Effects of a phosphodiesterase III inhibitor on circulating blood volume after cardiopulmonary bypass

Using a new method based on pulse dye densitometry, circulating blood volume (BV) was measured without direct sampling in patients undergoing open-heart surgery, and the effects of phosphodiesterase (PDE) III inhibitor administration during cardiopulmonary bypass (CPB) were evaluated. Sixteen patients scheduled for elective coronary artery bypass grafting were randomly assigned to the PDE III inhibitor group or control group. BV was determined before CPB, and immediately, and 4 and 12 h after operation. After declamping of the aorta, the PDE III inhibitor amrinone (1 mg/kg) was infused as a single bolus into the venous reservoir in the PDE III inhibitor group. BV decreased significantly soon after the operation in the control group. It did not decrease in the PDE III inhibitor group (48.6 ± 44 and 60.6 ± 8.0 ml/kg for the control and PDE III inhibitor groups, respectively). Four hours after surgery and beyond no significant changes in BV were observed in either group. The body fluid balance was negative in both groups. In conclusion, a single administration of PDE III inhibitor during CPB was found to sustain BV soon after operation and, therefore, is useful for postoperative management of open-heart surgery. Received: May 1, 2000 / Accepted: September 30, 2000     

Effects of phosphodiesterase inhibitors after coronary artery bypass grafting

The aim of this study was to estimate the postoperative effects of phosphodiesterase (PDE) inhibitors (milrinone and olprinone) after coronary artery bypass grafting (CABG). To prevent hypotension caused by the PDE inhibitors, low dose of catecholamines were used concomitantly. A total of 34 elective CABG cases were tested. In 12 cases, 0.25 microg kg(-1) min(-1) of milrinone, 3 microg kg(-1) min(-1) of dobutamine (DOB) and dopamine (DOA) were used concomitantly (Group-M). In another 10 patients, 0.1 microg kg(-1) min(-1) of olprinone and the same doses of the catecholamines were infused (Group-O). As a control, the same doses of DOA and DOB only were administered in 12 patients (Group-C). When the pump flow of the cardiopulmonary bypass (CPB) decreased to half, these drugs were given in all groups. Hemodynamics were recorded before CPB, just after the operation, and 3, 6, 12, 24, 48 and 72 h after the operation. Both milrinone and olprinone increased the cardiac index and decreased systemic vascular resistance to almost the same degree. Olprinone decreased mean aortic and pulmonary artery pressures, and also significantly reduced the preload of both right and left heart compared with milrinone. Significant hypotension was not detected due to the concomitant usage of low-dose catecholamines. This concomitant usage of PDE inhibitors and catecholamines allowed easy weaning from CPB, demonstrating excellent hemodynamics after CABG. Good oxygen demand and supply balance were maintained in peripheral tissue. These results suggest that these new PDE inhibitors may be effective not only for weaning from CPB but also for post-cardiotomy cardiogenic shock.     

成人瓣膜手术体外循环中应用不同利尿剂对电解质的影响

目的:观察托拉塞米与呋噻米用于成人瓣膜手术体外循环(cardiopulmonary bypass,CPB)中对电解质的影响。方法:随机选取择期CPB下行瓣膜置换术患者60例,分为托拉塞米组(A组)30例,呋噻米组(B组)30例,分别在CPB前、升主动脉阻断后15min、升主动脉开放15min、CPB停机时和术后2h抽取静脉血进行血气分析,记录K+、Na+、Mg++及Ca++离子浓度。同时记录2组患者转机中尿量及自动复跳率。结果:2组患者转机前、阻断升主动脉后15minK+、Na+、Mg++及Ca++离子浓度差异无统计学意义(P>0.05);A组患者开放升主动脉后15min血K+明显高于B组,差异有显著性统计学意义(P<0.01),Mg++、Ca++差异无统计学意义(P>0.05);停机时及术后2h,2组患者血K+、Na+、Mg++及Ca++差异无统计学意义(P>0.05)。2组患者转中尿量及自动复跳率差异无统计学意义。结论:托拉塞米可以用作CPB下瓣膜置换术的利尿剂,但要注意防止复跳时的高钾。     

High mobility group box 1 levels in on and off-pump cardiac surgery patients

High mobility group box 1 (HMGB1), which has properties similar to those of proinflammatory cytokines, is released from activated immune cells and necrotic cells. It is known that cardiopulmonary bypass (CPB) induces systemic inflammation and aortic cross-clamping induces myocardial ischemia. This study was conducted to clarify whether HMGB1 is released in CPB-supported cardiac surgery in comparison to off-pump coronary artery bypass grafting (OPCAB) where CPB is not used.Nineteen adult patients undergoing cardiac surgery involving CPB (CPB group) and 5 OPCAB patients (OPCAB group) were included in this study. Plasma concentrations of proinflammatory cytokines including HMGB1 were measured before, during, and after cardiac surgery. The plasma HMGB1 level was significantly increased at one hour after aortic declamping in the CPB group and at 30 minutes after revascularization in the OPCAB group. The peak HMGB1 level was slightly higher in the CPB group than that in the OPCAB group. These values decreased toward baseline value after surgery in both groups. TNF-α and IL-1β were not detectable throughout the study period in either group. IL-6 and IL-10 increased after aortic declamping in the CPB group and after coronary revascularizations in the OPCAB group.Based on these results, we conclude that the major factor involved in the increase in HMGB1 level might be myocardial ischemia/reperfusion during cardiac surgery. Activation of immune cells, altered tissue perfusion, and pulmonary ischemia and reperfusion could be additional factors that increase the HMGB1 level in CPB-supported cardiac surgery.     

Efficacy of the phosphodiesterase inhibitor enoximone in complicated cardiac surgery

Acute myocardial dysfunction during cardiac surgery involves various pathophysiologic mechanisms such as reduction in myocardial contractility and an increase in afterload induced by peripheral vasoconstriction. In 30 consecutive patients undergoing coronary artery bypass grafting (CABG) and ten consecutive patients with aortic valve replacement (AVR), in whom therapy with catecholamines was expected to be necessary during and after weaning from cardiopulmonary bypass (CPB) on the basis of a retrospective study ("control" patients), 1.0 mg/kg of the phosphodiesterase (PDE) inhibitor enoximone was administered ten minutes prior to weaning from bypass (enoximone group). In eight CABG and four AVR patients weaning was possible without further pharmacologic support. Significantly less epinephrine was used in enoximone pretreated patients (8.8 +/- 3.0 micrograms/min) than in the control patients (21.4 +/- 4.4 micrograms/kg). The use of additional vasodilators was significantly less pronounced in these patients as well. Seven CABG and four AVR patients in the enoximone group needed additional vasoconstrictors (norepinephrine) to counteract marked, unwanted decrease in peripheral vascular resistance with a decrease in mean arterial pressure (MAP). Hemodynamic monitoring revealed a higher level in heart rate in the control patients with arrhythmia in seven of the CABG patients: MAP, right atrial pressure, cardiac index, and pulmonary capillary wedge pressure were without significant differences between the groups. Pulmonary artery pressure and TSR, however, increased more in the control group, indicating an increase in right and left ventricular afterload. The results of this study demonstrate that patients at risk of circulatory failure during or after weaning from CPB profit from pretreatment with PDE-III inhibitor enoximone due to a reduction in catecholamines and an improvement in hemodynamics.     

Isolated cerebral and myocardial perfusion during aortic arch repair in neonates

OBJECTIVES: To prevent possible neurologic injury after hypothermic circulatory arrest, aortic arch obstruction with cardiac defects is repaired in one stage using isolated cerebral and myocardial perfusion (ICMP). This study investigated serum S-100 protein(S-100) levels in neonates undergoing ICMP. METHODS: Between February 2000 and January 2001, 19 neonate patients underwent repair of critical congenital heart defects. Seven of these patients with aortic coarctation(n = 3) or interrupted aortic arch (n = 4) with ventricular septal defect(ICMP group) underwent primary total repair. An arterial cannula was inserted either into the ascending aorta or into a polytetrafluoroethylene graft which was anastomosed to the innominate artery. During arch repair, a cross-clamp was placed between the innominate and left carotid arteries, and an end-to-end arch anastomosis was performed with cerebral perfusion and heart beating. During ICMP the flow was reduced to maintain a radial artery pressure of 30-45 mmHg. The remaining 12 patients underwent complete transposition of great arteries(n = 9) or total anomalous pulmonary venous connection(n = 3) using a cardiopulmonary bypass(CPB) with flow of 150-180 ml/kg/min(control group). Sequential blood samples for S-100 determinations were taken after induction of anesthesia, 30 min after aortic declamping(post-ACC), 30 min after CPB, and 24 hr after CPB. RESULTS: There were no early and late deaths. Neurologic symptoms were not observed in any patients. Mean ICMP time in ICMP group was 17 +/- 4 min. In all patients, S-100 showed the highest value post-ACC and then declined with time. There were no differences in S-100 between the groups at any other time point. CONCLUSIONS: Selective cerebral perfusion through the innominate artery may be able to maintain brain circulation.     

乌司他丁在婴幼儿体外循环手术期间的心肌保护作用

目的探讨乌司他丁在婴幼儿体外循环手术中对心肌缺血/再灌注损伤的保护作用。方法选择38例诊断为室间隔缺损的婴幼儿患者,随机分为试验组(n=18):1.2万U/kg乌司他丁;对照组(n=20):以等量生理盐水代替。记录阻断和转流时间,血管活性药物使用和心脏复跳情况。于转流前,主动脉开放即刻,开放30min,停机后4h、24h检测CK、CK-MB和cTnI,并观察心肌超微结构。结果①两组CK-MB、CK和cTnI转流前差异均无统计学意义,CPB后明显升高(P<0.05);试验组停机后4h、24h,CK、CK-MB较对照组低(P<0.05),cTnI主动脉开放30min,停机后4h、24h低于对照组(P<0.05)。②实验组多巴胺/多巴酚丁胺平均使用剂量少于对照组(P<0.05),心脏自动复跳率明显高于对照组(P<0.01),术后心肌组织超微结构显示心肌细胞损害较对照组轻。结论乌司他丁能降低CK、CK-MB、cTnI的释放,减轻婴幼儿体外循环手术中心肌损害,对心肌缺血/再灌注损伤有保护作用。     

Simple active air evacuation procedure for right ventricular failure caused by intracoronary air embolism

In cardiac surgical cases such as valve replacement, right ventricular failure caused by intracoronary air embolism sometimes occurs after aortic declamping and during weaning from cardiopulmonary bypass (CPB). The details are reported of a de-airing method which involves simply rotating the arterial cannula towards the base of the heart, with no need for a particular circuit. This method was used in ten patients who, following open-heart surgery, suffered postoperative right ventricular failure due to air embolism in the right coronary artery that did not respond to other de-airing methods. The technique resolved the problem in all patients, who were quickly weaned from CPB and ultimately discharged. Rotation of the arterial cannula may represent a simple means of resuscitating patients who have suffered right ventricular dysfunction that is unrelieved by other, conventional methods.     

持续低温心肌灌注体外循环不降温在心脏外科中的应用研究

目的探讨心脏持续低温灌注体外循环（CPB）不降温在心脏外科手术中的应用价值。方法将60例心脏病手术患者随机分为两组,即常温组和低温组各30例,对比研究两组CPB时间、主动脉阻断时间、手术时间、术后体温、多巴胺使用情况、血尿、心包纵隔总引流量、血细胞水平等检测指标间的差别。结果常温组CPB时间较低温组短（P〈0．05）,术后总引流量、使用多巴胺的量和时间以及血尿的发生较低温组低（P〈0．05）,手术时间较低温组明显缩短（P〈0．01）。结论心脏持续低温自体氧合血灌注体外循环不降温明显缩短了手术时间,心肌保护良好,值得在临床上推广运用。     

应用搏动性体外循环患者血浆丙二醛和超氧化物歧化酶的动态变化

对２０例心脏直视手术病人分别应用搏动性与非搏动性体外循环，动态观察体内丙二醛（ＭＤＡ）和超氧化物歧化酶（ＳＯＤ）变化。结果显示搏动组患者体外循环期间主动脉阻断及开放后血中ＳＯＤ升高，而ＭＤＡ无明显变化。提示搏动性灌注可能通过提高机体的抗氧自由基能力而改善组织的氧代谢。     

冠心病围术期肾素-血管紧张素-醛固酮系统变化的研究

目的:研究冠心病围术期肾素-血管紧张素(RAAS)及血流动力学变化规律。方法:37例冠心病分为5组。组1冠状动脉旁路移植术(CABG)+室壁瘤切除,组2体外循环(CPB)下CABG,组3非体外循环下的冠状动脉旁路移植术(OPCABG),组4激光心肌打孔组(TMLR)。用放免法测术前,主动脉阻断前(搭桥前或打孔前),开放时(搭桥结束时或打孔后),开放后3,6及24 h血管紧张素Ⅱ(AGⅡ)、醛固酮(ALD)和血流动力学指标。收集0～6 h、6～24 h尿钾总量。结果:AGⅡ:组1,2主动脉开放时,开放后3,6及24 h显著高于术前(P<0.05)。组间:组2术后3 h显著高于组3(P<0.05)。ALD组内:组1,2主动脉开放时,开放后3 h显著高于术前(P<0.05)。组间:组2开放时、术后3 h显著高于组3(P<0.05)。术后各组心排指数(CI)较术前明显增加(P<0.05)。尿钾:术后各组间尿钾排出总量差异无统计学意义。结论:冠心病术后早期RAAS活性升高,使用CPB的患者,升高更明显,但24 h以内恢复正常。冠心病行OPCABG,术后心功能恢复快,全身反应轻,如有适应症应积极选用此术式。TMLR患者全身反应,是冠心病外科治疗的有益补充。     

Prevention of ventricular fibrillation after aortic declamping during cardiac surgery

Ventricular fibrillation is common after aortic declamping during cardiac surgery, and the metabolic demands of such fibrillation, or its treatment by means of countershock, may contribute to myocardial injury. To determine the effects of administering intravenous lidocaine just before aortic declamping, we randomly divided 194 cardiac surgery patients into 2 groups. One hundred patients (group A) received lidocaine, 200 mg intravenously, 3 minutes before aortic declamping; and 94 patients (group B) received no medication before declamping. Multiple baseline variables, including clamp times, medications, electrolyte values, ventricular function, and the extent and type of surgery, were similar for both groups. After aortic declamping, 31 of the 100 patients in group A had ventricular fibrillation, as did 57 of the 94 patients in group B (p < 0.001). Of those who fibrillated, the group-A patients required a mean of 1.76 countershocks, whereas the group-B patients required a mean of 2.68 countershocks (p < 0.05). Serum potassium level also affected the incidence of ventricular fibrillation, independently of lidocaine. Elevated serum potassium levels were associated with a lower incidence of ventricular fibrillation. Although lidocaine was independently protective at all potassium levels, the combination of lidocaine and a high serum potassium level had the greatest effect in preventing fibrillation. In patients who had potassium levels higher than 5.1 mEq/l and who were also given lidocaine, the incidence of ventricular fibrillation was lower than 15%.     

Isoflurane pre-treatment before cardiopulmonary bypass alleviates neutrophil accumulation in dog lungs

Objective

This study investigated the effect of isoflurane pre-treatment on cardiopulmonary bypass (CPB)-related lung injury.

Methods

Twelve dogs were randomly divided into two groups of six each. In one group, 1.0 minimum alveolar concentration (MAC) of isoflurane was administered for 30 min before CPB, while the control group received no anaesthetic. Both groups then underwent 100 min of mild hypothermic CPB with 60-min aortic cross clamping. Haemodynamic parameters, respiratory mechanics and alveolar arterial oxygen difference (AaDO₂) were measured during the experiment. One hundred and fifty minutes after CPB, lung tissue samples from the non-dependent and dependent portions of the left and right lungs were harvested for polymorphonulear leukocyte (PMNs) counts.

Results

Following CPB, within the control group, pulmonary vascular resistance (PVR) was significantly increased at 60, 120 and 180 min after declamping, AaDO2 deteriorated at 180 min post-declamping, and dynamic lung compliance (DLC) was reduced dramatically after declamping. Isoflurane pre-treatment before CPB significantly reduced PVR compared to the controls. AaDO₂ was impaired at 180 min after declamping and DLC was decreased after declamping within the isoflurane group. No differences in AaDO₂ and DLC were found between the isoflurane and control groups. At 180 min after declamping, the PMN count in both the non-dependent and dependent regions of the isoflurane pre-treated lungs was significantly lower than that of the controls.

Conclusions

Our results suggest that 30-min pre-treatment with 1.0 MAC isoflurane before CPB caused a reduction in PMN accumulation in the dog lungs, inhibition of increases in PVR, and it did not affect AaDO2 in the early post-CPB stage.     

Effects of preemptive therapy with milrinone or amrinone on perioperative platelet function and haemostasis in patients undergoing coronary bypass grafting

Preemptive therapy with a phosphodiesterase III inhibitor preserves cardiac function and oxygen transport after cardiac surgery, and its safety on platelet function and haemostasis must be verified. We examined the effects of preemptively administered milrinone or amrinone on platelet function and haemostasis. In 45 cardiac surgery patients, we randomly administered milrinone 50 microg/kg plus 0.5 microg/kg/min for 10 hours, amrinone 1.5 mg/kg plus 10 microg/kg/min infusion for 10 hours, or placebo at release of aortic cross-clamp. Whole blood platelet aggregation, haematological values, and postoperative chest drainage were examined. Three patients in the placebo, 1 patient in the amrinone, and 2 patients in the milrinone groups received allogenic blood transfusion (654 +/- 365 ml) intraoperatively, but no patient postoperatively. The mean platelet counts 3 days postoperative in the milrinone and amrinone groups did not significantly differ from the placebo group (10.9 +/- 3.3 and 12.1 +/- 3.8, vs. 12.1 +/- 3.4x10(4) per cubic millimeter, respectively), and chest-tube drainage in the first 24 hours did not significantly differ (450 +/- 156 and 391 +/- 184, vs. 448 +/- 140 ml, respectively). Although there were changes in platelet aggregation consequent to surgery there was no significant differences in platelet aggregation or other haematological values among the three groups. Preemptive therapy of milrinone or amrinone does not deteriorate perioperative platelet function and haemostasis beyond surgical interventions.     

Activated protein C in the cardioplegic solution on a porcine model of coronary ischemia-reperfusion has deleterious hemodynamic effects

Summary Purpose: In reperfusion injury activation of coagulation and inflammation contribute to organ dysfunction. Activated protein C (APC) exhibits anticoagulant and anti-inflammatory properties in models of reperfusion injury. We hypothesized that APC could be cardioprotective after ischemia and cardiopulmonary bypass (CPB). Methods: 20 pigs, undergoing 120 min of CPB and aortic cross-clamping, were randomized to receive 1 mg of human APC or placebo to the last cardioplegic solution given 15 min before declamping to the systemic circulation. After aortic declamping the heart was supported by continuing CPB for 30 min followed by 30 min surveillance. Thrombin-antithrombin complexes, neutrophil L-selectin expression in blood and myeloperoxidase activity (MPO) of myocardial biopsies were measured. Results: There was no indication of APC-induced increased bleeding. Thrombin levels were significantly lower in the APC group than in the placebo group and so were the rates of thrombin formation during the first 3 min of reperfusion and between 10 and 30 min after declamping. There were no differences in MPO or in the proportion of L-selectin (+) to L-selectin (−) neutrophils between groups. Significant systolic hypotension in the APC group was observed at 30 and 45 min compared with the placebo group which associated with the increased mortality observed in the APC group (p = 0.019). Conclusions: Human APC in cardioplegic solution during CPB in pigs, decreased reperfusion induced thrombin formation with no associated bleeding. No anti-inflammatory effects of human APC were seen. However, in this setting, APC caused hemodynamic deterioration. The observed phenomenon could be explained by systolic hypotension potentially produced by the release of vasoactive substances generated by the APC activation of PARs in the endothelium.     

Blood lactate levels during cardiopulmonary bypass for valvular heart surgery

Cardiopulmonary bypass (CPB) is widely used to maintain systemic perfusion and oxygenation during open-heart surgery. Tissue hypoperfusion with resultant lactic acidosis during CPB, may occur during hypothermia, extreme haemodilution, low flow CPB, and excessive neurohormonal activation. There has been no documentation of the correlation between blood lactate level elevations in the perioperative period, and its relation to preoperative New York Heart Association (NYHA) classification and the use of ionotropic support during weaning from CPB, duration of postoperative ventilatory support and perioperative mortality. We studied the perioperative blood lactate levels in 82 patients undergoing valvular heart surgery. Arterial blood samples were collected at different stages of CPB. The observed mean baseline lactate levels were 1.9+/-0.8 mmol/L (normal range of 0.9 to 1.7 mmol/L). The mean circulating lactate levels at 15 min and 45 min after institution of CPB increased to 7.01+/-2.6 mmol/L and 9.92+/-3.5 mmol/L. A progressive decline in the mean lactate level, was seen during rewarming (at 35 degrees C), immediately off-bypass, 24 hours and 48 hours postoperatively with mean lactate levels being 7.01+/-3.2 mmol/L, 4.75+/-1.01 mmol/L, 3.06+/-1.1 mmol/L, and 2.10+/-1.05 mmol/L respectively. Comparison of mean lactate levels in NYHA class I, II, III, and IV patients showed that in the intraoperative period and immediately after CPB, the elevation in lactate levels were statistically significant (p< 0.001) in patients in NYHA Class IV. However the values, in all classes, were similar at 24 and 48 hours after CPB. Also, patients with lactate levels >4 mmol/ L required prolonged inotropic and ventilatory support.     

Hemostatic effects of antithrombin III supplementation during cardiac surgery: results of a prospective randomized investigation.

Failure to suppress thrombin generation during cardiac surgery promotes fibrin generation, fibrinolysis, and a consumptive coagulopathy. Acquired deficiencies of antithrombin III may play a contributory role. We hypothesized that antithrombin III supplementation to normal physiologic concentrations would decrease thrombin generation and potentially reduce peri-operative bleeding. Twenty patients undergoing coronary artery bypass graft surgery were randomized for this prospective, double-blind, placebo-controlled study. Ten patients received antithrombin III supplementation (50 U/kg) by intravenous infusion prior to incision, and 10 patients received a placebo. Blood samples were obtained pre-operatively, at 1 and 2 h following initiation of cardiopulmonary bypass (CPB), and at 1, 3, and 24 h after completion of CPB. Samples were analyzed for antithrombin III, thrombin-antithrombin III (TAT) complex, and D-dimer concentrations. Cumulative blood loss was recorded at 6 and 12 h after CPB. No statistically significant differences in patient demographics or total heparin dose administered were observed between groups. As expected, plasma antithrombin III concentrations were maintained near pre-operative values in the treatment group, but not in the placebo group. Despite this difference, no statistically significant alterations in generation of TAT complex, D-dimer, or blood loss occurred between groups. Antithrombin III supplementation to maintain normal physiologic concentrations during CPB did not alter significantly thrombin generation, fibrinolytic activity, or blood loss in adults undergoing elective cardiac surgery.     

不同体外循环方式在主动脉瘤外科手术中的应用

目的：探讨对不同部位、不同病变程度的主动脉瘤的体外循环方式的选择。方法：本组在体外循环下行主动脉瘤外科手术５６例，其中升主动脉瘤３８例，降主动脉瘤１８例。采用低温全身体外循环３１例；左心转流１５例；深低温停循环１０例，其中深低温停循环上腔静脉逆行灌注脑保护方法９例。结果：术中死亡１例，为巨大升主动脉瘤，因吻合口不能控制出血而死亡。术后死亡３例，１例为突发心室颤动，１例为术中大量气体进入主动脉，术后昏迷、肾功能衰竭死亡，第３例为降主动脉瘤术后突发心肌梗死。除１例因动脉插管进入夹层，在开始体外循环时即血压下降、心跳停止，以及术后长时间有神经精神症状外，其余病例均无神经系统并发症。结论：主动脉瘤手术的体外循环方式要根据病变情况决定。     

吸入NO对婴幼儿体外循环中肺表面活性物质的影响

目的: 探讨吸入一氧化氮(NO)对婴幼儿体外循环（cardiopulmonary bypass,CPB）中肺表面活性物质的影响。 方法: 将30例患室间隔缺损的婴幼儿随机分为对照组和NO组,NO组在CPB期间吸入40 μl/L NO直至关胸。CPB前、主动脉开放后1,5,10 min以少量生理盐水灌洗气道,分别测定气道吸出物(BAL)中总磷脂(TPL)、饱和卵磷脂(SatPC)、总蛋白(TP)值,并计算SatPC/TPL和SatPC/TP。结果: CPB后两组SatPC/TPL、SatPC/TP较CPB前明显降低(P<0.01)。NO组SatPC/TPL和SatPC/TP下降的幅度明显小于对照组(P<0.01)。结论: 婴幼儿CPB术中存在明显的肺损害,表现为一些亚临床性肺功能损伤。吸入40 μl/L的NO对CPB期间肺功能有明显的保护作用。     

长时间阻断主动脉的心肌保护与辅助循环脱机指征

长时间的心肌缺血是影响心肌保护的重要因素，也是不能脱离体外循环的常见原因之一。本文报告了４１例长时间阻断主动脉的心肌保护方法与辅助循环脱机指征，其中主动脉阻断时间（ＡＣＣＴ）＞１２０分３２例，ＡＣＣＴ＞１８０分９例；主动脉根部间断顺行灌注停搏液１４例；顺行灌注联合间断逆行灌注含血停搏液２０例；顺行灌注联合持续逆行灌注７例；主动脉开放前控制性热血再灌注１４例；结果显示：顺行灌注联合持续逆行灌注对心肌保护效果最佳，它可使主动脉阻断的安全时限达４小时左右。本文还就辅助循环方法与脱机指征进行讨论。作者主张根据左房压和平均动脉压的动态变化，调解辅助循环流量是脱机的可靠方法。