Blood usage in lung transplantation

BACKGROUND: Few published data are available regarding perioperative blood usage in lung transplantation. STUDY DESIGN AND METHODS: The medical records of all patients undergoing lung transplantation at a university medical center in 1994 and 1995 were reviewed. RESULTS: Ninety patients underwent lung transplantation during this period. Six patients were excluded: two received a living related-donor lung, three underwent retransplantation and one underwent concomitant repair of a tetralogy of Fallot. Of the 84 evaluable patients, 59 underwent single lung transplantation and 25 double lung transplantation. Double-lung recipients used more red cells (6.4 vs. 1.7 units, p = 0.0002) and were more likely to receive red cells, platelets, plasma, or any component (92 vs. 32%, p< or =0.0001) than were single-lung recipients. Double- lung recipients were more likely to require cardiopulmonary bypass (40 vs. 12%, p = 0.003), and cardiopulmonary bypass was associated with greater transfusion requirements (p< or =0.0001). However, among patients requiring cardiopulmonary bypass, blood use did not differ between those undergoing double lung transplantation and those undergoing single lung transplantation. In the subset of patients not requiring cardiopulmonary bypass, double-lung recipients received more red cells (4.5 vs. 0.7 units, p< or =0.0001) and more plasma (2.0 vs. 0.2 units, p = 0.006). CONCLUSION: Double-lung recipients require more perioperative transfusions than single-lung recipients. The greater transfusion requirement is due to the more frequent need for cardiopulmonary bypass as well as the greater complexity of the procedure. These data are useful for developing surgical blood ordering guidelines for lung transplantation.     

A multivariable model for predicting the need for blood transfusion in patients undergoing first-time elective coronary bypass graft surgery

BACKGROUND: The incidence of blood transfusion in coronary artery bypass graft (CABG) surgery remains high. Preoperative identification of those at high risk for requiring blood will allow for the cost-effective use of some blood conservation modalities. Multivariable analysis techniques were used in this study to develop a prediction rule for such a purpose. STUDY DESIGN AND METHODS: Data were prospectively collected for all patients undergoing elective first-time CABG surgery from January 1997 to September 1998 at a tertiary-care teaching hospital (n = 1007). The prediction rule was developed on the first two-thirds of the sample by using logistic regression methods to examine the relationship of patient demographics, comorbidities, and preoperative Hb with perioperative blood transfusion. The remaining one-third of the sample was used to validate the rule. RESULTS: The transfusion rate was 29.4 percent. The prediction rule included preoperative Hb (g/dL, OR 0.928, p<0.0001), weight (kg, OR 0.938, p<0.0001), age (years, OR 1.037, p<0.01), and sex (male/female, OR 0.493, p<0.01); receiver operating characteristic = 0.86. When externally validated, the rule had a sensitivity of 82.1 percent and a specificity of 63.6 percent (at a selected probability cutoff). CONCLUSION: A simple and valid prediction rule is developed for predicting the risk of blood transfusion in patients undergoing first-time elective CABG surgery.     

Blood use in elective surgery: the Austrian benchmark study

BACKGROUND: Benchmarking transfusion activity may help to eliminate inappropriate use of blood products. The goal of this study was to measure and to compare the current transfusion practice and to identify predictors of transfusion in public hospitals to develop strategies to optimize transfusion practices. STUDY DESIGN AND METHODS: This was a prospective observational study in 18 randomly selected public hospitals from April 2004 to February 2005. Primary outcome measures were the amount of intra- and postoperative blood components transfused and intercenter variability of transfusion rate. Secondary outcome measures were prevalence of preoperative anemia, calculated perioperative blood loss, and lowest measured perioperative hemoglobin (Hb) level. RESULTS: Adult patients undergoing primary unilateral total hip replacement (THR, n = 1401), primary unilateral knee replacement (TKR, n = 1296), hemicolectomy (HECOC, n = 148), and coronary artery bypass graft (CABG) surgery (n = 777) were enrolled. Due to the small number, data of HECOC patients were not fully analyzed. In the remaining procedures, there was a large intercenter variability in the percentage of patients who received transfusions: THR 16 to 85 percent, TKR 12 to 87 percent, and CABG 37 to 63 percent. In the patients who received transfusions, the number of red blood cells (RBC) units transfused varied significantly. There was also a considerable intercenter variability in RBC loss. The prevalence of preoperative anemia was 19 percent and identical in both sexes. The incidence of preoperative anemia was three times higher in patients who received transfusions compared to those who did not. CONCLUSION: This study demonstrates a high intercenter variability in RBC transfusions and RBC loss in standard surgical procedures. Whereas the variability in blood loss remains largely unexplained, the main predictors for allogeneic RBC transfusions are preoperative and nadir Hb and surgical RBC loss.     

Plasma fibrinogen level, bleeding, and transfusion after on-pump coronary artery bypass grafting surgery: a prospective observational study

BACKGROUND: Early identification of patients with increased risk of excessive bleeding and transfusion after cardiac surgery offers the possibility to initiate countermeasures. Fibrinogen is a key protein in the coagulation cascade and thus a potential biomarker for bleeding. We investigated the relationship between preoperative fibrinogen plasma concentration and postoperative bleeding and transfusion after coronary artery bypass grafting (CABG). STUDY DESIGN AND METHODS: A total of 170 patients (mean age, 67 ± 9 years; 75% men) undergoing isolated CABG were included in a prospective observational study. Patient variables (age, sex, operation time, anticoagulation therapy), preoperative laboratory variables (platelet [PLT] count, activated partial thromboplastin time, prothrombin time, and fibrinogen), postoperative bleeding volume, and transfusions during hospital stay were registered. Independent predictors of bleeding volume and transfusion were identified with multiple regression models. RESULTS: Postoperative bleeding volume correlated univariately with preoperative fibrinogen concentration (r = ?0.53, p < 0.001) and PLT count (r = ?0.26, p = 0.001) but only preoperative fibrinogen concentration was an independent predictor of postoperative bleeding volume. Twenty‐nine of the 170 patients (17%) received transfusions with blood products. Independent predictors of transfusion were preoperative fibrinogen concentration (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.1‐3.7 per 1‐unit decrease; p = 0.027), female sex (OR, 5.0; 95% CI, 1.8‐14.7; p = 0.002), and aortic cross‐clamp time (OR, 1.03; 95% CI, 1.01‐1.06 per minute; p = 0.013). CONCLUSION: The results indicate that preoperative fibrinogen concentration (even within the normal range) is a limiting factor for postoperative hemostasis. Preoperative measurement of fibrinogen concentration provides information about bleeding volume and transfusion requirements after CABG.     

Clinical outcomes of on-pump coronary bypass using heparin-bonded circuits and reduced anti-coagulation compare favorably with off-pump approach

Coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB), or off pump, has gained popularity by avoiding the postoperative morbidity related to the use of CPB. Previously, we have demonstrated that CABG done on pump using heparin-bonded cardiopulmonary bypass circuits (HBC) with a lower anti-coagulation protocol (LAP) attenuates these effects, reduces homologous blood product requirement, and improves clinical outcome when compared with conventional CPB circuits. Our purpose in this study was to compare off-pump CABG clinical outcomes to on-pump CABG using HBC with LAP. We retrospectively analysed preoperative and postoperative variables of all primary CABG (n=1214) performed at this institution from 1 January 1997 to 28 July 2000. These patients were divided into the on-pump (n=1152) and off-pump groups (n=62). HBC with LAP were used in all on-pump CABG cases. There was no statistical difference in preoperative comorbid risk factors except percentage of females (on pump, 30% vs. off pump, 44%; p=0.02) and body surface area (on pump, 1.94 +/- 0.25 ml vs. off pump, 1.85 +/- 0.22 ml; p=0.02). There was no difference in intraoperative and postoperative complications, risk-adjusted mortality, total blood product usage, or length of stay. The mean number of distal anastomoses performed was significantly different (on pump, 3.5 +/- 0.82 vs. off pump 1.8 +/- 0.82; p < 0.001). Despite similar preoperative risk factors, clinical outcomes and homologous blood requirements were not statistically different between the off-pump and on-pump groups. These endpoints should not be the only criteria to justify performing off-pump CABG.     

Outcome analysis of coronary artery bypass grafting: minimally invasive versus standard techniques

Minimally invasive coronary artery bypass grafting (MIDCAB) procedures are purported to result in improvements in patient management over standard techniques. A comparative study was performed on risk-stratified patients treated with either technique. Following institutional review board approval, a retrospective random chart review was conducted on 27 MIDCAB and 37 standard coronary artery bypass grafting (CABG) patients who were operated on over a 12-month period at the University of Nebraska Medical Center. Risk stratification was accomplished by dividing the two patient populations, MIDCAB and 'standard', into one of four subgroups based on a preoperative risk score. Risk stratification was achieved by dividing the patient populations into one of four subgroups: good, fair, poor and high risk. Both groups received similar operations and surgical interventions, except for the inclusion of cardiopulmonary bypass (CPB). Approximately 200 parameters were collected and analyzed in the following categories: anthropometric, operative and postoperative outcomes. The MIDCAB group had a significantly lower number of vessels bypassed (2.0+/-0.7 vs 3.4+/-0.9, p < 0.0001). Total postoperative blood product transfusions trended higher in the standard group (6.1+/-12.6 U) when compared to the MIDCAB patients (2.3+/-5.5 U, p < 0.15), although not statistically significant. Postoperative inotrope use was significantly less in the MIDCAB group (19% vs 59%, p < 0.002). Ventilator time in the MIDCAB group was 10.5+/-5.4 h vs 15.0+/-12.3 h in the standard group (p < 0.07). The MIDCAB group had an overall greater length of stay, but was only statistically different within the poor-risk subgroup (12.2+/-10.7 vs 7.5+/-3.9, p < 0.04). The results of this study show that when CPB is not utilized in treating patients undergoing CABG procedures, the benefits in regards to patient outcomes are unclear. This necessitates the need for further work when comparing outcomes for risk-stratified patients.     

Factors associated with the avoidance of red blood cell transfusion after hematopoietic stem cell transplantation

BACKGROUND: Red blood cell (RBC) transfusion is required frequently for most patients after hematopoietic stem cell transplantation (HSCT). RBC transfusion, however, can be associated with adverse events including transfusion reactions, acquiring transmissible disease, and delayed recovery. Factors associated with avoidance of transfusion are not well documented. STUDY DESIGN AND METHODS: Data concerning RBC transfusions between Day 0 and Day +30 were analyzed for patients undergoing HSCT at a single Canadian transplant center between January 2002 and December 2007. RESULTS: Of 555 patients undergoing HSCT with complete RBC transfusion data, 59 patients (10.6%) did not require RBC transfusion in the first 30 days after HSCT. Univariate analysis showed no significant difference in age, graft source, donor type, or conditioning regimen between transfused and nontransfused patients. Factors that were significantly associated with avoidance of transfusion included male sex (p = 0.0013), diagnosis, specifically plasma cell dyscrasias (p < 0.0001), early‐stage disease (p = 0.006), and higher baseline hemoglobin (Hb) at time of transplant (p < 0.0001). In multivariate analysis, higher pretransplant Hb, male sex, and early‐stage disease remained significantly associated with avoidance of RBC transfusion. Pretransplant Hb correlated inversely with the number of RBC transfusions (r = ?0.89). CONCLUSION: Increased pretransplant Hb, male sex, and early‐stage disease are associated with avoidance of RBC transfusion after HSCT. Interventions aimed at improving pretransplant Hb levels require further study.     

A randomized trial comparing acute normovolemic hemodilution and preoperative autologous blood donation in total hip arthroplasty

BACKGROUND: The value of acute normovolemic hemodilution (ANH) as compared to preoperative autologous blood donation (PABD) in orthopedic surgery is unknown. Therefore, a prospective, randomized study was conducted to compare these techniques in patients undergoing primary total hip arthroplasty. STUDY DESIGN AND METHODS: ANH patients underwent phlebotomy for up to 3 units, or to a target Hct level of 28 percent after induction of anesthesia. PABD patients were asked to donate up to 3 units before admission. RESULTS: Mean baseline Hct levels were not different in ANH and PABD patients (39. 7 +/- 4.5 vs. 41.8 +/- 3.8%, p = 0.09). No difference was found in allogeneic blood exposure among ANH and PABD cohorts: 4 (17%) of 23 ANH patients received a total of 9 allogeneic blood units, compared to no allogeneic transfusions in the PABD cohort (p = 0.30). Total blood costs associated with ANH were significantly (p<0.05) lower than blood costs associated with PABD ($151 +/- 154 vs. $680 +/- 253, respectively). CONCLUSION: In patients undergoing total hip arthroplasty, ANH is safe, can be considered equivalent to PABD in effectively reducing exposure to allogeneic RBCs, and is less costly than PABD.     

Cerebral Hemodynamics during Coronary Artery Bypass Graft Surgery: The Effect of Carotid Stenosis

Carotid stenosis is a frequent coexisting condition in patients undergoing coronary artery bypass graft (CABG) surgery. The impact of carotid stenosis on cerebral perfusion is not fully understood. The purpose of this study was to determine the impact of carotid stenosis on cerebral blood flow velocity in patients undergoing CABG. Seventy-three patients undergoing CABG were prospectively recruited and underwent preoperative Duplex carotid ultrasound to evaluate the degree of carotid stenosis. Intraoperatively, transcranial Doppler ultrasound was used to record the mean flow velocity (MFV) within the bilateral middle cerebral arteries. In addition, during the period of cardiopulmonary bypass, regulators of cerebral hemodynamics such as hematocrit, partial pressure of carbon dioxide and temperature were recorded. The ipsilateral middle cerebral artery mean flow velocity was compared in arteries with and without carotid stenosis using a repeated measures analysis. Seventy-three patients underwent intraoperative monitoring during CABG and 30% (n = 22) had carotid stenosis. Overall, MFV rose throughout the duration of CABG including when the patient was on cardiopulmonary bypass. However, there was no significant MFV difference between those arteries with and without stenosis (F = 1.2, p = .21). Further analysis during cardiopulmonary bypass, demonstrated that hemodilution and partial pressure of carbon dioxide may play a role in cerebral autoregulation during CABG. Carotid stenosis did not impact mean cerebral blood flow velocity during CABG. The cerebrovascular regulatory process appears to be largely intact during CABG.     

Soluble ST2 protein in cardiac surgery: a possible negative feedback loop to prevent uncontrolled inflammatory reactions

BACKGROUND: Recent reports have demonstrated that cardiopulmonary bypass (CBP) utilization leads to a TH2 cytokine bias in patients undergoing coronary artery bypass grafting (CABG) operation. The relation of soluble ST2 and secretion of IL-10, markers of TH2 T-cell activation, and IL-13 in relation to immunoglobulin isotope production is not known in patients undergoing On- versus Off-pump (CABG) procedure. METHODS: 30 patients were prospectively included in the study (On- vs Off-pump CABG, each n = 15). Serum samples were obtained prior to, and 30 min, 60 min and 24hrs after operation. ELISA was utilized to detect sST2 and IL-10, IL-13 and immunoglobulin isotype production. RESULTS: In both cohorts we could demonstrate a significant rise of ST2 24 hours after the CABG procedure. In the On-pump group ST2 levels (pg/ml) before the operation, at 30 and 60 minutes and after 24 hours were 115.3 +/- 25, 71.2 +/- 15, 114.1 +/- 26 and 4231.9 +/- 520, respectively. In the Off-pump group they were 200.3 +/- 109, 91.2 +/- 20, 137 +/- 29 and 4144.9 +/- 488 (both, p < 0.0001, p < 0.0001, respectively). IL-10 (pg/ml) levels rose from preoperative values of 6.2 +/- 1.6 in the On-pump group and 7.91 +/- 1.8 in the Off-pump group to 33.14 +/- 8.7 and 13.72 +/- 3 after 60 minutes (p 0.0189, p 0.0397, respectively). IL-13 levels and immunoglobulin production did not change significantly within the study period irrespective of the operation procedure used. CONCLUSION: In conclusion, our results demonstrate that sST2 and IL-10, markers of TH2 cytokine producing cells, are increased in CABG operation, irrespective of the procedure selected, and settles a longstanding controversy concerning the shift from Th1 to Th2 cells.     

Anemia-induced increase in the bleeding time: implications for treatment of nonsurgical blood loss

BACKGROUND: Preoperative bleeding time (BT) does not correlate with postoperative bleeding in patients subjected to surgical procedures. A significant positive correlation has been reported between the BT 2 hours after cardiopulmonary bypass surgery and the nonsurgical blood loss during the first 4 hours after bypass surgery. This study was done to investigate the effect of Hct and platelet count on the BT measurement in normal, healthy men and women. STUDY DESIGN AND METHODS: To assess the relative effect of RBCs and platelets on the BT, 22 healthy male and 7 healthy female volunteers were subjected to the removal of 2 units of RBCs (360 mL), followed by the return of the platelet-rich plasma (PRP) from both units and the infusion of 1000 mL of 0.9-percent NaCl. Four of the men and all seven women received their RBCs 1 hour after their removal. Shed blood levels of thromboxane B(2) (TXB(2)), 6-keto prostaglandin F(1 alpha), and peripheral venous Hct were measured. BTs were measured in 15 men and 13 women before and after a plateletpheresis procedure to collect 3.6 x 10(11) platelets per unit. RESULTS: The 2-unit RBC apheresis procedure produced a 60-percent increase in the BT associated with a 15-percent reduction in the peripheral venous Hct and a 9-percent reduction in the platelet count. The plateletpheresis procedure produced a 32-percent decrease in the platelet count, no change in peripheral venous Hct, and no change in the BT. After the removal of 2 units of RBCs, the shed blood TXB(2) level decreased significantly. Reinfusion of 2 units of RBCs restored the BT and restored the TXB(2) level to the baseline levels. CONCLUSION: The acute reduction in Hct produced a reversible platelet dysfunction manifested by an increase in BT and a decrease in the shed blood TXB(2) level at the template BT site. Return of the RBCs restored both the BT and the shed blood TXB(2) level to normal. The platelet dysfunction observed with the reduction in Hct was due in part to a reduction in shed blood TXB(2) and other, unknown mechanisms.     

Experience of a network of transfusion coordinators for blood conservation (Ontario Transfusion Coordinators [ONTraC])

BACKGROUND: The experiences of the development of a provincial program to promote blood conservation are herein reported. STUDY DESIGN AND METHODS: Transfusion coordinators were placed in 23 Ontario hospitals. Anonymized laboratory and clinical information was collected in a defined number of all consecutive patients admitted for three designated procedures: knee arthroplasty, abdominal aortic aneurysm (AAA), and coronary artery bypass graft (CABG) surgery (n approximately 1100, 300, and 300 at each time period, respectively). RESULTS: Considerable interinstitutional variation was observed in the proportion of patients who received transfusions. At 12 months, and over the 24-month period of the project, most hospitals demonstrated decreased use of allogeneic blood; at 12 months an approximate 24 percent reduction in patients undergoing knee surgery, 14 percent in AAA, and 23 percent in CABG was obtained. In addition, patients who received transfusions received less allogeneic blood. Patients who did not receive allogeneic transfusions had lower postoperative infection rates (p < 0.05) and length of stay (p < 0.0001); allogeneic transfusion was an independent predictor of increased length of stay. The main blood conservation measures employed during this time were education, preoperative autologous donation, erythropoietin, and cell salvage. CONCLUSION: The implementation of a provincial network of transfusion coordinators was feasible and allogeneic transfusion rates declined over the period the program has been in place.     

Highly positive intraoperative fluid balance during cardiac surgery is associated with adverse outcome

Hemodilution and increase in capillary permeability occurring with cardiopulmonary bypass (CPB) impose a risk for tissue edema and blood transfusion that may result in an increased complication rate after coronary artery bypass grafting (CABG). Of the 1280 consecutive patients undergoing isolated on-pump CABG, total fluid balance at the end of the operation was less than or equal to 500 mL in 1155 (Group 1) and more than 500 mL in 125 (Group 2). During CPB, blood was added to the reservoir only when the hematocrit fell to 17% or less and crystalloid solution only when the pump flow index fell below 2.0 L/min/m2. Anesthetic, surgical, and postoperative management and diagnoses were the same in all patients, and a single surgical and anesthesia team performed all operations. No patient was excluded from the study. Results: Hypertension, diabetes, chronic obstructive pulmonary disease, New York Heart Association (NYHA) Class III-IV, use of angiotensin converting enzyme (ACE) inhibitors, chronic renal failure, and female gender were the significant preoperative risk factors for increased volume replacement during CPB. The groups were similar in body mass index, preoperative hematocrit values, total fluid balance in the intensive care unit (ICU), and total chest tube output. However, red blood cells' transfusion rate, readmission rate to the ICU and length of hospital stay were significantly higher in Group 2 patients. Multiple logistic regression revealed that age > 70 years (p < 0.001, Odds Ratio (OR): 2, 95% CI: 1.4-2.8), and total fluid balance > 500 mL at the end of the operation (p < 0.01, OR: 2.2, 95% CI: 1.5-3.2) were the predictors of increased length of stay. For transfusion of red blood cells, age > 70 years (p < 0.0001, OR: 2.3, 95% CI: 1.6-3.3), and total fluid balance > 500 mL at the end of the operation (p < 0.001, OR: 2, 95% CI: 1.3-2.9) were the only significant risk factors. This study suggests that intraoperative volume overload increases blood transfusion and length of hospital stay in patients undergoing CABG.     

前蛙跳式自体预贮血在猪心脏体外循环手术模型中的应用

背景:同种异体输血在相同血型的人类中已经得到实现,但关于猪的血型类型及如何异体输血国内外无确切报道.目的:探讨术前蛙跳式自体预贮血在猪心脏体外循环手术模型中应用的可行性.方法:16只家猪随机区组法分为2组,自体预贮血组、同种异体输血组.另4头猪放血供同种异体输血组异体输血应用.两组猪均在体外循环下行心脏手术.自体预贮血组手术全程仅输自体血,同种异体输血组手术全程输注等量异体血.记录自体预贮血组放血前后的血红蛋白及血细胞压积,两组术前基础值、体外循环过程中、体外循环结束后及术后1 d的血红蛋白值.结果与结论:20只实验猪全身血容量 (2500±428) mL;自体预贮血组第1次预计放血量为(501±86) mL,实际放血量为(493±93) mL;第2次预计放血量为(750± 128) mL,实际放血量为(719±98) mL.自体预贮血组猪采血前后血红蛋白计数及血细胞压积差异有显著性意义(P < 0.01).自体预贮血组术后1 d时点血红蛋白数值明显高于同种异体输血组(P < 0.01),两组其余术前基础值、体外循环过程中、体外循环结束后时点血红蛋白数值差异无显著性意义(P > 0.05);与术前比较,两组术后1 d时点血红蛋白值显著低于术前基础值 (P < 0.01).自体预贮血组存活率明显高于同种异体输血组(P < 0.01).结果说明与同种异体输血相比,术前蛙跳式自体预贮血安全有效,术后猪成活率更高.

Abstract：

BACKGROUND: Allogeneic blood transfusion in humans of the same blood type has been implemented, but studies regarding swine blood type and how to perform allogeneic blood transfusion have been rarely reported. OBJECTIVE: To investigate the feasibility of preoperative autologous blood donation using the leap-frog technique for cardiopulmonary bypass surgery in a swine model.METHODS: Sixteen domestic swine were randomly divided into two groups: autologous blood donation and allogeneic blood transfusion. Another four swine were used as blood donors. Two groups of swine underwent cardiopulmonary bypass surgery. The autologous blood donation group received self-transfusion reserved before surgery while the allogeneic blood transfusion group received the same amount of allogeneic blood. Hemoglobin (Hb) concentration and hematocrit (Hct) level prior to and after donation in the autologous blood donation group was recorded. Hb concentration in the two groups was recorded prior to, during, immediately after, and 1 day after the surgery. RESULTS AND CONCLUSION: The total blood volume of each experimental swine was (2500±428) mL. For the autologous blood donation group, the predicted blood volume of the first donation was (501±86) mL and the actual blood volume was (493±93) mL; in the second donation, the predicted blood volume was (750±128) mL and the actual blood volume was (719±98) mL. There was a significant difference in Hb concentration and Hct level between prior to and after donation in the autologous blood donation group (P < 0.01). Hb concentration at 1 day after the surgery was significantly higher in the autologous blood donation group than in the allogeneic blood transfusion group (P < 0.01), while no significant difference in Hb concentration existed between these two groups prior to, during, and immediately after the surgery (P > 0.05). Compared with prior to surgery, Hb concentration in each group was significantly lower at 1 day after the surgery (P < 0.01). The autologous blood donation group exhibited significantly higher survival rate of swine than the allogeneic blood transfusion group (P < 0.01). These findings indicate that compared with allogeneic blood transfusion, preoperative autologous blood donation using the leap-frog technique appears to be a safe, effective method with a high survival rate for cardiopulmonary bypass surgery.     

Transfusion requirements in elective cardiopulmonary bypass surgery patients: predictive value of Multiplate and Thromboelastography (TEG) Platelet Mapping Assay

Managing haemostasis in patients undergoing cardiopulmonary bypass (CPB) surgery remains a challenge. There is no established laboratory test to predict transfusion requirements in cardiac surgery. We investigated whether preoperative Thromboelastography (TEG) with Platelet Mapping Assay (PMA) or Multiple Electrode Aggrometry (MEA) could predict transfusion requirements in patients undergoing elective coronary artery bypass grafting (CABG) or combined CABG with aortic or mitral valve replacement. We prospectively investigated 199 patients undergoing elective CABG or combined procedures. PMA and MEA were performed at baseline (after anaesthesia induction), upon arrival at the intensive care unit and on the first postoperative day. Patients receiving fresh frozen plasma and/or platelets (FFP/PLT) had a lower PMA maximum amplitude (MA) for adenosine diphosphate (PMA-ADP) and arachidonic acid (PMA-AA) at baseline, at arrival in the intensive care unit and the first postoperative day compared to non-transfused patients. Receiver operating characteristic curves on PMA showed that lower values predicted FFP/PLT transfusion: PMA-ActF 0.64 (p?=?0.04), PMA-ADP 0.69 (p?=?0.01) and PMA-AA 0.71 (p?=?0.002). In contrast, MEA values were not able to predict FFP/PLT transfusions. This study shows that preoperative PMA potentially is a better screening tool for platelet inhibition associated with transfusion requirements in patients undergoing CABG or combined procedures.     

Blood transfusions recruit the microcirculation during cardiac surgery

BACKGROUND: Perioperative red blood cell transfusions are commonly used in patients undergoing cardiac surgery to correct anemia caused by blood loss and hemodilution associated with cardiopulmonary bypass circulation. The aim of this investigation was to test the hypothesis that blood transfusion has beneficial effects on sublingual microcirculatory density, perfusion, and oxygenation. To this end, sidestream dark field (SDF) imaging and spectrophotometry were applied sublingually before and after blood transfusion during cardiac surgery. STUDY DESIGN AND METHODS: Twenty‐four adult patients undergoing on‐pump cardiac surgery, including coronary artery bypass grafting, cardiac‐valve surgery, or a combination of these two procedures, were included consecutively in this prospective, observational study. Sublingual microcirculatory density and perfusion were assessed using SDF imaging in 12 patients (Group A). Sublingual reflectance spectrophotometry was applied in 12 patients (Group B) to monitor microcirculatory oxygenation and hemoglobin (Hb) concentration. RESULTS: Blood transfusion caused an increase in systemic Hb concentration (p < 0.01) and hematocrit (p < 0.01). At the microcirculatory level, blood transfusion resulted in increased microcirculatory density (from 10.5 ± 1.2 to 12.9 ± 1.2 mm capillary/mm² tissue, p < 0.01) as shown using SDF imaging. In concert with the SDF measurements, spectrophotometry showed that microcirculatory Hb content increased from 61.4 ± 5.9 to 70.0 ± 4.7 AU (p < 0.01) and that microcirculatory Hb oxygen saturation increased from 65.6 ± 8.3% to 68.6 ± 8.4% (p = 0.06). CONCLUSION: In this study we have shown that blood transfusion: 1) improves the systemic circulation and oxygen‐carrying capacity, 2) improves sublingual microcirculatory density but not perfusion velocity, and 3) improves microcirculatory oxygen saturation.     

Oxidative injury and antioxidants in coronary artery bypass graft surgery: off-pump CABG significantly reduces oxidative stress

BACKGROUND: Coronary artery bypass grafting (CABG) can now be performed with or without cardiopulmonary bypass. The former entails global ischemia followed by reperfusion after declamping, whereas the latter does not. In view of growing evidence that reperfusion is associated with oxidative stress, we studied the extent of oxidative stress and antioxidant status in patients undergoing on-pump and off-pump CABG to determine whether the latter significantly reduces oxidative stress. METHODS: Thirty patients were initially enrolled for the study. The inclusion criteria included patients with atherosclerotic triple vessel disease, undergoing elective CABG, with good LV function, no major risk factors for surgery, with all biochemical investigations within normal limits, having stable angina and no history of previous infarct. Patients with valvular heart disease, ventricular aneurysm, heart failure and poor left ventricular function were excluded. These were alternately posted for on-pump and off-pump CABG. Eight patients were excluded as they developed unforeseen complications during the surgery. Out of the remaining 22 patients, 13 underwent off-pump CABG and 9 underwent on-pump CABG. Five blood samples were collected; baseline, 5, 15, 60 min and 24 h after reperfusion. Samples were analyzed for thiobarbituric acid reactive substances (TBARS), glutathione (G-SH) and catalase (CAT). The results were compared with their preanaesthetic levels in both the groups and also with 20 age- and sex-matched normal healthy individuals. RESULTS: Lipid peroxidation was significantly increased after reperfusion in patients undergoing on-pump CABG, maximum increase (p<0.0001) was seen 1 h after reperfusion, whereas off-pump CABG reduces oxidative stress. The G-SH levels were significantly decreased after reperfusion in on-pump and off-pump CABG patients, maximum decrease (p<0.0001) was seen 5 min after reperfusion in on-pump CABG. The catalase activity was significantly increased after reperfusion in on-pump and off-pump CABG patients, maximum increase (p<0.0001) was seen 1 h after reperfusion in on-pump CABG. CONCLUSION: Significant increase in oxidative stress was seen in patients undergoing on-pump CABG, whereas oxidative stress was less in off-pump CABG patients. The G-SH levels were decreased and Catalase activity was increased significantly in both on-pump and off-pump CABG patients.     

体外循环手术中血小板单采对血液的保护作用

目的　探讨在体外循环心脏手术中血小板单采对血液的保护作用 ;方法　选择 2 0例行心脏瓣膜手术患者 ,随机分为实验组和对照组 ,实验组采用血小板单采技术 +常规体外循环 ,对照组只采用常规体外循环 ,其他血液保护措施两组相同 ;结果　①实验组血小板采集量均在患者血小板总数的 2 0 %以上 ;②实验组术中血液制品 (全血和血浆 )用量较对照组明显减少 ,差异有显著性 ;③两组间Hb及Hct各时点变化趋势一致 ;④围手术期患者血小板计数的动态变化两组差异不大 ,而实验组恢复较快 ;⑤实验组术后血小板聚集功能明显优于对照组 ,差异有显著性 ;⑥实验组术后凝血酶原恢复时间明显较对照组快 ,差异有显著性 ;⑦实验组术后各分时段引流量较对照组明显减少 ,差异有显著性。结论　体外循环术中血小板单采能够保护血小板免遭体外循环的破坏 ,明显减少术后出血 ,起到良好的血液保护作用。     

Evaluation of oxygen extraction ratio as a physiologic transfusion trigger in coronary artery bypass graft surgery patients

BACKGROUND: Approximately 20 percent of all allogeneic blood transfusions are administered in connection with coronary artery bypass graft (CABG) operations. Transfusion practices vary across the country. The whole-body oxygen extraction ratio (O2 ER) reflects the adequacy of the patient's response to acute normovolemic anemia with an O2 ER of approximately 50 percent being shown to be an appropriate transfusion trigger. The present study monitored the O2 ER in patients undergoing CABG and determined if transfusion practices would have been different if an O2 ER > or = 45 percent were used as a transfusion trigger. STUDY DESIGN AND METHODS: Seventy patients with a postoperative Hct < = 25 percent were the test subjects. Arterial and mixed venous contents were determined before the operation, in the intensive care unit after the operation, and 12 hours after the operation. RESULTS: There were no deaths. Forty-one patients received allogeneic transfusion. These patients were older, weighed less, and had a preoperative Hct lower than the nontransfused patients. There were no significant differences between transfused and nontransfused patients with respect to postoperative Hct (21.0 +/- 0.4 vs. 22.2 +/- 0.4), cardiac index (2.5 +/- 0.1 vs. 2.7 +/- 0.1), O2 delivery (6.4 +/- 0.3 vs. 6.7 +/- 0.3), O2 consumption (2.5 +/- 0.1 vs. 2.5 +/- 0.1), and O2 ER (38.3 +/- 1.7 vs. 37.5 +/- 1.5). In the transfusion group, 7 of 21 patients had a postoperative O2 ER > or = 45 percent, while 3 of 35 in the nontransfused group had that result. CONCLUSION: The use of O2 ER as a transfusion trigger as part of a transfusion algorithm could lead to a reduction in allogeneic blood transfusion.     

A successful modification of ultrafiltration for cardiopulmonary bypass in children

Total body water (TBW) is increased after cardiopulmonary bypass (CPB) resulting in tissue oedema and organ dysfunction. Ultrafiltration has been used to reduce this accumulation of water, although conventional ultrafiltration seemed ineffective in reducing the rise in TBW after CPB in our clinical experience. We describe a modified technique in which ultrafiltration is performed in the first 10 minutes after the patient is weaned from bypass, returning nearly all the blood in the circuit to the patient and elevating the haematocrit (Hct) to any predetermined level. We carried out a pilot study on 21 children aged 4-144 months undergoing open-heart surgery and CPB for congenital heart defects. They were divided into three comparable groups: (1) controls (n = 6); (2) conventional ultrafiltration (n = 7); and (3) modified ultrafiltration (n = 8). TBW (bio-impedance), Hct, osmolality, mean corpuscular volume and mean corpuscular haemoglobin concentration were recorded at frequent intervals. Control patients showed elevation of TBW by 18.2% median (range 14.5-20.3), conventional ultrafiltration by 12.4% (7.9-15.0), modified ultrafiltration by 5.7% (4.5-7.1) (p less than 0.0001 compared to controls, p. less than 0.005 compared to conventional ultrafiltration, Mann-Whitney U test). Hct could be elevated to preoperative levels only by the modified method. Mean corpuscular volume, and mean corpuscular haemoglobin concentration osmolality were unaltered. Ultrafiltration by the modified method was more effective than conventional ultrafiltration in reducing the rise in TBW and elevating Hct after CPB.