Does β2-adrenergic stimulation attenuate fluid extravasation during hypothermic cardiopulmonary bypass? An experimental study in pigs

Objectives: Hypothermic cardiopulmonary bypass (CPB) is associated with increased fluid filtration, edema formation and, occasionally, organ dysfunction. Cold-induced reduction in endothelial barrier function may play a role. β(2)-adrenergic activation elevates cellular cyclic adenosine monophosphate (cAMP) which maintains endothelial barrier properties. In this study, we tested whether β-adrenergic stimulation could influence the increase in fluid extravasation observed during hypothermic CPB. Materials and methods: Fourteen pigs randomly received terbutaline infusion (T-group) (n=7) or a control infusion (C-group) (n=7). All animals were given 60 min of normothermic CPB, followed by 90 min of hypothermic CPB. Fluid input and losses, plasma volume, colloid osmotic pressures (plasma, interstitial fluid), hematocrit, serum proteins and total tissue water content were measured and the fluid extravasation rates (FER) calculated. Statistics: by SPSS. Values presented as mean ± SD. Repeated measure analysis of variance was performed and a t-test used when appropriate. RESULTS: The commencement of normothermic CPB resulted in a 20% hemodilution, with an abrupt increase in fluid requirements during the first 10 min. FER increased from 0.18 (0.06) pre-bypass to 0.78 (0.27) ml/kg/min (T-group) (p=0.002) and from 0.16 (0.05) to 0.93 (0.26) ml/kg/min (C-group) (p<0.001) with no between-group differences. Thereafter, FER stabilized at a level of 0.32 (0.13) and 0.27 (0.14) ml/kg/min in the T-group and C-group, respectively. After the start of cooling, FER increased in the T-group to 0.55 (0.12) ml/kg/min (P=0.046) and in the C-group to 0.54 (0.13) ml/kg/min (P=0.006), with no between-group differences (P=0.738). CONCLUSION: In the present experimental study, we were unable to demonstrate any clinically relevant modulating effect of terbutaline on fluid extravasation during hypothermic cardiopulmonary bypass.     

A hyperosmolar-colloidal additive to the CPB-priming solution reduces fluid load and fluid extravasation during tepid CPB

Cardiopulmonary bypass(CPB) is associated with fluid overload. We hypothesized that fluid gain during CPB could be reduced by substituting parts of a crystalloid prime with 7.2% hypertonic saline and 6% poly (O-2-hydroxyethyl) starch solution (HyperHaes). 14 animals were randomized to a control group (Group C) or to Group H. CPB-prime in Group C was Ringer's solution. In group H, 4 ml/kg of Ringer's solution was replaced by the hypertonic saline/hydroxyethyl starch solution. After 60 min stabilization, CPB was initiated and continued for 120 min. All animals were allowed drifting of normal temperature (39.0 degrees C) to about 35.0 degrees C. Fluid was added to the CPB circuit as needed to maintain a 300-ml level in the venous reservoir. Blood chemistry, hemodynamic parameters, fluid balance, plasma volume, fluid extravasation rate (FER), tissue water content and acid-base parameters were measured/calculated. Total fluid need during 120 min CPB was reduced by 60% when hypertonic saline/hydroxyethyl starch solution was added to the CPB prime (p < 0.01). The reduction was related to a lowered FER. The effect was most pronounced during the first 30 min on CPB, with 0.6 (0.43) (Group H) compared with 1.5 (0.40) ml/kg/min (Group C) (p < 0.01). Hemodynamics and laboratory parameters were similar in both groups. Serum concentrations of sodium and chloride increased to maximum levels of 148 (1.5) and 112 (1.6) mmol/l in Group H. To conclude: addition of 7.2% hypertonic saline and 6% poly (O-2-hydroxyethyl) starch solution to crystalloid CPB prime reduces fluid needs and FER during tepid CPB.     

The influence of mean arterial blood pressure during cardiopulmonary bypass on postoperative renal dysfunction in elderly patients

The aim of the study was to find out if there is an optimal mean arterial blood pressure (MABP) during cardiopulmonary bypass (CPB) for renal function in elderly patients during the early postoperative period. We analysed the data of 122 patients >70 years of age with normal preoperative renal function who had been subjected to coronary artery bypass grafting (CABG) procedures on CPB. Patients were divided into 3 groups, according to MABP during CPB: group MP (n=50) included patients whose MABP was maintained between 60-70 mmHg; group LP (n=36), the MABP was <60 mmHg; and group HP (n=36) where the MABP was >70 mmHg. The patients' clinical data were evaluated during the first three postoperative days. The rate of renal impairment (urine output <50ml/h) in the early postoperative period after cardiac surgery did not differ among the groups. Oliguria developed in 3 patients (6%) of the MP group, in 2 patients (5.6%) in the LP group and in 6 patients (16.7%) in the HP group (χ(2)=3.6, df=2, p=0.161). Evaluation of MABP on renal excretion showed that there was no difference in urine output among the groups. Serum creatinine levels at the end of the first postoperative day in groups MP, LP and HP were 102.7±20.1, 116.4±58.6 and 113.2±39.8 μmol/L, respectively (F=0.5, df=2, p=0.640). There were no significant differences among the groups at the end of the second and the third day either. Volume balance at the end of surgery and during the early postoperative period was similar in all groups. The need for diuretics did not differ among the groups. The length of postoperative hospital stay was not significantly different among the groups. Our study did not reveal any relationship between a MABP of 48-80 and postoperative renal dysfunction in elderly patients after CABG surgery.     

Synergy of isoflurane preconditioning and propofol postconditioning reduces myocardial reperfusion injury in patients

Either isoflurane preconditioning or high-dose propofol treatment has been shown to attenuate myocardial IRI (ischaemia/reperfusion injury) in patients undergoing CABG (coronary artery bypass graft) surgery. It is unknown whether isoflurane and propofol may synergistically attenuate myocardial injury in patients. The present study investigated the efficacy of IsoPC (isoflurane preconditioning), propofol treatment (postconditioning) and their synergy in attenuating postischaemic myocardial injury in patients undergoing CABG surgery using CPB (cardiopulmonary bypass). Patients (n = 120) selected for CABG surgery were randomly assigned to one of four groups (n = 30 each). After induction, anaesthesia was maintained either with fentanyl and midazolam (control; group C); with propofol at 100 μg x kg(-1) of body weight x min(-1) before and during CPB followed by propofol at 60 μg x kg(-1) of body weight x min(-1) for 15 min after aortic declamping (group P); with isoflurane 1-1.5% end tidal throughout the surgery (group I) or with isoflurane 1-1.5% end tidal before CPB and switching to propofol at 100 μg x kg(-1) of body weight x min(-1) during CPB followed by propofol at 60 μg x kg(-1) of body weight x min(-1) for 15 min after aortic declamping (group IP, i.e. IsoPC plus propofol postconditioning). A joint isoflurane and propofol anaesthesia regimen synergistically reduced plasma levels of cTnI (cardiac troponin I) and CK-MB (creatine kinase MB) and f-FABP (heart-type fatty acid-binding protein) (all P < 0.05 compared with control, group P or group I) and facilitated postoperative myocardial functional recovery. During reperfusion, myocardial tissue eNOS (endothelial NO synthase) protein expression in group IP was significantly higher, whereas nitrotyrosine protein expression was lower than those in the control group. In conclusion, a joint isoflurane preconditioning and propofol anaesthesia regimen synergistically attenuated myocardial reperfusion injury in patients.     

The importance of colloid osmotic pressure during open heart surgery in infants

Fifty-five infants with transposition of the great arteries and with total anomalous pulmonary venous return underwent intracardiac repair under combined surface/perfusion hypothermia and total circulatory arrest in 1975 to 1983. Although cardiopulmonary bypass (CPB) time is limited when hypothermic circulatory arrest is employed, fluid balance derangement is one of the major postoperative complications. Fluid balance at the end of CPB averaged +299.5 ml (+63.4 ml/kg) when hemodilution with lactated Ringer's was utilized (Group A). Since colloid osmotic pressure (COP) plays an important role in regulating fluid balance, colloid hemodilution prime (whole blood and plasma) was employed in the last 3 years (Group B). COP and total protein concentration during CPB with colloid prime were maintained at around 19 mmHg and 5 g/100 ml, respectively. In Group B, fluid balance at the end of CPB averaged +81.1 ml (+16.3 ml/kg) and was significantly less than in Group A (p less than 0.01). The ICU stay period for survivors in Group B (average 10.9 days) was reduced to half the period in Group A (average 20.6 days) (p less than 0.05). The mortality rate in Group A was 42%, whereas 23% in Group B. It was concluded that well-maintained COP levels during CPB with colloid hemodilution prime reduced fluid accumulation in the body and made patient care easier following open heart surgery in infants.     

异丙酚对犬急性心肌缺血再有灌注损伤时血流动力学的影响

目的研究不同剂量的异丙酚对犬急性心肌缺血再灌注损伤时血流动力学的影响。方法杂种家犬18只随机分为NS组(生理盐水对照组,2ml     

Global and regional cerebral blood flow in neonatal piglets undergoing pulsatile cardiopulmonary bypass with continuous perfusion at 25 degrees C and circulatory arrest at 18 degrees C.

To investigate the influence of hypothermic cardiopulmonary bypass (HCPB) at 25 degrees C and circulatory arrest at 18 degrees C on the global and regional cerebral blood flow (CBF) during pulsatile perfusion, we performed the following studies in a neonatal piglet model. Using a pediatric physiologic pulsatile pump, we subjected six piglets to deep hypothermic circulatory arrest (DHCA) and six other piglets to HCPB. The DHCA group underwent hypothermia for 25 min, DHCA for 60min, cold reperfusion for 10 min, and rewarming for 40 min. The HCPB group underwent 15 min of cooling, followed by 60 min of HCPB, 10min of cold reperfusion, and 30 min of rewarming. The following variables remained constant in both groups: pump flow (150 ml/kg/min), pump rate (150 bpm), and stroke volume (1 ml/kg). During the 60-min aortic crossclamp period, the temperature was kept at 18 degrees C for DHCA and at 25 degrees C for HCPB. The global and regional CBF (ml/100g/min) was assessed with radiolabeled microspheres. The CBF was 48% lower during deep hypothermia at 18degrees C (before DHCA) than during hypothermia at 25 degrees C (55.2 +/- 14.3ml/100g/min vs 106.4 +/- 19.7 ml/100 g/min; p < 0.05). After rewarming, the global CBF was 45% lower in the DHCA group than in the HCPB group 48.3 +/- 18.1 ml/100g/min vs (87 +/- 35.9ml/100g/min; p < 0.05). Fifteen minutes after the termination of CPB, the global CBF was only 25% lower in the DHCA group than in the HCPB group (42.2 +/- 20.7 ml/100 g/min vs 56.4 +/- 25.8ml/100g/min; p = NS). In the right and left hemispheres, cerebellum, basal ganglia, and brain stem, blood flow resembled the global CBF. In conclusion, both HCPB and DHCA significantly decrease the regional and global CBF during CPB. Unlike HCPB, DHCA has a continued negative impact on the CBF after rewarming. However, 15 min after the end of CPB, there are no significant intergroup differences in the CBF.     

Intercompartmental fluid volume shifts during cardiopulmonary bypass measured by A-mode ultrasonography

To investigate the time course of fluid extravasation during cardiopulmonary bypass (CPB), we measured the peripheral tissue thickness (TT) by A-mode ultrasound in 34 patients undergoing elective cardiac surgery. TT of the forehead was determined by a handheld A-mode ultrasound device and 10 MHz Transducer at nine defined intervals, from the night before surgery until the first postoperative day. Mean calculated loss of 1700 +/- 40 mL (SEM) water during the fasting period resulted in a significant reduction of TT by 0.28 +/- 0.03 mm. From induction to start of CPB, rehydration with 1000 mL of fluid was performed and TT increased to baseline. After 60 min of extracorporal circulation, forehead TT increased significantly by 0.75 +/- 0.08 mm and remained unchanged until the end of surgery when the measured fluid gain was 1580 +/- 138 mL. At discharge from ICU, negative fluid regimen resulted in a balance of -127 +/- 146 mL whereas TT declined significantly to +0.16 +/- 0.09 mm compared to baseline. Dehydration due to fasting and the marked interstitial fluid extravasation during CPB could be detected by the changes of the peripheral TT. We conclude that parts of the fluid load during CPB are shifted from the intravascular compartment to the interstitial space in a time-dependent manner.     

Rabbit model of cardiopulmonary bypass.

Mainly because of technical problems, the use of rabbits as a cardiopulmonary bypass (CPB) animal model with direct cannulation of the ascending aorta is known to be extremely difficult. The objectives of this study were the establishment of a CPB model in rabbits with direct cannulation of the ascending aorta, and the evaluation of the protective effect of steroid on the development of brain edema during circulatory arrest (CA) in an established rabbit CPB model. Fifteen New Zealand white rabbits were divided into three groups; control CA group, CA with Trendelenberg position, and CA with Trendelenberg position and steroid administration. After anesthetic induction and tracheostomy, median sternotomy was performed. An aortic cannula (3.3 mm) and a venous cannula (14 Fr) were inserted into the ascending aorta and the right atrium, respectively. The CPB circuit consisted of a roller pump and a bubble oxygenator. With 120-150 ml of blood, the priming volume of the circuit was approximately 450 ml, and CPB at a flow rate of 80-85 ml/kg/min was initiated. Blood in the priming solution was obtained from donor rabbits through cardiac puncture. Ten minutes later, CA with cessation of CPB was established for 40 min at 20 degrees C (rectal temperature). After CA, CPB was restarted with a 20 min period of rewarming. Ten minutes after weaning, the animal was sacrificed. Between 1 and 2 g of the brain was removed and the water content was determined and compared between groups. CPB with CA was successfully performed in all cases, with a flow rate of 60-100 ml/kg/min maintained throughout the CPB procedure. At that time, blood gases were reasonably maintained and aortic pressure ranged from 35 to 55 mmHg. After weaning from CPB, all hearts resumed beating spontaneously. Among the three groups, there were no statistically significant differences in the water content of the brain. These results indicate that: (1) if the proper technique is used, CPB in rabbits with direct cannulation of the ascending aorta is a reliable procedure, and (2) the effect of steroid on the prevention of brain edema related to the Trendelenburg position during CA is not established within the scope of this study.     

脂化前列腺素E1对体外循环稳定期脑灌注压和颈静脉血氧饱和度的影响

目的：探讨在体外循环稳定期使用脂化前列腺素E1对脑灌注压和颈静脉血氧饱和度的影响.方法：30例预计在体外循环下行冠状动脉旁路手术的患者随机分为3组：PGE125组（n=10）：输注脂化前列腺素E125 ng/（kg·min）;PGE1 50组（n=10）：输注脂化前列腺素E150 ng/（kg·min）;对照组（CON组,n=10）：输注等量生理盐水.观察并记录基础状态下MAP、颈静脉血氧饱和度（SjvO2）,颈静脉球血压（IJP）,脑灌注压值（CPP）,血色素（Hb）,鼻温;在体外循环开始20 min,血压平稳时,开始按分组情况给药,记录给药后2,5,10,20,30 min以及停止输注后30 min以上参数.结果：与CON组比较,PGE1 50组T20和T30的MAP,CPP均显著降低（P＜0.05）,且PGE1 50组与PGE125组比较亦显著降低（P＜0.05）.T20,T30两时点上PGE1 25和PGE1 50组的MAP,CPP均较基础值T0明显降低（P＜0.05）.IJP和SjvO2在各组,各时点上均无显著差异.结论：在体外循环过程中使用脂化前列腺素E1可使体循环血压和脑灌注压下降,但对脑氧供需平衡不产生明显影响.     

A comparison of cardiopulmonary resuscitation with cardiopulmonary bypass after prolonged cardiac arrest in dogs. Reperfusion pressures and neurologic recovery.

Resuscitability and outcome after prolonged cardiac arrest were compared in dogs with standard external cardiopulmonary resuscitation (CPR) vs. closed-chest emergency cardiopulmonary bypass (CPB). Ventricular fibrillation (VF) was with no blood flow from VF 0 min to VF 10 min. Subsequent CPR basic life support (BLS) was from 10 min to VF 15 min. Then, group I (n = 13) received CPR advanced life support (ALS) from VF 15 min until restoration of spontaneous circulation to occur not later than VF 40 min. Group II (n = 14) received CPR-ALS from VF 15 min to VF 20 min without defibrillation, and then total CPB to defibrillation attempts started at VF 20 min, followed by assisted CPB to 2 h. Total ischemia time (no-flow time plus CPR time of MAP less than 50 mmHg) was unexpectedly shorter in group I (14.3 +/- 2.5 min) than in group II (18.6 +/- 2.3 min) (P less than 0.01). During CPR-BLS, coronary perfusion pressures were 25 +/- 9 mmHg in group I and 18 +/- 8 mmHg in group II (NS). Epinephrine during CPR-ALS, before countershock, raised coronary perfusion pressure to 40 +/- 10 mmHg in group I and 27 +/- 10 mmHg in group II (NS). In group II, coronary perfusion pressure increased during total CPB to 58 +/- 16 mmHg (P less than 0.01 vs. group I). Spontaneous normotension was restored in 11/13 dogs of group I and all 14 dogs of group II (NS). Ten dogs in each group followed protocol and survived to 96 h. Five of ten in group I and six of ten in group II were neurologically normal (NS). We conclude that: (1) Reperfusion with CPB yields higher coronary perfusion pressures than reperfusion with CPR-ALS; and (2) even after no blood flow for 10 min, optimized CPR can result in cardiovascular resuscitability and neurologic recovery, similar to those achieved by CPB.     

Microcirculatory effects of changing blood hemoglobin oxygen affinity during hemorrhagic shock resuscitation in an experimental model

Microvascular responses to blood volume restitution using red blood cells (RBCs) with modified hemoglobin (Hb) oxygen affinity were studied in the hamster window chamber model during resuscitation from hemorrhagic shock. Allosteric effectors inositol hexaphosphate and 5-hydroxymethyl-2-furfural were introduced into the RBCs by electroporation to decrease and increase Hb-oxygen affinity. In vitro P50s (partial pressure of oxygen at 50% Hb saturation) were modified to 10 and 50 mmHg (normal P50, 32 mmHg). Awake hamsters were subjected to hemorrhage of 50% of blood volume, followed by a shock period of 1 h, and then resuscitated with 25% blood volume with high or low P50 RBCs (hematocrit, 50%). After resuscitation, base excess was significantly lower than baseline in the high-P50 RBC group (HP50; 0.3 +/- 2 vs. 5.0 +/- 1.7 mM) and MAP was lower than baseline in the low-P50 RBC group (LP50; 93 +/- 6 vs. 109 +/- 6 mM). Arteriolar diameter and flow were significantly lower in the HP50. Functional capillary density in the HP50 was significantly lower than LP50 at 60 and 90 min after resuscitation. There was no significantly difference in arteriolar PO2. Tissue PO2, venular PO2, and oxygen delivery were higher in LP50 than in HP50. There was no significant difference in oxygen extraction. Oxygen extraction ratio (oxygen extraction/oxygen delivery) x 100 was significantly higher in HP50 than in LP50. These results suggest that lowering blood P50 in resuscitation provides improved microvascular function in comparison with higher P50.     

冠状动脉搭桥患者围术期血浆15-F2t-isoprostane含量变化及临床意义

目的　分析常温心脏手术中血浆游离 15 F2 t isoprostane浓度变化及其与术后早期心功能的关系。方法　选择 30例在常温体外循环 (CPB)下行冠状动脉搭桥术患者 ,根据术后有 (组 )、无 (组 )应用正性肌力药物分为两组。 CPB中采用间断温血灌注 ,分别于麻醉诱导后、阻升主动脉后 30 min以及开放升主动脉后 10、30和 12 0 min抽取中心静脉血样 ,采用有高度特异性的兔血清抗体用酶标放射免疫法测量血浆中游离 15 F2 t isoprostane含量。术中至术后 6 h进行连续心排量测量。结果　 15 F2 t isoprostane血浆含量于阻升主动脉后 30 m in、开放升主动脉后 10 min显著升高 ,开放升主动脉 30 m in以后开始下降。组 患者血浆 15F2 t isoprostane含量的升高呈递减趋势 ,至开放升主动脉后 30 min恢复正常 ;相反 ,术后需两种以上正性肌力药物支持以维持心脏指数 (CI) >2 .2 L· m in- 1· m- 2的患者 (组 )血浆 15 F2 t isoprostane含量至开放升主动脉后 30 m in均显著高于正常。术后 CI与开放升主动脉后 10和 30 min时血浆游离 15 F2 t isoprostane含量呈良好的负相关性 (r=- 0 .95 ,P<0 .0 1)。结论　术中 15 F2 t isoprostane血浆含量与术后心功能的恢复密切相关。     

血管加压素对心肺转流术后血管麻痹综合征患者血流动力学的影响

目的评价血管加压素对心肺转流术(CPB)后血管麻痹综合征患者血流动力学的影响。方法选取CPB下心脏手术后发生血管麻痹综合征患者14例,分为去甲肾上腺素(NE)组(NE组)和血管加压素(AVP)组(AVP组)。NE组患者输注NE维持平均动脉血压>65 mmHg,当NE输注速率>0.4μg/(kg.min)则加用AVP 0.01～0.04 U/min;AVP组患者输注AVP0.01～0.04 U/min,必要时使用NE维持患者平均动脉血压>65 mmHg。于血管麻痹综合征诊断时(T1,基础值)、注药后24 h(T2)、48 h(T3)、72 h(T4)分别记录两组患者心率(HR)、平均动脉压(MAP)、平均肺动脉压(MPAP)、心排血量(CO)、肺毛细血管楔压(PCWP)、中心静脉压(CVP)及尿量,计算体循环血管阻力(SVR)及肺循环血管阻力(PVR)。并记录儿茶酚胺药物使用量及不良反应。结果两组患者年龄、体重、性别构成比,术前EF、术前治疗用药情况、CPB时间、主动脉阻断时间比较差异无统计学意义(P>0.05)。两组患者血压维持稳定。与NE组比较,AVP组SVR T2时增加;HR T2～3时显著降低(P<0.05);NE需要量T2～4明显降低(P<0.05);尿量明显增加(P<0.05)。结论 AVP可以改善CPB术后血管麻痹综合征患者的血流动力学。     

The effect of cardiopulmonary bypass resuscitation on cardiac arrest induced lactic acidosis in dogs

The adequacy of end organ blood flow following a cardiac arrest varies depending on the artificial reperfusion technique utilized and may critically affect patient outcome. Both oxygen consumption (VO2) and arterial lactate values have previously been used to assess tissue perfusion. Cardiopulmonary bypass resuscitation (CPB) is a reperfusion technique capable of providing near normal end organ blood flow. The purpose of this investigation was to study the effect of femoro-femoral veno-arterial CPB resuscitation compared to standard CPR on VO2 and arterial lactic acid values after a prolonged cardiac arrest. Ten mongrel dogs were electrically fibrillated and left in cardiopulmonary arrest without therapy for 12 min. Resuscitation was attempted according to a standardized protocol utilizing either CPB (n = 5) or standard external CPR (n = 5). Oxygen consumption values and arterial lactic acid samples were obtained at baseline, at timed intervals throughout resuscitation and after return of spontaneous circulation in successfully resuscitated dogs. Baseline hemodynamic and biochemical measurements were similar in both treatment groups (P greater than 0.05). Oxygen consumption (440 +/- 50 ml/min/M2) and mean arterial lactic acid values (7.44 +/- 2.25 mmol/l) were significantly higher at 1 min of resuscitation in CPB-treated dogs compared to dogs treated with CPR (60 +/- 10 ml/min/M2) (3.16 +/- 0.69 mmol/l) respectively (P less than 0.05). Mean arterial lactic acid values rose significantly at each sampling interval during CPR (P less than 0.05) but began to decrease after 5 min of resuscitation in the CPB animals and were not significantly different than baseline after 60 min of bypass (P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

新型白细胞滤器LD-1对犬体外循环中血小板的影响

目的研究新型白细胞滤器LD1对血小板数量和功能的影响。方法25～30kg蒙古犬12只随机分为对照组(C组)和过滤组(LD组):C组不使用白细胞滤器;LD组将白细胞滤器LD1安装于体外循环(CPB)的静脉回流端,在CPB开始2min后打开滤器,过滤5min。两组分别于CPB前、CPB10min、40min、75min、停CPB、鱼精蛋白中和肝素5min及停CPB后2h取静脉血测定血常规,于CPB前、鱼精蛋白中和肝素5min后及停CPB后2h取静脉血4.5ml,测定血小板聚集功能。结果①LD组WBC在CPB后10min各时间点均低于C组,Plt在CPB10min时也明显降低,但在停CPB后2h基本恢复正常,且明显高于C组。②CPB后,血小板聚集功能两组均降低,但组间比较无显著差异。结论CPB中使用白细胞滤器LD1能保护CPB后血小板数量,但较少影响血小板聚集功能。     

舒芬太尼与芬太尼用于小儿先心病手术的对比研究

【目的】研究比较舒芬太尼与芬太尼在小儿先心病手术中对血流动力学、血浆儿茶酚胺的影响。【方法】选取心功能Ⅰ～Ⅱ级,无严重肝肾功能疾患的先心病患儿40例,随机分为芬太尼组（F组,n=20）和舒芬太尼组（S组,n=20）。F组麻醉诱导时给予芬太尼20μg／kg,划皮前、体外转流前分剐追加芬太尼10μg／kg;S组麻醉诱导时给予舒芬太尼2μg／kg,术中静脉持续输注舒芬太尼2μg／（kg·h）,体外转流期间1μg／（kg·h）。在麻醉诱导后（T0）、开胸前（T1）、体外转流30min（T2）和停体外转流2h（T3）等时点记录心率（HR）、平均动脉压（MAP）监测值,并在T1、T2、T3等时点采血测定血浆多巴胺及乳酸含量。【结果】F组与S组麻醉效果均较满意,但T0时点心率均明显下降;S组T1、T3时点的心率下降更为明显（P〈0．05）;F组在T2时点乳酸水平升高较S组明显（P〈0．05）。【结论】舒芬太尼与等效剂量的芬太尼均能有效抑制血浆儿茶酚胺的释放,可以安全应用于小儿先心病手术的麻醉。     

Organ-specific extravasation of albumin-bound Evans blue during nonresuscitated hemorrhagic shock in rats

Shock-induced enhanced capillary permeability is associated with alterations in the interstitial matrix composition and contributes to organ damage. This study was designed to evaluate albumin extravasation in various organ tissues during severe, hemorrhagic shock without fluid resuscitation and reperfusion. Target value of hemorrhagic shock was a reduction of cardiac output (CO) by 50% induced by removal of blood. Twelve anesthetized Sprague-Dawley rats (260-325 g) kept under continuous hemodynamic monitoring were randomly assigned to a group of hemorrhagic shock (n = 6) and a control group of normovolemic animals (n = 6). After 30 min of shock 50 mg/kg b.w. Evans blue (EB) was injected intravenously followed by an incubation period of 20 min. Exsanguination and wash out of the intravascular space was performed by a pressure-controlled perfusion with heparinized saline before harvesting organs to quantify albumin-bound EB extravasation. We found that withdrawal of 4.7 +/- 0.4 mL (mean, +/-SEM) blood, which accounts for 21.1% of the calculated total blood volume, resulted in a reduction of CO from 36.1 +/- 3.1 to 19.4 +/- 2.7 mL/min. Simultaneously, MAP decreased from 98 +/- 6 to 40 +/- 1 mmHg. In hemorrhaged rats, the interstitial concentration of EB in lung and kidney was significantly higher than observed in intact animals, whereas heart, spleen, liver, ileum, skeletal muscle, and skin showed no significant microvascular damage. We conclude that despite the absence of fluid resuscitation and reperfusion, microvascular damage in lung and kidney is evident within the first thirty minutes of hemorrhagic shock.     

Low molecular starch versus gelatin plasma expander during CPB: does it make a difference?

BACKGROUND: Non-protein plasma expanders carry a risk of potentially severe allergic reactions. As prime for cardiopulmonary bypass, we routinely use a gelatin plasma expander. Plasma expanding during anesthesia is achieved with high molecular starch (200/0.5 kDalton) in combination with Ringer Lactate solution (RL) and in the Intensive Care Unit (ICU) with a low molecular starch (130/0.4 kDalton). We evaluated the feasibility of low molecular starch in combination with RL (group LMSRL) versus gelatin plasma expanding (group GPE) for priming CPB circuits in patients undergoing cardiac surgery in a randomized prospective trial. METHODS: One hundred and eighty adults who underwent primary valve or coronary artery bypass graft (CABG) surgery were equally stratified into 3 series of 60 patients with the routinely used oxygenators; Capiox RX-25, CML Duo and Quadrox-D. Then they were randomised by drawing lots and allocated into the LMSRL or GPE groups. We compared hematocrit, hemoglobin, platelet count, activated clotting time (ACT), lactate and colloid osmotic pressure (COP), blood loss, transfusion need, urine production and ICU stay. In addition, we monitored the average trans-oxygenator fluid resistance (AFR) for each type of oxygenator. RESULTS: The COP is significantly lower in the LMSRL group (20mmHg +/- 0.2 versus 18 mmHg +/- 0.2, p < 0.0001); as was the total use of plasma expanders (3846 ml +/- 98 versus 3059 ml +/- 77, p < 0.001). All other parameters were not significantly different. When comparing the observed AFR for the three types of oxygenators, a lower AFR in the LMSRL group (p < 0.02) was noted for the Capiox RX-25. CONCLUSIONS: This study shows a lower need for plasma expanders in patients who receive only starch plasma expanders. Further, we noted a lower COP in the LMSRL group, but since the mean COP was >17 +/- 0.2 mmHg, this cannot be considered of clinical importance. In conclusion, our study result supports the use of low molecular starch as a good alternative choice for priming CPB.     

Activated plasma coagulation β-Factor XII-induced vasoconstriction in rats

By inducing BK (bradykinin)-stimulated adrenomedullary catecholamine release, bolus injection of the β-fragment of activated plasma coagulation Factor XII (β-FXIIa) transiently elevates BP (blood pressure) and HR (heart rate) of anaesthetized, vagotomized, ganglion-blocked, captopril-treated bioassay rats. We hypothesized that intravenous infusion of β-FXIIa into intact untreated rats would elicit a qualitatively similar vasoconstrictor response. BN (Brown Norway) rats received for 60 min either: (i) saline (control; n=10); (ii) β-FXIIa (85 ng/min per kg of body weight; n=9); or (iii) β-FXIIa after 2ADX (bilateral adrenalectomy; n=9). LV (left ventricular) volume and aortic BP were recorded before (30 min baseline), during (60 min) and after (30 min recovery) the infusion. TPR (total peripheral resistance) was derived from MAP (mean arterial pressure), SV (stroke volume) and HR. Saline had no haemodynamic effects. β-FXIIa infusion increased its plasma concentration 3-fold in both groups. In adrenally intact rats, β-FXIIa infusion increased MAP by 6% (5±2 mmHg) and TPR by 45% (0.50±0.12 mmHg/ml per min), despite falls in SV (-38±8 μl) and HR [-18±5 b.p.m. (beats/min)] (all P<0.05). In 2ADX rats, β-FXIIa had no HR effect, but decreased SV (-89±9 μl) and MAP (-4±1 mmHg), and increased TPR by 66% (0.59±0.15 mmHg/ml per min) (all P<0.05). After infusion, adrenally intact rats exhibited persistent vasoconstriction (MAP, 10±1 mmHg; TPR, 0.55±0.07 mmHg/ml per min; both P<0.05), whereas in 2ADX rats, MAP remained 5±1 mmHg below baseline (P<0.05) and TPR returned to baseline. End-study arterial adrenaline (epinephrine) concentrations in the three groups were 1.9±0.6, 9.8±4.1 and 0.6±0.2 nmol/l respectively. Thus, in neurally intact lightly anaesthetized untreated rats, β-FXIIa infusion induces both adrenal catecholamine-mediated and adrenally independent increases in peripheral resistance.