深度血液稀释并中度低温期不同流量体外循环的临床应用

双瓣置换术30例,采用深度血液稀释建立体外循环(CPB),降温至鼻咽温(T)26 ℃稳定3 min后,分为高(H)、低(L)两组流量转流各15例,复温后L组可适宜增加流量,H组各期保持高流量不变;33 ℃时开放主动脉,视心功能情况适时停机.于CPB各时点抽取动脉血测定血红蛋白(HB)、血乳酸(Lac),同期记录T、流量(Q)、静脉血氧饱合度(SvO2).结果低温期两组SvO2均可维持于正常水平,但H组明显升高(P<0.01);复温后两组SvO2均下降,主动脉开放时L组显著低于H组(P<0.01),一直持续到停机时(P<0.05);CPB开始后两组血Lac水平呈累积性升高,复温后H组上升速度明显减慢(P<0.05).认为深度血液稀释并中低温CPB全程采用高流量灌注更加合理.     

小体质量婴幼儿体外循环管理策略及合理使用超滤的重要性

目的:总结392例8kg以下患儿体外循环(CPB)管理经验,探讨小体质量婴幼儿CPB中超滤和围体外循环期液体管理的重要性。方法:2006年7月至2008年8月392例8kg以下患儿在CPB下行心脏手术。患儿分成2组:A组(2006年7月至2007年7月)共208例,B组(2007年8月至2008年8月)共184例,比较2组术前、围体外循环期的临床情况及术后的结果,总结小体质量婴幼儿CPB管理经验。结果:2组患儿一般临床资料,CPB时间和阻断时间以及术后结果没有统计学意义;CPB过程中2组悬浮红细胞和血浆的用量没有明显差别;B组白蛋白(7.1±3.4)g的应用明显低于A组(8.1±2.9)g;B组晶体用量明显多于A组;B组总超滤量明显高于A组。结论:改良超滤技术+白蛋白的应用可以改善小体质量患儿围体外循环期管理质量,但需要科学管理和有效的监测。     

逆行自体血预充在体外循环心脏瓣膜置换手术中的应用

目的:探讨逆行自体血预充(RAP)对心脏瓣膜置换手术中血液稀释及围术期输血量的影响。方法:将30例心脏瓣膜置换术患者随机分为RAP组和常规预充组,每组15例。常规预充组采用常规晶体预充液预充,RAP组使用患者自身血液替换部分常规晶体预充液。监测体外循环前、中、结束时以及术后1h、3h等各个时间点的乳酸(Lac)和红细胞压积(Hct)水平,并观察两组患者围术期输血量和胸腔引流量。结果:逆行自体血预充能有效减轻心脏瓣膜置换手术中的血液稀释程度,维持术中较高的Hct水平,对机体血液有较好保护作用,有效减少了围术期输血量。结论:逆行自体血预充能有效减轻心脏瓣膜置换手术中的血液稀释程度,维持术中较高的Hct水平,对机体血液有较好保护作用,有效减少围术期输血量。     

非体外循环冠状动脉旁路移植术围术期不同时机应用主动脉内球囊反搏的临床观察

目的:比较在非体外循环冠状动脉旁路移植术(OPCAB)围术期不同时机应用主动脉内球囊反搏的临床效果。方法:回顾分析OPCAB围术期应用主动脉球囊反搏(IABP)的患者80例,其中术前应用组20例,术中应用组31例,术后组29例。比较三组患者术中被迫紧急建立心肺转流(CPB)转为体外循环下冠状动脉旁路移植术(ONCAB)的比例,术后应用体外膜肺氧合(ECMO)的比例、住院期间病死率;以及三组IABP反搏时间、气管插管时间、ICU时间及术后住院天数。观察术后1 d、术后2 d血浆肌钙蛋白I(cTnI)、肌酸磷酸激酶同工酶(CKMB)水平。结果:术中应用组被迫紧急建立体外循环改为ONCAB比例高于术前应用组;IABP反搏时间、气管插管时间,术前应用组少于术后组;术前应用组的术后住院天数少于其他两组。术后组术后2d cTnI高于术前应用组;术后1d、2d CKMB水平,术前应用组也明显低于另外两组。结论:危重患者OPCAB术前应用IABP可以改善围术期的管理,提高救治成功率。     

大鼠体外循环基础上应用停跳液心脏停跳模型的建立

目的:在大鼠普通体外循环(CPB)模型基础上,建立灌注心停跳液心脏停跳(CA)模型,比较CA模型与普通CPB模型实验大鼠心肌缺血再灌注损伤情况;观察CA模型大鼠术后的存活和恢复情况。方法:借助血管穿刺置管技术,在大鼠普通CPB模型基础上,通过右侧颈总动脉置入双腔气囊导管,充气套囊、阻断升主动脉及灌注心脏停跳液使心脏停搏。比较CPB模型大鼠(n=6)和CA模型大鼠(n=15)心肌缺血再灌注损伤的区别;分别在术后1 d、1周和2周3个时点观察CA模型大鼠恢复情况(n=5)。结果:CA大鼠在心脏缺血再灌注60 min后,心型脂肪酸结合蛋白(HFABP)和心肌肌钙蛋白I(cTnI)明显高于术前基础值和普通CPB组水平,在复灌后3 h达到顶峰,术后1 d降低,在术后1周和2周的观察时点回降至术前水平。左心室射血分数(EF)在2组动物之间差别不大;舒张早期血流峰值/舒张晚期血流峰值比值(E/A比值)在CPB后降低,而在CA后进一步下降。CA组大鼠均存活,但术后质量明显降低,在术后1周时最为显著,2周时大鼠质量已经恢复,并且超过术前水平。结论:本实验在普通的CPB模型基础上成功的建立了CA模型。同普通CPB模型大鼠相比,CA模型大鼠在CPB心脏缺血再灌注后,出现了明显的心肌损伤。CA大鼠具有较高的存活率。     

体外循环下老年室间隔缺损修补术患者血液相关指标的改变

目的探讨体外循环(CPB)下室间隔缺损(VSD)修补手术的VSD老年患者血气、水电解质、血液等相关指标变化情况。方法比较80例VSD患者CPB过程中不同的时间点包括转机后5 min(T1)、升主动脉开放30 min(T2)的血液指标包括二氧化碳分压(PCO2)、二氧化碳总量(TCO2)、血糖(GLu)、乳酸(Lac)、血红蛋白(Hb)、血细胞比容(Hct)、pH、Ca2+、K+、Na+等的改变。结果 T2时pH高于T1时(t=2.079,P=0.039),而PCO2低于T1时(t=1.952,P=0.042),T2时Hct显著低于T1时(t=3.446,P<0.01),而Glu显著高于T1时(t=5.207,P<0.01);T2时Ca2+(t=7.589,P<0.01)、K+(t=19.61,P<0.01)水平均显著高于T1时。结论 CPB下行VSD修补术的老年室间隔缺损患者需实时监测血气、血糖和电解质变化。     

术前自体血小板分离在心脏手术中的血液保护作用

大部分心脏手术需要在体外循环(cardiopulmonary bypass,CPB)下进行,CPB期间血小板数量的减少和功能的下降是术后凝血功能障碍和异常出血的重要原因之一。CPB前,利用自体血小板分离技术将部分血小板从患者全血中分离出来制成富血小板血浆(platelet-rich plasma,PRP),在CPB结束鱼精蛋白中和后再回输入病人体内,以减少围术期的出血量和血液制品输注量。PRP是一种可行的血液保护方法。     

低温体外循环对心脏瓣膜置换术患者异丙酚血药浓度及麻醉深度的影响

采用麻醉深度监测仪监测行低温体外循环(CPB)下心脏瓣膜置换术患者大脑状态指数(CSI).记录CPB前、CPB开始后不同时间点的CSI、鼻咽温度、平均动脉压、心率、血红蛋白,并在相同时间点抽取桡动脉血5 ml,测定异丙酚血药浓度.发现CPB后2 min异丙酚血药浓度下降,30 min时上升至CPB前水平;CPB期间各时间点的CSI明显低于CPB前(P均<0.01),CPB停止后恢复至CPB前水平.认为低温CPB开始阶段,异丙酚血药浓度明显下降,30 min后恢复至CPB前水平;CSI在低温期间维持在较低水平,并随鼻咽温度下降而降低.异丙酚血药浓度与CSI的变化没有直线相关关系.     

胃肠激素和胃黏膜pH值在体外循环心脏手术中的变化

目的:探讨体外循环(cardiopulmonary bypass,CPB)中血乳酸,胃黏膜pH值,胃肠激素变化.方法:20例心脏直视手术患者,分别在麻醉前、CPB前、CPB 15-min、开放升主动脉后5min、停止CPB 20 min和术后3 h,测定红细胞压积,血乳酸(Lae),计算胃黏膜pH值(pHi).放射免疫法测定降钙素基因相关肽(CGRP)、胃泌素(GAS)和胃动素(MOT)浓度.结果:GAS和MOT在CPB15 min浓度均显著高于CPB前(89.72±21.59 vs 57.20±13.26.271.35±45.61 vs 196.93±42.56,均P＜0.05),相反,CGRP在CPB中浓度与CPB前相比明显降低(63.17±20.26 vs 115_37±29.04,P＜0.05).尽管体外循环期间血Lac浓度高于CPB前,pHi低于CPB前,但与体外循环前相比差异无显著性.结论:CPB过程中随时间延长,血清中MOT和Gas显著增高,CGRP显著降低,pHi下降是CPB术后发生胃肠道并发症的潜在的危险因素.     

小型猪体外循环手术中的麻醉管理

目的研究小型猪体外循环（CPB）手术中的麻醉管理及全麻效果的评价方法。方法小型猪32例,诱导用氯胺酮和戊巴比妥肌注,维持用氯胺酮、戊巴比妥钠、咪达唑仑和哌库溴铵静注,转机后停用戊巴比妥;记录生命体征、血流动力学和动脉血气分析、诱导时间、CPB转机时间、主动脉阻断时间、全麻维持时间、呼吸机辅助时间等。结果诱导期1例死于呼吸心跳骤停,31例各期血流动力学平稳,麻醉诱导（8±3）min,CPB转机（67±8）min,主动脉阻断（33±4）min,麻醉维持时间（185±17）min。诱导和维持效果达Ⅰ级者分别占71．9％和74．2％。结论合理选择麻醉方法,精确调整剂量,简明评价效果,减轻再灌注损伤和积极维护心肺功能,是小型猪CPB手术成功的关键。     

Continuous antegrade blood cardioplegia: cold vs. tepid

BACKGROUND: Continuous antegrade blood cardioplegia (CABCP) is used at different temperatures. We investigated the consequences of CABCP at 6 degrees C (COLD) vs. 28 degrees C (TEPID). METHODS: Anesthetized open-chest pigs (25 +/- 2 kg) were placed on cardiopulmonary bypass (CPB). The hearts were arrested for 30 min by 6 degrees C cold or 28 degrees C tepid CABCP (n = 8 each). After an initial 3 min antegrade application of high potassium (20 mEq) cold (6 degrees C) blood cardioplegia, the hearts were arrested for a subsequent 27 min by normokalemic blood delivered antegrade at either 6 degrees C or 28 degrees C. After this, the hearts underwent perfusion with warm systemic blood for an additional 30 min on CPB. Biochemical cardiac data (MVO2 [ml/min/100 g], release of creatine kinase [CK U/min/100 g] and lactate [mg/min/100 g]) were measured during CPB. Total tissue water content (%) and left ventricular stroke work index (SWI g x m/kg) were determined 30 min after discontinuation of CPB and compared to pre-CPB controls. RESULTS: Cold CABCP kept all hearts continuously arrested. The COLD hearts showed no biochemical or functional disturbance. The TEPID hearts intermittently fibrillated and required additional high potassium BCP shots. The TEPID hearts showed a marked CK leakage (2.6 +/- 0.4 vs. 0.7 +/- 0.4), lactate production (4.0 +/- 1.6 vs. extraction from the COLD group) despite the non-ischemic protocol, an impaired initial oxygen consumption (4.2 +/- 1.3 vs. 7.1 +/- 1.6) at the end of cardiac arrest, the formation of myocardial edema (79.5 +/- 1.0 vs. 77.0 +/- 0.8), and a depressed recovery of SWI (0.69 +/- 0.15 degrees vs. 1.41 +/- 0.13). *p < 0.05 for comparison of TEPID vs. COLD hearts using Student's t-test for unpaired data; degrees p < 0.05 for intergroup-comparison of TEPID vs. COLD vs. controls using ANOVA adjusted for repeated measures. CONCLUSIONS: Uninterrupted cardioplegia can be safely performed with cold normokalemic CABCP. In contrast, tepid normokalemic CABCP leads to fibrillation, jeopardizes the heart, and should be avoided.UND     

Unsuspected hemodynamic alterations during endotracheal suctioning

Endotracheal suctioning of intubated patients is associated with hemodynamic complications including arterial hypoxemia, cardiac arrhythmias, hypotension and even death. Prior investigations of this subject focus primarily on arterial hypoxemia. Our observations of ETS revealed significant falls in the mixed SvO2 and we postulated that alterations in VO2 or CO must be occurring. This study was then designed to determine the alterations in CO, VO2, SaO2 and the resulting effect on SvO2 during ETS. Ten critically ill intubated patients with pulmonary artery catheters in place, were studied during routine ETS by the nursing staff. We found that ETS produced a significant decrease in SvO2 which was predominantly due to an increased VO2 accompanied by an inadequate rise or even fall in CO. Alterations in SaO2 appeared to be modest and were insensitive indicators of alterations in SvO2.     

Continuous tepid blood cardioplegia can preserve coronary endothelium and ameliorate the occurrence of cardiomyocyte apoptosis

OBJECTIVE: In modern cardiac surgery, crystalloid or blood cardioplegic solutions have been used widely for myocardial protection; however, ischemia does occur during protection with intermittent infusion of cold crystalloid or blood cardioplegic solutions. The present study was designed to evaluate the effect of different cardioplegic methods on myocardial apoptosis and coronary endothelial injury after global ischemia, cardiopulmonary bypass (CPB), and reperfusion in anesthetized open-chest dogs. METHODS: The dogs were classified into five groups to identify the injury of myocardium and coronary endothelium: group 1, normothermic CPB without cardiac arrest; group 2, hypothermic CPB with continuous tepid blood cardioplegia, and with cardiac arrest; group 3, hypothermic CPB with intermittent cold blood cardioplegia, and with cardiac arrest; group 4, hypothermic CPB with intermittent cold crystalloid cardioplegia, and with cardiac arrest; and group 5, sham-operated control group. During CPB, cardiac arrest was achieved with different cardioplegia solutions for 60 min, followed by reperfusion for 4 h before the myocardium and coronary arteries were harvested. Coronary arteries were harvested immediately and analyzed by scanning electron microscopy. Cardiomyocytic apoptosis was detected using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling, Western blot, and DNA ladder methods. RESULTS: Regardless of the detection method used, significantly higher percentages of apoptotic cardiomyocytes were found in group 3 and group 4 than in other groups. Expression of caspase-3 correlated with increased apoptosis. Scanning electron microscopy revealed severe endothelial injury of coronary arteries in group 3 and group 4. CONCLUSION: These results point to an important explanation for the difference in cardiac recovery after hypothermic ischemia and arrest with various cardioplegic solutions.     

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。     

三种心脏停搏液对未成熟猪体外循环中的心肌保护效果

目的比较St．Thomas停搏液（STH液）、氧合血停搏液和组氨酸一色氨酸一酮戊二酸停搏液fhistidine—tryptophan—ketoglutarate,HTK液）对未成熟猪围体外循环（cardiopulmonarybypass,CPB）期的心肌保护效果。方法21只年龄为（15～20）天、体重为（4．5～8．0）kg的中华小型猪随机分为STH液组、氧合血停搏液组和HTK液组,每组7只。分别于CPB前（T1）、升主动脉阻断（aorticcross—clamping,ACC）后10min（T2）、升主动脉开放（cross—clampingremission,CCR）后5min（T3）、CPB后5min（T4）、CPB后60min（T5）、CPB后120min（T6）抽取颈动脉血,实验结束后取少量右房心肌组织。ELISA法测肌酸激酶同工酶（CK—MB）、肌钙蛋白T（cTnT）和肌钙蛋白Ⅰ（cTnI）的含量,电镜下观察心肌超微结构的变化;同时记录每只动物的用血量。结果停跳前各组血浆CK—MB、cTnI、cTnT组间差异均无统计学意义（P〉0．05）;随着体外循环进行,各组血浆心肌生化标志物含量逐渐增加,HTK液组和氧合血停搏液组心肌生化标志物漏出率小于STH液组,差异有统计学意义（P〈0．05）。氧合血停搏液组和HTK液组相比,血浆心肌生化标志物含量无明显差异（P〉0．05）。氧合血停搏液组、HTK液组动物心肌细胞线粒体超微结构Flameng评分低于sTH液组（P〈0．05）。结论氧合血停搏液和HTK液组心肌细胞线粒体的损伤程度小,对未成熟心肌的保护效果均优于STH液组。     

Prevalence of high hematocrits in patients with interstitial lung disease in Mexico City.

Erythrocytosis, a known response to chronic hypoxemia, is considered infrequent in interstitial lung diseases. We studied the prevalence of high hematocrit (Hct) values and the relationship between Hct and SaO2 in 79 patients with chronic pigeon breeder's lung (PBL) and 34 with idiopathic pulmonary fibrosis (IPF), all of whom lived in the Mexico City metropolitan area (2,240 m above sea level). Lung biopsy was performed in 31 patients with IPF and 71 with PBL. We analyzed only one simultaneous measurement of Hct and SaO2 per patient (usually the initial measurement) before treatment. No additional cause for anemia or erythrocytosis was detected. Forty-eight percent of the patients with PBL (38/79) and 62 percent of those with IPF (21/34) had high Hct values (greater than 2 SD above mean values for Mexico City); in 14 (12.3 percent) of the 113 patients (nine with PBL and five with IPF), the Hct was above 60 percent. The Hct and SaO2 values displayed a poor correlation for the whole group: Hct = 65.7-0.16(SaO2), r = 0.24, p = 0.012. The correlation between Hct and SaO2 was nonsignificant if patients were separated by diagnosis. For an SaO2 of less than 80 percent, the slope of SaO2 vs Hct was zero. Half of our patients with PBL and IPF had Hct values that were high for the altitude. In most cases, Hct responses fell within the confidence limits reported as normal at high altitudes. We found a poor relationship between Hct and awake SaO2.     

A continuous monitoring technique for management of acute pulmonary failure

Continuous monitoring of mixed venous oxygen saturation (SvO2) and arterial oxygen saturation (SaO2) was used to guide cardiovascular and pulmonary physiologic manipulations in three patients. An index, termed the "shunt index" (SI), of venoarterial admixture (Qva/Qt) was calculated at the bedside. SI correlated significantly in each patient with Qva/Qt (p less than .01). In one of the patients, continuous end-tidal CO2(ETCO2) was also monitored, allowing rapid titrations of ventilator settings and cardiovascular support free from the need to sample arterial and mixed venous blood to assess the effect of each intervention.     

Akt信号通路在紫绀型先天性心脏病患儿心肌慢性缺氧适应中的作用

目的:探讨Akt信号通路在紫绀型先天性心脏病患儿心肌慢性缺氧适应中的意义。方法:收集紫绀型和非紫绀型先天性心脏病患儿共50例,其中紫绀型26例(紫绀组),动脉血氧饱和度(SaO2)60%～89%;非紫绀型24例(非紫绀组),SaO2>95%,均不伴肺动脉高压[肺动脉收缩压<30mmHg(1mmHg=0.133kPa)]。心脏外科手术体外循环前留取右心耳组织,应用Western blot方法检测心肌组织蛋白激酶B(总Akt)和磷酸化蛋白激酶B(Ser473P-Akt)表达水平,免疫组织化学技术检测心肌组织总Akt和Ser473 P-Akt蛋白表达部位与水平。结果:与非紫绀组相比,紫绀组患儿心肌组织Ser473P-Akt蛋白表达水平明显增高(P<0.01),而2组患儿总Akt蛋白表达水平差异无统计学意义(P>0.05)。紫绀组患儿心肌组织Ser473P-Akt蛋白大部分表达在心肌细胞的胞质,胞核亦有微弱表达,而非紫绀组心肌细胞则无明显Ser473P-Akt蛋白表达。2组患儿总Akt蛋白绝大部分也表达在心肌细胞的胞质,胞核亦有微弱表达,但表达部位和水平差异无统计学意义。紫绀组患儿心肌组织Ser473 P-Akt蛋白表达水平与患儿术前SaO2呈负相关(r=-0.771,P<0.01)。结论:Akt信号通路激活可能是紫绀型先天性心脏病患儿心肌慢性缺氧适应的重要信号调控机制之一。     

Improvement of Functional Recovery of Donor Heart Following Cold Static Storage with Doxycycline Cardioplegia

Injury to the donor heart during cold preservation has a negative impact on graft survival before transplantation. This study aims to examine whether doxycycline, known as an MMP-2 inhibitor, has a positive effect on donor heart preservation via its antioxidant action when added to standard preservation solution. Hearts were obtained from 3-month-old male Wistar rats and randomly divided into three groups: hearts stored for 1 h at 4 °C (1) with doxycycline preservation solution (DOX cardioplegia) with low Ca²⁺; (2) with standard cardioplegia with low Ca²⁺; and (3) unstored hearts. All hearts were perfused in working mode, arrested at 37 °C, removed from the perfusion system, reattached in Langendorff perfusion system, and converted to working mode for 1 h. At the end of the storage period, hearts preserved in DOX cardioplegia had significantly less weight gain than those preserved in the standard cardioplegia. DOX cardioplegia-induced preservation resulted in significantly higher heart rates and better recovery quality during reperfusion in aortic flow compared to the standard cardioplegia group. Recovery in the left ventricular function and Lambeth Convention Arrhythmia scores during 1 h reperfusion were also significantly better in the DOX cardioplegia group. Biochemical data showed that DOX cardioplegia prevented an increase in MMP-2 activity and blocked apoptosis through increased activity of the pro-survival kinase Akt in the donor heart homogenates. DOX cardioplegia also led to a balanced oxidant/antioxidant level in the heart homogenates. This is the first study to report that cardioplegia solution containing doxycycline provides better cardioprotection via the preservation of heart function, through its role in controlling cellular redox status during static cold storage.