Influence of early re-infusion of autologous shed mediastinal blood on clinical outcome after cardiac surgery.

Various strategies have been proposed to decrease allogeneic blood transfusion requirements after cardiac surgery. The aim of the study was to evaluate the efficacy of collected and re-infused autologous shed mediastinal blood on a patient's postoperative course. Ninety patients who underwent heart surgery with cardiopulmonary bypass (CPB) were studied. The patients were divided into two groups: Group 1 (n=41) received the centrifuged autologous shed mediastinal blood collected from the cardiotomy reservoir 4 hours after surgery; in Group 2 (n=49) all shed mediastinal blood was discarded (control group). Haemoglobin (Hb), haematocrit (Hct), C-reactive protein values, and leucocyte count were compared before surgery, at 4 h and 20 h after surgery, and on the fifth postoperative day. We have measured serum procalcitonin (PCT) concentration at 4 h and 20 h after CPB. We assessed drained blood loss within 20 postoperative hours. Leucocyte count, Hb, Hct values, C-reactive protein, and procalcitonin concentration did not differ between the groups before and at 4 h after surgery. Hb, Hct level, and leucocyte count were similar at 20 hours and on the fifth day after surgery. At 20 hours after surgery, an increase of serum PCT concentration (>0.5-2 ng/mL) was more frequent in Group 2 (58.3% vs. 33.3%; p = 0.03). On the fifth postoperative day, C-reactive protein concentration was lower in Group 1 (71.74 +/- 15.23; p <0.01) compared to Group 2 (93.53 +/- 20.3). Postoperative blood loss did not differ between the groups. Requirement for allogeneic blood transfusion was significantly lower in Group 1 (14.6% vs. 38.8%; p < 0.02). Patients in Group 1 developed less infective complications compared with Group 2 (2.4% and 16.3%, respectively; p < 0.05). The length of postoperative in-hospital stay was shorter in Group 1 compared with Group 2 (9.32 +/- 2.55 and 16.45 +/- 6.5, respectively; p < 0.05). We conclude that postoperative re-infusion of autologous red blood cells processed from shed mediastinal blood did not increase bleeding tendency and systemic inflammatory response and was effective in reducing the requirement for allogeneic transfusion, the rate of infective complications and the length of postoperative in-hospital stay.     

Size makes a difference: use of a low-prime cardiopulmonary bypass circuit and autologous priming in small adults

Low hematocrit (Hct < 20) during cardiopulmonary bypass (CPB) is associated with higher mortality and other adverse outcomes. More frequently, low Hct is encountered in patients with small body size and women patients. This prompted us to take an aggressive approach in our care of these patients, involving a strategy for predicting patients at risk of low Hct, with the aid of an electronic worksheet that accurately predicts CPB Hct, and two prevention strategies: use of a low-prime CPB circuit (LP) for all adult patients with a body surface area (BSA) < 1.7 m(2) and use of autologous circuit priming (AP), in addition to the low-circuit volume in some patients. The two cohorts of patients in whom these techniques were employed were compared to a group matched for body size where our standard adult circuit (STD) was used. There were 233 patients in the standard group, 139 in the LP group, and 68 in the LP/AP group. The CPB circuit prime volume was 1,710 ml for the STD group and 1,110 ml for the LP group. Use of autologous priming techniques further reduced the prime volume by 545 +/- 139 ml. The incidence of low Hct (<20%) during CPB was thus reduced from 70% to 15% (p = 0.001) when using both techniques together without increasing red blood cell (RBC) transfusions. These changes in perfusion management resulted in a reduction in the incidence of renal complications (STD = 9.4%, LP = 6.5% (ns) and LP/AP = 0%,     

Prospective study on cardiopulmonary bypass prime reduction and its effect on intraoperative blood product and hemoconcentrator use

PURPOSE: Evaluate the feasibility and clinical significance of crystalloid prime reduction during the initiation of cardiopulmonary bypass (CPB) using a modified bridge on the cardioplegia delivery system. METHODS: Prospective trial of crystalloid prime reduction using a standard Duraflow-coated CPB circuit and Vanguard 2:1 cardio plegia delivery system. Standard prime volume was 1500 cc of Plasmalyte. Prime was reduced via the bridge in the cardioplegia system during initiation of CPB. Packed red blood cells (PRBC) were transfused for hematocrit (Hct) less than 24% while rewarming. A hemoconcentrator was used if the patient's circulating blood volume exceeded 150% of calculated. All data were prospectively collected. RESULTS: Two hundred and twenty-two consecutive patients undergoing cardiac surgery utilizing CPB were evaluated. There were 107 patients with normal prime volume (NPV) and 115 patients with reduced prime volume (RPV). There was no significant difference in sex, mean age, weight, body surface area (BSA), pre-op Hct, procedure time or procedure between the two groups. There was no difference in total crystalloids infused by the anesthetists (average NPV 1205 cc versus RPV 1148 cc). The average RPV was 622 cc (range 400-1100 cc) or a 59% reduction. Post-op Hct revealed no difference (NPV 28% versus RPV 29%). There was a 24% reduction in patients requiring PRBC (NPV n=23 versus RPV n=18). The use of hemoconcentrators was reduced by 49% (NPV n=18 versus RPV n =11). The average urine output for both groups exceeded 100 cc/hour while on CPB. CONCLUSION: Using a modified cardioplegia delivery system is a safe and effective method of CPB prime reduction. A RPV resulted in fewer patients requiring PRBC transfusions and fewer hemoconcentrators used. Based on our experience, we would recommend attempting to reduce prime volume in all patients undergoing CPB.     

自体血逆预充在婴儿体外循环中的应用

目的将逆行自体血液预充(RAP)应用于婴儿体外循环(CPB)中,以降低婴儿围手术期异体血输入量。方法 160名婴儿先天性心脏病患者随机分为实验组和对照组,每组各80例,实验组在CPB开始前行RAP置换液量(47.1±10.9)mL,对照组不做RAP,通过计算在CPB预充液中加入异体血,维持CPB中Hct 25%。分别监测2组患儿CPB前(T1)、CPB开始15 min(T2)、CPB停止后(T3)及术后24 h的Hct、乳酸(Lac)、静脉血氧饱和度(SvO2),以及围手术期的输血量和术后24 h胸腔引流量。结果与对照组相比,实验组患儿通过RAP减少预充液量(47.1±10.9)mL,实验组Hct、Lac、SvO2在各时间点与对照组比较差异无统计学意义(P>0.05)。围手术期的异体输血量实验组(101.62±55.84)mL,对照组(123.88±56.96)mL(P<0.05),术后24 h胸腔引流量,实验组(86.42±28.26)mL、对照组(105.40±38.24)mL(P<0.05)。结论 RAP应用于婴儿CPB手术可以有效减少围手术期患儿的异体血输入量。     

Pump blood processing, salvage and re-transfusion improves hemoglobin levels after coronary artery bypass grafting, but affects coagulative and fibrinolytic systems

Cell saving systems are commonly used during cardiac operations to improve hemoglobin levels and to reduce blood product requirements. We analyzed the effects of residual pump blood salvage through a cell saver on coagulation and fibrinolysis activation and on postoperative hemoglobin levels. Thirty-four elective coronary artery bypass graft (CABG) patients were randomized. In 17 patients, residual cardiopulmonary bypass (CPB) circuit blood was transfused after the cell saving procedure (cell salvage group). In the other 17 patients, residual CPB circuit blood was discarded (control group). Activation of the coagulative, fibrinolytic and inflammatory systems was evaluated pre-operatively (Pre), 2 hours after the termination of CPB (T0) and 24 hours postoperatively (T1), measuring prothrombin fragment 1.2 (PF 1.2), plasmin-anti-plasmin (PAP), plasminogen activator inhibitor-1 (PAI-1) and interleukin-6 (IL-6). The cell salvage group of patients had a significant improvement in hemoglobin levels after processed blood infusion (2.7 ± 1.7 g/dL vs 1.2 ± 1.1 g/dL; p=0.003). PF1.2 levels were significantly higher after infusion (T0: 1175 ± 770 pmol/L vs 730 ± 237 pmol/L; p=0.037; T1: 331 ± 235 pmol/L vs 174 ± 134 pmol/L; p=0.026). Also, PAP levels were higher in the cell salvage group, although not significantly (T0: 253 ± 251 ng/mL vs 168 ± 96 ng/mL; p: NS; T1: 95 ± 60 ng/mL vs 53 ± 32 ng/mL; p: NS). No differences were found for PAI-1, IL-6, heparin levels or for red blood cell (RBC) transfusions. The cell salvage group of patients had increased chest tube drainage (749 ± 320 vs 592 ± 264; p: NS) and fresh frozen plasma transfusion rate (5 (29%) pts vs 0 pts; p<0.04). Pump blood salvage with a cell saving system improved postoperative hemoglobin levels, but induced a strong thrombin generation, fibrinolysis activation and lower fibrinolysis inhibition. These conditions could generate a consumption coagulopathy.     

法乐四联症根治术体外循环的血液保护

目的探讨法乐四联症患者体外循环术前自体采血对患者的保护作用。方法选择40例紫绀伴有红细胞比容偏高的法乐四联症患者,体外循环术前自体采血,观察患者采血过程及术中术后的循环稳定性,以及组织灌注和氧合情况。结果所有患者采血期间无缺氧表现,无低血压和心律失常发生,而组织灌注和氧合得到改善。体外循环中患者红细胞比容稀释到20%~30%,循环稳定。手术后未出现肉眼血尿。结论法乐四联症患者体外循环术前自体采血的方法安全可靠,术中血液破坏减少,循环稳定,并可降低术后并发症的发生。     

Association of admission hematocrit with 6-month and 1-year mortality in intensive care unit patients

BACKGROUND: This study examined the association of hematocrit (Hct) levels measured upon intensive care unit (ICU) admission and red blood cell transfusions to long‐term (1‐year or 180‐day) mortality for both surgical and medical patients. STUDY DESIGN AND METHODS: Administrative and laboratory data were collected retrospectively on 2393 consecutive medical and surgical male patients admitted to the ICU between 2003 and 2009. We stratified patients based on their median Hct level during the first 24 hours of their ICU stay (Hct < 25.0%, 25% ≤ Hct < 30%, 30% ≤ Hct < 39%, and 39.0% and higher). An extended Cox regression analysis was conducted to identify the time period after ICU admission (0 to <180, 180 to 365 days) when low Hct (<25.0) was most strongly associated with mortality. The unadjusted and adjusted relationship between admission Hct level, receipt of a transfusion, and 180‐day mortality was assessed using Cox proportional hazards regression modeling. RESULTS: Patients with an Hct level of less than 25% who were not transfused had the worst mortality risk overall (hazard ratio [HR], 6.26; 95% confidence interval [CI], 3.05‐12.85; p < 0.001) during the 6 months after ICU admission than patients with a Hct level of 39.0% or more who were not transfused. Within the subgroup of patients with a Hct level of less than 25% only, receipt of a transfusion was associated with a significant reduction in the risk of mortality (HR, 0.40; 95% CI, 0.19‐0.85; p = 0.017). CONCLUSION: Anemia of a Hct level of less than 25% upon admission to the ICU, in the absence of a transfusion, is associated with long‐term mortality. Our study suggests that there may be Hct levels below which the transfusion risk‐to‐benefit imbalance reverses.     

The impact of an hematocrit of 20% during normothermic cardiopulmonary bypass for elective low risk coronary artery bypass graft surgery on oxygen delivery and clinical outcome – a randomized controlled study [ISRCTN35655335]

Introduction

Cardiopulmonary bypass (CPB) induces hemodilutional anemia, which frequently requires the transfusion of blood products. The objective of this study was to evaluate oxygen delivery and consumption and clinical outcome in low risk patients who were allocated to an hematocrit (Hct) of 20% versus 25% during normothermic CPB for elective coronary artery bypass graft (CABG) surgery.

Methods

This study was a prospective, randomized and controlled trial. Patients were subjected to normothermic CPB (35 to 36°C) and were observed until discharge from the intensive care unit (ICU). Outcome measures were calculated whole body oxygen delivery, oxygen consumption and clinical outcome. A nonparametric multivariate analysis of variance for repeated measurements and small sample sizes was performed.

Results

In a total of 54 patients (25% Hct, n = 28; 20% Hct, n = 26), calculated oxygen delivery (p = 0.11), oxygen consumption (p = 0.06) and blood lactate (p = 0.60) were not significantly different between groups. Clinical outcomes were not different between groups.

Conclusion

These data indicate that an Hct of 20% during normothermic CPB maintained calculated whole body oxygen delivery above a critical level after elective CABG surgery in low risk patients. The question of whether a transfusion trigger in excess of 20% Hct during normothermic CPB is still supported requires a larger prospective and randomized trial.     

Beneficial effects of using a minimal extracorporeal circulation system during coronary artery bypass grafting

Background: In this study, we assessed clinical results by using a minimal extracorporeal circuit (MECC) and compared it to a conventional cardiopulmonary bypass (CPB) system in patients undergoing coronary artery bypass grafting (CABG) procedures. Methods and Materials: From August to October 2006, forty consecutive patients undergoing isolated CABG procedures were randomly assigned to either a miniaturized closed circuit CPB with the Maquet-Cardiopulmonary MECC system (Group M, n=20) or to a conventional CPB system (Group C, n=20). Clinical outcomes were observed before, during and after the operation. Besides evaluating the perioperative clinical data, serial blood venous samples were obtained after induction, 30 minutes after CPB initiation, 2h, 6h, 12h, and 24h post-CPB. The focus of our study was on myocardial damage (cTnI), neutrophil and platelet counts, activated partial thromboplastin time (aPTT) and free hemoglobin. Results: Both the transfusion of packed red blood cells and fresh frozen plasma were significantly lower in Group M compared to Group C (p<0.05). The levels of cTnI were lower in Group M at 2h, 6h and 12h post-CPB than in Group C (p<0.01). The values of aPTT in Group M recovered to normal levels after surgery, but were prolonged in Group C at early post-CPB and were statistically longer than Group M at 2h, 6h, and 12h post-CPB (p<0.05). The concentrations of free hemoglobin in Group C were higher than in Group M during and post-CPB, and there was a statistical difference at 2h post-CPB (p<0.05). Conclusion: In conclusion, the MECC system is a safe alternative for patients who undertake extracorporeal circulation (ECC) for CABG surgery. Lower transfusion requirements and less damage to red cells may further promote the use of MECC systems, especially in higher risk patients.     

Transfusions during cardiopulmonary bypass: better when triggered by venous oxygen saturation and oxygen extraction rate

During cardiopulmonary bypass (CPB), red blood cell transfusions may be required to correct dilutional anemia. The decision-making process for transfusions is usually based on the level of hemoglobin.This study investigates the hypothesis that oxygen-derived variables (mixed venous oxygen saturation, SvO(2), and oxygen extraction rate, O(2)ER) may be more reliable predictors of the efficacy of the transfusion. Thirty-six patients for 41 transfusion episodes during CPB were retrospectively analyzed. For each patient, oxygen-derived variables, including SvO(2) and O(2)ER, were measured before and after the transfusion. No changes in pump flow were allowed between the two measurements. The efficacy of transfusion was defined as an increase in SvO(2) of at least 5%. We identified 11 transfusion episodes leading to an efficacious SvO (2) increase. Factors associated with the efficacy of the transfusion were a low SvO(2) and a high O(2)ER. No association was found with hemoglobin values, unless for a trend for efficacy of transfusion in patients with very low (<6 g/dL) hemoglobin values. Cut-off values of 68% for SvO(2) and 39% for O(2)ER were predictive for the efficacy of red blood cell transfusions, with a high accuracy (c-statistics 0.856 and 0.848, respectively) and negative and positive predictive values exceeding 82%. In conclusion, SvO(2) and O(2)ER are better than the hemoglobin value for guiding the decision-making process of red blood cell transfusions to correct hemodilutional anemia during CPB.     

Blood use in patients undergoing repeat coronary artery bypass graft procedures: multivariate analysis

BACKGROUND : The prevailing clinical opinion is that patients undergoing repeat coronary artery bypass graft (CABG) operation require more blood transfusions than do patients undergoing primary CABG operation. To determine the extent of this increased demand and the variables responsible for it, the cases of 196 patients who had undergone primary procedures and 65 patients who had had repeat procedures at the same institution were reviewed. STUDY DESIGN AND METHODS : To analyze the differences in transfusion requirements for these two groups, the following data were obtained: number of transfusions given between the time of surgery and the time of hospital discharge; preoperative hemoglobin (Hb), hematocrit (Hct), prothrombin time, and platelet count; Hb and Hct at hospital discharge; time the patient was on cardiopulmonary bypass; number and type of grafts; estimates of intraoperative blood loss; and chest-tube blood shed during the first 48 hours after surgery. RESULTS : The groups were comparable with respect to age, body weight, preoperative Hb and Hct, number of grafts, and aspirin exposure. Patients in the repeat group had 35-percent greater blood loss and required 75-percent more blood components than did the patients undergoing primary procedures. The mean number of blood components transfused per patient was as follows: red cells, 3.8 +/? 0.5 units in repeat patients and 2.2 +/? 0.2 units in primary patients (p = 0.002); platelets, 2.9 +/? 0.9 vs. 1.1 +/? 0.2 (p = 0.043); fresh-frozen plasma, 1.6 +/? 0.4 vs. 0.8 +/? 0.1 (p = 0.044). Analysis of variables by regression method for repeat patients showed a predictive effect of blood loss (p < 0.0001), prolonged time on cardiopulmonary bypass (p < 0.0001), preoperative Hb (p = 0.0003), and aspirin exposure (p = 0.0094) on red cell transfusion rate in repeat patients (R-square = 0.7778, Prob > f = 0.0001). CONCLUSION : Repeat CABG patients have higher transfusion rates. These findings may be attributed to the increased microvascular bleeding, prolonged time on cardiopulmonary bypass, lower preoperative Hb, and the use of preoperative antiplatelet medications.     

Repair of hypoplastic left heart syndrome of a 4.25-kg Jehovah's witness

The care of patients who refuse homologous transfusions has challenged cardiac surgery teams to refine blood conservation techniques and question standard transfusion practices. We cared for a newborn child with hypoplastic left heart syndrome (HLHS) whose parents refused to give consent to care for the child that involved the transfusion of homologous blood. A Norwood Stage I procedure was planned with the understanding that transfusions would be avoided, if possible. A court order was obtained that specified the conditions under which the attending physicians would transfuse the newborn. The birth weight of the patient was 4.25 kg. A low prime cardiopulmonary bypass (CPB) circuit and aggressive blood conservation techniques that included modified ultrafiltration (MUF) allowed the completion of the repair and CPB portion of the operation without the use of blood. The lowest hematocrit during CPB was 20%. After an unsuccessful attempt to separate from CPB, blood was transfused. Recovery was consistent for HLHS patients following Norwood Stage I. However, at 1 month postoperatively, the patient did require a shunt reduction for pulmonary overcirculation. Norwood Stage II repair was completed at age 4 months without donor blood. The key to a successful outcome is a well-thoughtout plan by the surgeon, anesthesiologist and perfusionist. This plan should include careful monitoring of the patient's oxygenation and cardiovascular status.     

The effects of intermittent prebypass heparin dosing in patients undergoing coronary artery bypass grafting

In this study, 10 patients (Group B) were given three consecutive prebypass doses of heparin (100 IU/kg) with a 4 min interval prior to cardiopulmonary bypass (CPB) institution. They were compared with 10 patients (Group A) receiving the standard single prebypass heparin dose (300 IU/kg). The haemostatic response and anticoagulant monitoring during the perioperative period were investigated by point-of-care and several coagulation tests. Results of both groups were also correlated to blood loss. Three patients in Group B required additional heparin during bypass as compared with six patients in Group A. This suggests that intermittent prebypass heparin dosing is more effective in maintaining adequate levels of anticoagulation during CPB. Group B had a lower mean decrease in factor VIII (13.9% versus 43.2%), fibrinogen (38.5% versus 46.6%), antithrombin III (34.7% versus 40.1%) and platelet count (23.2% versus 28.9%) during bypass while only one unit of red cell concentrate was required postoperatively as compared with four units in Group A. In one patient, high fibrinolytic assays were associated with a haemorrhagic pericardial effusion occurring beyond 24 hours postsurgery.     

Preoperative platelet-rich plasmapheresis and hemodilution with an autotransfusion device in total hip replacement surgery

The effectiveness of both preoperative autologous donation (PAD) and intraoperative autotransfusion (IAT) with an autotransfusion device has recently been questioned. Preoperative apheresis, with separation of concentrated platelet rich-plasma (c-PRP) and erythrocyte concentrate (ERC), represents an aggressive use of the autotransfusion device. Can such a procedure replace PAD in total hip replacement surgery (THR)? Eighty patients undergoing THR were investigated in a prospective and randomized study. Forty patients underwent PAD, and 2 units of ERC + plasma were retrieved within 4 weeks preoperatively. Another 40 patients underwent an immediately preoperative apheresis with a concomitant hemodilution with 4% albumin, retrieving c-PRP (30% of the platelet pool) and 2 units of ERC. Both groups used IAT up to 2 hours postoperatively, with 3% dextran-60 as a plasma substitute according to our standard of care. There were no differences in blood loss, B-hemoglobin or allogeneic transfusions between the groups: 85% of the patients did not receive allogeneic blood. Both apheresis and reinfusion of c-PRP had minor impact on the coagulation parameters. Platelet count increased slightly but significantly (P<0.05) from 154 to 179 x 10(9)/L after the c-PRP at wound closure. Preoperative apheresis with an autotransfusion device, separating platelet-rich plasma and erythrocyte concentrate, is a useful alternative for patients who are unable to utilize the PAD technique for either religious or practical reasons.     

Role of hemodilutional anemia and transfusion during cardiopulmonary bypass in renal injury after coronary revascularization: implications on operative outcome

OBJECTIVE: Acute renal injury and failure (ARF) after cardiopulmonary bypass (CPB) has been linked to low on-pump hematocrit (hematocrit). We aimed to 1) elucidate if and how this relation is modulated by the duration of CPB (TCPB) and on-pump packed red blood cell transfusions and 2) to quantify the impact of post-CPB renal injury on operational outcome and resource utilization. DESIGN: Retrospective review. SETTING: A Northwest Ohio community hospital. PATIENTS: Adult coronary artery bypass surgery patients with CPB but no preoperative renal failure. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We quantified post-CPB renal injury via 1) the peak postoperative change in serum creatinine (Cr) level relative to pre-CPB values (%DeltaCr) and 2) ARF, defined as the coincidence of post-CPB Cr > or =2.1 mg/dL and >2 times pre-CPB Cr. The separate effects of lowest hematocrit, intraoperative packed RBC transfusions, and TCPB on %DeltaCr and ARF were derived via multivariate regression, overlapping quintile subgroup analyses, and propensity matching. Lowest hematocrit (22.0% +/- 4.6% sd), TCPB (94 +/- 35 mins), and pre-CPB Cr (1.01 +/- 0.23 mg/dL) varied widely. %DeltaCr varied substantially (24 +/- 57%), and ARF was documented in 89 patients (5.1%). Both %DeltaCr (p < .001) and ARF (p < .001) exhibited sigmoidal dose-dependent associations to lowest hematocrit that were 1) modulated by TCPB such that the renal injury was exacerbated as TCPB increased, 2) worse in patients with relatively elevated pre-CPB Cr (> or =1.2 mg/dL), and 3) worse with intraoperative packed red blood cell transfusions (n = 385; 21.9%), in comparison with patients at similar lowest hematocrit. Operative mortality (p < .01) and hospital stays (p < .001) were increased systematically and significantly as a function of increased post-CPB renal injury. CONCLUSIONS: CPB hemodilution to hematocrit <24% is associated with a systematically increased likelihood of renal injury (including ARF) and consequently worse operative outcomes. This effect is exacerbated when CPB is prolonged with intraoperative packed red blood cell transfusions and in patients with borderline renal function. Our data add to the concerns regarding the safety of currently accepted CPB practice guidelines.     

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.     

The effect of postoperative normovolaemic anaemia and autotransfusion on blood saving after internal mammary artery bypass surgery

The efficacy of two blood conservation techniques in decreasing and in preventing the use of homologous blood products was retrospectively studied in 150 patients undergoing internal mammary artery bypass surgery. Patients were matched according to prebypass blood haemoglobin (Hb) content and body surface area and were allocated to one of three groups: in the patients of group 1 (n = 50), normovolaemic anaemia (NA) was accepted postoperatively (haematocrit [Hct] was accepted to a minimum level of 25%); the patients of group 2 (n = 50) were treated with postoperative autotransfusion (AT) of mediastinal shed blood and acceptance of NA. Group 3 (n = 50) contained control patients, not treated with NA or with AT (Hct was accepted to a minimum level of 30%). Patients of group 1 required 3.0 +/- 0.3 units of homologous blood products, but the patients of groups 2 and 3 received significantly more (p less than 0.01) units: 3.9 +/- 0.2 and 4.5 +/- 0.3 units. No donor blood products were needed in 36%, 9% and 5% of the patients in groups 1, 2 and 3 respectively. The net postoperative blood loss was similar in the groups: 1229 +/- 92 ml in group 1, 1098 +/- 74 ml in group 2 and 1243 +/- 72 ml in group 3. However, total blood loss (1982 +/- 135 ml), including the retransfused part (954 +/- 89 ml), was significantly larger (p less than 0.01) in group 2, than in groups 1 and 3.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of fresh versus old stored blood in the priming solution on whole blood lactate levels during paediatric cardiac surgery

It has been suggested that lactate levels may predict morbidity and mortality in paediatric patients during corrective open-heart surgery. Packed red blood cells (PRBC) are frequently necessary for priming the reservoir used in cardiopulmonary bypass (CPB). The storage of PRBC might cause a significant increase in lactate levels. The purpose of the present study was to quantify the increase in lactate levels in stored red blood cells over time and to compare lactate levels after transfusions of fresh (< or =12 days) versus old blood (>12 days) in 20 patients. We found an increase in lactate levels from 6.0 to 44.7mmol/L (mean 17.0+/-7.8 mmol/L) during storage. Lactate levels were also significantly higher after the onset of CPB in paediatric patients transfused with old blood than in patients transfused with fresh blood (1.43+0.36 versus 3.46+/-0.63, p=0.0006). Our results suggest that the higher lactate levels found after the initiation of CPB should be used with caution when assessing tissue hypoxia and predicting outcome.     

High or low hematocrits during cardiopulmonary bypass for patients undergoing coronary artery bypass graft surgery? An evidence-based approach to the question

We have observed an inverse relationship between a CPB Hct <20% and the need for cardiac support and hospital mortality. These data call for an aggressive and concerted effort to avoid a CPB Hct of <20%. The focus should be directed at women and small men since this subset of patients are most likely to experience low CPB Hct. A comprehensive, multimodality blood-conservation plan that involves the use of erythropoietin, aprotinin, preoperative autologous donation, shed blood reinfusion, and minimal phlebotomy for blood testing was proposed by Rosengart and colleagues based on their experience in caring for 50 Jehovah's Witness patients. Efforts to conserve blood and ensure hemostasis should cover the entire spectrum of care, including preoperative phlebotomy (for blood tests), diagnostic and interventional procedures, and intraoperative and postoperative care. Further work is needed to understand the mechanism for the relationship between low Hct and adverse outcomes. Each open-heart center should consider the Hct question carefully, examining both the published literature and their own results related to CPB Hct and patient outcomes.     

Clinical effects of reverting from leukoreduced to nonleukoreduced blood in cardiac surgery

BACKGROUND: A reduction in postoperative length of stay (PLOS) was recently demonstrated with the use of leukoreduced (LR) blood in cardiac surgery patients compared to a historical cohort who received non-LR blood. Follow-up data are now presented in a similar population after a 12-month period in which LR blood was no longer routinely used. STUDY DESIGN AND METHODS: This is an extension of a study in which all patients admitted over a 12-month period for open heart surgery were given LR blood (Group 2) and were compared against a historical cohort given non-LR blood (Group 1). This study measures the outcomes of a new cohort of patients admitted during a 12-month period where LR blood was no longer routinely used (Group 3). RESULTS: PLOS increased in patients who received transfusions with non-LR blood (Group 3, n = 595) versus patients with LR blood (Group 2, n = 645; p = 0.045 by nonparametric rank U test). Mean PLOS increased from 9.5 days (95% confidence interval [CI], 8.9-10.0) to 10.8 days (95% CI, 10.0-11.6). In comparison, an earlier cohort who received non-LR blood (Group 1, n = 501) had a mean PLOS of 10.1 days (95% CI, 9.4-10.7). With the exception of decreased red blood cell (RBC) usage in Group 3, there were no significant differences in non-RBC blood usage, estimated blood loss, bypass time, mediastinitis rates, operative mortality rate, or overall mix of cases. CONCLUSIONS: The use of non-LR blood for cardiac surgery was associated with an increased PLOS compared to the use of LR blood and supports our previous demonstration of the benefits of LR blood in cardiac surgery.