High‐dose aprotinin,blood product transfusions,and short‐term outcome in neonates and infants: a pediatric cardiac surgery center experience

Background: The efficacy of aprotinin, the most popular antifibrinolytic agent in congenital cardiac surgery, was still uncertain in small infants when its prophylactic use was suspended for safety reasons. The aim of this study is to describe associations between the prophylactic use of high‐dose aprotinin, the need for blood product transfusions, and short‐term outcome in neonates and infants with cardiac surgery. Methods/materials: This retrospective study included all patients younger than 1 year undergoing surgery with cardiopulmonary bypass through 42 months, before and after withdrawal of aprotinin. Each patient who received aprotinin was matched with a control with similar baseline and surgical characteristics, who have not received any antifibrinolytic agent. Associations between the use of aprotinin and the exposure to red blood cells, fresh frozen plasma, and platelet transfusions were estimated from a logistic regression model, and the exposure to additional transfusions from a polytomous regression model. Results: Matching resulted in two groups of 283 patients each, well balanced except for the priming volume and the ultrafiltration rate, larger in the aprotinin group. After adjustment for the priming volume and ultrafiltration rate, there was no significant association between the use of aprotinin, the exposure to any blood product transfusion, or the exposure to additional transfusions, the rate of re‐exploration for bleeding, and short‐term outcome. Two patients in the control group required re‐exploration for bleeding. Conclusions: No association was found between the prophylactic use of aprotinin, blood product transfusions, and short‐term outcome in this population of neonates and infants.     

Treatment and monitoring of coagulation abnormalities in children undergoing heart surgery

Bleeding is a considerable clinical problem during and after pediatric heart surgery. While the primary cause of bleeding is surgical trauma, its treatment is often complicated by the presence of coagulopathy. The principle causes of coagulopathy are discussed to provide a context for treatment. The role of laboratory and point of care tests, which aim to identify the cause of bleeding in the individual patient, is also discussed. An attempt is made to examine the current evidence for available therapies, including use of blood products and, more recently proposed, approaches based on human or recombinant factor concentrates.     

Benefits and risks of red blood cell transfusion in pediatric patients undergoing cardiac surgery

As the number of neonates and young infants undergoing cardiac surgery requiring cardiopulmonary bypass (CPB) increases, red blood cell (RBC) transfusion will continue to be an integral part of the practice of pediatric cardiac anesthesiology. The decision of when to transfuse RBCs to these patients is complex and influenced by multiple factors such as size, presence of cyanotic heart disease, complexity of the surgical procedure, and the hemostatic alterations induced by CPB. The known benefits of RBC transfusion include an increase in the oxygen-carrying capacity of blood, improved tissue oxygenation, and improved hemostasis. Unfortunately, there is no minimum hemoglobin level that serves as a transfusion trigger for all pediatric patients undergoing cardiac surgery. Physiologic signs such as tachycardia, hypotension, low mixed venous oxygen saturation and increased oxygen extraction ratios can provide objective evidence of the need to augment a given hemoglobin level. Nevertheless, the benefits of RBC transfusion must be balanced against its risks and, in recent years, RBC transfusion has been subjected to intense scrutiny. The adverse consequences of RBC transfusion include the transmission of infectious diseases and immune-mediated and nonimmune-mediated complications. Advances in donor selection, infectious disease testing of donated blood, use of leukocyte reduction and irradiation of blood in defined situations have improved the safety of the blood supply in terms of infection transmission. However, a growing number of prospective randomized clinical trials are finding an association between RBC transfusion and an increased risk of morbidity and mortality even with the use of leuko-reduced blood. Thus, it is becoming increasingly important that the decision to transfuse RBCs be made with a thorough understanding of the benefit-to-risk ratio. This review addresses the benefits and risks of RBC transfusion, pertinent data acquired in the setting of congenital cardiac surgery and techniques designed to minimize the need for RBC transfusion.     

Perioperative monitoring of thromboelastograph on blood protection and recovery for severely cyanotic patients undergoing complex cardiac surgery

In this study, we assessed the clinical effect of a new transfusion therapy guided by thromboelastograph (TEG) on blood protection. Thirty-one children with severe cyanosis (hematocrit ≥54%), who were diagnosed as having transposition of the great arteries or double outlet right ventricle with or without pulmonary valve stenosis, and underwent arterial switch operation or double roots transplantation, were involved and were divided into two groups. In group F (n=17), the transfusion therapy after cardiopulmonary bypass was performed with fibrinogen administration combined with traditional transfusion, guided by TEG. In group C (n=14), traditional transfusion guided by clinical experiences only was performed. We observed the blood protection effects and recovery conditions of these patients. In surgery, compared with group C, the chest closure time, fresh-frozen plasma (FFP), and platelet (PLT) volume used at closure time had no significant reductions in group F (P>0.05, respectively), and the patients in group F had no significant reductions in the amount of chest drainage (P>0.05). The total PLT and total red blood cells usage were also the same (P>0.05). But during the first 24h, FFP usage in the intensive care unit (ICU) and total perioperative FFP usage had significantly dropped in group F (P<0.05); the mechanical ventilator time, ICU stay, and hospitalization time in group F were much shorter than those in group C (P<0.05). So, TEG was effective in perioperative blood protection. Fibrinogen could be a substitute for FFP to restore hemostasis and improve the prognosis for these patients.     

Intraoperative cell salvage in infants undergoing elective cardiac surgery: a prospective trial

BACKGROUND: For a long time intraoperative cell salvage was considered not to be applicable in paediatric patients due to technical limitations. Recently, new autotransfusion devices with small volume centrifugal bowls and dedicated paediatric systems allow efficient blood salvage in small children. The purpose of this prospective non-randomised study was to determine the impact of intraoperative cell salvage on postoperative allogeneic blood products transfusion in infant patients undergoing cardiac surgery with cardiopulmonary bypass. METHODS: Two consecutive cohorts (122 patients) were studied. The first cohort underwent procedures between January 2004 and July 2005 with only blood salvage from the residual volume. The second cohort consisted of patients operated on from August 2005 to December 2006, with additional use of intraoperative cell salvage. The following variables were analysed: peri- and postoperative blood loss, transfusion of homologous blood products and cell salvage product, haematological and coagulation data, measured before, during and after the operation. RESULTS: Additional intraoperative cell salvage significantly enhanced the amount of cell saving product available for transfusion (183+/-56 ml vs 152+/-57 ml, p=0.003) and significantly more patients in this group received the cell saving product postoperatively. Consequently, allogeneic blood transfusion was significantly reduced in volume as well as in frequency. We did not observe any adverse effects of intraoperative cell salvage. CONCLUSION: Intraoperative cell salvage, employed as an adjuvant technique to the residual volume salvage in infants undergoing first time cardiac surgery with cardiopulmonary bypass, was a safe and effective method to reduce postoperative allogeneic blood transfusion. Considering current cell salvage related expense and the cost reduction achieved by diminished allogeneic transfusion, intraoperative cell salvage in infants demonstrated no economic benefit.     

紫绀与非紫绀先心患儿动脉血与呼气末二氧化碳分压差的比较

目的本研究旨在分析紫绀型与非紫绀型先心患儿术中动脉血与呼气末二氧化碳分压的差值(Pa-ETCO2),评估过度通气对Pa-ETCO2的影响,分析七氟醚的浓度变化对Pa-ETCO2的影响。方法选择择期行心脏手术的患儿120例,男60例,女60例,年龄1个月~6岁,ASAⅡ或Ⅲ级,根据心脏内左向右或右向左分流按随机区组设计分为六组,每组20例:A1组,紫绀患儿接受0.5MAC七氟醚吸入麻醉;A2组,紫绀患儿接受1.0 MAC七氟醚吸入麻醉;B1组,非紫绀患儿接受0.5 MAC七氟醚吸入麻醉;B2组,非紫绀患儿接受1.0MAC七氟醚吸入麻醉;C1组,紫绀对照组,单纯静脉麻醉,不接受任何干预因素;C2组,非紫绀对照组,单纯静脉麻醉,不接受任何干预因素。所有患者开放动静脉后选择气管内插管全身麻醉。分别于切皮前、开胸行过度通气后(对照组不行过度通气)及关胸前5min记录患者的PETCO2、SpO2、PaCO2、SaO2、Hct及体温(鼻咽温和肛温)。结果切皮前,六组患儿Pa-ETCO2均大于正常值,且B1组明显小于A1组,B2组明显小于A2组,C2组明显小于C1组(P0.01)。与切皮前比较,过度通气后A1、A2、B1、B2组的Pa-ETCO2明显减小(P0.05或P0.01)。过度通气对非紫绀组的影响更明显。与切皮前比较,关胸前5min B1、B2、C2组的Pa-ETCO2明显增大(P0.01),而A1、A2、C1组的Pa-ETCO2明显减小(P0.05)。A1组与A2组,B1组与B2组各时点Pa-ETCO2差异均无统计学意义。结论紫绀型先心患儿的Pa-ETCO2明显大于非紫绀型先心患儿,因此,在紫绀型先心患儿中加强对动脉血气分析的校正是十分重要的。过度通气可以明显减小非紫绀型先心患儿中的Pa-ETCO2,但对紫绀型先心患儿不建议使用。七氟醚在一定范围内浓度的增加不会影响Pa-ETCO2。     

Cyanotic congenital heart disease (CCHD): focus on hypoxemia,secondary erythrocytosis,and coagulation alterations

Children with cyanotic congenital heart disease (CCHD) have complex alterations in their whole blood composition and coagulation profile due to long‐standing hypoxemia. Secondary erythrocytosis is an associated physiological response intended to increase circulating red blood cells and oxygen carrying capacity. However, this response is frequently offset by an increase in whole blood viscosity that paradoxically reduces blood flow and tissue perfusion. In addition, the accompanying reduction in plasma volume leads to significant deficiencies in multiple coagulation proteins including platelets, fibrinogen and other clotting factors. On the one hand, these patients may suffer from severe hyperviscosity and subclinical ‘sludging’ in the peripheral vasculature with an increased risk of thrombosis. On the other hand, they are at an increased risk for postoperative hemorrhage due to a complex derangement in their hemostatic profile. Anesthesiologists caring for children with CCHD and secondary erythrocytosis need to understand the pathophysiology of these alterations and be aware of available strategies that lessen the risk of bleeding and/or thrombosis. The aim of this review is to provide an updated analysis of the systemic effects of long‐standing hypoxemia in children with primary congenital heart disease with a specific focus on secondary erythrocytosis and hemostasis.     

Pharmacokinetics of alcuronium in children with acyanotic and cyanotic cardiac disease undergoing cardiopulmonary bypass surgery

The aim of this study was to determine the pharmacokinetic parameters for alcuronium in children with cyanotic or acyanotic congenital cardiac disease undergoing cardiopulmonary bypass surgery and to compare these parameters with previously reported values in children and adults with normal cardiac function. Seven children with acyanotic disease and seven with cyanotic disease were studied. Alcuronium (base) was administered in an initial dosage of 0.25 mg·kg^?1 with additional doses as needed to maintain paralysis. Using time averaged data, cyanotic children had lower mean clearance, elimination half-life and volume of distribution at steady state than the acyanotic children; none of these differences was, however, statistically significant. In this study, children with acyanotic and cyanotic cardiac disease undergoing bypass, had a diminished clearance (P < 0.05) and a smaller volume of distribution (P < 0.05) than normal children and a shorter elimination half-life (P < 0.05) than adults. Onset of cardiopulmonary bypass caused an immediate marked decrease in alcuronium plasma concentrations which remained low in the acyanotic children at the completion of bypass.     

Validation of a definition of excessive postoperative bleeding in infants undergoing cardiac surgery with cardiopulmonary bypass

Objective

To derive and validate an objective definition of postoperative bleeding in neonates and infants undergoing cardiac surgery with cardiopulmonary bypass.

Blood coagulation and autologous blood transfusion in cardiac surgery

Study Objective: To review the basic pathophysiology of altered coagulation associated with cardiopulmonary bypass and autologous blood transfusion in cardiac surgery.

Design: Review of rational use of heparin, mechanisms and treatment of coagulation disorders, and autologous blood transfusion.

Setting: Cardiac surgery in community and academic hospitals.

Patients: Adult cardiac surgical patients.

Main Results: Heparin is most commonly used for anticoagulation during cardiopulmonary bypass. Although activated clotting time is widely used to assess heparin-induced anticoagulation, the minimum time to prevent clotting during cardiopulmonary bypass remains unclear. Activated clotting time is affected by many factors other than heparin, such as antithrombin III, blood temperature, platelet count, and age. The rational use of activated clotting time still must be defined.

The frequency of abnormal bleeding after cardiopulmonary bypass is significant. Although inadequate surgical hemostasis is the most frequent cause of bleeding, altered coagulation often is present. A decreased number of functional platelets is one of the important causes of bleeding diathesis. Platelet dysfunction is induced by perioperative medication such as aspirin. Cardiopulmonary bypass decreases functional platelets by degranulation, fragmentation, and loss of fibrinogen receptors. Medications such as prostacyclin and iloprost may be useful to protect these platelets. Desmopressin increases factor VIII:C and von Willebrand's factor, leading to a decrease in bleeding time. Desmopressin may be useful to decrease blood loss in repeat cardiac operations, complex cardiac surgery, and abnormal postoperative bleeding.

Patients undergoing coronary artery bypass grafting immediately after streptokinase infusion also are at risk for abnormal bleeding. Transfusion of fresh frozen plasma and cryoprecipitate may be necessary.

Autologous blood transfusion is cost-effective and the safest way to avoid or decrease homologous blood transfusion. Predonation, intraoperative salvage, and postoperative salvage are encouraged. Erthroprotein may be useful in increasing the amount of predonation red cells.

Conclusions: Coagulation disorders in cardiac surgery are caused by many factors, such as heparin, platelet dysfunction, and fibronolysis. Rational use of blood component therapy and medications such as heparin, protamine, and desmorpessin are mandatory. Autologous blood transfusions is very useful in decreasing or obviating the use of homologous blood transfusion.