盐酸戊乙奎醚预先给药对新生大鼠内毒素性急性肺损伤时NF-κB活性的影响

Objective To investigate the effects of penehyclidine (PHCD) pretreatment on nuclear factor kappa B ( NF-kB ) activity during lipopolysaccharide ( LPS )-induced acute lung injury ( ALl ) in neonate rats.Methods Thirty 7-day old Wistar rats of both sexes weighing 18-21 g were randomly divided into 3 groups ( n =10 each): group Ⅰ control (group C); group Ⅱ LPS; group Ⅲ PHCD. Group Ⅱ and Ⅲ received intraperitoneal ( group IP) LPS 3 mg/kg. In group Ⅲ PHCD 5 mg/kg was administered IP at 30 min before LPS respectively. The animals were killed at 4 h after LPS administration. The lungs were immediately removed. The W/D lung weight ratio was measured. The TNF-α, IL-1 βand IL-10 content in the lung were detected by ELISA and expression of NF-kB p65 was detected by immuno-histochemical staining.Results LPS significantly increased W/D lung weight ratio, TNF-α, IL-1 β, IL-10 content and NF-kB p65 expression in the lung as compared with control group. PHCD administered before LPS significantly attenuated the LPS-induced changes. Electron microscopy showed that PHCD before LPS significandy ameliorated the LPS-induced histological damages. Conclusion Pretreatment with PHCD can attenuate LPS-induced acute lung injury though inhibition of NF-kB activation and inflammatory response of lung tissue in neonate rats.     

盐酸戊乙奎醚对内毒素性急性肺损伤大鼠肺组织Toll样受体4mRNA和Toll样受体2mRNA表达的影响

Objective To investigate the effect of penehyclidine (PHCD) on Toll-like receptor 4 (TLR4)mRNA and Toll-like receptor 2 (TLR2) mRNA expression in the lung tissue in rats with acute lung injury induced by lipopolysaccharide (LPS) .Methods Sixty healthy SD rats of both sexes weighing 200-220 g were randomly divided into 5 groups ( n = 12 each) :control group (group C) , LPS group and P1-3 groups. Acute lung injury was induced by intraperitoneal (IP) LPS 8 mg/kg in LPS and P1-3 groups. PHCD 0.3, 1.0 and 3.0 mg/kg were given IP after LPS administration in P1-3 groups. The animals were anesthetized at 6 h after IP LPS. Blood samples were collected for determination of serum TNF-α and IL-6 concentrations ( by ELISA) and then sacrificed, the lungs were immediately removed for determination of TLR4 mRNA and TLR2 mRNA expression (by RT-PCR), and microscopic examination. Results LPS significantly increased TLR4 mRNA and TLR2 mRNA expression in the lung tissue and serum TNF-α and IL-6 concentrations. PHCD 1.0 or 3.0 mg/kg significantly inhibited LPS-induced increase in TLR4 mRNA and TLR2 mRNA expression in the lung tissue and serum TNF-α and ILr6 concentrations.The lung histopathologic damage was significantly ameliorated in P2 and P3 groups as compared with group LPS.Conclusion PHCD can protect the lungs against LPS-induced acute lung injury through inhibiting TLR4 mRNA and TLR2 mRNA expression in the lung tissue and reducing the inflammatory response.     

盐酸戊乙奎醚对内毒素性急性肺损伤大鼠肺组织Toll样受体4mRNA和Toll样受体2mRNA表达的影响

Objective To investigate the effect of penehyclidine (PHCD) on Toll-like receptor 4 (TLR4)mRNA and Toll-like receptor 2 (TLR2) mRNA expression in the lung tissue in rats with acute lung injury induced by lipopolysaccharide (LPS) .Methods Sixty healthy SD rats of both sexes weighing 200-220 g were randomly divided into 5 groups ( n = 12 each) :control group (group C) , LPS group and P1-3 groups. Acute lung injury was induced by intraperitoneal (IP) LPS 8 mg/kg in LPS and P1-3 groups. PHCD 0.3, 1.0 and 3.0 mg/kg were given IP after LPS administration in P1-3 groups. The animals were anesthetized at 6 h after IP LPS. Blood samples were collected for determination of serum TNF-α and IL-6 concentrations ( by ELISA) and then sacrificed, the lungs were immediately removed for determination of TLR4 mRNA and TLR2 mRNA expression (by RT-PCR), and microscopic examination. Results LPS significantly increased TLR4 mRNA and TLR2 mRNA expression in the lung tissue and serum TNF-α and IL-6 concentrations. PHCD 1.0 or 3.0 mg/kg significantly inhibited LPS-induced increase in TLR4 mRNA and TLR2 mRNA expression in the lung tissue and serum TNF-α and ILr6 concentrations.The lung histopathologic damage was significantly ameliorated in P2 and P3 groups as compared with group LPS.Conclusion PHCD can protect the lungs against LPS-induced acute lung injury through inhibiting TLR4 mRNA and TLR2 mRNA expression in the lung tissue and reducing the inflammatory response.     

七氟烷预处理对脂多糖致大鼠急性肺损伤的保护作用

Objective To investigate the effects of sevoflurane pretreatment on Lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats. Methods Seventy -two Sprague -Dawley rats were randomly divided into 6 groups: NS group, LPS group and sevoflurane pretreatment (S-l h group, S-6 h group, S-12 h group and S-24 h group). The rat model of ALI was established by intratracheal instillation of LPS. Animals were sacrificed at 6 h after LPS or NS administration. Leukocyte count, concentration of TNF-α and IL-β in bronchoalveolar lavage fluid (BALF); pulmonary capillary permeability, myeloperoxidase (MPO) activity of lung tissue; lung histological changes were compared in rats with or without sevoflurane pretreatment (2.4% inspired for 30 min) at different times before LPS instillation. Results Compared with the NS group,severe injury of lung tissues and increase in leukocyte count in BALF, Production of TNF-α and IL-1β in BALF, pulmonary capillary permeability and MPO activity in the lung were significantly increased in rats treated with LPS (P<0.01). MPO activity, leukocyte count and production of IL-1βin BALF were reduced when sevoflurane was given 1 or 24 h before but not at 6 or 12 h before LPS instillation(P<0.01). Sevoflurane pretreatment also attenuated pulmonary capillary permeability and production of TNF-α in BALF (P<0.01). Pulmonary capillary permeability and concentration of TNF-α in S-l h and S-24 h group was lower than S-6 h and S-12 h group (P<0.01). Sevoflurane pretreatment was effective at 1 h and 24 h suggesting sevoflurane has early and late protection against LPS-induced lung injury. Conclusion Sevoflurane pretreatment has protective effects against acute lung injury when given 1 or 12 h before LPS instillation.     

七氟烷预处理对脂多糖致大鼠急性肺损伤的保护作用

Objective To investigate the effects of sevoflurane pretreatment on Lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats. Methods Seventy -two Sprague -Dawley rats were randomly divided into 6 groups: NS group, LPS group and sevoflurane pretreatment (S-l h group, S-6 h group, S-12 h group and S-24 h group). The rat model of ALI was established by intratracheal instillation of LPS. Animals were sacrificed at 6 h after LPS or NS administration. Leukocyte count, concentration of TNF-α and IL-β in bronchoalveolar lavage fluid (BALF); pulmonary capillary permeability, myeloperoxidase (MPO) activity of lung tissue; lung histological changes were compared in rats with or without sevoflurane pretreatment (2.4% inspired for 30 min) at different times before LPS instillation. Results Compared with the NS group,severe injury of lung tissues and increase in leukocyte count in BALF, Production of TNF-α and IL-1β in BALF, pulmonary capillary permeability and MPO activity in the lung were significantly increased in rats treated with LPS (P<0.01). MPO activity, leukocyte count and production of IL-1βin BALF were reduced when sevoflurane was given 1 or 24 h before but not at 6 or 12 h before LPS instillation(P<0.01). Sevoflurane pretreatment also attenuated pulmonary capillary permeability and production of TNF-α in BALF (P<0.01). Pulmonary capillary permeability and concentration of TNF-α in S-l h and S-24 h group was lower than S-6 h and S-12 h group (P<0.01). Sevoflurane pretreatment was effective at 1 h and 24 h suggesting sevoflurane has early and late protection against LPS-induced lung injury. Conclusion Sevoflurane pretreatment has protective effects against acute lung injury when given 1 or 12 h before LPS instillation.     

c-Jun氨基末端激酶在大鼠内毒素性急性肺损伤中的作用

Objective To evaluate the role of c-Jun N-terminal kinase (JNK) in lipopolysaccharide (LPS)-induced acute lung injury ( ALI) in rats.Methods Eighty male SD rats weighing 250-300 g were randomly divided into 4 groups ( n = 20 each) : control group (group C) ; ALI group; LPS + SP600125 (JNK inhibitor)group (group S) and LPS+ DMSO (the solvent) group (group DMSO) . ALI was induced by intravenous LPS 5mg/kg. In S and DMSO groups, SP600125 30 mg/kg and DMSO 0.2 ml were injected intravenously after LPS administration respectively. Ten animals were sacrificed by exsanguinafions at 4 h after LPS administration in each group. The broncho-alveolar lavage fluid (BALF) was colleted. The TNF-α and IL-1β concentrations in BALF were measured. The lungs were removed for microscopic examination and determination of W/D lung weight ratio. The other 10 animals in each group were observed for 48 h survival rate. Results Intravenous LPS significantly increased TNF-α and IL-1β concentrations in BALF and W/D lung weight ratio, decreased 48 h survival rate and induced histologic damage. Intravenous SP600125 30 mg/kg significantly attenuated the above-mentioned LPS-induced changes. Conclusion Activation of JNK is involved in the development of endotoxin-induced ALI in rats.     

c-Jun氨基末端激酶在大鼠内毒素性急性肺损伤中的作用

Objective To evaluate the role of c-Jun N-terminal kinase (JNK) in lipopolysaccharide (LPS)-induced acute lung injury ( ALI) in rats.Methods Eighty male SD rats weighing 250-300 g were randomly divided into 4 groups ( n = 20 each) : control group (group C) ; ALI group; LPS + SP600125 (JNK inhibitor)group (group S) and LPS+ DMSO (the solvent) group (group DMSO) . ALI was induced by intravenous LPS 5mg/kg. In S and DMSO groups, SP600125 30 mg/kg and DMSO 0.2 ml were injected intravenously after LPS administration respectively. Ten animals were sacrificed by exsanguinafions at 4 h after LPS administration in each group. The broncho-alveolar lavage fluid (BALF) was colleted. The TNF-α and IL-1β concentrations in BALF were measured. The lungs were removed for microscopic examination and determination of W/D lung weight ratio. The other 10 animals in each group were observed for 48 h survival rate. Results Intravenous LPS significantly increased TNF-α and IL-1β concentrations in BALF and W/D lung weight ratio, decreased 48 h survival rate and induced histologic damage. Intravenous SP600125 30 mg/kg significantly attenuated the above-mentioned LPS-induced changes. Conclusion Activation of JNK is involved in the development of endotoxin-induced ALI in rats.     

Effect of Radix Paeoniae Rubra on the expression of HO-1 and iNOS in rats with endotoxin-induced acute lung injury

Objective: To investigate the effect of Radix Paeoniae Rubra (RPR) on the expression of heme oxygenase (HO-1) and induced nitric oxide synthase (iNOS) in endotoxin-induced acute lung injury in rats and its protective mechanism. Methods: Forty Wistar rats were divided randomly into 5 groups with 8 rats in each group: saline control group (NS group), lipopolysaccharide group ( LPS group), RPR-treatment group, RPR-prevention group and Hemin group. The effect of RPR on protein content, the ratio of neutrophiles in bronchoalveolar lavage fluid, malondialdehyde ( MDA ) content in the lung and the activity of serum NO were observed. Arterial blood was drawn for blood-gas analysis. The expression of HO-1 and iNOS in lung tissues was detected by immunohistochemitry and morphometry computer image analysis. The histological changes of the lung were observed under light microscope. Results: Compared with that in NS group, the expression of HO-1 and iNOS was markedly increased in LPS group (P<0.01). In RPR-treatment, RPR-prevention , and Hemin groups, the expression of iNOS was significantly lower, while the expression of HO-1 was higher than that in LPS group (P<0.05). The protein content, the ratio of neutrophiles in bronchoalveolar lavage fluid, the content of MDA and the activity of serum NO in LPS group were significantly higher than those in NS group (P<0.01). There was a significant decrease in the level of arterial bicarbonate and partial pressure of oxygen in the LPS group (P<0.01); these parameters of lung injury however, were significantly lower in RPR-treatment. RPR-prevention, and Hemin groups than LPS group (P<0. 05 or P< 0.01). The pathologic changes of lung tissues were substantially attenuated in RPR-treatment, RPR-prevention, and Hemin groups than LPS group. Conclusions: The high expression of HO-1 reflects an important protective function of the body during lipopolysaccharide-induced acute lung injury. The protective effect of RPR on lipopolysaccharide-induced acute lung injury is related to the inhibition of iNOS expression and the induction of HO-1 expression.     

Effect of Radix Paeoniae Rubra on the expression of HO-1 and iHOS in rats with endotoxin-induced acute lung injury

Objective ： To investigate the effect of Radix Paeoniae Rubra （RPR） on the expression of heme oxygenase （ HO- 1 ） and induced nitric oxide synthase （ iNOS ） in endotoxin- induced acute lung injury in rats and its protective mechanism. Methods： Forty Wistar rats were divided randomly into 5 groups with 8 rats in each group： saline control group （NS group ）, lipopolysaccharide group （LPS group）, RPR-treatment group, RPR-prevention group and Hemin group. The effect of RPR on protein content, the ratio of neutrophiles in bronchoalveolar lavage fluid, malondialdehyde （MDA） content in the lung and the activity of serum NO were observed. Arterial blood was drawn for blood-gas analysis. The expression of HO-1 and iNOS in lung tissues was detected by immunohistochemitry and morphometry computer image analysis. The histological changes of the lung were observed under fight microscope. Results： Compared with that in NS group, the expression of HO-1 and iNOS was markedly increased in LPS group （P 〈0.01）. In RPR-treatment, RPR-prevention, and Hemin groups, the expression of iNOS was significantly lower, while the expression of HO-1 was higher than that in LPS group （P〈0.05）. The protein content, the ratio of neutrophiles in bronchouiveolar lavage fluid, the content of MDA and the activity of serum NO in LPS group were significantly higher than those in NS group （ P〈0.01 ）. There was a significant decrease in the level of arterial bicarbonate and partial pressure of oxygen in the LPS group （P 〈0.01）; these parameters of lung injury however, were significantly lower in RPR-treatment, RPR- prevention, and Heroin groups than LPS group （P〈0.05 or P〈0.01 ）. The pathologic changes of lung tissues were substantially attenuated in RPR-treatment, RPR- prevention, and Hemin groups than LPS group. Conclusions ： The high expression of HO-1 reflects an important protective function of the body during lipopolysaccharide-induced acute lung injury. The acute lung injury is related to the inhibition of iNOS expression and the induction of HO-1 expression.     

七氟烷后处理对大鼠肺缺血再灌注损伤的影响

Objective To investigate the effects of aevoflurane postconditioning on lung iscbemia-reperfusion (IR) injury in rats and the mechanism involved. Methods Ninety-six male SD rots weighing 270-330 g were randomly divided into 4 groups (n = 24 each): sham operation group (group S), group IR, sevoflurane preconditioning group (group SPr), and sevoflurane postconditioning group (group SPo). The animals were anesthetized with intraperitoneal 10% chloral hydrate 400 mg/kg, tracheostomized and mechanically ventilated. Lung IR was produced by occlusion of the hilum of the left lung for 45 min and then it was unclamped for reperfusion, in group SPr, sevoflurane was inhaled at the end-tidal concentration of 2.1% 30 min before lung ischemia. In group SPo, sevoflurane was inhaled at the end-tidal concentration of 2.1% immediately before reperfusiun. Six rats from each group were sacrificed at 30 min, 1 h, 2 h, and 4 h of reperfnsion respectively. The TNF-α, IL-1 and IL-6 concentrations, and WBC count in broncho-alveolar lavage fluid (BALF) were determined.The percentage of PMN in WBC was calculated. The lungs were removed for determination of the cdntent of TNF-α, IL-1 and IL-6 in the lung tissues and microscopic examination. The apoptosis index (AI) was calculated by TUNEL assay. Lung injury was scored. Results The levels of TNF-α, IL-1 and IL-6 in lung tissues and BALF, AI, WBC count, percentage of PMN, and lung injury scores were significantly higher in group IR than in group S (P < 0.01). The content of TNF-α, IL-1 and IL-6 in lung tissues was significantly higher in group SPr and SPo than in group S (P < 0.01). The indices mentioned above were all significantly lower in group SPr and SPo than in group IR (P < 0.05 or 0.01). No significant differences were found in the indices mentioned above between group SPr and SPo (P > 0.05). Conclusion Sevoflurane postconditioning can protect the lungs from IR injury by decreasing the inflammatory reaction and inhibiting the apoptosis in pulmonary vascular endothelial and alveolar epithelial cells, and the effect is similar to that of sevoflurane preconditioning.     

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.     

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.     

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.