真皮下血管网薄皮瓣的自由基测定

以１２只猪为模型，在其两侧背部各制备真皮下血管网薄皮瓣，筋膜皮瓣和真皮下血管网皮片，长均１５ｃｍ，宽为３ｃｍ，各２４个，术后７天观察其成活长度，并取离蒂部４、８和１２ｃｍ处的以上三种皮瓣（片）的真皮下层组织行自由基测定。结果真皮下血管网薄皮瓣成活长度较筋膜皮瓣增加了３８％，分析了真皮下血管网膜皮瓣超长成活的因素之一是皮瓣内自由基产生较少。     

猪SVN皮瓣成活长度的实验研究

以１２只家猪为模型，形成真皮下血管网皮瓣（ＳＶＮ皮瓣）和筋膜皮瓣，共４８个，大小为７５ｃｍ×３ｃｍ。术后７天筋膜皮瓣成活长度为５．８ｃｍ，ＳＶＮ皮瓣的成活长度为８ｃｍ，较筋膜皮瓣增加了３８％，皮瓣远端愈合类似真皮下血管网皮片。此结果表明，ＳＶＮ皮瓣是超薄超长皮瓣和真皮下血管网皮片的联合体，并对此进行了讨论     

真皮下血管网薄皮瓣的自由基测定

以12只猪为模型,在其两侧背部各制备真皮下血管网薄皮瓣、筋膜皮瓣和真皮下血管网皮片,长均为15 cm,宽为3 cm,各24个。术后7天观察其成活长度,并取离蒂部4、8和12 cm处的以上三种皮瓣(片)的真皮下层组织行自由基测定。结果真皮下血管网薄皮瓣成活长度较筋膜皮瓣增加了38%。分析了真皮下血管网薄皮瓣超长成活的因素之一是皮瓣内自由基产生较少。     

自由基与轴型真皮下血管网皮瓣成活的实验研究

目的：研究自由基在轴型真皮下血管网皮瓣成活机制的作用。方法：在１０只白家猪侧腹部和臀部制备真皮下血管网皮瓣（实验组）和轴型筋膜皮瓣（对照组）各３０块。皮瓣大小５ｃｍ×１５ｃｍ，术后７天测定二组皮瓣的成活长度，并对距蒂部５ｃｍ、１０ｃｍ和１５ｃｍ处的实验组全层、对照组皮肤层和脂肪层３种组织的自由基含量进行了检测。结果：实验组成活长度为１０．８±１．２４ｃｍ，对照组为８．５±１．６２ｃｍ（Ｐ＜０．０１）；实验组５ｃｍ、１０ｃｍ和对照组皮肤层５ｃｍ处自由基含量较低，对照组脂肪层１０ｃｍ和１５ｃｍ处含量最高。结论：对照组中远端皮下脂肪组织在皮瓣的成活过程中产生的自由基较多而不利于其成活，成活长度较实验组减少了２１．３％；而实验组因去除了中远端大部分脂肪组织，自由基含量明显减少，成活长度增加。     

真皮下血管网薄皮瓣的实验研究与临床应用

以１２只家猪为实验动物，对随意型真皮下血管网薄皮瓣及岛状真皮下血管网薄皮瓣的减薄层次、范围及其血供的可靠性进行研究。结果表明：随意型及岛状真皮下血网薄皮瓣减薄层次，在真皮下血管网的下方保留０．３ｃｍ脂肪和在真皮下血管网的下方保留１／３浅筋膜层，两种减薄层次的成活率无显著差异。随意型真皮下血管网薄皮瓣成活的长宽比例为２．５：１，术后６天可断蒂。岛状真皮下血管网薄皮瓣可减薄６０％～７０％。临床应用随意     

真皮下血管网薄皮瓣血管构筑变化与成纤维细胞生长因…

为了探讨真皮下血管网薄皮瓣的成活机理，以兔为实验动物，在其背侧形成１５ｃｍ×３ｃｍ的真皮下血管网薄皮瓣，利用微循环显微镜，病理切片，组织化学染色等手段进行观察。结果表明真皮下血管网薄皮瓣术后远，中，近段血管构筑具有明显差别：近段同正常皮肤，中段为极度活跃的血管增生，远段为中度血管增长。     

真皮下血管网薄皮瓣血管构筑变化与成纤维细胞生长因子的关系

为了探讨真皮下血管网薄皮瓣的成活机理，以兔为实验动物，在其背侧形成１５ｃｍ×３ｃｍ的真皮下血管网薄皮瓣，利用微循环显微镜、病理切片、组织化学染色等手段进行观察。结果表明真皮下血管网薄皮瓣术后远、中、近段血管构筑具有明显差别：近段同正常皮肤，中段为极度活跃的血管增生，远段为中度血管增生。皮瓣中段血管构筑的变化起一个“中介蒂”的作用，是皮瓣能够早期断蒂及超过传统长宽比例可以成活的基础。成纤维细胞生长因子是促使皮瓣血管构筑变化的重要因素之一。     

真皮下血管网皮瓣成活机理的实验研究

作者以家猪躯干部皮瓣为实验模型，研究了真皮下血管网皮瓣的血供方式及成活机理。采用成活长度、ＥＣＴ测定核素分布范围等方法证实，超长真皮下血管网皮瓣远侧部分得不到来自蒂部的血供，这种皮瓣实际上是真皮下血管网皮瓣与皮片的复合物，超长超宽真皮下血管网皮瓣实际上大部分不是皮瓣而是皮片。超长超宽真皮下血管网皮瓣的成活大部分依赖创面及创周血供，为皮片样成活。     

颈胸真皮下血管网薄皮瓣修复颌颈部瘢痕

目的探讨颈胸真皮下血管网薄皮瓣修复颌颈部瘢痕的临床效果。方法１９９０年３月～１９９８年５月应用颈胸真皮下血管网薄皮瓣修复颌颈烧伤瘢痕畸形２１例,皮瓣最大１４ｃｍ×８ｃｍ,最小８ｃｍ×５ｃｍ,供瓣区直接拉拢缝合。结果除１例皮瓣远端部分坏死外,其余２０例皮瓣均完全成活。随访６个月～３年６个月,皮瓣功能及外形均满意。结论颈胸真皮下血管网薄皮瓣可提供的皮瓣面积大,质地柔软,手术较为简便,适合颌颈部较大面积缺损的修复。     

真皮下血管网薄皮瓣血运重建方式的实验研究

目的 探讨真皮下血管网薄皮瓣的成活机理。方法 分别在３组家兔背部形成真皮下血管网薄皮瓣、真皮下血管网皮片、传统随意皮瓣。运用组织透明技术,观察３组动物术后１～７ｄ、１４ｄ血管构筑变化的差异。结果 真皮下血管网薄皮瓣段存在一血管增生快速密集区－“中介蒂”,其血运重建过程明显早于传统随意皮瓣、真皮下血管网皮片。结论 本研究证实了“中介蒂”的存在,且这是真皮下血管网薄皮瓣可早期断蒂、有一定限度超长成活的     

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.     

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.     

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.     

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.     

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.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.