经肝动脉灌注平阳霉素碘油乳剂对兔正常肝脏组织的影响

目的：探讨平阳霉素碘油乳剂（PLE）经肝动脉灌注对兔正常肝脏组织的影响。方法：14只4～5个月龄日本大耳白兔，体重（2.5±0.2）kg，按注入生理盐水或PLE的量分为假手术组、实验A组（低剂量组）和实验B组（高剂量组）。各组兔均开腹穿刺肝动脉，按分组剂量注入PLE。术后1，2，4，6周取病理切片，HE染色，光镜下观察肝脏组织学改变;免疫组织化学（免疫组化）染色标记血小板衍化生长因子B链（PDGF-B），并行图象分析。结果：A组HE染色肝细胞呈一过性水样变，变性在2周时最重，至6周已明显减轻。B组HE染色2周时肝细胞明显水样变，4周时可见汇管区纤维组织增生，6周时部分肝组织出现明显假小叶结构。免疫组化染色显示，PDGF-B在肝细胞胞膜及纤维间隔中有明显表达。结论：经肝动脉灌注PLE可导致正常肝脏组织产生不同程度的肝纤维化;PDGF-B参与了肝纤维化的病理过程。     

医用胶原蛋白海绵治疗重度肝破裂的临床研究

目的：探讨医用胶原蛋白海绵对重度肝破裂创面的治疗作用。方法：将重度肝破裂患者以入院先后为序，随机分成治疗组（68例）和对照组（64例）。治疗组和对照组分别用医用胶原蛋白海绵片和明胶海绵片对肝创面进行止血和填塞。结果：治疗组的止血时间为(19.65±1.28)min，术中出血量为(301.57±56.18)mL均少于对照组［分别为(34.3±1.2)min及(642.3±61.8)mL］(均P<0.05)。治疗组术后腹腔引流量为(380.45±12.34)mL,并发胆瘘(1.5%)及再出血(3.0%)均少于对照组［分别为(693.2±219.4)mL,6.3%及9.5%］(均P<0.05);治疗组术后住院时间(24.01±4.89)d短于对照组(35.8±5.9)d(P<0.05)。术后CT复查显示治疗组创面肝组织修复时间(30.30+6.42)d短于对照组(62.1±7.2)d(P<0.05)。结论：胶原蛋白海绵对肝创面止血效力强于明胶海绵，与创面的黏附力强，术后并发症少，恢复快，是一种治疗肝破裂的有效、安全而可靠的生物材料。     

Bcl-2反义寡核苷酸对VP-16抑制人胆管癌细胞株增殖和诱导凋亡的影响

目的:探讨bcl-2 反义寡核苷酸（ASODN）对VP-16抑制人胆管癌QBC939细胞生长和诱导细胞凋亡的影响。方法:合成特异性靶向Bcl-2 ASODN，并将其转染QBC939细胞;四甲基噻唑蓝（MTT）试验检测Bcl-2 ASODN对VP-16抑制QBC939细胞增殖的影响;流式细胞术观察Bcl-2 ASODN对VP-16诱导QBC939细胞凋亡的影响。结果:ASODN组细胞的存活率显著低于无义寡核苷酸（NSODN）组(P＜0.05);ASODN+VP-16组细胞存活率显著低于ASODN组及VP-16组(P＜0.05);ASODN组、ASODN+VP-16组和VP-16组细胞凋亡率显著高于对照组和NSODN组（P＜0.05);ASODN+VP-16组细胞凋亡率显著高于ASODN组及VP-16组(P＜0.05)。结论:Bcl-2 ASODN对VP-16抑制人胆管癌QBC939细胞生长和诱导细胞凋亡有促进作用。     

腹腔镜联合纤维胆道镜行胆总管切开取石30例临床观察

目的:探讨电视腹腔镜胆总管切开纤维胆道镜取石在胆囊良性疾病合并胆管总管结石治疗中的应用效果。方法:总结分析30例胆囊良性疾病合并胆总管结石行腹腔镜胆囊切除+胆总管切开纤维胆道镜取石T 形管引流治疗的临床资料。结果:28例治愈，残留结石2例（经T管再次纤维胆道镜取尽治愈）。平均住院天数9 d。结论:腹腔镜联合纤维胆道镜行胆囊切除+胆总管切开取石 T 管引流术治疗胆囊良性疾病合并胆总管结石是安全、有效的。     

小鼠全肝缺血再灌注时肺泡巨噬细胞TLR2的激活与肺损伤的机制

目的：探讨肺泡巨噬细胞Toll样受体2（TLR2）的激活机制及其在肝脏缺血再灌注（HIR）中肺损伤的意义。方法：用野生型小鼠C3h/Heouj和TLR4缺失小鼠C3h/Hej建立HIR动物模型。于再灌注1，6，12h后经支气管肺泡灌洗液获取肺泡巨噬细胞，采用荧光定量PCR方法检测TLR2/4mRNA的表达。同时检测支气管肺泡灌洗液中内毒素及肿瘤坏死因子（TNF）的水平，肺组织湿干重比值，肺组织髓过氧化物酶的浓度，并进行肺组织学评分。结果：C3h/Heouj组HIR缺血再灌后各时点肺泡巨噬细胞TLR2/4mRNA表达升高，TLR2mRNA表达持续升高，TLR4mRNA6h达到最高值。同时C3h/Heouj组HIR后支气管肺泡灌洗液中TNF水平明显升高，肺损伤加重，肺组织湿干重比值持续升高，肺组织髓过氧化物酶持续增加(P<0.05)。C3h/Hej组HIR后TLR2mRNA表达仅轻度升高，且支气管肺泡灌洗液中TNF水平低于C3h/Heouj组(P<0.05)，肺损伤轻于C3h/Heouj组(P<0.05)。结论：HIR可致肺泡巨噬细胞表面TLR4的激活，可上调TLR2的表达，从而可加重HIR时的肺损伤。     

胆内瘘:附32例漏诊分析

目的:探讨胆内瘘术前漏诊的原因及减少漏诊的方法。方法:回顾性分析32例胆内瘘漏诊患者的临床资料,平均年龄52.1(25~72)岁,患者分别行B超,T管造影,消化道钡餐,胃镜,胆道镜,ERCP,PTC检查,所有患者均行手术治疗。结果:32例均为术前漏诊者,占同期收治的44例胆内瘘的72.73%。32例均术中确诊。结论:胆内瘘术前漏诊率高,应提高对该病的警惕性;注意寻找该病的特征性表现;尤其当B超发现有胆道积气时,应行进一步检查 如内镜和造影检查,这是提高术前诊断的重要方法。     

医源性血管损伤的救治:附24例报告

目的：总结医源性血管损伤的防治经验。方法：对3年来救治的24例各种医源性血管损伤的临床资料进行回顾性分析。结果：24例中肠系膜上动脉、静脉损伤7例，门静脉损伤3例，颈动脉损伤4例，髂、股动脉损伤6例，其他为腘动脉、腋动脉、肾动脉、胃左动脉等损伤。治疗方法：血管修补6例，血管吻合5例，血管置换2例，血管结扎3例，介入下带膜支架型人工血管封堵2例，其他为取栓、溶栓、填塞等处理。24例中22例成功治愈，1例术后24h大出血死亡，1例术后5d死亡。结论：医源性血管损伤只要高度重视，辨明解剖、充分准确、仔细操作是可以预防和减少的。一旦发生医源性血管损伤要查找原因，针对情况选择不同的处理方式，若缺乏有效的处理技术应及时求援或转院治疗。     

原位肝移植中受体血管异常时的肝动脉重建

摘要：目的 探讨原位肝移植中动脉异位重建的方法及效果。 方法 回顾性分析我院10年来的440例肝移植中36例因受体血管异常而行异位重建的方法及术后处理措施等。 结果 36例中行供肝动脉与受体肾下腹主动脉吻合20例，与肾上腹主动脉吻合10例，与胃左动脉吻合4例，与脾动脉吻合2例。5例围手术期死亡，但吻合口通畅，31例存活3个月至4年无血管相关并发症，仅1例术后2个月因胆道缺血坏死行再次肝移植。 结论 肝移植时受体肝动脉有病变或异常改变时，应将受体肾下或肾上腹主动脉、脾动脉、胃左动脉与供肝动脉进行异位重建，可取得满意效果。     

In sight on multiple morphological abno rmalities of sperm flagella in male infertility:what is new?

The syndrome of multiple morphological abnormalities of the sperm flagella(MMAF)is a specific kind of asthenoteratozoospermia with a mosaic of flagellar morphological abnormalities(absent,short,bent,coiled,and irregular flagella).MMAF was proposed in 2014 and has attracted increasing attention;however,it has not been clearly understood.In this review,we elucidate the definition of MMAF from a systematical view,the difference between MMAF and other conditions with asthenoteratozoospermia or asthenozoospermia(such as primary mitochondrial sheath defects and primary ciliary dyskinesia),the knowledge regarding its etiological mechanism and related genetic findings,and the clinical significance of MMAF for intracytoplasmic sperm injection and genetic coun sell ng.This review provides the basic kno wledge for MMAF and puts forward some suggestions for further investigations.     

CD44V6,c-Met在原发性肝癌中的表达及其临床意义

摘要：目的:探讨黏附分子CD44V6与原癌基因c-Met共同在原发性肝癌中的表达、相关性及其与临床病理指标、复发、预后之间的关系。方法:采用免疫组织化学方法检测50例肝癌组织及46例癌旁组织中CD44V6,c-Met的表达情况，并分析肝癌细胞中CD44V6,c-Met的表达与临床资料的关系。结果:(1)CD44V6在肝癌组织中的阳性表达率为30.0%，CD44V6表达与静脉侵犯明显有关(P<0.05)。(2)c-Met阳性表达率为52.0%，c-Met表达与Edmondson分级明显有关(P<0.05)。(3) CD44V6与c-Met表达呈有关(P<0.05)。(4)CD44V6,c-Met阳性表达患者较CD44V6,c-Met阴性表达患者术后2年内的复发率明显升高（P<0.05）；CD44V6,c-Met阳性表达组术后生存率均明显低于阴性表达组（P<0.01）。结论:CD44V6,c-Met在肝癌的发生、发展有重要作用。     

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.