不同潮气量机械通气对创伤后急性呼吸窘迫综合征疗效的影响

目的探讨小潮气量(LTV)加呼气末正压(PEEP)机械通气(MV)治疗创伤后急性呼吸窘迫综合征(ARDS)的疗效。方法以18例常规潮气量(8～12ml/kg)MV为对照组,20例小潮气量(5～7ml/kg)加用PEEP的MV模式为观察组,比较两组间血气,RR、HR、MAP、CVP、呼吸机所致肺损伤(VILI)、多脏器功能不全(MODS)发生率及ARDS病死率。结果两组PaO2差异无显著性意义(P>0.05);观察组PaCO2高于对照组(P<0.05);观察组无VILI、MODS及死亡病例发生,对照组2例VILI、2例ARDS并发MODS死亡。结论在ARDS治疗中采用小潮气量加PEEP及允许范围内高碳酸血症(PHC)的保护性通气策略,可明显改善缺氧,减少VILI发生,从而降低其病死率。     

金雀异黄素预先给药对大鼠机械通气所致肺损伤的作用

目的 研究特异性蛋白酪氨酸激酶抑制剂金雀异黄素预先给药对大鼠机械通气所致肺损伤（VILI）的作用。方法 30只健康SD大鼠，随机分为3组，每组10只，A组采用8ml／kg潮气量机械通气；B组采用40ml／kg潮气量机械通气；C组采用40ml／kg潮气量机械通气，并在机械通气前30min腹腔注射金雀异黄素50mg／kg。3组呼吸频率均为80次／min，吸／呼比（I：E）为1：1，PEEP为0，吸人气体为室内空气。机械通气2h后处死大鼠，取肺组织，光镜下观察病理学，测定髓过氧化物酶（MPO）活性、磷酸化p38（p-p38）、p38水平；收集支气管肺泡灌洗液，测定总蛋白、肿瘤坏死因子-α（TNF-α）水平，并进行白细胞（WBC）计数。结果与A组比较，B组支气管肺泡灌洗液总蛋白、WBC计数、TNF-α及肺组织MPO、P—p38／p38水平升高（P〈0．05或0．01），肺组织病理学改变严重；与B组比较，C组上述指标降低（P〈0．01或0．05），肺组织病理学改变明显减轻。结论 金雀异黄素50mg／kg预先给药可减轻大鼠VILI，其机制与抑制了p38通路的激活有关。     

急性呼吸窘迫综合征患者适应性支持通气的效果

目的 评价适应性支持通气（ASV）模式与间歇正压通气（IPPV）模式在急性呼吸窘迫综合征（ARDS）患者中的效果。方法 ARDS患者30例，年龄19—46岁，男18例，女12例，ASAⅢ或Ⅳ级。先应用IPPV模式，吸入氧浓度60％，PEEP为0，潮气量（VT）10ml／kg，吸呼比（I：E）1：2，维持8h后随机选择换用ASV或继续IPPV通气模式，通气时依次按0、5、10cm H2O增加PEEP，每一PEEP水平的通气时间为60min，在同样的分钟通气量的设置下，4h后更换另一种通气模式，仍按0,5、10cm H2O增加PEEP，每一PEEP水平的通气时间为60min。每个PEEP水平通气50min时，用Swan-Ganz导管、心电监测仪、呼吸机监测记录血液动力学、呼吸力学和氧代谢数据。结果 与IPPV模式比较，ASV模式下气道峰值压降低，肺动态顺应性（Cdyn）、动脉氧分压（PaO2）和氧供（DO2）增加（P〈0．05）。两种通气模式的血液动力学参数比较差异无统计学意义（P〉0．05）。结论 ASV模式比IPPV模式更有利于ARDS患者的通气治疗。     

胃减容术3种机械通气对患者氧合情况的比较

目的：探讨病态肥胖患者行腹腔镜胃减容术时，3种机械通气参数对患者氧合情况的影响。方法：选择行腹腔镜胃减容术的病态肥胖24例，按手术时间顺序分为3组，每组8例。A组：潮气量12ml／kg，呼吸频率10次／min；B组：潮气量20ml／kg，呼吸频率10次／min；C组：潮气量12ml／kg，呼吸频率20次／min。分别于气腹前（T1）、气腹后（T2）抽取动脉血测量pH、PO2、PCO2、Plat（平台压）、Peak（峰压）、AaDO2（肺泡-动脉氧分压差）。结果：气腹后B组Plat（33．2±1．8）cmH2O、Peak（36．3±1．6）cmH2O显著高于A组Plat（29．5±3．9）cmH2O（q=3．053，P〈0．05）、Peak（33．0±2．9）cmH2O（q：2．823，P〈0．05）和C组Plat（28．0±4，1）cmH2O（q：4．290，P〈0．05）、Peak（31．8±2．8）cmH2O（q：4．704，P〈0．05）。其他观察指标无统计学差异。结论：病态肥胖患者在腹腔镜下施行胃减容术时，加大潮气量20ml／kg或加快呼吸频率20次／min不能改善患者的氧合情况。     

参附注射液在全麻复苏中应用对通气功能的影响及其机制

目的 探讨参附注射液（SFI）对全麻苏醒期通气功能的影响及其机制。方法 86例ASA Ⅰ-Ⅱ级静吸复合麻醉2～4h的择期普外手术患者，手术结束后未醒、未有自主呼吸进入麻醉恢复室（PACU）进行机械通气。随机分两组，每组43例。观察组入室后静脉滴注SFI lml／kg加入乳酸钠林格液共100ml，对照组入室后以等量乳酸钠林格液100ml代替SFI静脉滴注。监测用药前机控呼吸气道内压力值、停机时气道内压力值、潮气量、分钟通气量及用药前后动脉血气分析（pH、PaCO2、PaO2／FiO2）及血氧饱和度。于用药前（To）、用药后5min（T1）、15min（T2）、45min（T3）抽静脉血测定血浆β-内啡肽（β-EP）。结果 用药后气道内压力值比用药前降低（P＜0．05），也低于同时段的对照组（P＜0．05）；潮气量比对照组大（P＜0．01）；氧合指数（PaO2／FiO2）改善（P＜0．05）；PaCO2停机后均有所上升，但两者差异无显著性；pH变化在治疗满意范围，观察组更接近正常；观察组血浆β-EPT1比To上升，T2更明显（P＜0．01）；对照组则下降，T2与观察组T2相比下降明显（P＜0.001）。结论 SFI用于催醒，能改善通气功能和氧合指数，其机制可能与血浆β-EP升高有关。     

高呼气末正压小潮气量通气对肺功能正常患者血流动力学的影响

目的 观察肺功能正常的患者术后使用不同水平呼气末正压(PEEP)小潮气量通气对血流动力学的影响.方法 102例ASA Ⅰ或Ⅱ级,择期全麻下耳鼻喉科术后患者,随机均分为六组.研究组使用保护性肺通气模式,潮气量5 ml/kg,根据PEEP 0、5、10、15和20 emH2O分为P0、P5、P10、P15和P20.五组.对照组(C组)使用常规机械通气模式,潮气量10 ml/kg.观察保护性肺通气前(T1)及保护性肺通气30 min后(T2)的血流动力学的改变.结果 与C组及T1时比较,T2时加速度指数(ACI)在P0、P5、P10和P15组升高,P20组降低;心脏指数(CI)、左室做功指数(LCWI)、平均动脉压(MAP)在P20组降低(P＜0.05);胸腔液体水平(TFC)P10P15和P20组T2时明显低于T1时(P＜0.05).结论 对肺功能正常患者实施小潮气量的保护性肺通气,PEEP在0和5 cmH2O2水平,对血流动力学无明显影响;当PEEP在10和15 cmH2O冰平时ACI增强和TFC减少,有潜在血流动力学危害;当PEEP在20 cmH2O时CI和MAP均降低.有明显血流动力学波动.     

不同潮气量机械通气对大鼠肺组织内毒素CD14受体表达的影响

目的 观察不同潮气量机械通气对大鼠肺组织内毒素CD14受体表达的影响。方法 成年雄性SD大鼠30只，体重200～300g，随机分为3组（n=10）：正常对照组（C组）、小潮气量机械：通气组（S组）和大潮气量机械通气组（L组）。S组潮气量（VT）8ml／kg，N组VT40ml／kg；吸：呼比均为1：1；调整呼吸频率60—80次／min，维持呼气末二氧化碳分压在35—45mmHg。分别于机械通气前（基础值）、机械通气1、2、3h行动脉血气分析，机械通气3h时放血处死大鼠，采用逆转录聚合酶链反应测定肺组织内毒素CD14受体mRNA表达；用免疫组织化学法测定左肺支气管灌洗液内毒素CD14受体蛋白表达。结果 与C组比较，L组机械通气1h时动脉血pH值、氧分压升高，动脉血二氧化碳分压降低，肺组织内毒素CD14受体蛋白及mRNA表达均升高（P〈0．01）。结论 大潮气量机械通气3h可上调大鼠肺组织内毒素CD14受体表达。     

血管紧张素Ⅱ受体在大鼠机械通气所致肺损伤中的作用

【摘要】目的研究血管紧张素Ⅱ受体（AT1型）在机械通气所致肺损伤中的作用。方法40只健康SD大鼠随机分成4组（n=10）：对照组（A组）、正常潮气量机械通气组（B组）、大潮气量机械通气组（C组）和大潮气量机械通气加洛沙坦预处理组（D组）。A组不行机械通气，B组潮气量（VT）为10ml／kg，C组VT为40ml／kg，D组实验前1周每天用血管紧张素Ⅱ受体（AT1型）特异性阻滞剂洛沙坦溶液100mg灌胃后，行大潮气量机械通气，VT为40ml／kg。机械通气2h后处死大鼠，收集肺组织和支所管肺泡灌洗液，光镜下观察肺组织病理改变，RT-PCR法检测A组、B组和C组肺组织中AT。受体mRNA的表达，同时测定支气管肺泡灌洗液总蛋白、白细胞计数、肺湿，干重比（W／D）和中性粒细胞髓过氧化物酶（MPO）、巨噬细胞炎症蛋白-2（MIP-2）的水平。结果C组和D组肺泡间隔明显增厚，肺泡腔内有渗出物，可见较多的炎性细胞浸润，其病理损伤程度较A组和B组重。与A组和B组比较，C组和D组AT1受体mRNA表达、支气管肺泡灌洗液中总蛋白浓度、白细胞计数、MIP-2浓度和肺组织中MPO活性、W／D均增高（P〈0．01）；与C组比较，D组上述各项指标均降低（P〈0．05或0．01）。结论AT1受体参与了大鼠机械通气所致肺损伤。     

压力控制通气在急性呼吸窘迫综合征患者的应用

目的观察急性呼吸窘迫综合征（ARDS）患者应用压力控制通气（PCV）治疗时的气道压力、氧合、血液动力学变化,探讨其治疗效果和肺保护作用。方法18例ARDS患者在使用小潮气量（6～8ml／kg）、〈25次／分的频率容量控制通气（VCV）,气道峰压接近35～40cmH2O,而氧合改善仍不满意时,改为PCV方式机械通气,观察此时气道压力、氧合、血液动力学指标的变化。结果在呼出潮气量相近的情况下,PCV时的气道峰压较VCV时明显降低,平均气道压、中心静脉压升高,但无显著性差异;平均动脉压无明显变化;PCV治疗后24hPaO2、氧合指数明显升高,心率显著减慢,吸气压力增大时潮气量随之增加,未发生气压伤。结论PCV治疗ARDS在改善氧合、减少气压伤、实施肺保护方面较VCV更为有效。     

经皮氧分压监测在急性呼吸窘迫综合征治疗中的应用

目的观察经皮氧分压（PtcOz）在急性呼吸窘迫综合征（ARDS）患者中的变化特点，了解其在ARDS治疗中的作用。方法采用经皮氧分压监测仪对49例ARDS患者实施连续动态监测PtcO2，记录通气前和通气后4、8、16、24hPtcO2值，同期抽取动脉血检测PaO2、SaO2，记录心率（HR）和平均动脉压（MAP）。并比较存活组与死亡组不同时间PtcO2的差异。结果SaO2、HR、MAP随时间变化的程度不明显（均P〉0．05），PtcO2和PaO2随时间变化显著（均P〈0．05）；存活组（35例）与死亡组（14例）PtcO2比较，差异有显著性意义（P〈0．05）。结论PtcO2监测对ARDS治疗能提供连续、可靠的指导作用，PtcO2早期的变化对判断预后有一定帮助。     

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.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

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.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

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.     

Immunomodulation in Transplantation with Photopheresis

Abstract: Photopheresis is a technique in which peripheral blood mononuclear cells, in the presence of a photoacti-vatable compound, are exposed extracorporeally to ultraviolet A light and reinfused, inducing a host autoregula-tory immune response. Experimental work and ongoing clinical studies are helping to define the role of this novel, safe, and non-toxic immunomodulating technology in the field of transplantation.