B组为空白对照组。分别于术前、术毕、术后24h抽静脉血测ET-1、NO、6-Keto-PGF1α血浆浓度。结果A组术后血压平稳，与术前比无明显变化。B组术后24h血压明显升高，收缩压（SBP）、舒张压（DBP）较术前分别升高了16．5％、15．9％。A组和B组ET-1浓度在术后24h较术前均有明显升高，但B组升高更明显（A组为29．2％，B组为77．0％，P〈0．01）；术后24hA组和B组NO浓度较术前分别降低了33．3％和60．0％，6-Keto-PGF1α浓度分别降低了20．3％和42．0％（P〈0．01）。A组术后出现心绞痛及心电图心肌缺血1例，B组6例。结论术后镇痛可减轻手术创伤及术后疼痛引起的舒缩血管物质分泌失衡状态，减少冠心病患者心肌缺血的发生率。     

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.