Haemostatic profile of small children during and following cardiopulmonary bypass

Objective: We evaluated changes of the haemostatic system during pediatric cardiac surgery during and after cardiopulmonary bypass (CPB).Method: Twenty-five children under 15 kg of body weight under-going open-heart surgery were divided into three groups; 9 patients (Group A), no bank blood was used throughout the surgery; 8 patients (Group B), packed red cells were used in the priming of CPB circuit; 8 patients (Group C) in cyanotic condition, for whom surgery was performed without bank blood. CPB caused a significant decrease of platelet counts in all three groups, the levels of which remained similar next morning.Results: Platelet counts decreased more significantly in Group C (59±27 k/mm³) than in Group A (119±42 k/mm³) and B (104±27 k/mm³). Platelet function-platelet activating factor test (HemoSTATUS^TM) did not significantly decrease throughout the perioperative period in Group A. Hemo-STATUS^TM value decreased during CPB and recovered after CPB in Group B and C. Prothrombin time international ratio (PT-INR) and activated partial thromboplastin time were significantly prolonged just after CPB and recovered until next morning in all three groups. PT-INR was more prolonged in Group C (2.92±0.62) than in Group A (2.08±0.27) and B (2.42±0.42). There was no significant difference in postoperative bleeding for the first 12 hours among the three groups.Conclusion: Although extreme hemodilution during CPB significantly impairs the coagulation and platelet system, these changes are usually transient and tolerable with minimal postoperative hemorrhage. However, a prolonged CPB and preoperative cyanotic condition may induce a critical decrease of platelet counts and increase postoperative bleeding.     

Effects of calcium on left ventricular function early after cardiopulmonary bypass

Evaluation of the effects of intravenous CaC1₂on systolic and diastolic function early after separation from cardiopulmonary bypass (CPB) Prospective study University hospital Twenty patients scheduled for elective coronary artery surgery Left ventricular (LV) pressures were measured with fluid-filled catheters. Data were digitally recorded during pressure elevation induced by tilt-up of the legs. Transgastric short-axis echocardiographic views of the LV were simultaneously recorded on videotape. Measurements were obtained before the start of CPB, 10 minutes after termination of CPB, after intravenous administration of CaC1₂, 5 mg/kg, and 10 minutes later.

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Systolic function was evaluated with the slope (Ees, mmHg/mL) of the systolic pressure-volume relation. Diastolic function was evaluated with the chamber stiffness constant (Kc, mmHg/mL) of the diastolic pressure-volume relation. CaC1₂increased Ees from 2.62 ± 0.46 to 5.58 ± 0.61 (mean ± SD), but induced diastolic dysfunction with an increase in Kc from 0.011 ± 0.006 to 0.019 ± 0.007. These changes were transient and had disappeared within 10 minutes after administration of CaC1₂. CaC1₂early after CPB transiently improved systolic function at the expense of an increase in ventricular stiffness, suggesting temporary diastolic dysfunction.     

Increased levels of S-100 protein after cardiac surgery with cardiopulmonary bypass and general surgery in children

The aim of this study was to evaluate changes in concentrations of the neurospecific protein S-100 in relation to cardiac surgery with cardiopulmonary bypass (CPB) and noncardiac general surgery in children below 3 years of age. Seventeen children underwent surgery for congenital heart disease and all survived without clinical signs of neurological complications. Samples for plasma concentrations of S-100 in these patients were taken on three occasions in connection with surgery: before the start of surgery, after CPB and finally 16-20 h after CPB. In the noncardiac group of 31 children, S-100 concentrations were measured on two occasions: before surgery and during surgery. In both groups, a significant increase in S-100 concentrations was observed during surgery, although the increase in the CPB group was significantly higher than in the noncardiac group. The CPB group included four children with Down's syndrome who had higher mean S-100 concentrations on all sampling occasions compared to the remaining patients. The peak S-100 concentrations after cardiac surgery were related to the duration of CPB, the time from the termination of CPB to the first post-CPB sample, as well as mean arterial pressure and cerebral arteriovenous lactate difference during rewarming. All the children studied (Down's patients excluded) had age-dependent plasma concentrations of S-100 measured before surgery. It can be concluded that CPB initiates a marked but transient release of S-100 into the systemic circulation during open heart surgery in children who are not developing clinical signs of neurological sequelae.     

体外循环后胰腺功能的变化

目的观察体外循环下行心脏瓣膜替换术患者胰腺内、外分泌功能的变化,研究其对围手术期治疗的意义。方法采集１６例心脏瓣膜病患者８个时相点全血,测定血糖、乳酸、胰岛素、Ｃ肽、淀粉酶及脂肪酶,分析其变化规律。结果术后围手术期显现出高糖血症和高乳酸血症,二者呈现显著正相关（Ｐ＝０００５）,其峰值于术日１９点,至术后第３日缓慢降到基线水平。胰岛素水平于８个观测时相点测定平均数值基本处于正常水平,仅第３日晨显示轻度升高。血中Ｃ肽水平一直处在稍高于正常范围,在术日１９点达高峰,接近正常倍值。血中淀粉酶与脂肪酶的统计平均数基本处于正常值范围,仅术后第４日脂肪酶稍高出正常值。本组淀粉酶正常１２例,异常４例（２５％）：单纯高淀粉酶血症２例,淀粉酶与脂肪酶均升高者２例（１６％）。高脂肪酶血症８例（５０％）。结论体外循环对围手术期胰腺功能产生病理生理学影响,表现出内、外分泌功能均有一定的改变     

The effects of cardiopulmonary bypass on postoperative oxygen metabolism

The relationships between oxygen delivery (DO₂), oxygen consumption (VO₂), and the extraction rate (ER=VO₂/DO₂x100) in patients undergoing cardiopulmonary bypass (CPB) may differ from the normal physiologic state due to the oxygen debt acquired during CPB. Blood gas analysis and hemodynamic parameters were repeatedly measured for the determination of DO₂ and VO₂ in 40 patients undergoing CPB, every 8h during the first 48h postoperatively. As a control, 20 patients who had suffered acute myocardial infarction (AMI) were also studied using the same protocol. In the CPB group, a regression analysis showed that VO₂ was significantly dependent on DO₂, even within the physiologic range of DO₂ (>500 ml/min per m²); VO₂=121.4+0.0844×DO₂ (r=0.254,P=0.023). Conversely, in the AMI group, no such supply-dependent consumption was observed within the same range of DO₂. At an ER of 30%, which is the optimal value in general, the DO₂ of the CPB group was 575 ml/min per m² and that of the AMI group was 493 ml/min per m². All these results suggest that patients undergoing CPB need a much higher oxygen supply to recover from the oxygen debt acquired during open heart surgery.     

Fibrinolysis in pediatric patients undergoing cardiopulmonary bypass

Thromboelastographic evaluation of the influence of fibrinolysis on blood loss and blood product transfusions in children during cardiac surgery. Prospective study. University-affiliated, pediatric medical center. Two hundred seventy-eight consecutive children undergoing cardiac surgery. Blood sampling for coagulation tests, including native and protamine-modified thromboelastography. Blood coagulation tests were measured before, during, and after cardiopulmonary bypass (CPB). Demographic data, perioperative blood loss, and blood product transfusions were prospectively recorded. Fibrinolysis was defined as thromboelastography of A30/MA less than 0.85 (MA, maximum amplitude; A30, amplitude 30 minutes after MA) and was noted in 3% of children pre-CPB, 16% during CPB, and 3% post-CPB. Fibrinolysis before CPB was associated with poor cardiac output. Fibrinolysis during CPB occurred in young children (aged 350 ± 836 days) undergoing complex surgery with prolonged CPB (119 ± 48.8 minutes) and deep hypothermia (25.6°C ± 4.7°C). These patients received blood products after CPB and were not fibrinolytic after transfusion. They incurred similar blood loss (in mL/kg) and received similar volumes of blood products (mL/kg) as age-matched and surgery-matched patients without fibrinolysis. A group of children at risk for fibrinolysis during CPB was identified. However, fibrinolysis during CPB did not influence blood loss or the total volume of blood products transfused.     

心内直视手术前后甲状腺激素监测

目的 为了了解体外循环（ＣＰＢ）手术前后甲状腺激素代谢的变化规律,及其与心功能变化的相关性。方法 以３６例患者ＣＰＢ术前２小时、术后１￣５天血浆甲状腺激素进行监测,另对其中１６例手术前后心功能变化进行动态监测,并观察它们之间的相互关系。结果 术前血浆甲状腺激素水平正常。ＦＴ３、ＦＴ４、ＴＴ３、ＴＴ４术后均呈现先下降后逐渐回升的变化趋势。ＴＳＨ术后第１天升至最高水平（Ｐ〈０．０５）,此后缓慢下降至术     

Temporary cardiopulmonary bypass and isolated lung ventilation for tracheal stenosis and reconstruction

A 27-yr-old lady with a past history of prolonged ventilationpresented with worsening respiratory distress caused by trachealstenosis. She required urgent tracheal resection and reconstruction.Because of the risk of an acute respiratory obstruction, spinalanaesthesia was used to establish cardiopulmonary bypass bycannulating the femoral artery and femoral vein. Adequate gasexchange was possible with full flow rate. Thoracotomy was thencarried out to mobilize the left main bronchus. After successfullysecuring an airway by intubation of the left main bronchus,cardiopulmonary bypass was discontinued and tracheal resectionand anastomosis was done under conventional one lung anaesthesia. Br J Anaesth 2003; 91: 742–4     

The degree of atherosclerosis in the descending aorta does not predict poor in-hospital outcome after surgery requiring cardiopulmonary bypass

OBJECTIVE: This study examined if the degree of atherosclerosis in the descending aorta is an independent predictor of poor in-hospital outcome for patients presenting for surgery involving cardiopulmonary bypass. DESIGN: The degree of atherosclerosis of the descending aorta was retrospectively reviewed in patients presenting for surgical procedures involving cardiopulmonary bypass from January 1, 2000, to December 31, 2003. Preoperative risk factors and in-hospital postoperative outcome parameters were obtained. SETTING: University teaching hospital. PARTICIPANTS: There were 310 consecutive patients enrolled in the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Two hundred forty-seven patients had coronary artery bypass grafting with or without valvular surgery, and 63 patients had isolated valvular surgery. The degree of atherosclerosis was rated as normal in 86 (28%), mild in 106 (34%), moderate in 69 (22%), and severe in 49 (16%) patients. Adjusting only for the degree of atherosclerosis, the total intensive care unit (ICU) time and the number of deaths were significantly higher in those patients with severe disease. Multivariable models adjusting for patients' risk factors showed a significant influence of atherosclerosis on total ICU time but not on other outcomes. The strongest predictor of poor outcome was a history of previous stroke (cerebral vascular accident). Other significant factors predicting poor outcome included previous coronary artery bypass surgery, a history of congestive heart failure, a history of dialysis, advanced age, and female sex. CONCLUSIONS: The degree of atherosclerosis in the descending aorta is not an independent predictor of poor in-hospital outcome after surgery involving cardiopulmonary bypass.     

Cognitive dysfunction after cardiopulmonary bypass

Cognitive dysfunction remains a significant complication after cardiopulmonary bypass, despite continuous improvement in the overall outcome in open‐heart surgery. Embolization of the atheromatous material, most notably during removal of the aortic clamp, is a major cause. Strategies have been developed to minimize cerebral embolization. Modified surgical techniques include the use of hypothermic circulatory arrest, venting of the left ventricle, minimizing aortic manipulation, and the use of epiaortic ultrasound to locate and avoid trauma to the aortic atheromatous plaque. Use of an intra‐aortic filter has been shown recently to reduce intraoperative cerebral embolic events and improve postoperative neurocognitive outcomes. Off‐pump coronary artery bypass technique has also been claimed to have lower neurological complications, which is probably attributable to the avoidance of aortic cannulation and cardiopulmonary bypass. Its role on cerebral protection is, however, debatable. Chinese Abstract

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Volume 6 , Issue 1 February 2002

Pages 1-3     

Autotransfusion management during and after cardiopulmonary bypass alters fibrin degradation and transfusion requirements

The coagulation-fibrinolytic profile during cardiopulmonary bypass (CPB) has been widely documented. However, less information is available on the possible persistence of these alterations when autotransfusion is used in management of perioperative blood loss. This study was designed to explore the influence of autotransfusion management on intravascular fibrin degradation and postoperative transfusions. Thirty patients, undergoing elective primary isolated coronary bypass grafting, were randomly allocated either to a control group (group A; n=15) or an intervention group (group B; n=15) in which mediastinal and residual CPB blood was collected and processed by a continuous autotransfusion system before re-infusion. Intravascular fibrin degradation as indicated by D-dimer generation was measured at five specific intervals and corrected for hemodilution. In addition, chest tube drainage and need for homologous blood were monitored. D-dimer generation increased significantly during CPB in group A, from 312 to 633 vs. 291 to 356 ng/mL in group B (p = .001). The unprocessed residual blood (group A) revealed an unequivocal D-dimer elevation, 4131 +/- 1063 vs. 279 +/- 103 ng/mL for the processed residual in group B (p < .001). Consequently, in the first post-CPB period, the intravascular fibrin degradation was significantly elevated in group A compared with group B (p = .001). Twenty hours postoperatively, no significant difference in D-dimer levels was detected between both groups. However, a significant intra-group D-dimer elevation pre- vs. postoperative was noticed from 312 to 828 ng/mL in group A and from 291 to 588 ng/mL in group B (p < .01 for both). Postoperative chest tube drainage was higher in the patients from group A, which also had the highest postoperative D-dimer levels. Patients in group A perceived a higher need for transfusions of red cells suspensions postoperatively. These data clearly indicate that autotransfusion management during and after CPB suppresses early postoperative fibrin degradation. Keywords: cardiopulmonary bypass, cardiotomy suction, coronary surgery, autotransfusion, fibrin degradation.     

Anaesthetic management of an insulin-dependent diabetic child during cardiopulmonary bypass

The management of an insulin-dependent diabetic child presenting for correction of complex congenital heart disease requiring cardiopulmonary bypass is described. A constant rate glucose infusion and variable rate insulin infusion, combined with frequent serum glucose measurements, allowed prompt response to the glucose alterations associated with surgery and cardiopulmonary bypass.     

Con: Calcium is not routinely indicated during separation from cardiopulmonary bypass

Severe hypocalcemia is uncommon in adult cardiac surgery patients; the nearly ubiquitous mild hypocalcemia does not impair myocardial performance. Clinicians should recognize that in certain circumstances, calcium may interact negatively with catecholamines such as epinephrine or dobutamine. Lastly, evidence suggests that calcium influx during ischemia-reperfusion contributes to myocardial dysfunction after CPB. Therefore, there appears to be no justification for the practice of routinely administering large doses of calcium salts to adult cardiac surgery patients after CPB.     

Evaluation of biocompatible cardiopulmonary bypass circuit use during pediatric open heart surgery

The contact of blood with nonbiological surfaces during cardiopulmonary bypass (CPB) induces a whole body inflammatory response and increases postoperative morbidity directly related to bleeding complications and end organ dysfunction. Methods to reduce these effects have included modification of extracorporeal circuits through biocompatible coating of disposables and the application of various pharmacological agents. Biocompatible coated surfaces are designed to mimic physiologic surfaces. This study was designed to ascertain the effects of using coated circuits during pediatric CPB. After Institutional Review Board approval and parent/guardian consent, patients undergoing CPB, weighing less than 15 kg, with target CPB temperatures more than 28 degrees C, were enrolled into the Coated Circuit Group using an entirely biocompatible CPB circuit with poly(2-methoxyethylacrylate) (PMEA) and a biocompatible coated oxygenator (n = 16). Those patients were retrospectively matched to control patients having the same congenital repair with respect to patient size, surgeon, anesthesiologist, bypass time, cross-clamp time, bypass temperature, and noncoated bypass disposables; (n = 16). CPB data collected included on-bypass platelet count, hematocrit (HCT), and CPB blood product use. Postprotamine data collected in the operating room included blood product use, time from initial protamine administration to chest closure, platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT), and international normalized ratio (INR). Postoperative intensive care unit (ICU) data included blood product use, HCT, chest tube output, platelet count, PT, aPTT, INR, blood gases, lactate, and ventilator settings at 1, 2, 4, 6, 12, and 24 hours. Other data collected included intubation time, length of time to chest tube removal, and length of ICU stay. Statistical significance (p < .05) was seen in units of platelets transfused postprotamine, ventilator peak inflation pressure (PIP) on admission to the ICU, postoperative day 0 packed red blood cells (PRBC) and fresh frozen plasma (FFP) transfused, and lactate at 1, 2, 4, 6, and 12 hours postoperative. Several parameters approached statistical significance, including PRBC transfused postprotamine, time from protamine administration to chest closure, postoperative day 0 platelets transfused, and ICU stay. The data suggest that PMEA biocompatible CPB circuits can be used safely during pediatric heart surgery, resulting in a decrease in postoperative blood product use, improved postoperative lung function, and a reduction in the time spent in the ICU.     

Effects of organic nitrate vasodilators on platelet function before and after cardiopulmonary bypass

Various in vitro , ex vivo and in vivo tests have shown that organic nitrates attenuate platelet function. Because organic nitrates are commonly administered to patients undergoing cardiac surgery, the postoperative bleeding tendency observed in these patients might be strengthened by nitrates. Therefore, we compared the acute effects of nitroglycerin (0.5 μg kg^-1 min^-1) and isosorbide dinitrate (0.5 or 2.5 ng kg^-1 min^-1) with those of placebo on platelet function both before and after cardiopulmonary bypass in 40 patients undergoing coronary artery bypass grafting (CABG). Bleeding time, platelet retention on glass beads, i.e. platelet adhesiveness, and thromboel-astograph tracings were used as indicators of platelet function. Although nitroglycerin and isosorbide dinitrate induced significant haemodynamic changes, e.g. decreases in arterial and pulmonary arterial pressure, they had no significant effects on the indices of platelet function. We conclude that, when given in haemodynamically effective doses, neither nitroglycerin nor isosorbide dinitrate have any measurable acute effect on platelet function as evaluated with on-site tests in patients undergoing CABG surgery.     

Cisatracurium pharmacokinetics and pharmacodynamics during hypothermic cardiopulmonary bypass in infants and children

Background: Hypothermia potentiates neuromuscular blockade in adults during cardiopulmonary bypass (CPB) but the pediatric literature is sparse. Temperature‐dependent Hoffman degradation of cisatracurium may allow reduction in infusion rate (IR) during hypothermia. The effect of hypothermic CPB on the pharmacokinetics (PK) and pharmacodynamics (PD) of cisatracurium has not been described in children. Methods and materials: Using neuromuscular monitoring with a Datex Relaxograph, cisatracurium IR was adjusted to obtain a pseudo‐steady state during each phase of surgery (pre‐CPB, CPB, post‐CPB). Paired samples were taken at each phase. Cisatracurium plasma concentrations (Cpss) were determined by HPLC. Core and skin temperatures were recorded. Results: Data from ten infants were analyzed: Group 1: mean 33.6°C; Group 2: mean 21.9°C. To maintain T1% between 5% and 10% in Group 2, the IR was decreased by a mean of 89% (P < 0.001). IR was not significantly different in Group 1. Post‐CPB IR approximated pre‐CPB rates in both groups. During CPB, Cpss fell by 27% in Group 1 and by 50% in Group 2 (P = 0.039). Post‐CPB Cpss was not significantly different to pre‐CPB in either group. Clearance did not change significantly in Group 1 but fell significantly in Group 2 during CPB (P = 0.002). Clearance post‐CPB was unchanged from pre‐CPB. Conclusions: Cisatracurium IR may be decreased by around 60% during CPB with moderate hypothermia but can be maintained at baseline during mild hypothermia.     

不同年龄发绀型先心病患儿围体外循环期凝血功能的比较

Objective To investigate the changes in blood coagulation during cardiopulmonary bypass (CPB) in children of different ages undergoing open heart surgery for cyanotic congenital heart disease.Methods Sixty children with cyanotic congenital heart disease undergoing open heart surgery under CPB were divided into 3 age groups: Group A(age≤12 mort, n=25), Group B (12mon＜age≤24 mon, n= 17) and Group C (24 mon＜ age＜4 yr, n=18). Venous blood samples were taken immediately after induction of anesthesia(T1) and at 10 min after protamine administration (T2)for determination of activated coagulation time (SonACT), clot rate and platelet function (PF) using Sonoclot coagulation and platelet function analyzer-type DP2951 (Sieuco Co., USA).Results There was significant difference in SonACT, clot rate and PF at T1 among the 3 groups: the SonACT was significantly shorter in Groups B and C than in Group A, the clot rate was significantly higher in Group B than in Group C, and the PF was significantly lower in Group C than in Group A. At T2 , the SonACT was significantly prolonged in all 3 groups, the clot rate was significantly decreased in Groups A and B, and the PF was significantly decreased in Group A.Conclusion There are significant differences in blood coagulation and PF among the 3 different age groups of children with cyanotic congenital heart disease after induction of anesthesia and CPB has different effects on their blood coagulation and PF.