Anesthetic management for surgical removal of renal carcinoma with caval or atrial tumor thrombus using deep hypothermic circulatory arrest

Twenty cases of renal carcinoma with tumor thrombus extending into the vena cave or atrium, in which cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) were used, are reviewed. Arterial, central venous (n = 9), or pulmonary artery catheters (n = 11), ECG, and rectal or bladder and pharyngeal temperatures were used for monitoring. The anesthetic was a high-dose narcotic supplemented with a nondepolarizing relaxant and a volatile agent. The surgery consisted of mobilization of the kidney followed by CPB via strial and aortic cannulae, cooling via CPB, axsanguination, and removal of thrombus during DHCA. Duration of cooling was 21 ± 7 minutes to a pharyngeal temperature of 15.8° ± 2.6°C with α-stet pH management; DHCA lasted 26 ± 10 minutes, and rewarming was continued to a mean pelvic temperature of 36.2°C. Duration of surgery was 8.1 ± 1.6 hours. The mean initial hematocrit was 33.5%, mean lowest Hct during CPB was 16.9%, and mean Hct at the end of surgery was 30%. Intraoperatively, 9.0 ± 6.4 units of blood were used, and most patients received component therapy. Average crystalloid use was 7 L, and albumin or hetastarch (1.3 ± 0.9 L) was used in 13 patients. One patient with severe cardiac disease could not be weaned from CPB. In the 19 operative survivors, there were no neurological deficits. There was one late death from pulmonary complications. The use of thiopental (n = 13), dexamethasone (n = 11), or mannitol (n = 19) was not clearly related to outcome. Hypothermia, hemodilution, α-stet pH management, and normoglycemia are believed to be important aspects of perioperative care. Practical problems included blood loss, coagulopathy, and temperature decrease after CPB.     

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.     

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。     

Adequacy of perfusion during hypothermia: regional distribution of cardiopulmonary bypass flow, mixed venous and regional venous oxygen saturation - hypothermia and distribution of flow and oxygen

BACKGROUND: Hypothermia during CPB is used to reduce metabolic activity, thus protecting organs and tissues. The aim of this study was to investigate the relationship between regional and mixed venous oxygen saturation and distribution of pump flow with respect to hypothermia. METHODS: Twenty-five patients undergoing a Ross procedure were included in a prospective, controlled study. During standard CPB, temperature was reduced stepwise to 28 degrees C. Blood gases (a-stat regimen) were analysed in samples from the inferior (IVC) and the superior vena cava (SVC), arterial and mixed venous blood. Flow was detected separately in the SVC, IVC, arterial, and collecting venous line. Samples were taken, and flows were measured before CPB, during hypothermia, during rewarming, and 30 min after CPB discontinuation. RESULTS: Oxygen saturation in the IVC was lower than in the SVC and in mixed venous blood at all times (max. difference - 17.3 +/- 3.0 % during hypothermia, - 23.8 +/- 2.9 % during rewarming, p < 0.01). There was a statistical correlation of mixed and IVC venous oxygen saturation (r = 0.79, p < 0.001) but not of SVC venous blood. Hypothermia had a major influence on pump flow distribution as backflow from the SVC decreased significantly in favour of IVC flow with increasing degree of hypothermia (increase of flow difference from 1.15 +/- 0.23 l/min to 1.49 +/- 0.36 l/min, p < 0.01). Temperature profiles were similar when detected in aorta, pulmonary artery, tympanum and nasopharygeum, but differed significantly from other sites. CONCLUSIONS: During hypothermic CPB, regional deoxygenation occurs in spite of normal mixed venous saturation. The level of hypothermia has a major impact on bypass flow distribution with cerebral perfusion reduction. Methods of regional oxygenation assessment are needed, and altered strategies during hypothermia have to be taken into consideration.     

Noninvasive transcutaneous access flow measurement before and after hemodialysis: impact of hematocrit and blood pressure

BACKGROUND/AIMS: The dialysis outcome is strongly affected by the function of the vascular access. It has been suggested that access clotting may be related to increased hematocrit (Hct) or excessive ultrafiltration during dialysis. The present study was designed to evaluate the changes of vascular access flow during hemodialysis in 18 end-stage renal disease patients with native arteriovenous fistulas and the possible correlations with Hct and mean arterial pressure (MAP). METHODS: We utilized a noninvasive vascular access flow measurement technique, based on a transcutaneous optical sensor, to evaluate the flow in the access before and after a single hemodialysis session. At the beginning and at the end of the session, the blood flow was measured noninvasively, placing the sensor approximately 2 in from the point of insertion of the arterial needle. At the same time, Hct and MAP were measured directly. All patients were on hemodialysis for more than 3 months. RESULTS: There was a significant increase in Hct, likely due to ultrafiltration and consequent hemoconcentration, from the beginning to the end of the dialysis session. In detail, the Hct increased from 32.6 +/- 1.9 to 35.4 +/- 1.8% (p < 0.001), while the MAP did not present significant variations. The blood flow did not show significant variations, increasing from 780 +/- 312 to 919 +/- 411 ml/min after the session. Because of the stability of the MAP, we could dissociate the effects of the Hct from those of the MAP on blood flow variations. CONCLUSION: Our study suggests that the blood flow in native fistulas is not affected by the acute rise in Hct due to ultrafiltration during hemodialysis. The transcutaneous access flow measurement technique appears to be reliable and accurate, and it could represent an important diagnostic tool.     

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.     

体外循环术中自体血回收对血液成分及凝血功能的影响

目的观察体外循环术中不同自体血回收方式对患者血液成分及凝血功能的影响。方法随机将60例体外循环下心脏手术的成人患者分为A、B两组,均为30例。A组为观察组,全部术野出血用自体血液回收机离心洗涤后于手术结束前回输体内。B组为对照组,不采用自体血液回收机,将肝素化后的术野出血直接吸回体外循环系统停机前回输体内,鱼精蛋白拮抗后机器余血打入输血袋,于手术结束前静脉回输。对两组患者麻醉前、体外循环中及术毕静脉血进行血常规及凝血四项指标的测定,记录停机后两组激活凝血时间（ACT）及术后24h内胸腔引流量和输注异体血用量,并对以上观察结果进行比较分析。结果①观察组患者术后24h内胸腔引流量及异体血用量明显少于对照组,差异有统计学意义（P〈0．05）。②与术前相比,两组患者血红蛋白（Hb）、红细胞比容（Hct）和血小板（PLT）均明显下降,凝血酶原时间（PT）、活化部分凝血活酶时间（APTT）和凝血酶时间（TT）明显延长,但两组间比较差异无统计学意义。③术毕观察组Hb和Hct值较体外循环中明显回升,且与对照组相比差异有统计学意义,但仍略低于术前。④两组术毕PLT、PT、APTT和TT均明显低于术前,但仍在正常范围内,两组间差异无统计学意义。结论体外循环期间自体血回收对患者血液成分及凝血功能的影响不明显,是一种有效的血液保护方法。     

Myocardial oxygen balance and cardiopulmonary bypass in patients undergoing coronary artery bypass grafting

The frequency of anaerobic myocardial metabolism was studied in 14 patients undergoing coronary artery bypass surgery during enflurane-supplemented high-dose fentanyl anesthesia and compared with other clinical monitors of myocardial ischemia including the configuration of the pulmonary capillary wedge pressure (PCWP) and electrocardiographic findings. Hemodynamic parameters, coronary sinus blood flow, myocardial oxygen and lactate extractions, and a seven-lead ECG were recorded before and after cannulation of the aorta and vena cava, during total cardiopulmonary bypass (CPB) in a vented heart, during rewarming after global myocardial ischemia and cold cardioplegia, and 15 minutes after coming off bypass. The cannulation for CPB induced no changes in the central or coronary hemodynamics, but four patients had abnormal lactate metabolism. Two of these also had ST segment depression, and two had prominent AC waves on the PCWP tracing. Coronary sinus blood flow and myocardial oxygen extraction were maintained at the beginning of CPB, but lactate extraction decreased markedly or turned to lactate production, and ECG changes indicating myocardial ischemia were seen in five patients. During rewarming and after CPB, all patients had abnormal lactate metabolism despite decreased myocardial oxygen extraction, adequate coronary perfusion pressure, and adequate coronary sinus blood flow. During these periods most patients also had cardiac conduction disturbances that made the interpretation of the ST segment impossible. Only one patient had clearly abnormal AC and V waves on the PCWP tracing after CPB. Two patients had ECG evidence of a perioperative myocardial infarction, but they had no significant clinical consequences. Four patients had a fascicular block at discharge. These results indicate that anaerobic myocardial metabolism is common during and after CPB, and that associated myocardial ischemia cannot always be reliably detected by changes in the ECG or the PCWP tracings.     

Low hematocrit per blood viscosity ratio as a mortality risk factor in coronary heart disease

Increased blood viscosity has not been associated with mortality risk in coronary heart disease (CHD). We aimed to investigate the predictive power of hematocrit per blood viscosity (Hct/BV) ratio as a marker of rheological oxygen carrying capacity of the blood to assess mortality risk of CHD. Elective coronary angiography was performed and CHD was proved in 109 patients in 1996 and 1997. In 78 cases (72%) complete follow up information was obtained in February 2006. During the follow up time (mean 8.9 years) 10 patients died due to cardiac cause (group C). Two patients died due to non-cardiac cause and 66 were still alive at the end of the follow up period (group NC, n=68). Mean hematocrit per blood viscosity (Hct/BV) ratio was significantly lower in group C comparing to NC (87+/-5; 93+/-9 Pa(-1)s(-1), SD, respectively, p=0.022). Other factors (body mass index, serum cholesterol, fibrinogen, hematocrit, plasma and blood viscosity, cardiac index, left ventricular ejection fraction) provided no statistical differences. Kaplan-Meier survival analysis showed only the impact of fibrinogen and Hct/BV ratio on cardiac mortality (p=0.029 and 0.009, respectively). Receiver operating characteristic curves proved only Hct/BV ratio to be able to differentiate between groups (area under curve: 0.716, p=0.028). Hct/BV ratio showed significant negative correlation with the frequency of hospital admissions (r=-0.377, p=0.03). Low Hct/BV ratio can be regarded as a risk factor of cardiac death in CHD.     

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.     

发绀患者体外循环中不同氧浓度管理对心肌的影响

目的 观察在发绀患者心内畸形矫治术中使用不同氧浓度管理对心肌的影响.方法 选择2009年1月至2011年9月期间74例发绀型先心病患者随机分为两组：常规组37例,采用氧浓度（FiO2）80%～100%、动脉氧分压（PaO2） 300～380 mm Hg启动体外循环（CPB）;逐级增氧组37例,FiO2 20%、PaO2 80～100 mm Hg启动CPB,在随后10～30 min逐渐增加FiO2 30%～50%,CPB中控制血流复温前PaO2≤130 mm Hg,血流复温后PaO2逐级增加至200～300 mm Hg,保持红细胞压积28%～30%,灌注流量100～180 ml/kg.监测心肌生化变化：气管插管后（T1）、CPB后10 min（T2）、升主动脉开放（CCR）后10 min（T3）、术后6 h（T4）及24 h（T5）抽外周血监测肌酸激酶同工酶（CK-MB）及肌钙蛋白I（cTnI）浓度.结果 CK-MB及cTnI浓度：气管插管后、CPB后10 min两组差异无统计学意义（P＞0.05）;CCR 10 min、术后6 h及24 h逐级增氧组水平显著低于常规组（P＜0.05）.结论 发绀患者CPB中采用逐级增氧管理模式,通过缩小CPB和患者自身的氧分压差,减少自由基等生成,可降低CK-MB及cTnI释放,从而减轻心肌损伤.     

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.     

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     

小型猪体外循环动物模型建立及麻醉管理

目的:探讨小型猪体外循环(CPB)实验模型的建立和麻醉管理。方法: 小型猪12头,全麻诱导插管后,应用全血冷灌方法建立中低温阻闭升主动脉的体外循环模型,并于围CPB期进行动、静脉血氧饱和度(SaO2、SvO2)、血细胞比容(Hct)及乳酸水平(Lac)测定,同时监测围CPB期血流动力学变化。结果: 转流过程中SaO2、SvO2均在正常范围,Lac水平随CPB时间延长,显著升高,Hct在CPB后呈中度稀释,平均血压在CPB后自主循环恢复后经过较短时间恢复到正常范围内。结论: 全血冷灌法建立的小型猪CPB模型,可做为CPB条件下开展研究的动物模型。     

Glucose homeostasis. Comparison between hypothermic and normothermic cardiopulmonary bypass.

STUDY OBJECTIVE: Disturbance in blood glucose homeostasis during cardiac surgery may cause visceral and metabolic alterations. Hypothermic CPB induces glucose and hormonal changes. As normothermic CPB is used at some institutions, a comparison of blood glucose and plasma hormones between hypothermic and normothermic CPB was performed. DESIGN: Prospective nonrandomized study. SETTING: University cardiac center. PATIENTS: Twenty-two nondiabetic adults undergoing elective coronary bypass and/or valvular surgery. INTERVENTIONS: Group 1 (n = 12) underwent hypothermic CPB (25 degrees C) and group 2 (n = 10) normothermic CPB (37 degrees C). In both groups nonpulsatile CPB was achieved with a membrane oxygenator and dextrose-free crystalloid priming. Dextrose was not administered during surgery but was infused postoperatively (125 mg/kg/h). MEASUREMENTS AND RESULTS: Eight blood samples were drawn during the period of arrival in the operating room (control) to the third postoperative hour. During hypothermic CPB in group 1, blood glucose level increased to 154 +/- 20 mg/dl (mean +/- SD) associated with a decrease in plasma insulin and an increase in epinephrine, despite a decrease in cortisol and growth hormone. During rewarming, the blood glucose value continued to increase (to 197 +/- 35 mg/dl) associated with an increase in glucagon, growth hormone and catecholamines, despite a 374 percent increase in insulin. During CPB in group 2, insulin, glucagon, cortisol and catecholamines were significantly higher than during hypothermic CPB so that the blood glucose level was not significantly different between the two groups during CPB. Blood glucose value was higher in group 1 than in group 2 at closure of the chest (208 +/- 30 vs 175 +/- 19 mg/dl, respectively, p less than 0.02) and at the third postoperative hour (271 +/- 30 vs 221 +/- 51 mg/dl, p less than 0.01). In both groups, however, the postoperative increase in blood glucose was accompanied by a similar increase in insulin, cortisol and catecholamines but glucagon was lower after hypothermic CPB. CONCLUSIONS: Hyperglycemia occurred perioperatively in cardiac surgery with dextrose-free priming both during hypothermic and normothermic CPB but normothermic CPB resulted in a slow and steady increase in both glucose and insulin concentrations without the major perturbations that occurred with hypothermic CPB. Postoperatively, higher blood glucose was observed in the hypothermic CPB group.     

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).     

Influence of colforsin daropate hydrochloride on internal mammary artery grafts.

The effect of colforsin daropate hydrochloride (colforsin), a water-soluble forskolin derivative, on blood flow in internal mammary artery (IMA) grafts was evaluated in a prospective randomized study of 26 patients undergoing coronary artery bypass grafting. Patients were randomized to receive either colforsin treatment (colforsin; n=14) or no colforsin treatment (control; n=14). Administration of colforsin (0.5mg x kg(-1) min(-1)) was started after induction of anesthesia and was continued for 6 h. IMA blood flow and hemodynamic measurements were assessed perioperatively. During cardiopoulmonary bypass (CPB), perfusion flow was adjusted to 2.5 L/m2 and IMA free blood flow was measured. IMA blood flow was also measured 1 h after CPB by an ultrasonic flow meter. Systemic vascular resistance was significantly lower in the colforsin group during and after CPB. IMA blood flow was significantly greater in the colforsin group than in the control group during (44 +/- 2 vs 33 +/- 3 ml min-1 x m(-2), p=0.02) and after CPB (38 +/- 6 vs 20 +/- 3ml x min(-1) m(-2), p=0.01). IMA blood flow 1 h after CPB correlated inversely with concurrent systemic vascular resistance (r=-0.61, p=0.001). Intraoperative administration of colforsin daropate hydrochloride caused potent vasodilation, resulting in an increase in IMA blood flow. The results indicate that the regimen can be used perioperatively in patients undergoing coronary artery bypass grafting.     

Cardiopulmonary bypass: studies on its damaging effects

Despite the widespread safe application of cardiopulmonary bypass (CPB) for cardiac surgery, it is inherently a pathologic state. CPB produces a generalized inflammatory reaction involving at least the complement, coagulation, kallikrein, and fibrinolytic cascades. Marked alterations in organ perfusion and metabolism occur during CPB which are further affected by the perfusion flow rate. During hypothermic CPB at 20 degrees C, there is a progressive decrease in perfusion of the microcirculation at flow rates less than 1.2 liters/min/m2. Experimental studies suggest that brain oxygen consumption and resistance remain relatively constant as flow rates are reduced during hypothermia, and the brain becomes the passive recipient of proportionally more blood flow. Recent ultrafiltration studies have demonstrated a specific increase in microvascular permeability to proteins after 2 h of normothermic CPB. This provides experimental support to the well-known clinical observation of increased interstitial fluid following CPB. The development of uniformly safe CPB depends upon prevention of the abnormalities of the microcirculation and upon neutralization of the deleterious effects of inflammatory mediators.     

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.