Higher hematocrit improves liver blood flow and metabolism during cardiopulmonary bypass in piglets

OBJECTIVES: Hemodilution has been applied conventionally during cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) to counteract the increase in viscosity and deleterious rheological effects caused by hypothermia. However, liver dysfunction after low-flow bypass and DHCA is common, and little is known about the effects of hematocrit (Hct). The purpose of the present study is to evaluate the impact of two hemodilution priming protocols used clinically on liver perfusion and metabolism. MATERIALS AND METHODS: Ten piglets were randomized into 2 groups. One group (n = 5) had a crystalloid prime resulting in an Hct of about 15 % (low hematocrit; group L), the other (n = 5) a total-blood prime (Hct = 25 %; high hematocrit; group H). All animals underwent 70 min cooling at full flow (150 ml/kg/min), 30 min of low flow (50 ml/kg/min) at 15 degrees C followed by 45 min of DHCA and 75 min of rewarming at full flow. Liver blood flow (LBF) was assessed at the beginning of CPB at 34 degrees C, at the end of cooling at 15 degrees C, at the end of low flow, 5 min after the start of warming, and at the end of rewarming at 34 degrees C by injections of radioactive microspheres. Liver function was evaluated at the same time using the MEGX test, which measures the metabolism of lidocaine. RESULTS: LBF was insignificantly reduced during cooling, decreased during low flow (p = 0.001), and increased again after DHCA with the highest flow at the end of rewarming. LBF tended to be lower at all times in group L (p = 0.096). The liver lidocaine metabolic rate did not significantly decrease during cooling and low flow, but was increased at the end of rewarming (p = 0.01); the metabolism was higher in group H (p = 0.025). Multiregression analysis revealed liver blood flow (p = 0.003) and hematocrit (p < 0.001) as independent determinants of the liver lidocaine metabolism; arterial blood pressure and temperature did not have significant influence in this model. CONCLUSION: Hemodilution results in a tendency towards reduced liver blood flow during CPB; much worse is the resulting impaired liver metabolism, independent of reduced blood flow and pressure. Avoidance of low hematocrit during CPB may be a useful adjunct to preserve liver function in patients undergoing cardiac surgery with long duration CPB and DHCA.     

Optimizing cerebral oxygenation during cardiac surgery: a review of experimental and clinical investigations with near infrared spectrophotometry

OBJECTIVES: Near-infrared spectrophotometry (NIRS) is a promising method for non-invasive monitoring of cerebral oxygenation and hemodynamics. This paper reviews studies in which we aimed to validate NIRS in an experimental model of cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) (validation study), use the method in experimental settings to optimize cerebral oxygenation during CPB (oxygenation study), and test its utility during routine cardiac surgery (clinical study). METHODS: Validation study: Forty 8-10 kg piglets underwent 60 min of DHCA at 15 degrees C, were extubated on the first postoperative day, and sacrificed on the 4th postoperative day for histologic investigations. During CPB and DHCA, the animals were investigated by NIRS (monitoring of cerebral oxygenated hemoglobin (HbO2) and oxidized cytochrome aa3 (Cytox)) and magnetic resonance spectroscopy (MRS) (monitoring of cerebral adenosine triphosphate (ATP) and phosphocreatine (PCr). Oxygenation study: A normoxic (n = 5) and a hyperoxic group (n = 5) of piglets underwent 120 min of DHCA and 6 h of reperfusion with NIRS monitoring. Neuronal damage was evaluated by histology. Clinical study: Patients (n = 41) undergoing routine cardiac surgery were investigated by NIRS and neuropsychological testings. RESULTS: Validation study: Reductions of CytOx and HbO2 values were closely correlated with decreases in ATP, PCr, and pHi. The changes in CytOx and PCr showed the strongest correlation (r = 0.623). Maximal CytOx reduction during DHCA predicted brain damage. Oxygenation study: Histology revealed a significant increase in brain damage in the normoxic group. Cytox and HbO2 tended to be lower during DHCA (p = 0.16). Clinical study: During CPB, arterial PCO2, pH and temperature were closely related to CytOx and HbO2. Patients who suffered from neuropsychological deficits had a lower CytOx minimum compared to those without these. CONCLUSIONS: NIRS measurements, especially the CytOx signal, correlate well with high energy phosphates and have a high sensitivity to predict histologic brain damage. NIRS is an important and useful tool in studies investigating cerebral oxygenation during CPB. The CytOx signal predicted impaired neuropsychological outcome in patients. Therefore, the CytOx signal holds much interest for future studies.     

Clinical experience with intracoronary tissue plasminogen activator: Results of a multicenter registry

Clinical experience with the use of intracoronary tissue plasminogen activator (t-PA) is limited. We therefore undertook this study to document current clinical usage of intracoronary t-PA during a 2-yr period in a multicenter registry. Intracoronary t-PA was utilized on 206 occasions in 198 patients (154 men and 44 women; mean age, 59 ± 12 yr). The mean dose of intracoronary t-PA was 31 ± 15 mg. Indications for use included acute myocardial infarction (MI) (n = 83), preexisting thrombus with (n = 49) or without (n = 41) percutaneous transluminal coronary angioplasty (PTCA), unstable angina (n = 14), abrupt vessel closure (n = 11), and post-PTCA “clean-up” (n = 8). The Thombolysis in Myocardial Infarction (TIMI Phase I) criteria were used to assess perfusion and degree of thrombus formation. Overall, the mean TIMI flow grade increased from 1.2 ± 1.1 before treatment to 2.3 ± 1.0 after treatment (P<0.0001); the mean TIMI thrombus grade decreased from 3.2 ± 1.0 before treatment to 1.6 ± 1.4 after treatment (P<0.0001). Complications included bleeding (9.2%), MI (17.6%), need for coronary artery bypass grafting (CABG) (9.2%), need for repeat PTCA/atherectomy/stents (4.9%), and ventricular fibrillation (1.7%, all associated with opening totally occluded vessels). There were 14 subsequent in-hospital deaths: 13 of the patients who died had originally presented with MI; the other had experienced abrupt vessel closure during a PTCA procedure. Intracoronary t-PA appears to be effective in improving distal flow and decreasing thrombus burden; however, intracoronary delivery of t-PA has associated risks. Further prospective evaluations of intracoronary t-PA will be necessary to determine the optimal clinical situations for its use, as well as the appropriate dose regimen.     

新型无血预充体外循环深低温停循环模型

目的：体外循环（cardiopulmonary bypass, CPB）及深低温停循环（deep hypothermic circulatory arrest, DHCA）在临床中得到广泛应用。然而,DHCA仍伴随着一定的并发症及死亡率。由于缺少高生存率的DHCA动物模型,探究DHCA的病理生理机制及保护策略仍受到一定限制。我们的目的是通过对临床使用材料进行改进,建立一种新型的安全的无血预充的小动物DHCA模型,以满足DHCA并发症病理生理的研究。 方法：取20只成年SD大鼠（14-16周,200-300克）。CPB管道由改良储血器、定制的小动物膜肺、滚压泵、硅胶管道以及自制热交换管道,管道预充量不足10ml。右颈静脉、右颈动脉及左股动脉插管,右心房血液通过右颈静脉插管引流,通过左股动脉进行灌注。体外循环流量为全流量,大鼠体温降至18℃并进行45分钟全身停循环,随后进行60分钟复温。管道内血液离心并回输浓缩红细胞。血流动力学及体外循环指标在术中实时记录。 结果：所有CPB及DHCA过程均成功完成。实验中无大鼠死亡。各时间点血气分析均正常。术后心功能及血压均稳定。所有大鼠生命指征平稳。 结论：新型无血预充深低温停循环大鼠模型可以安全建立。     

中度低温停循环结合选择性脑灌注在婴儿主动脉弓部手术中的应用

目的 总结中度低温停循环(moderate hypothermia circulatory arrest,MHCA)结合选择性顺行脑灌注(sective antegrade cerebral perfusion,SACP)技术在婴儿主动脉弓重建手术中的应用经验.方法 回顾性分析上海市儿童医院心胸外科于2012年1月至2018年12月间完成的主动脉弓病变合并心内畸形矫正的患儿50例.依据中心温度将患儿分为深低温停循环(deep hypothermia circulatory arrest,DHCA)组及MHCA组,每组25例.所有患儿均在体外循环(cardiopulmonary bypass,CPB)下行一期手术治疗.主动脉弓重建过程中采用低温停循环技术,通过无名动脉SACP(25~40 ml·kg^-1·min^-1)的CPB管理方法.心肌保护采用康斯特器官保护液(HTK液).记录两组患者的一般资料及术中、术后指标.结果 两组均无与CPB相关的神经系统并发症.两组患儿年龄、体重、病种、术前肝肾功能及术前左心室射血分数值比较差异均无统计学意义(P>0.05).CPB时间MHCA组较DHCA组明显缩短[(120.00±22.60)min比(137.40±22.88)min,P=0.019];术后24 h胸腔引流量及正性肌力药物评分MHCA组较DHCA组明显减少,分别为[(49.84±20.66)ml比(78.20±52.31)ml,P=0.03;(9.72±2.47)分比(12.24±3.07)分,P=0.004].结论 在婴儿主动脉弓重建手术中,采用DHCA或MHCA结合SACP的技术均能均减少术后神经系统并发症发生,不增加术后其他并发症.MHCA可减少CPB时间、术后胸腔引流量及术后血管活性药物的使用量.     

Site-specific intracoronary thrombolysis with urokinase-coated hydrogel balloons: Acute and follow-up studies in 95 patients

Conventional balloon angioplasty in the presence of intracoronary thrombus is associated with an elevated risk for acute myocardial infarction, emergency bypass surgery, and death. The purpose of this study was to assess the safety and efficacy of a new technique to treat thrombus-containing stenoses consisting of the local delivery of urokinase directly to the site of intraluminal clot with hydrogel-coated balloons. Ninety-five patients with angiographically apparent intracoronary thrombus were treated with urokinase-coated hydrogel balloons either prior to (n = 74) or following (n = 21) conventional balloon angioplasty. Clinical diagnoses for the study group included acute myocardial infarction in 50 patients, postinfarction angina in 23 patients, and unstable angina in 22 patients. All hydrogel balloons were initially coated with urokinase by immersing the inflated balloon in a concentrated Abbokinase solution (50,000 units/ml) for 60 s. All patients were subsequently treated with drug-coated balloons using a balloon:artery ratio of 1:1, a mean of 2.2 ± 1.2 inflations, and a mean total inflation time of 7.5 ± 4.9 min. Use of urokinase-coated balloons resulted in angiographic disappearance of intracoronary thrombus in 78 patients, improvement in 14, and no change in the remaining 3 patients. Following hydrogel balloon use for the entire 95 patients, TIMI flow increased from 1.4 ± 1.2 to 2.9 ± 0.4, minimal lumen diameter increased from 0.4 ± 0.4 to 2.0 ± 0.6 mm, and thrombus score decreased from 2.0 ± 0.9 to 0.2 ± 0.6 (all P < 0.01). Procedural and early in-hospital complications were noted in 7 of the 95 patients (7.4%) and included abrupt closure in 3 patients, distal embolization in 1 patient, no reflow in 1 patient, sidebranch occlusion in 1 patient, and late closure in 1 patient. Two of the 3 patients with abrupt closure and the single patient with late closure required intracoronary stenting to maintain vessel patency. Two of these 7 patients sustained small myocardial infarctions, although no patient required emergency bypass surgery or experienced a procedural death. Late clinical follow-up (mean = 8.3 ± 6.6 months; range = 2 wk to 29 mo) demonstrated adverse recurrent events in 29 of the 95 patients (30.5%), including death (n = 5), myocardial infarction (n = 2), and recurrence of angina (n = 22). The results of this study suggest that intracoronary thrombolysis can be safely and rapidly achieved by using limited quantities of urokinase delivered directly to the site of intraluminal clot with hydrogel balloons. Use of this technique may result in improved acute outcomes in comparison with conventional techniques currently being used to treat thrombus-containing stenoses. Cathet. Cardiovasc. Diagn. 41:246–253, 1997. © 1997 Wiley-Liss, Inc.     

体重≤5kg婴儿简单先天性心脏病外科术中微小化体外循环管路应用改良超滤和常规超滤的比较

目的:比较利用微小化体外循环(CPB)管路行简单心脏手术时是否使用改良超滤(MUF)对体重≤5 kg先天性心脏病(先心病)婴儿的影响.方法:选取2018年1月至2020年6月在我院行CPB下简单心脏手术,体重≤5 kg先心病婴儿(手术年龄:18天～11个月)208例.其中,CPB中使用MUF的婴儿纳入MUF组(n=12...     

自体血回输在非体外循环冠状动脉旁路移植术中应用的必要性研究

目的 探讨非体外循环冠状动脉旁路移植术(OPCAB)中应用自体血回输的必要性。方法 2015年2月至2015年3月间40例行OPCAB的患者随机分为试验组(自体血回输)和对照组,收集围术期输血及肝肾功能等临床资料,确定自体血回输在OPCAB术中是否必须应用。结果 两组患者围术期均未输血,自体血回输可以显著提高患者术后早期的红细胞压积(35.93±3.68 vs 32.29±4.67),同时引起术后早期肝功能指标升高,但无统计学差异。结论 自体血回输可以显著提高术后早期的红细胞压积,但对围术期输血影响有限,并且可能造成术后肝功能损伤,因此并非全部患者术中均需应用自体血回输。     

Cardiopulmonary Bypass and Serum Thyroid Hormone Profile in Pediatric Patients with Congenital Heart Disease

Objective: To study the effect of cardiopulmonary bypass (CPB) on serum thyroid hormone profile in children undergoing open‐heart surgery. Design: Prospective cross‐sectional study. Setting: Multispecialty tertiary level referral center. Patients: One hundred consecutive patients (age 15.9 ± 14.6 months, weight 6.7 ± 2.5 kg) undergoing open‐heart surgery under CPB. Interventions: None. Outcome Measures: Levels and trends of serum total thyroxine (TT4), free thyroxine (FT4), total tri‐iodothyronine (TT3), free tri‐iodothyronine (FT3) and thyroid stimulating hormone (TSH), survival, inotropic score, duration of mechanical ventilation, postoperative complications. Results: TT4 levels were 9.08 ± 3.6, 6.4 ± 2.5, 6.24 ± 2.1, 6.43 ± 2.4, 7.20 ± 3.0 µg/dL at baseline and at 1, 24, 48 and 72 hours; FT4 levels were 1.82 ± 0.5, 1.49 ± 0.3, 1.29 ± 0.3, 1.32 ± 0.4, and 1.43 ± 0.5 ng/dL; TT3 levels were 1.81 ± 0.4, 1.31 ± 0.3, 0.99 ± 0.2, 1.0 ± 0.37, and 1.17 ± 0.48 ng/ml; FT3 levels were 4.09 ± 1.0, 3.02 ± 0.8, 2.21 ± 0.6, 2.22 ± 0.7, and 2.66 ± 1.05 pg/ml; TSH levels were 5.40 ± 3.8, 2.0 ± 3.1, 1.24 ± 1.1, 2.90 ± 3.3, and 4.03 ± 3.4 mIU/L. There was significant fall (29.1% for FT4, 32.1% for TT4, 77% for TSH, 46% for FT3 and 45% for TT3, p < 0.0001). When area under curve (AUC) TT4 was compared between survivors (n = 87) and nonsurvivors (n = 12), significantly larger AUC was seen in survivors (492.81 ± 158.6) than nonsurvivors (360.75 ± 179.6 p = 0.0125). In survivors >72 hours, AUC TT4 was larger in patients with uneventful postoperative course versus those with postoperative complications (516.48 ± 18.6 vs. 394.78 ± 29.9, p = 0.001). AUC TT4 showed significant inverse correlation with inotropic score and borderline inverse correlation with duration of mechanical ventilation. Conclusion: Children undergoing surgery under CPB showed significant fall in thyroid hormones. Because TT4 level is modifiable, prophylactic administration of TT4 for improving outcomes needs to be studied further.     

连续缝合法修补膜周部大室间隔缺损

目的:总结用连续缝合法修补膜周部大室间隔缺损(VSD)的外科技术并进行疗效评价。方法:膜周部大VSD患者229例。男性123例(54%),女性106例(46%);年龄(13.6±16.7)岁,体质量(32.4±33.4)kg,膜周偏小梁部76例(33%),膜周偏流入部71例(31%),膜周偏流出部82例(36%),有假性膜部瘤形成84例(37%)。手术均在浅低温体外循环下矫治。结果:阻断时间和转机时间分别为(25±18)min、(46±32)min,手术后无死亡。主要并发症为:暂时性Ⅲ°房室传导阻滞(AVB)1例(0.4%),Ⅱ°AVB 2例(0.9%),完全性右束支传导阻滞(CRBBB)8例(3.5%),其中2例于2周内消失,1例于手术后1年复查时消失。三尖瓣轻度关闭不全2例,轻-中度1例,其它5例(2.2%)。随访3个月～3年,所有患者手术效果良好。结论:连续缝合法修补膜周部大VSD具有简化手术操作技术、减少手术阻断及转流时间、减少心内异物存留、降低传导阻滞及残余分流发生率的优点,其早-中期临床效果满意。     

六月龄以下婴儿体外循环探讨

目的探讨六月龄以下婴儿的体外循环方法和效果。方法对我院1996年8月至2005年7月施行的168例六月龄以下婴儿心脏手术的体外循环方法予以回顾性总结。结果本组168例婴儿体外循环手术,分别应用深低温停循环灌注法、低温低流量灌注、中度低温停跳体外循环及浅低温不停跳法体外循环。死亡25例,转流时间长,术后低心排,肾衰为主要死因。结论六月龄以下婴儿体重小、血容量少、组织器官发育不成熟,选择适当的体外循环方法,重视心肺功能的保护是确保体外循环成功的关键。     

Prolonged Holding of Whole Blood at 22 °C Does Not Increase Activation in Platelet Concentrates

Objectives: Platelets prepared after holding of whole blood overnight at 22 °C have a well-preserved metabolism. However, the possibility that such prolonged incubation with active granulocytes may increase platelet activation has not been fully tested. Methods: We investigated this possibility by flow cytometric analysis of membrane glycoproteins (GPs) Ib and IIb/IIIa and the activation markers CD62P and CD63 in platelet concentrates (PCs) prepared from whole blood that was held for either 6 h without cooling plates (n = 20) or for 24 h on cooling plates of 1,4-butanediol (n = 20). PCs were prepared by the platelet-rich plasma method and analyzed on the second storage day. Results: Platelet yield and aggregation response to ristocetin, collagen and epinephrine + ADP were similar in both types of PCs, as was the mean fluorescence intensity for GPs Ib and IIb/IIIa. PCs prepared by the overnight-hold method did not differ from those obtained 6 h after collection in the percentage of platelets expressing CD62P (12.3±6.2% vs. 14.1±4.0%; p > 0.1) or CD63 (9.8±6.4% vs. 8.8±3.6%; p > 0.1). Conclusion: Prolonged holding of whole blood at 22 °C prior to component preparation does not increase the level of platelet activation.     

Left atrial appendage thrombus is not uncommon in patients with acute atrial fibrillation and a recent embolic event: A transesophageal echocardiographics tudy

Objectives. The objective of this study was to determine the frequency of left atrial thrombus in patients with acute atrial fibrillation.Background. It is commonly assumed but unproved that left atrial thrombus in patients with atrial fibrillation begins to form after the onset of atrial fibrillation and that it requires ≥3 days to form. Thus, patients with acute atrial fibrillation (i.e., <3 days) frequently undergo cardioversion without anticoagulation prophylaxis.Methods. Three hundred seventeen patients (250 men, 67 women; mean [±SD] age 64 ± 12 years) with acute (n = 143) or chronic (n = 174) atrial fibrillation were studied by two-dimensional transesophageal echocardiography.Results. Left atrial appendage thrombus was present in 20 patients (14%) with acute and 47 patients (27%, p < 0.01) with chronic atrial fibrillation. In patients with a recent embolic event, the frequency of left atrial appendage thrombus did not differ between those with acute (5 [21%] of 24) and those with chronic (12 [23%] of 52, p = NS) atrial fibrillation. Patients with acute versus chronic atrial fibrillation, respectively, did not differ (p = NS) in mean age (64 ± 13 vs. 65 ± 11 years), frequency of concentric left ventricular hypertrophy (32% vs. 26%), hypertension (32% vs. 41%), coronary artery disease (35% vs. 39%), congestive heart failure (43% vs. 48%), mitral stenosis (4% vs. 7%) or mitral valve replacement (1.4% vs. 6%). The minimally detectable difference in proportions between patients with acute and chronic atrial fibrillation based on a power of 0.80 and base proportion of 0.20 was 14%.Conclusions. Left atrial thrombus does occur in patients with acute atrial fibrillation <3 days in duration. The frequency of left atrial thrombus in patients with recent emboli is comparable between those with acute and chronic atrial fibrillation. These data suggest that patients with acute atrial fibrillation for <3 days require anticoagulation prophylaxis or evaluation by transesophageal echocardiography before cardioversion and should not be assumed to be free of left atrial thrombus.     

Association of coronary lipid core plaque with intrastent thrombus formation

Background : Optical coherence tomography (OCT) and near‐infrared spectroscopy (NIRS) allow assessment of the anatomy (OCT) and composition (NIRS) of coronary lesions. We sought to examine the association between pre‐stenting lipid core plaque (LCP), as assessed by NIRS and post‐stenting thrombus formation, as assessed by OCT. Methods : We reviewed the angiograms of nine patients who underwent coronary stenting in association with NIRS and OCT imaging. A large LCP by NIRS was defined as at least three 2‐mm yellow blocks on the NIRS block chemogram with >200° angular extent. Intracoronary thrombus was defined as a mass of medium reflectivity protruding into the vessel lumen, discontinuous from the surface of the vessel wall. Results : Mean age was 67 ± 7 years, and all patients were men, presenting with stable angina (56%), unstable angina (11%), or acute myocardial infarction (33%). The mean vessel lipid core burden index (LCBI) was 120 ± 45, and the mean highest 6‐mm LCBI was 386 ± 190. Three patients had a large LCP and two of them (66%) developed intrastent thrombus after stent implantation compared to none of six patients without large LCPs (0%, P = 0.02). The thrombus resolved after intracoronary glycoprotein IIb/IIIa administration and balloon postdilation. Postprocedural myocardial infarction occurred in 33% versus 17% of patients with and without large LCP, respectively (P = 0.57). Conclusion : Stenting of large LCPs may be associated with intrastent thrombus formation, suggesting that more intensive anticoagulant and/or antiplatelet therapy may be beneficial in such lesions. © 2012 Wiley Periodicals, Inc.     

Identification and characterization of dehydrocholic acid reductase system in the cytosol of human red blood cells

We conducted in vivo and in vitro studies of the reductive metabolism of the cholagogue, dehydrocholic acid (DHCA). Immediately after the intravenous administration of 1 g of DHCA in normal subjects (n=6), the concentration of the reductive metabolite, 3α-hydroxy-7,12-dioxo-cholanoic acid (unconjugated form), increased sharply in the systemic conjugated form), increased sharply in the systemic circulation, rising to 95.8 μM 10 min after administration. The results of in vitro experiments with DHCA and whole blood showed that 3α-hydroxy-7,12-dioxo-cholanoic acid and 3β-hydroxy-7,12-dioxo-cholanoic acid were produced from DHCA. In vitro experiments using DHCA and the red blood cell fraction, and DHCA and the red blood cell cytoplasmic fraction gave similar results to those described above with whole blood. However, a reductive metabolite was not formed by the incubation of DHCA and the red blood cell membrane fraction. These findings indicated that, contrary to the conventional theory that intravenously administered DHCA is subjected to reductive metabolism only in the liver, reduction also occurs in the systemic circulation, and the mechanism for this reductive metabolism is present in the cytoplasmic fraction of red blood cells. Further investigation to characterize this reductive metabolic system revealed an optimum temperature of 37°C, an optimum pH of 7.4, a Km value of 2.0×10^?3M, and inactivation by heart treatment (70°C for 2 min).     

Bloodless open heart surgery: simple and safe.

OBJECTIVES: The use of blood or blood products is routine in cardiac surgery, but is associated with various complications. Aware of this, we have always tried to avoid the use of blood products whenever possible. In this study we sought to evaluate the results of this policy. METHODS: The records of 1505 adult patients who underwent coronary (732) or valve (773) surgery under cardiopulmonary bypass (CPB) in 2002 and 2003 were reviewed retrospectively. Of these, 1058 were male (70.3%) and the mean age was 62.1+/-11.4 years. Mean weight was 68.5+/-10.2 kg and body surface area was 1.7+/-0.2 m2, corresponding to a blood volume of 4119.9+/-593.6 ml. Preoperative hematocrit (Hct) was 40.6+/-4.2% and the prothrombin index was 87.0+/-17.4%. A bloodless prime of the bypass circuit was used for all patients with Hct > or =36%. The prime volume was reduced to the minimum possible. Plasma was used when coagulation was deficient. All blood remaining in the CPB circuit was reinfused at the end of the procedure, either in the operating room or in the ICU. Shed mediastinal blood was retransfused in the first 6 hours in the ICU. RESULTS: Operative mortality was 0.7% for coronary and 0.5% for valve patients. Blood or blood products were not used in 77.3% of the patients (88.7% of coronary and 66.5% of valve patients). Blood and/or plasma was initially added to the prime in 18.2% of cases and during CPB in 11%. Hct was 28.9+/-4.0% after initiation and 28.8+/-3.9% after discontinuation of CPB. The number of units (300 cc) of blood used was 0.25.57 per patient (1.09+/-0.73 per patient transfused). The number of units (300 cc) of plasma used was 0.24+/-0.72. Reoperation for bleeding was required in 2.4% of the patients. CONCLUSIONS: This blood-sparing policy is simple, effective and safe, resulting in low mortality and morbidity rates. More than three quarters of the patients did not require blood or blood products. Additional measures are possible to further decrease the use of blood products.     

Cerebral oxygen monitoring during neonatal cardiopulmonary bypass and deep hypothermic circulatory arrest

BACKGROUND: This study was undertaken to investigate the physiological effects of cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) on cerebral oxygen metabolism estimated by near-infrared spectroscopy (NIRS). METHODS: Ten newborn piglets (2.1 to 2.6 kg) were monitored with right frontal NIRS; the right jugular bulb was cannulated for intermittent sampling of jugular venous blood. All animals underwent CPB, cooling to a core temperature below 15 degrees C, 60 minutes of DHCA followed by subsequent reperfusion and rewarming. Continuously recorded NIRS data and intermittent jugular venous blood values were compared. RESULTS: NIRS performance was examined over the jugular venous oxygen saturation (SjvO2) range of 40 to 98 %, a linear correlation was found between SjvO2 and NIRS-derived regional cerebral oxygen saturation (rSO2) (r = 0.91, p < 0.001). A correlation was observed between the cellular oxidation NIRS-parameter cytochrome oxidase aa3 (CytOx) slope during the DHCA period in relation to rectal and nasopharyngeal temperature immediately before the onset of DHCA (r = 0.75 and 0.85, p < 0.001). CONCLUSIONS: This study suggests that NIRS-measured hemoglobin oxygenation parameters may reflect functional changes in cerebral hemodynamics and brain tissue oxygenation, while CytOx values represent related effects on intracellular oxidative metabolism.     

Effect of hypothermia on median nerve somatosensory evoked potentials

Median nerve sornatosensory evoked potentials (SEP) were monitored in ten patients undergoing cardiac surgery with hypothermic cardiopulmonary bypass (CPB). Anesthesia was induced and maintained with sufentanil, oxygen, and pancuronium. Esophageal, nasopharyngeal, rectal, and blood temperatures were continuously monitored. SEPs were recorded before induction of anesthesia, after induction, and during cooling and rewarming on CPB. There was a strong negative correlation between SEP latencies and temperature (except rectal) (r = −.91, P < .001), for cortical latency and esophageal temperature. A decrease in esophageal temperature of 1°C resulted in an increase in SEP latency of 1 ms. There was also a weak positive correlation between evoked potential amplitude and temperature (r = .19) for cortical amplitude and esophageal temperature.     

Retrograde cerebral perfusion as an adjunct to prolonged hypothermic circulatory arrest.

STUDY OBJECTIVE: This study was designed to evaluate the use of retrograde cerebral perfusion (RCP) combined with deep hypothermic circulatory arrest (DHCA) in the treatment of complex congenital and adult cardiac disease. DESIGN: Retrospective chart review of 52 cardiac surgery patients (34 male and 18 female; age range, 3 weeks to 89 years old; mean age, 60 years old) who received RCP in conjunction with DHCA from July 1991 through August 1998. RESULTS: Surgical procedures consisted of the following: (1) repair of ascending aortic aneurysms (n = 16); (2) repair of type A aortic dissection (n = 16); (3) repair of arch aneurysms (n = 10); (4) renal cell carcinoma with tumor extension to the inferior vena cava (IVC) and right atrium (n = 5); (6) coronary artery bypass grafting and concomitant aortic valve replacement with calcified aorta (n = 2); (7) Norwood procedure and take down of a Pott's shunt (n = 2); and (8) massive air embolism treatment (n = 1). Mean RCP time was 39 min (range, 3 to 88 min). Thirteen patients had RCP times > 60 min. Mean core temperature (rectal or bladder) was 19 degrees C (range, 15 degrees to 28 degrees C). There were six early deaths, four of which were related to persistent low-output cardiac failure, and two resulted from perioperative stroke. All remaining patients recovered fully without neurologic deficits. CONCLUSION: RCP is a reliable and technically appealing tool that does the following: (1) it improves DHCA safety and is applicable in a variety of clinical settings with relative ease; (2) it potentially provides oxygen and nutritional support to the brain during DHCA; (3) it helps remove air and other debris from the cerebral vessels; and (4) it is useful in dealing with congenital heart disease and tumor extension into the IVC.     

Superiority of gold versus platinum irrigated tip catheter ablation of the pulmonary veins and the cavotricuspid isthmus: a randomized study comparing tip temperatures and cooling flow requirements

Gold versus Platinum Irrigated Tip Ablation Catheters. Introduction: In order to optimize power delivery into the myocardium during radiofrequency ablation (RFA) without overheating the electrode tip, active cooling of the tip electrode as well as electrode tips made of gold have evolved. Recently, an externally irrigated gold tip electrode ablation catheter has been developed to combine the advantages of these 2 technologies. We sought to investigate the procedural parameters tip temperature, delivered power and cooling flow requirements of the irrigated gold tip catheter in comparison to the conventional irrigated platinum iridium (Pt) tip catheter in pulmonary vein isolation (PVI) and cavotricuspid isthmus (CTI) ablation. Methods and Results: Sixty patients referred for first PVI were randomized into ablation with irrigated gold tip catheter versus irrigated Pt tip catheter. Forty‐nine patients received ablation of CTI following PVI. Mean and standard deviation from all measurements were calculated for each patient. During RFA of pulmonary veins, mean catheter tip temperature was significantly lower in the gold group (35.4 ± 0.9 °C vs 38.2 ± 0.8 °C, P < 0.001), and total amount of delivered energy was higher (1303.1 ± 81.1 W vs 1223.7 ± 115.6 W, P = 0.004). During CTI ablation, necessary saline flow was almost 2.5‐fold lower in the gold group (22.5 ± 5.9 mL/min vs 52.5 ± 9.7 mL/min, P < 0.001), accompanied by significantly lower tip temperature (39.1 ± 0.6 °C vs 40.5 ± 1.4 °C, P < 0.001). Conclusion: The irrigated gold tip electrode allows to deliver significantly more energy at a lower electrode tip temperature in RFA of PV and CTI in comparison to the irrigated Pt tip electrode. The required saline flow during CTI ablation is much lower than in Pt. (J Cardiovasc Electrophysiol, Vol. 23, pp. 717‐721, July 2012)