Clinical monitoring of activated clotting time during cardiothoracic surgery: comparing the Hemochron® Response and Hemochron® Signature Elite.

INTRODUCTION: The Activated Clotting Time (ACT) is commonly used to manage anticoagulation during cardiac surgery. The aim of this study was to compare the older manually operated Hemochron® Response and the automated Hemochron® Signature Elite. METHODS: In this observational study the clinically relevant differences of both devices were investigated simultaneously, using duplicate measurements, in 29 patients who underwent a Coronary Artery Bypass Grafting (CABG) or Aortic Valve Replacement (AVR) in order to determine reliability, bias, and to detect which method has the lowest variation. Blood samples were obtained from the arterial line prior to surgery, after administration of 300 IU/kg heparin, 5 minutes after initiation of cardiopulmonary bypass and successively every 30 minutes, and after protamine administration. RESULTS: A total of 202 measurements were performed. Of these 10 measurements were out of range in the Response and 9 in the Elite. About 27 single unstable magnet errors were seen in the Response versus no measurement errors in the Elite. No statistically significant differences between the Response (p = 0.22, Wilcoxon rank) and Elite (p = 0.064) duplicates were observed. The Response values were consistently higher during heparinization than the Elite measurements (p = 0.002, repeated measurements) with an average positive bias of around 56 seconds during heparinization (Bland-Altman). Overall, the coefficient of variation (CoV) increased during heparinization. CONCLUSION: The Elite was more reliable, but the variation was higher for the Elite than the Response. The observed positive bias in the Response compared to the Elite could affect heparin administration during surgery making the two systems not interchangeable.

Does Intraoperative Cell Salvage Reduce Postoperative Infection Rates in Cardiac Surgery?

OBJECTIVE: Primary outcome was the risk for infections after cell salvage in cardiac surgery. DESIGN: Data of a randomized controlled trial on cell salvage and filter use (ISRCTN58333401). SETTING: Six cardiac surgery centers in the Netherlands. PARTICIPANTS: All 716 patients undergoing elective coronary artery bypass grafting, valve surgery, or combined procedures over a 4-year period who completed the trial. INTERVENTIONS: Postoperative infection data were assessed according to Centre of Disease Control and Prevention/National Healthcare Safety Network surveillance definitions. MEASUREMENTS AND MAIN RESULTS: Fifty-eight (15.9%) patients with cell salvage had infections, compared with 46 (13.1%) control patients. Mediation analysis was performed to estimate the direct effect of cell salvage on infections (OR 2.291 [1.177;4.460], p = 0.015) and the indirect effects of allogeneic transfusion and processed cell salvage blood on infections. Correction for confounders, including age, seks and body mass index was performed. Allogeneic transfusion had a direct effect on infections (OR = 2.082 [1.133;3.828], p = 0.018), but processed cell salvage blood did not (OR = 0.999 [0.999; 1.001], p = 0.089). There was a positive direct effect of cell salvage on allogeneic transfusion (OR = 0.275 [0.176;0.432], p < 0.001), but a negative direct effect of processed cell salvage blood (1.001 [1.001;1.002], p < 0.001) on allogeneic transfusion. Finally, there was a positive direct effect of cell salvage on the amount of processed blood. CONCLUSIONS: Cell salvage was directly associated with higher infection rates, but this direct effect was almost completely eliminated by its indirect protective effect through reduced allogeneic blood transfusion.

Additional filtering of blood from a cell salvage device is not likely to show important additional benefits in outcome in cardiac surgery.

BACKGROUND: Several authors and manufacturers of cell salvage devices recommend additional filtering of processed blood before transfusion. There is no evidence to support this practice. Therefore, we compared the clinical outcome and biochemical effects of cell salvage with or without additional filtering. STUDY DESIGN AND METHODS: The patients, scheduled for coronary artery bypass grafting, valve replacement, or combined procedures were part of our randomized multicenter factorial study of cell salvage and filter use on transfusion requirements (ISRCTN 58333401). They were randomized to intraoperative cell salvage or cell salvage plus additional WBC depletion filter. We compared the occurrence of major adverse events (combined death/stroke/myocardial infarction) as primary outcome and minor adverse events (renal function disturbances, infections, delirium), ventilation time, and length of stay in the intensive care unit and hospital. We also measured biochemical markers of organ injury and inflammation. RESULTS: One hundred eighty-nine patients had cell salvage, and 175 patients had cell salvage plus filter and completed the study. Demographic data, surgical procedures, and amount of salvaged blood were not different between the groups. There was no difference in the primary outcome with a risk of 6.3% (95% confidence interval [CI], 3.34-11.25) in the cell salvage plus filter group versus 5.8% (95% CI, 3.09-10.45) in the cell salvage group, a relative risk of 1.08 (95% CI, 0.48- 2.43]. There were no differences in minor adverse events and biochemical markers between the groups. CONCLUSION: The routine use of an additional filter for transfusion of salvaged blood is unlikely to show important additional benefits.

Incidence of Massive Transfusion and Overall Transfusion Requirements During Lung Transplantation Over a 25-Year Period.

OBJECTIVE: To establish the incidence of massive transfusion and overall transfusion requirements during lung transplantation, changes over time, and association with outcome in relation to patient complexity. DESIGN: Retrospective cohort study. SETTING: University hospital. PARTICIPANTS: All 514 adult patients who underwent transplantation from 1990 until 2015. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patient records and transfusion data, divided into 5-year intervals, were analyzed. The incidence of massive transfusion (>10 units of red blood cells [RBCs] in 24 h) was 27% and did not change over time, whereas the median (interquartile range) transfusion requirement in the whole cohort decreased from 8 (5-12) to 3 (0-10) RBCs (p < 0.001). In patients transplanted from the intensive care unit, the incidence of massive transfusion increased over time from 25% to 54% (p = 0.04) and median transfusion requirements from 4.5 (3-8.5) units to 14.5 (5-26) units of RBCs (p = 0.03). Multivariable analysis showed that circulatory support, pulmonary hypertension, re-transplantation, cystic fibrosis, Eisenmenger syndrome, bilateral transplantation, and low body mass index were associated with massive transfusion. Patients with massive transfusion had more primary graft dysfunction grade III at 0, 24, 48, and 72 hours (p < 0.001), higher 30-day mortality (13% v 4%; p < 0.001), and lower 5-year survival (hazard ratio 3.67 [95% confidence interval 1.72-7.85]; p < 0.001). CONCLUSION: The incidence of massive transfusion did not change over time, whereas transfusion requirements in the whole cohort decreased. In patients transplanted from the intensive care unit, massive transfusion and transfusion requirements increased. Massive transfusion was associated with poor outcome.

Additional postoperative cell salvage of shed mediastinal blood in cardiac surgery does not reduce allogeneic blood transfusions: a cohort study.

OBJECTIVES: Does additional postoperative collection and processing of mediastinal shed blood with a cell salvage device reduce the number of allogeneic blood transfusions compared to intraoperative cell salvage alone? METHODS: A single-centre cohort study in which adult patients with coronary artery bypass grafting or aortic valve replacement were allocated to either a C.A.T.S(®) group with intraoperative blood processing only or a CardioPat(®) group with both intra- and postoperative blood processing. The primary endpoint was the number of allogeneic blood transfusions during hospital admission. RESULTS: The study included 99 patients; 50 in the C.A.T.S(®) and 49 in the CardioPat(®) group.There was no difference in the number of red blood cells (RBC) (C.A.T.S(®) group 43 units versus CardioPat(®) 50 units, p=0.74), fresh frozen plasma (C.A.T.S(®) 8 units versus CardioPat(®) 8 units, p=1.00) or platelets (C.A.T.S(®) 5 units versus CardioPat(®) 4 units, p=1.00) transfused during the hospital stay.Cardiac creatinine kinase (CK-MB) and troponin levels did not differ between the groups although a significant time effect (p<0.001) was present. Creatinine kinase (CK) levels were not different between the groups three hours after arrival in the intensive care unit (ICU) (CardioPat(®) group versus C.A.T.S(®) group, p=0.17). But, compared to the C.A.T.S(®) group on the first (350 [232-469] IU/L) and second postoperative days (325 [201-480] IU/L), the increase in CK levels was more in the CardioPat(®) group on the first (431 [286-642] IU/L, p=0.02) and second postoperative days (406 [239-760] IU/L, p=0.05), resulting in a difference between the groups (p=0.04) CONCLUSIONS: Postoperative cell salvage does not reduce transfusion requirements compared to intraoperative cell salvage alone, but results in elevated total CK levels that suggest haemolysis.

An assessment of clinical interchangeability of TEG and RoTEM thromboelastographic variables in cardiac surgical patients.

BACKGROUND: Bedside thromboelastography is increasingly used, but an assessment of the clinical interchangeability of the 2 major systems, TEG (Hemoscope) and RoTEM (Pentapharm), has not been performed. METHODS: We measured blood samples from 46 cardiac surgical patients after induction of anesthesia with kaolin TEG(R) (kaoTEG), native TEG(R) (natTEG), intrinsic RoTEM (inTEM), and extrinsic RoTEM (exTEM). Each measurement consisted of reaction time (R), coagulation time (K), maximum amplitude (MA), and angle (alpha). Bland-Altman plots and mixed-model analysis were used. To assess repeatability, we made 7 replicated measurements in rapid succession in 2 volunteers. RESULTS: One hundred sixty-six measurements were available for analysis. The R time of the kaoTEG (345 + or - 102 seconds, mean + or - sd) was longer than that of the inTEM (179 + or - 74 seconds, P < 0.001) and the exTEM (55 + or - 28 seconds, P < 0.001). The K time of the kaoTEG (78 + or - 18s) was not different from that of the inTEM (75 + or - 52 seconds, P = 0.60) but was longer than the K time of the exTEM (61 + or - 24 seconds, P < 0.003). The MA of the kaoTEG (71 + or - 6.5 mm) was larger than the MA of the inTEM (67 + or - 5.2 mm, P < 0.02) and almost similar to that of the exTEM (69 + or - 6.3 mm). The alpha of the kaoTEG (72 degrees + or - 4.1 degrees ) was not significantly different from that of both the inTEM (76 degrees + or - 7 degrees ) and the exTEM (79 degrees + or - 4.5 degrees ). The variability for MA and alpha was <10%. The repeatability of the R and K times was poor in both devices, whereas the repeatability of the MA and alpha was sufficient for clinical purposes. CONCLUSIONS: The TEG and RoTEM measurements demonstrated a close correlation for the MA, but the alpha did not for the R and K variables. The kaoTEG had the best agreement with the exTEM measurement. Therefore TEG and RoTEM measurements are not completely interchangeable, and the clinical interpretation of thromboelastograhic data should be used with caution.

Hemorrhagic complications during extracorporeal membrane oxygenation - The role of anticoagulation and platelets.

PURPOSE: Hemorrhagic complications during extracorporeal membrane oxygenation are frequent and have a negative impact on outcome. We studied the association between activated partial thromboplastin time or platelet count and the occurrence of hemorrhagic complications. The secondary objective was to determine risk factors for hemorrhagic complications. METHODS: Retrospective cohort study in a single-center Dutch university hospital. We included all adult patients on extracorporeal membrane oxygenation admitted to the intensive care unit between 2010 and 2017. RESULTS: We included 164 consecutive patients of which 73 (45%) had a hemorrhagic complication. The most prevalent hemorrhagic complications were surgical site (62%) and cannula site bleeding (18%). Survival to discharge was 67% in the patients without a hemorrhagic complication and 33% in the patients with hemorrhagic complications (p < .01). A higher activated partial thromboplastin time in the 24 h prior was associated with the occurrence of hemorrhagic complications (adjusted hazard ratio per 10 s increase 1.14; (95% CI 1.05-1.24). Venoarterial extracorporeal membrane oxygenation, duration of support, and higher activated partial thromboplastin time were risk factors for the occurrence of hemorrhagic complications. CONCLUSIONS: Higher activated partial thromboplastin time is associated with the occurrence of hemorrhagic complications.

Do repeated runs of a cell saver device increase the pro-inflammatory properties of washed blood?

OBJECTIVE: Intra-operative cell salvage is increasingly used, especially in longer cases with continuing blood loss. However it is unknown if the quality of processed blood is affected when larger quantities of blood are processed. We hypothesized that the quality of the washed blood decreases after multiple runs. METHODS: Intra-operative cell salvage was performed in 42 consecutive patients undergoing cardiac surgery. When 1250 ml of blood was collected in the blood collection reservoir, this was processed and returned to the patient. In 21 patients more than 2500 ml of blood was collected during the whole procedure, thus allowing at least two subsequent runs with the auto-transfusion device. Blood samples were drawn from the blood collection reservoir of the cell saver device before, and from the processed blood after each run. RESULTS: After the first run interleukin-6 concentrations were reduced with 85% (from 21+/-35 microg/l to 3.1+/-4.4 microg/l), whereas after the second run 72% was removed (63+/-69 microg/l to 17.6+/-25.3 microg/l). Leukocyte counts almost doubled after both processing runs (from 2.6+/-1.5 x 10(9)/l to 5+/-3.6 x 10(9)/l) and from 3.9+/-2.2 x 10(9)/l to 7.7+/-5.9 x 10(9)/l), hemoglobin concentration (14.8+/-1.6 mmol/l vs 15.0+/-1.1 mmol/l), free hemoglobin (2.3+/-1.6g/l vs 2.1+/-1.4 g/l) and platelet counts (18+/-9 x 10(9)/l vs 28+/-23 x 10(9)/l) were not different between the two runs. CONCLUSIONS: Our results suggest, based on interleukin-6 and free hemoglobin washout that the quality of the processed blood remains constant with multiple runs of the cell saver device.

Donor Hypernatremia is Not Related with the Duration of Postoperative Mechanical Ventilation, Primary Graft Dysfunction, or Long-Term Outcome Following Lung Transplantation.

BACKGROUND Donor hypernatremia has been associated with reduced graft and recipient survival after heart, liver, kidney, and pancreas transplantation. However, it is unknown what effect donor hypernatremia has on graft and recipient outcomes after lung transplantation. The aim of this study was to investigate the relation of donor hypernatremia with the duration of postoperative mechanical ventilation, the incidence of severe primary graft dysfunction, and survival following lung transplantation. MATERIAL AND METHODS We analyzed all consecutive lung transplantations performed in adult patients at our center between 1995 and 2016. During the study period, donor hypernatremia was not considered a reason to reject lungs for transplantation. Donors were classified into 3 groups: normonatremia (sodium <145 mmol/L), moderate hypernatremia (sodium 145-154 mmol/L), or severe hypernatremia (sodium ≥155 mmol/L). Short-term outcome was defined by the duration of mechanical ventilation and incidence of primary graft dysfunction; long-term outcome was defined by 10-year mortality. RESULTS Donor hypernatremia was recorded in 275 (58%) of the 474 donors. There were no differences in baseline characteristics between the 3 study groups. The duration of mechanical ventilation was similar for all groups (8±25, 7±17, and 9±15 days respectively, P=0.204). Severe primary graft dysfunction was not different between the 3 groups (29%, 26%, 28%, P=0.724). Donor hypernatremia was not associated with (graft) survival, or after correction for potential confounders. CONCLUSIONS Donor hypernatremia was not associated with a worse outcome in lung transplant recipients. Thus, in contrast to solid organ transplantation, donor hypernatremia is not a contraindication for lung transplantation.

Extracorporeal Life Support as a Bridge to Lung Transplantation: A Single-Center Experience With an Emphasis on Health-Related Quality of Life.

BACKGROUND: Extracorporeal life support (ECLS) as a bridge to lung transplantation is increasingly used, but information on long-term outcome is scarce. We aim to summarize our experience with an emphasis on health-related quality of life. Secondary outcomes include ICU and hospital stay and pre- and post-transplant mortality. METHODS: A retrospective cohort study of all adult subjects receiving ECLS as a bridge to lung transplantation from 2010 to 2014 was reviewed and compared with all adult subjects who underwent bilateral lung transplantation in the same period. For the ECLS group, the general health status was assessed with the use of the EuroQol Group 5-Dimension Self-Report Questionnaire. RESULTS: A total of 130 bilateral transplants were performed, 9 transplants were performed after ECLS therapy. Another 11 subjects died on the waiting list while receiving ECLS. Quality of life, at 12 months after surgery, from a subject's perspective was comparable in both groups with a median score of 80 on the visual analog scale. The median (interquartile range [IQR]) EuroQol Group 5-Dimension Self-Report Questionnaire 3L score from the societal perspective in the ECLS group was 0.73 (0.5-0.9). Median (IQR) ICU stay was 25 d (9-68 d) for the ECLS group versus 7 d (4-18 d) for the control group (P = .001), and in-hospital stay was 66 d (40-114 d) versus 42 d (29-62 d) (P = .004). CONCLUSIONS: ECLS can be used as a bridge to lung transplantation. A significant number of subjects were not bridged successfully due to different reasons. Outcomes after successful transplantation after ECLS might be comparable with the general population undergoing lung transplantation in terms of quality of life, lung function, performance tests, and mortality, although ICU and hospital stay are longer.

The activated clotting time in cardiac surgery: should Celite or kaolin be used?

Objectives: Both kaolin- and Celite-activated clotting times (ACT) are used to guide anticoagulation during cardiopulmonary bypass. It is unknown whether these methods lead to similar management procedures for anticoagulation in patients and are thus interchangeable in terms of bias, precision and variability. Methods: We randomized 97 patients undergoing coronary artery bypass grafting or aortic valve replacement to either kaolin- or Celite-guided anticoagulation. The ACT was measured simultaneously with the other method. We administered 300 IU/kg heparin to obtain initial ACT values greater than 400 s and additional heparin in each group using the minimum value of duplicate measurements according to a predefined protocol. The primary end point was the total heparin dose and the number of heparin supplements. Results: The total heparin dose per patient in the 48 Celite-guided patients was 35 271 ± 12 406 IU with 51 supplements and in the 49 kaolin-guided patients, 35 997 ± 11 540 IU ( P = 0.77) with 56 supplements ( P = 0.53). Postoperative thrombin generation time, fibrinolytic response time, chest tube loss and transfusion requirements were not different between the two groups. However, the methods differed in individual patients with regard to supplemental heparin ( P = 0.002). Bias between methods at baseline was +10.3%, Celite being higher, and changed to a value of -12.9% at 2 h bypass. The coefficient of variation at baseline for individual patients was 2.6 times larger with kaolin than with Celite ( P < 0.001). Correlation between ACT values at baseline was only 45%. Conclusions: Kaolin- and Celite-guided management of anticoagulation is clinically not different, but the methods are not interchangeable. Clinical registration number: www.trialregister.nl identifier 1738.

Intraoperative cell salvage during cardiac surgery is associated with reduced postoperative lung injury.

OBJECTIVES: In addition to its blood-sparing effects, intraoperative cell salvage may reduce lung injury following cardiac surgery by removing cytokines, neutrophilic proteases and lipids that are present in cardiotomy suction blood. To test this hypothesis, we performed serial measurements of biomarkers of the integrity of the alveolar-capillary membrane, leucocyte activation and general inflammation. We assessed lung injury clinically by the duration of postoperative mechanical ventilation and the alveolar arterial oxygen gradient. METHODS: Serial measurements of systemic plasma concentrations of interleukin-6 (IL-6), myeloperoxidase, elastase, surfactant protein D (SP-D), Clara cell 16 kD protein (CC16) and soluble receptor for advanced glycation endproducts (sRAGEs) were performed on blood samples from 195 patients who underwent cardiac surgery with the use of a cell salvage (CS) device (CS, n = 99) or without (CONTROL, n = 96). RESULTS: Postoperative mechanical ventilation time was shorter in the CS group than in the CONTROL group [10 (8-15) vs 12 (9-18) h, respectively, P = 0.047]. The postoperative alveolar arterial oxygen gradient, however, was not different between groups. After surgery, the lung injury biomarkers CC16 and sRAGEs were lower in the CS group than in the CONTROL group. Biomarkers of systemic inflammation (IL-6, myeloperoxidase and elastase) were also lower in the CS group. Finally, mechanical ventilation time correlated with CC16 plasma concentrations. CONCLUSIONS: The intraoperative use of a cell salvage device resulted in less lung injury in patients after cardiac surgery as assessed by lower concentrations of lung injury markers and shorter mechanical ventilation times.

Angiopoietin/Tie2 Dysbalance Is Associated with Acute Kidney Injury after Cardiac Surgery Assisted by Cardiopulmonary Bypass.

INTRODUCTION: The pathophysiology of acute kidney injury (AKI) after cardiac surgery is not completely understood. Recent evidence suggests a pivotal role for the endothelium in AKI. In experimental models of AKI, the endothelial specific receptor Tie2 with its ligands Angiopoietin (Ang) 1 and Ang2 are deranged. This study investigates their status after cardiac surgery, and a possible relation between angiopoietins and AKI. METHODS: From a cohort of 541 patients that underwent cardiac surgery, blood and urine was collected at 5 predefined time points. From this cohort we identified 21 patients who had at least 50% post-operative serum creatinine increase (AKI). We constructed a control group (n = 21) using propensity matching. Systemic levels of Ang1, Ang2, and sTie2 were measured in plasma and the AKI markers albumin, kidney injury molecule-1 (KIM-1) and N-acetyl-beta-D-glucosaminidase (NAG) were measured in the urine. RESULTS: Ang2 plasma levels increased over time in AKI (from 4.2 to 11.6 ng/ml) and control patients (from 3.0 to 6.7 ng/ml). Ang2 levels increased 1.7-fold more in patients who developed AKI after cardiac surgery compared to matched control patients. Plasma levels of sTie2 decreased 1.6-fold and Ang1 decreased 3-fold over time in both groups, but were not different between AKI and controls (Ang1 P = 0.583 and sTie2 P = 0.679). Moreover, we found a positive correlation between plasma levels of Ang2 and urinary levels of NAG. CONCLUSIONS: The endothelial Ang/Tie2 system is in dysbalance in patients that develop AKI after cardiac surgery compared to matched control patients.

Effects of cell-saving devices and filters on transfusion in cardiac surgery: a multicenter randomized study.

BACKGROUND: Cell-saving devices (CS) are frequently used in cardiac surgery to reduce transfusion requirements, but convincing evidence from randomized clinical trials is missing. Filtration of salvaged blood in combination with the CS is widely used to improve the quality of retransfused blood, but there are no data to justify this approach. METHODS: To determine the contribution of CS and filters on transfusion requirements, we performed a multicenter factorial randomized clinical trial in two academic and four nonacademic hospitals. Patients undergoing elective coronary, valve, or combined surgical procedures were included. The primary end point was the number of allogeneic blood products transfused in each group during hospital admission. RESULTS: From 738 included patients, 716 patients completed the study (CS+filter, 175; CS, 189; filter, 175; neither CS nor filter, 177). There was no significant effect of CS or filter on the total number of blood products (fraction [95% confidence interval]: CS, 0.96 [0.79, 1.18]; filter, 1.17 [0.96, 1.43]). Use of a CS significantly reduced red blood cell transfusions within 24 hours (0.75 [0.61,0.92]), but not during hospital stay (0.86 [0.71, 1.05]). Use of a CS was significantly associated with increased transfusions of fresh frozen plasma (1.39 [1.04, 1.86]), but not with platelets (1.25 [0.93, 1.68]). Use of a CS significantly reduced the percentage of patients who received any transfusion (odds ratio [95% confidence interval]: 0.67 [0.49, 0.91]), whereas filters did not (0.92 [0.68, 1.25]). CONCLUSIONS: Use of a CS, with or without a filter, does not reduce the total number of allogeneic blood products, but reduces the percentage of patients who need blood products during cardiac surgery.

Clinical evaluation of a new fat removal filter during cardiac surgery.

OBJECTIVES: Fat microemboli are generated during cardiac surgery that are associated with post-operative organ injury. Recently, a fat removal filter has been developed, based on a polyester leukocyte depletion filter. However, the efficacy of such a filter in a clinical setting is unknown. In this study we tested the efficacy of this filter. METHODS: Coronary artery bypass patients were randomly divided into two groups. Group I: filtration of cardiotomy suction blood during cardiopulmonary bypass with a fat removal filter (n=14). Group II: control patients without filtration (n=14). Filter efficacy was evaluated in group I using biochemical assays and thin layer chromatography of blood samples taken simultaneously before and after the filter. In addition, clinical and biochemical markers for organ injury were determined in both groups. RESULTS: The fat filter removed triglycerides (0.9+/-0.08 vs. 0.63+/-0.08 mmol l(-1), P=0.004, paired t-test), leukocytes (4.3+/-0.8 x 10(9) vs. 2.3+/-0.6 x 10(9)l(-1), P=0.03), and platelets (116+/-26 x 10(9) vs. 75+/-21 x 10(9)l(-1), P=0.003) from the blood samples taken before and after the filter. Chromatography showed a significant reduction in free fatty acids, phospholipids and triglycerides. Clinically, leukocyte counts were similar, but platelet counts were higher (181+/-14 x 10(9) vs. 117+/-8.6 x 10(9)l(-1) control, P<0.001) in group I on the first postoperative day. CONCLUSIONS: The fat filter removed 40% fat, leukocytes and platelets from cardiotomy suction blood during cardiac surgery. A larger scale study is necessary to determine clinical effects on organ damage.

Platelet function in stored heparinised autologous blood is not superior to in patient platelet function during routine cardiopulmonary bypass.

BACKGROUND: In cardiac surgery, cardiopulmonary bypass (CPB) and unfractionated heparin have negative effects on blood platelet function. In acute normovolemic haemodilution autologous unfractionated heparinised blood is stored ex-vivo and retransfused at the end of the procedure to reduce (allogeneic) transfusion requirements. In this observational study we assessed whether platelet function is better preserved in ex vivo stored autologous blood compared to platelet function in the patient during CPB. METHODOLOGY/PRINCIPAL FINDING: We measured platelet aggregation responses pre-CPB, 5 min after the start of CPB, at the end of CPB, and after unfractionated heparin reversal, using multiple electrode aggregometry (Multiplate®) with adenosine diphosphate (ADP), thrombin receptor activating peptide (TRAP) and ristocetin activated test cells. We compared blood samples taken from the patient with samples taken from 100 ml ex-vivo stored blood, which we took to mimick blood storage during normovolemic haemodilution. Platelet function declined both in ex-vivo stored blood as well as in blood taken from the patient. At the end of CPB there were no differences in platelet aggregation responses between samples from the ex vivo stored blood and the patient. CONCLUSION/SIGNIFICANCE: Ex vivo preservation of autologous blood in unfractionated heparin does not seem to be profitable to preserve platelet function.

Bivalirudin is inferior to heparin in preservation of intraoperative autologous blood.

INTRODUCTION: Bivalirudin is used as an alternative to heparin in cardiac surgery, and may be superior to heparin with regard to platelet function. Bivalirudin however, is prone to cleavage by thrombin resulting in coagulation in areas of stasis. MATERIAL AND METHODS: We compared the preservation of platelet function and the quality of anticoagulation in autologous blood of 26 cardiac surgical patients collected intraoperatively and anticoagulated ex vivo with either bivalirudin or heparin, with supplementation of bivalirudin over time and prevention of stasis. RESULTS: We found in both preservatives a reduction in ADP-induced platelet aggregation response over a period of 105 minutes (median, IQR: 73-141) as measured by Multiplate®. Supplementation of additional bivalirudin (23 ± 1.1 µg/ml/hr) and prevention of stasis was not able to prevent thrombin generation. We found a 5-fold increase in levels of prothrombin fragment 1+2 in bivalirudin preserved autologous blood as compared to heparin preserved blood (F(1+2) levels median 8.9 nM [quartile percentiles 4.2-12.4] vs 1.3 nM [0.6-2.1], P=0.001 Mann-Whitney, n=10). CONCLUSIONS: Our study suggests that preservation of platelet function in autologous blood anticoagulated with bivalirudin is not a suitable alternative to heparin.

Leucocyte filtration of salvaged blood during cardiac surgery: effect on red blood cell function in concentrated blood compared with diluted blood.

OBJECTIVE: Leucocyte filtration of salvaged blood has been suggested to prevent patients from receiving activated leucocytes during auto-transfusion in cardiac surgery. This study examines whether leucocyte filtration of salvaged blood affects the red blood cell (RBC) function and whether there is a difference between filtration of the concentrated and diluted blood on RBC function. METHODS: Forty patients undergoing cardiac surgery with cardiopulmonary bypass were randomly divided into a group receiving leucocyte filtration of concentrated blood (High-Hct, n=20) and another group receiving leucocyte filtration of the diluted blood (Low-Hct, n=20). During operation, all the salvaged blood, as well as the residual blood, from the heart-lung machine was filtered. In the High-Hct group, blood was concentrated with a cell saver prior to filtration, whereas in the Low-Hct group, blood was filtered without concentration. RBC function was represented by RBC aggregation and deformability measured by a laser-assisted optical rotational cell analyser and by the RBC 2,3-diphosphoglycerate (2,3-DPG) and adenosine triphosphate (ATP) contents with conventional biochemical tests. RESULTS: Leucocyte filtration of diluted blood with a low haematocrit (14+/-4%) did not affect RBC function. However, when the concentrated blood with a high haematocrit (69+/-12%) was filtered, there was a reduction of ATP content in RBCs after passing through the filter (from 1.45+/-0.57 micromol g(-1) Hb to 0.92+/-0.75 micromol g(-1) Hb, p<0.05). For patients who received the concentrated blood, their in vivo RBC function did not differ from those who received diluted blood. CONCLUSIONS: Leucocyte filtration of the diluted salvaged blood during cardiac surgery does not affect RBC function, but it tends to deplete the ATP content of RBCs as the salvaged blood has been concentrated prior to filtration.