Factors associated with blood loss and blood product transfusions: a multivariate analysis in children after open-heart surgery.

In this prospective cohort study of 548 children undergoing open-heart surgery, we evaluated demographic and perioperative factors to identify variables associated with perioperative blood loss and blood product transfusions. Using multivariate analysis, younger patient age was found to be the variable most significantly associated with bleeding and transfusions. Higher preoperative hematocrit, complex surgery, lower platelet count during cardiopulmonary bypass (CPB), and longer duration of deep hypothermic circulatory arrest were also significantly associated with bleeding and transfusion. Excessive postoperative chest tube (CT) drainage was associated with intraoperative bleeding. Independently associated variables accounted for 76% of the variability in CT output measured after 2 h in intensive care. Patients were subdivided into children aged < or =1 yr (infants) and children >1 yr; infants bled more intraoperatively (P<0.005); had greater cumulative CT output at 2, 6, 12, and 24 h (P<0.0001); and received more blood products (P<0.0001). Factors associated with bleeding and transfusions varied with patient age. Lower body core temperature during CPB was highly associated with blood loss and transfusions in infants, whereas resternotomy, preoperative congestive heart failure, and prolonged duration of CPB were significant factors associated with bleeding and transfusions in children >1 yr old. IMPLICATIONS: Knowledge of the factors associated with blood loss and blood product transfusions can help to identify children at risk of excessive bleeding after open-heart surgery.     

Do preoperative laboratory tests predict blood transfusion needs in cardiac operations?

We retrospectively compared preoperative prothrombin (PT), partial thromboplastin (PTT), dilute whole blood clot lysis and bleeding times, fibrinogen level, and platelet count with subsequent blood component administration in 92 patients who had undergone cardiac operations with cardiopulmonary bypass (CPB). Abnormal results for one or more tests were found in 34% of 71 adults and 81% of 21 children and teenagers. The patients with abnormal test(s) received no more whole blood and packed red cell units, platelets, or plasma than those with normal tests in either age group. No individual or multiple test abnormalities predicted excess blood component transfusion, even when low-grade abnormalities were excluded. The high rate of abnormal tests in patients less than 20 years of age was not due to polycythemia and may indicate a need for age-specific reference ranges. Baseline PT, PTT, and platelet count may aid in the evaluation of the potential for subsequent development of coagulopathy, but we conclude that further preoperative testing may be reserved for infants, polycythemic individuals, or others in whom history or drug use suggests potential bleeding problems.     

Coagulation tests predict bleeding after cardiopulmonary bypass

To determine the accuracy of coagulation profile laboratory tests, thromboelastography, and Sonoclot (SCT) values for predicting microvascular bleeding after cardiopulmonary bypass (CPB). A prospective, blinded trial. A large academic medical center. Eighty-two adult patients undergoing elective cardiac surgery. Ten minutes after CPB, thromboelastography, SCT, and coagulation profile tests (bleeding time, prothrombin time, activated partial thromboplastin time, fibrinogen, fibrin split products, platelet count, mean platelet volume, and platelet hematocrit) were determined from a whole blood sample taken from an existing arterial catheter. Patients were subjectively defined as “bleeders” or “non-bleeders” by blinded clinical observers. Preoperative baseline tests were also obtained.

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Thirty of the 82 patients (36.6%) were characterized as bleeders. Coagulation profile tests had the best correlation with intraoperative and postoperative blood loss. The specificity, sensitivity, and negative and positive predictive values were determined by receiver operating characteristic analysis, and the test values that differentiated normal from abnormal (bleeding) patients were determined. The coagulation profile laboratory tests had the greatest maximal sensitivity and specificity for predicting bleeding. These predictive values were outside the normal range for these laboratory tests. The thromboelastography values that produced maximal sensitivity and specificity were in the normal range for that test. Contrary to previous studies, coagulation profile tests had the greatest sensitivity and specificity to differentiate patients with excessive bleeding (abnormal) from those without excessive bleeding (normal) after CPB. Therefore, these tests should be used to guide transfusion therapy in patients who have excessive bleeding after CPB.     

A multivariate analysis of factors affecting blood component requirement in pediatric open heart surgeries

Background

Bleeding in children after Cardiopulmonary Bypass (CPB) can be an important cause of morbidity and mortality. Multiple perioperative factors have been evaluated to predict bleeding and hence blood and blood component requirements in such children.

Materials and methods

Perioperative blood and blood product transfusion data were recorded for 264 children who underwent open heart procedures. Preoperative factors like patient age, sex, body surface area, hemoglobin, hematocrit, platelet count and cyanosis were compared with the Packed Red Cell (PRC), Fresh Frozen Plasma (FFP) and Random Donor Platelet (RDP) units transfused. Intraoperative factors like cardiopulmonary bypass time (CPB Time), prime type (heme prime done or not) and core body temperature attained during the surgery were also evaluated for the same. The results were statistically analyzed.

Results

Variables found to have a positive correlation with PRC use (i.e., those with p-value?<?0.05) are CPB time, heme prime and Partial Thromboplastin Time (PTT). However, age, hematocrit and cyanosis were negatively associated with PRC use. CPB time also had a positive correlation with Fresh Frozen Plasma and Random donor platelet usage. FFP use was positively correlated with heme prime performed. Cryoprecipitate consumption was positively correlated with preoperative cyanosis and hematocrit of the patient.

Conclusion

We identified patient??s age, preoperative hematocrit and coagulation profile, presence of cyanosis along with intraoperative parameters like prime type and CPB time as significant determinants of blood consumption especially packed red cells.     

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.     

Rapid evaluation of coagulopathies after cardiopulmonary bypass in children using modified thromboelastography

Complex coagulopathies follow cardiopulmonary bypass (CPB) in children. However, objective laboratory data that can be acquired rapidly to guide their management are lacking. Because thromboelastography has proven useful in this regard, we evaluated the use of celite or tissue factor (TF) activation and heparinase modification of blood samples to allow rapid determination of thromboelastogram data in children younger than 2 yr undergoing CPB. Celite or TF activation shortened the initiation of clotting and, thus, the time required for the important thromboelastogram alpha and maximum amplitude values to begin evolving. Although thromboelastogram alpha and maximum amplitude values were increased with these activators, correlations persisted between platelet count or fibrinogen level and each of these values. The additional use of heparinase allowed thromboelastograms to be obtained during CPB with values not different from those obtained without heparinase after protamine administration. Therefore, celite- or TF-activated, heparinase-modified thromboelastograms begun during CPB allow objective data to be available by the conclusion of protamine administration to help restore hemostasis after CPB in children. Thromboelastography identified transient fibrinolysis during CPB in some children that resolved by the conclusion of protamine administration. Future investigations of the effectiveness of modified thromboelastography-guided coagulopathy management after CPB in children are needed. Implications: Thromboelastography is useful in assessing the coagulopathies that follow cardiopulmonary bypass in children. Modifying blood samples with celite or tissue factor and heparinase allows thromboelastography begun before the termination of cardiopulmonary bypass to become a rapid point-of-care monitor to provide objective data for guiding blood component therapy to manage these coagulopathies.     

Comparison of viscoelastic measures of coagulation after cardiopulmonary bypass

Postoperative hemorrhage remains a major cause of morbidity after cardiopulmonary bypass (CPB). Treatment remains empiric because of the need for immediate correction and the lack of availability of rapid intraoperative coagulation monitoring (except for ACT) at most institutions. Thrombelastography (TEG) and Sonoclot analysis (SCT) are measures of viscoelastic properties of blood which allow rapid intraoperative evaluation of coagulation factor and platelet activity as well as overall clot integrity from a single blood sample. Routine coagulation tests (RCT) including activated clotting time (ACT), prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen level (FIB), and platelet count (PLT) were determined and compared to TEG and SCT to assess which best predicted clinical hemostasis after CPB. Forty-two patients prospectively felt to be at high risk for excessive post-CPB bleeding had blood obtained for RCT, TEG, and SCT analysis before systemic heparinization and 30 min after protamine administration. Nine of 42 patients had excessive chest tube drainage, but no reoperations were required. After CPB, mean values for RCT were normal, but there were abnormalities in TEG and SCT parameters that reflect platelet-fibrin interaction. Both TEG and SCT were 100% accurate in predicting bleeding in these nine patients and, overall, both tests were significantly better predictors of postoperative hemorrhage than RCT. We conclude that viscoelastic determinants of clot strength may be abnormal after CPB and that SCT and TEG are, therefore, more useful than RCT for the detection and management of coagulation defects associated with CPB.     

Prediction of massive blood transfusion in cardiac surgery

PURPOSE: In cardiac surgery with cardiopulmonary bypass (CPB), excessive blood loss requiring the transfusion of multiple red blood cell (RBC) units is a common complication that is associated with significant morbidity and mortality. The objective of this study was to develop a prediction rule for massive blood transfusion (MBT) that could be used to optimize the management of, and research on, at-risk patients. METHODS: Data were collected prospectively over the period from 2000 to 2005, on patients who underwent surgery with CPB at one hospital. Patients who received > or = five units of RBC within one day of surgery were classified as MBT. Logistic regression was used to appropriately select and weigh perioperative variables in the prediction rule, which was developed on the initial 60% of the sample and validated on the remaining 40%. RESULTS: Of the 10,667 patients included, 925 (8.7%) had MBT. The clinical prediction rule included 12 variables (listed in order of predictive value: CPB duration, preoperative hemoglobin concentration, body surface area, nadir CPB hematocrit, previous sternotomy, preoperative shock, preoperative platelet count, urgency of surgery, age, surgeon, deep hypothermic circulatory arrest, and type of procedure) and was highly discriminative (c-index = 0.88). In the validation set, those classified as low-, moderate-, and high-risk by a simple risk score derived from the prediction rule had a 5%, 27%, and 58% chance of MBT, respectively. CONCLUSION: A clinical prediction rule was developed that accurately identified patients at low-risk or high-risk for MBT. Studies are needed to determine the external generalizability and clinical utility of the prediction rule.     

Efficacy of epsilon-aminocaproic acid in children undergoing cardiac surgery.

OBJECTIVE: To compare coagulation test results, blood loss, and blood product transfusions between patients receiving prophylactic epsilon-aminocaproic acid (EACA) and a control group matched for age, resternotomy, and surgery in children undergoing cardiac surgery. DESIGN: Nested case-control study. SETTING: University-affiliated, pediatric medical center. PARTICIPANTS: Same study period; 70 patients in EACA group and 70 patients in control group. INTERVENTIONS: Prophylactic EACA administered intravenously (load, 150 mg/kg, infusion; 30 mg/kg/h) to 70 patients at increased risk for bleeding (reoperation or Ross procedure). MEASUREMENTS AND MAIN RESULTS: Coagulation test values were measured before, during, and after cardiopulmonary bypass (CPB). Intraoperative blood loss, postoperative chest tube output, and allogenic blood product transfusions were recorded. Comparison of demographic and surgical data indicated close matching of the EACA and control groups. The EACA group ([median, 25th to 75th quartile] 15.6 mL/kg; 9.2 to 26.3 mL/kg) had less intraoperative blood loss than the control group (22.2 mL/kg; 14.3 to 36.3 mL/kg; p = 0.02). Postoperative chest tube output at 6 hours (p = 0.08), 12 hours (p = 0.07), and 24 hours (p = 0.08) was not significantly different between groups. Fewer EACA group patients required reexploration for bleeding (p < 0.05). There was no difference between groups in blood products transfused (in milliliters per kilogram or allogenic exposure per patient). Thromboelastography values (maximum amplitude [MA], whole blood clot lysis index at 30 minutes after MA) during CPB were better preserved in the EACA group. CONCLUSION: EACA reduced intraoperative blood loss but did not significantly decrease blood product transfusions. Lack of efficacy may be related to relative underdosing and should be further studied.     

Plateletworks platelet function test compared to the thromboelastograph for prediction of postoperative outcomes

Approximately 3.5 million units of platelets are transfused in the United States each year to patients undergoing open-heart surgery with cardiopulmonary bypass (CPB). CPB is a known contributor to platelet loss and platelet dysfunction leading to disruption of hemostasis. Impaired hemostasis results in excess bleeding in 5-25% of all patients undergoing CPB. For this reason, it may be beneficial to measure platelet number and function in these patients. The purpose of this study was to compare the Plateletworks platelet function analyzer to the thromboelastograph (TEG) in predicting postoperatiave hemostatic outcomes as measured by blood product use and chest tube (CT) drainage. This study consisted of 35 adult patients undergoing cardiac surgery with cardiopulmonary bypass at Rush-Presbyterian-Saint Luke's Medical Center (RPSLMC). The Plateletworks and TEG tests were performed preoperatively, after protamine was given, and 24 hours postoperatively on all patients. Plateletworks demonstrated a statistically significant change in platelet function as shown by the adenosine diphosphate (ADP) reagent tube from the preoperative period to the removal of the aortic cross clamp (p = .011). The TEG did not demonstrate a significant change in the k-time and maximum amplitude (MA), but did show a significant change in the alpha-angle from the pre-operative to postoperatiave sample (p = .035). A correlation was found between Plateletworks collagen reagent tubes preoperatively and CT drainage (p = .048, r -0.324). No statistical correlation was established between TEG parameters and CT drainage at any time interval. TEG preoperative MA showed a correlation to receipt of blood products (p = .016). When comparing the Plateletworks to the TEG in this study, the Plateletworks system was a more useful predictor of blood product use and chest tube drainage.     

Preoperative plateletpheresis does not reduce blood loss during cardiac surgery

Acute preoperative plateletpheresis has been reported to be effective in reducing blood loss and blood component transfusion while improving haematological profiles in patients undergoing open-heart surgery. However, in these studies, the concomitant use of cell saver techniques may have been responsible for the beneficial effects because they remove free haemoglobin and activated procoagulants and, therefore, could mask the deleterious effects of combined plateletpheresis and cardiopulmonary bypass (CPE). In the present study, 40 patients undergoing primary myocardial revascularization were randomly divided into two groups: a control group without plateletpheresis performed, and a second group in which preoperative platelet-rich plasma 10 ml · kg^?1 (PRP group) was collected and later reinfused after reversal of heparin. Standardized surgery, anaesthesia and CPB without concomitant cell saver techniques were employed. In the PRP group, blood transfusion was reduced (1.5 ± 1.3 vs 2.4 ± 1.3 units, P < 0.05) but this was accompanied by lower postoperative haemoglobin concentrations. There were no differences in blood loss (992.6 ± 327.4 vs 889.6 ± 343.7 ml), fresh frozen plasma (2/19 vs 3/20 patients) or platelet requirements (1/19 vs 1 /20 patients). Reinfusion of autologous PRP did not improve platelet count and function, nor tests of coagulation. Fibrinogen concentrations were lower in the PRP group on the operative day (P < 0.05), suggesting increased fibrinogen consumption; and more patients in the PRP group had low haptoglobin levels during CPB (8/19 vs 0/20 patients, P < 0.005), which indicated greater haemolysis in this group. We conclude that acute preoperative plateletpheresis offers no advantage in haemostasis during elective primary myocardial revascularization surgery.     

Intraoperative use of platelet-plasmapheresis in vascular surgery

STUDY OBJECTIVE: To determine, in a pilot study, whether pheresis of plasma and platelets before surgical blood loss, with reinfusion of the autologous plasma and platelets after completion of the aortic reconstruction, will result in decreased bleeding and decreased transfusion of allogenic blood components in patients undergoing elective aortic reconstruction. DESIGN: Randomized study. SETTING: University medical center. INTERVENTIONS: Patients were randomized to perioperative (acute) platelet plasmapheresis (APP group) versus conventional blood component therapy (control group). In the APP group, blood was withdrawn after induction of anesthesia, to sequester approximately 300 mL of platelet rich plasma (PRP); platelet poor plasma (PPP) and red blood cells (RBC) were sequestered as well. An autotransfusion device was used to collect and re-infuse autologous RBC during the course of the operation in both groups. After completion of the aortic reconstruction, autologous PRP and PPP were re-infused in the APP group. Blood loss, volume of blood component transfusions, and preoperative and postoperative hemoglobin (Hb), hematocrit (Hct), platelet, international normalized ratio (INR), and activated partial thromboplastin time (aPTT) were recorded. MEASUREMENTS AND MAIN RESULTS: There was no difference between groups in demographics, preoperative laboratory values, or surgical procedures, although more patients were treated for aneurysms (73% vs. 60%) and fewer for occlusive disease (20% vs. 40%) in the control versus APP group. Also, there were no differences between the control and APP groups in duration of operation, blood loss, volume of colloid infused, or volume of allogenic RBC and plasma transfused. Patients in the APP group received a greater volume of crystalloid solution (9.1 +/- 3.4 L vs. 6.8 +/- 3.0 L; p = 0.002), but fewer units of allogenic platelets than the control group (0.7 +/- 1.0 units vs. 0.2 +/- 0.4 units; p < 0.04). There were no differences in postoperative Hb, Hct, INR, aPTT, or fibrinogen. The platelet count was lower in the APP group than in the control group (123 +/- 40 x 10(3)/mm(3) vs. 182 +/- 51 x 10(3)/mm(3); p = 0.004). CONCLUSIONS: Perioperative platelet plasmapheresis led to fewer allogenic platelet transfusions in patients undergoing elective aortic reconstruction. However, there was no decrease in blood loss and no reduction in transfusion of allogenic RBC or plasma. Perioperative platelet plasmapheresis is not recommended for routine use in elective aortic reconstruction.     

The predictive value of modified computerized thromboelastography and platelet function analysis for postoperative blood loss in routine cardiac surgery

Hemorrhage after cardiopulmonary bypass (CPB) remains a clinical problem. Point-of-care tests to identify hemostatic disturbances at the bedside are desirable. In the present study, we evaluated the predictive value of two point-of-care tests on postoperative bleeding after routine cardiac surgery. Prospectively, 255 consecutive patients were studied to compare the ability of modified thromboelastography (ROTEG) as well as a platelet function analyzer (PFA-100) to predict postoperative blood loss. Measurements were performed at three time points: preoperatively, during CPB, and after protamine administration with three modified thromboelastography and PFA tests. The best predictors of increased bleeding tendency were the tests performed after CPB. The angle alpha is the best predictor (area under the receiver operating characteristic curve 0.69) and, in combination with the adenosine diphosphate-PFA test, the predictive accuracy is enhanced (area under the receiver operating characteristic curve 0.73). The negative predictive value for the angle alpha is 82%, although the positive predictive value is small (41%). Thromboelastography is a better predictor than PFA. In routine cardiac surgery, impaired hemostasis as identified by point-of-care tests does not inevitably lead to hemorrhage postoperatively. However, patients with normal test results are unlikely to bleed for hemostatic reasons. Bleeding in these patients is probably caused surgically. The high negative predictive value supports early identification and targeted treatment of surgical bleeding by distinguishing it from a significant coagulopathy. IMPLICATIONS: Thrombelastography and platelet function analysis in routine cardiac surgery demonstrate high negative predictive values for postoperative bleeding, which supports early identification and targeted treatment of surgical bleeding by distinguishing it from a significant coagulopathy. The positive predictive values are small. The best predictors are thrombelastography values obtained after cardiopulmonary bypass.     

Platelet-monocyte pro-coagulant interactions in on-pump coronary surgery.

OBJECTIVE: Platelets and monocytes possess haemostatic properties, but the clinical effect of platelet-monocyte interactions on haemostasis following coronary surgery is not known. The study characterises the platelet and monocyte responses in cardiac surgery and its impact on haemostasis. METHODS: In 1342 patients, changes in white blood cell counts (WBC), monocyte counts and platelet counts were measured. PMC formation was analysed by flow-cytometry using monoclonal antibodies against pan-leucocyte marker CD45, monocyte marker CD14 and platelet marker CD42. TF expression was determined using monoclonal antibodies against, CD45, CD14 and human-TF. Continuous variables were expressed as mean+/-SD. Changes in monocyte and platelet counts over time were considered as repeated measures data, and analysed using Generalised Estimating Equations (GEE). Multivariate regression analysis was used to evaluate the effect of several factors on blood loss. RESULTS: A monocytosis occurs with on-pump coronary surgery, but is less pronounced than with off-pump surgery. No difference was seen in patients having redo-surgery or more complex cardiac surgery. Factors associated with monocytosis on multivariate analysis were higher body mass index (p=0.02), diabetes (p=0.035) and smoking (p=0.01). Older patients manifested a lower response (p<0.001). Cross-clamp fibrillation was associated with a lower (p=0.048) monocytic response than was cardioplegia. PMC formation dropped following administration of heparin, peaked at 5 min of CPB, and declined by 2h of CPB (p=0.04). A return towards preoperative levels was found during postoperative days 1-5. No significant change in monocyte TF expression occurred. The mean postoperative blood loss was 581.2+/-292.8 ml, and inversely related to increasing preoperative platelet counts (p<0.001), and to higher monocyte % counts (p=0.012). Patients, who were female (p<0.001), had higher body mass indices (p<0.001), and higher core body temperatures during surgery (p=0.013), as well as patients having perioperative aprotinin (p<0.001) related to less blood loss. CONCLUSIONS: A higher postoperative platelet count as well as monocyte% significantly and independently decreases postoperative blood loss following cardiac surgery.     

SMA circuits reduce platelet consumption and platelet factor release during cardiac surgery

Background. Platelet count and function are particularly damaged by cardiopulmonary bypass (CPB). This study evaluated the effects of a novel CPB circuit in terms of platelet count and activation, and postoperative need for blood products.

Methods. One hundred patients undergoing coronary grafting were randomized in two groups: control group (n = 50) and test group (n = 50, surface modifying additives circuit, SMA group). Blood samples were taken before, during, and after CPB. Postoperative blood loss, number of transfused blood products, and postoperative variables were recorded.

Results. The platelet count decreased less in the SMA group compared to the control group (end of CPB: respectively, 165 ± 9 × 10³/mm³ vs 137 ± 8 × 10³/mm³; p < 0.01). This was paralleled by a reduction in β-thromboglobulin plasma levels in the SMA group. There was a trend to decreased blood loss in the SMA group, but the difference was significant only in patients taking aspirin preoperatively (p < 0.05). In the SMA group nearly 50% less fresh frozen plasma and platelet units were administered (p < 0.01). No operative deaths were observed.

Conclusions. The use of circuits with surface additives is clinically safe, preserves platelet levels, and attenuates platelet activation. This may lead to a reduced need for blood products.     

Effect of autologous platelet-rich plasma (PRP) in cardiac surgery

Autologous platelet-rich plasma (PRP) was harvested before cardiopulmonary bypass (CPB). After heparin neutralization, it was returned to patients. The purpose of this study was to examine platelet function and the amount of blood loss and blood transfusion after transfusion of PRP. Twenty-eight patients undergoing elective coronary artery bypass grafting and other procedures were divided into three groups: group A; patients undergoing CAGB between May and October 1997 (n = 10), group B; patients undergoing other between May and October 1997 (n = 8), group C; patients undergoing CAGB before May 1997 (n = 10). Blood cell count, platelet aggregation in response to ADP, and platelet adhesion were measured before CPB, just after CPB, after infusion of protamine and PRP, 24 hrs after CPB and 48 hrs after CPB. Blood loss and blood transfusion in group. A and group C were examined after CPB. There was no significant difference in platelet count between group A and group B. There was significant difference in platelet aggregation in group A. There was no significant difference in blood loss after CPB between group A and group C, but there was a significant difference in blood transfusion between group A and group C. These results suggest that PRP was useful to preserve platelet function and to decrease blood loss after CPB in cardiac surgery.     

An analysis of risk factors of perioperative bleeding in surgical repair of abdominal aortic aneurysm

BACKGROUND: In surgical repair of abdominal aortic aneurysm (AAA), excessive bleeding which causes postoperative complications is sometimes observed. To determine the risk factors of perioperative excessive blood loss, this retrospective study was performed. METHODS: Design. A retrospective study. Setting. An academic medical center. Participants. One hundred and forty patients underwent elective surgical repair of an abdominal aortic aneurysm (AAA) at our institution from 1995 through 1997. Measurements. The present study includes critical review of 140 consecutive charts of patients undergoing elective surgical repair of AAA. Preoperative laboratory data, intraoperative data and amount of blood loss to identify risk factors of perioperative blood loss. Factors which were found to be significantly associated with the amount of perioperative blood loss were preoperative plasma fibrin degradation product (FDP) level (r=0.445), amount of immediate re-infusion of shed blood (r=0.438), and duration of operation (r=0.411). RESULTS: Preoperative fibrinogen level correlated with perioperative blood loss little (r=-0.187). Preoperative platelet count or the other coagulation profile did not affect the amount of perioperative blood loss. The patients whose preoperative FDP were more than 40 microg x ml(-1) significantly increased the risk of excessive blood loss compared with less than 40 microg x ml(-1). CONCLUSIONS: The significant preoperative risk factor of perioperative blood loss was only FDP level in present study. Especially, the patients whose preoperative FDP were more than 40 microg x ml(-1) increased the risk of excessive blood loss.     

A trial of fresh autologous whole blood to treat dilutional coagulopathy following cardiopulmonary bypass in infants

BACKGROUND: Transfusion of fresh whole blood is superior to blood component therapy in correcting coagulopathies in children following cardiopulmonary bypass (CPB); however, a supply of fresh homologous whole blood is difficult to maintain. We hypothesized that transfusion of fresh autologous whole blood obtained prior to heparinization for CPB and infused following CPB would be associated with improved coagulation function when compared with standard therapy. METHODS: A total of 32 infants 5-12 kg undergoing noncomplex open cardiac surgery were randomly assigned to either the treatment or control group. In the treatment group, 15 ml x kg(-1) of autologous whole blood was collected into a CPDA bag prior to heparinization while 15 ml x kg(-1) of 5% albumin was infused intravenously. After reversal of heparin, coagulation tests were drawn in both groups, and the autologous whole blood was infused over 20 min in the treatment group. RESULTS: The treatment group had greater (P < 0.05) improvement in platelet count, prothrombin time, and fibrinogen than the control group. CONCLUSIONS: We conclude that collection of fresh autologous whole blood prior to heparinization and reinfusion following CPB is associated with greater improvement of coagulation status after CPB in infants.     

急性等容血液稀释用于心血管外科血液保护的效果

目的 比较急性等容血液稀释(ANH)联合术中血液回收与单纯术中血液回收用于心血管外科血液保护的临床效果。方法 将术前血红蛋白Hb≥130g/L的心血管外科成年病人140例随机分成两组:A+C组,ANH联合术中血液回收(ANH量 8～12ml/kg,n=70);C组,术中单纯血液回收(n=70)。分别记录两组病人术前及术后24h血红蛋白(Hb)、血球压积(HCT)、血小板(PLT);回收血量;体外循环(CPB)总转流时间;术后24h引流量;全血用量;血浆用量;悬浮红细胞用量;冷沉淀用量;血小板用量和总住院时间。结果 两组病人一般情况无显著差异,术前各实验室指标无显著差异;A+C组术中血液回收量(581.8±28.2)ml少于C组(785.4±43.8)ml,有显著差异(P<0.001);A+C组术后24hHb(122.2±18.8)g/l高于C组(112.3±15.6)g/l,有显著差异(P<0.01),HCT(35.2±5.5)高于C组(33.2±4.5),亦有显著差异(P<0.05);A+C组全血用量(81.7±23.0)ml少于C组(217.4±35.7)ml,有显著差异(P<0.01)A+C组有15例,C组有6例未输异体血;两组间CPB时间、总住院时间及其它血制品用量无显著差异。结论ANH联合术中血液回收比较术中单纯血液回收用于心血管外科血液保护可减少异体血需要及用量,值得推广。     

Clinical Experience with the Nikkiso Centrifugal Pump

Abstract: The Nikkiso HPM-15 is a minimally sized centrifugal pump. Preliminary results regarding clinical use of this pump for cardiopulmonary bypass (CPB) procedures have been reported previously. Recently, we have managed some additional cases using a newly developed controller. This article reports our clinical experiences with the use of this pump. We have managed 23 cases with a Nikkiso centrifugal pump. Twenty-two patients underwent CPB and 1 patient with fulminant viral myocarditis underwent percutaneous cardiopulmonary support (PCPS). With this pump, the circuit was extremely easy to prepare and deaeration was achieved readily. Hemodynamics during CPB and PCPS were stable in all cases. The increase in serum-free hemoglobin levels during CPB with this pump was as low as that seen in preliminary tests. A decrease in the platelet count was observed after the initiation of CPB with this pump; however, platelet counts returned to preoperative values 7 days after surgery. Moreover, urine output during CPB with this pump was as high as that seen in preliminary tests. No abnormalities in renal or liver function occurred during CPB. It appears that this new centrifugal pump is safe and easy to operate, and we conclude that it is useful for CPB and PCPS.