Suction Blood Research Articles

Clinical advantages of using mini-bypass systems in terms of blood product use, postoperative bleeding and air entrainment: an in vivo clinical perspective☆

In an effort to minimize the effect of extracorporeal circulation (ECC), mini-bypass is gaining clinical acceptance in routine coronary artery bypass grafting (CABG). These small circuits target combine the clinical advantages of reduced prime, 100% bio-coating and suction blood separation. We demonstrate that the use of mini-bypass in routine CABG reduces homologous blood product use and postoperative bleeding. Our goal was to also demonstrate that these small systems are effective in gaseous microemboli (GME) management as compared to a conventional extracorporeal system. Prospective, randomized study comparing 30 mini-bypass (Dideco ECC.O) to 30 conventional systems (n=30, Dideco 903 Avant). Study included CABG cases only, independent of preoperative coagulative status; clinic ethical committee approval and informed patient consent was obtained before initiating study. There were no statistical differences in terms of patient demographics. Statistically significant differences were seen in transfusion frequency (27% of the study group vs 43% in the control group, p=0.05), transfused volume (133.3+/-244.5 ml vs 325+/-483.1 ml, p<0.05), fresh frozen plasma (0 unit vs 3 units, p<0.001), postoperative bleeding (301.8+/-531.9 ml vs 785.5+/-1000.4 ml, p<0.05) and GME activity post-arterial filter (0.14 microl vs 5.32 microl, p<0.05). The adoption of mini-bypass significantly potentially reduces hemodilution, donor blood usage, postoperative bleeding and exposure to GME in routine CABG patients as compared to the use of conventional extracorporeal circulation circuits.

Cell Salvage Alters the Systemic Inflammatory Response After Off-Pump Coronary Artery Bypass Grafting Surgery

Retransfused cardiotomy suction blood contains elevated inflammatory markers and is a bypass independent source of inflammatory mediators. We hypothesized that, during off-pump coronary artery bypass (OPCAB) grafting surgery, avoiding retransfusion of unwashed cardiotomy suction blood would beneficially alter both urinary and plasma cytokine concentrations and be renoprotective. Thirty-seven OPCAB surgery patients were randomly allocated to control (retransfusion of unwashed shed blood) and treatment (retransfusion of washed shed blood or discarding of unwashed blood) groups. Over 72 hours we measured plasma (tumor necrosis factor-alpha [TNF-alpha], interleukin-8, interleukin-6, interleukin-10, TNF soluble receptor-2, and interleukin-1 receptor antagonist) and urinary TNF soluble receptor-2 and interleukin-1 receptor antagonist and markers of renal injury and dysfunction (N-acetyl beta D glucosaminidase and alpha1-microglobulin). We demonstrated elevated proinflammatory cytokines in cardiotomy suction blood, which were effectively eliminated by cell salvage. After retransfusion, in comparison with controls, the treatment group had reduced plasma TNF soluble receptor-2. As compared with controls, treatment group patients also demonstrated significantly reduced levels of the urinary anti-inflammatory cytokine TNF soluble receptor-2. There were no between group differences in markers of renal injury or dysfunction. We have demonstrated that the management of shed mediastinal blood alters perioperative, systemic, plasma and urinary cytokine homeostasis at OPCAB surgery but does not impact on subclinical renal injury or dysfunction in this low risk group of patients.

Laparoscopy Assisted Minilaparotomy Radical Retropubic Prostatectomy (LaMRRP) for Localized Prostate Cancer

Compared with radical retropubic prostatectomy(RRP), laparoscopic surgery significantly reduces postoperative discomfort, the length of the hospital stay and the length of the convalescent period. However, the procedure of laparoscopic radical prostatectomy(LRP) is difficult to master. Therefore, we considered the surgical technique that is minimally invasive like LRP and it does not require a considerable learning curve and brings good results, like conventional RRP.Materials and Methods: From January to May 2006 at our institution, we performed LaMRRP on 7 patients who were diagnosed with clinically localized prostate cancer. Under general anesthesia, a 5cm midline incision was made suprapubically and a 10mm trocar is introduced extraperitoneally at the umbilicus for the camera. The assistant port consisted of a 5mm trocar that was placed for blood suction and for vesicourethral anastomosis. We performed the operation under direct vision through the small window and using a video monitor. The surgical procedures followed the steps employed in conventional RRP.Results: We successfully performed the operation in all cases without any extension of the incision. The mean patient age is 68.4 years old(range: 59-75). The mean operating time was 320 min(range: 290-360). The mean blood loss was 1,380ml(range: 1,150-1,800). There were no major complications. The postoperative pain was noticeably reduced compared with conventional RRP. The urethral catheter was left in place for 18 days (range: 14-25) in all the patients and postoperative cystography showed no leakage.Conclusions: We could perform LaMRRP with using enhanced surgical views, and there was no long learning curve and no additional expense. The results of LaMRRP were not significantly different from that of conventional RRP. Therefore, LaMRRP could be a useful method for the treatment of localized prostate cancer.

Invited commentary

This article addresses an important and very interesting topic (ie, the potential deleterious effects of retransfusion cardiotomy suction blood to the cardiopulmonary circulation) [1Carrier M. Denault A. Lavoie J. Perrault L.P. Randomized controlled trial of pericardial blood processing with a cell-saving device on neurologic markers in elderly patients undergoing coronary artery bypass graft surgery.Ann Thorac Surg. 2006; 82: 51-56Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar]. In a small material such as this study, S100B sampling is the end point that would yield the most interesting results. The authors have chosen to use only one time for sampling, and rather soon after the operation. The sampling after a couple of hours is known to be fraught with methodological problems, which the authors also point out. It would be interesting to see a couple of S100B samples between 6 and 24 hours. Lacking these data, it is difficult to draw any eligible conclusions from S100B levels in this series of patients. Albeit the shortcomings of the study, such as small sample size and suboptimal timing of S100B sampling, the findings of the study raises some interesting thoughts. In the cell-saver group they had 3 patients with a history of stroke and none in the control group. In outcome they found no strokes in the cell-saver group but one in the control group. Although, not even close to any statistical significance, this finding provokes the interesting question as to whether removing unwanted substances such as cytokines, S100B, and lipid particles will decrease the risk of focal ischemic brain damage. It is well known that lipid particles from shed blood will end up in different organs of the body. The hypothesis that lipid particles could be a mechanism behind focal ischemic brain damage is very interesting, and will hopefully be addressed in studies with a larger cohort.

Hemodynamic effects of cardiotomy suction blood

Cardiac surgery induces a systemic inflammatory activation, which in severe cases is associated with peripheral vasodilation and hypotension. Cardiotomy suction blood contains high levels of inflammatory mediators, but the effect of cardiotomy suction blood on the vasculture is unknown. We investigated the effect of cardiotomy suction blood on systemic vascular resistance in vivo and whether cell-saver processing of suction blood affects the vascular response. Twenty-five patients undergoing coronary surgery (mean age, 68 +/- 2 years; 80% men) were included in a prospective randomized study. The patients were randomized to retransfusion of cell-saver processed (n = 13) or cell-saver unprocessed (n = 12) suction blood during full cardiopulmonary bypass. Mean arterial blood pressure was continuously registered during retransfusion, and systemic vascular resistance was calculated. Plasma concentrations of tumor necrosis factor alpha, interleukin 6, and complement factor C3a were measured in suction blood. Retransfusion of cardiotomy suction blood induced a transient reduction in systemic vascular resistance in all patients. The peak reduction was significantly less pronounced in the group receiving cell-saver processed blood (-12% +/- 2% vs -28% +/- 3%, P = .001). There was a significant correlation between tumor necrosis factor alpha concentration in retransfused cardiotomy suction blood and peak reduction of systemic vascular resistance (r = 0.60, P = .002). The results suggest cardiotomy suction blood is vasoactive and might influence vascular resistance and blood pressure during cardiac surgery. The observed vasodilation is proportional to the inflammatory activation of suction blood and can be reduced by processing suction blood with a cell-saving device before retransfusion.

A Novel Contrast Removal System From the Coronary Sinus Using an Adsorbing Column During Coronary Angiography in a Porcine Model

This study examined the efficacy of a novel system to remove contrast from the coronary sinus (CS) using an adsorbing column during coronary angiography. Contrast-induced nephropathy (CIN) has become a serious problem for patients with pre-existing renal insufficiency undergoing percutaneous coronary intervention (PCI). Eight swine were studied to evaluate the efficacy of the contrast removal system. A newly developed 8-F blood suction catheter was inserted into the CS via the right femoral vein. The venous blood from the CS was transferred into the 500-ml contrast-adsorbing column using an extracorporeal system. A total of 155 ml of contrast medium was infused selectively into the coronary artery. Five swine were treated extracorporeally for 90 min using adsorbing columns, and three were treated without columns as a control group. The mean calculated iodine removal rate was 49.4%. The area under the curve of the iodine concentration in the group treated with the column was significantly smaller, by 60%, than that of the group treated without the column (p = 0.0003). No significant adverse effects were observed in the subjects' vital signs throughout the experiments. The contrast removal system from CS is effective and safe during coronary angiography in swine. This technique may be useful for preventing CIN in patients with renal insufficiency undergoing PCI.

Effects of poly-2-methoxyethylacrylate (PMEA)-coating on CPB circuits

Objectives. In this study, the immuno- and neuroprotective effect of a novel cardiopulmonary bypass coating was investigated. Design. Thirty nine patients scheduled for elective coronary artery bypass grafting were randomly assigned to either PMEA-coated (n = 19) or non-coated CPB circuits (n = 20). Pericardial suction blood was separated and retransfused only if needed at the end of operation. Neurocognitive functions were examined preoperatively and 7–10 days postoperatively using a standard neuropsychological test battery. Assuming an inflammatory etiology, the most cogent inflammatory markers were perioperatively analyzed. Results. Postoperatively, patients of the PMEA-coated group performed better in Go/NoGo and Mini-Mental-test than patients of the non-coated group (p < 0.04). Other neurocognitive testing did not reveal significant differences between the groups. Although most inflammatory parameters showed a significant intraindividual increase during or shortly after CPB, there was no difference in inflammatory alteration between the groups. Conclusions. PMEA-coating of cardiopulmonary bypass surfaces revealed some minor benefits in preservation of neurocognitive functions after surgery. The immediate inflammatory response remained mostly unaffected. Suction blood separation may additionally contribute to proper postoperative outcome.

Pericardial suction blood separation attenuates inflammatory response and hemolysis after cardiopulmonary bypass

Objectives. Retransfusion of pericardial suction blood (PSB) is critically considered under the aspect of the biocompatibility of the cardiopulmonary bypass (CPB). We investigated various indicators of inflammation and blood cell activation associated with CPB and re-transfusion of PSB during cardiac surgery. Design. Thirty-five patients undergoing elective coronary artery bypass grafting were prospectively randomized into two groups. In group A (n = 15, retransfusion group) the pericardial suction blood was continuously retransfused during CPB, in group B (n = 20, no-retransfusion group) the suction blood was separated. Parameters indicating the status of the inflammation and blood cell activation were analyzed before and at the end of CPB, latest after 90 minutes on CPB. Results. Patients’ perioperative data did not differ between groups. The inflammatory markers C-reactive protein, PMN-Elastase and Interleukin-6 increased in both groups after CPB (p < 0.04) with significantly lower values in the no-retransfusion group (p < 0.02). Leukocytes and platelet activation markers β-Thromboglobulin and soluble P-Selectin also experienced a significant elevation during observation time (p < 0.02) without any difference between the groups. Free hemoglobin and LDH tremendously increased during CPB with lower values in the no-retransfusion group. Conclusions. Cardiotomy suction is a major cause of hemolysis and contributes significantly to the systemic inflammatory response.

Transit care of the ventilated critically ill in commercial airliners

Air ambulances and customized military aircraft are established modes of transporting critically ill patients. Defence services and aid agencies even have flying hospitals, replete with operating theatres and ICUs. With burgeoning travel by an increasingly elderly population, a growing number of travelling Australians suffer critical illnesses overseas. Transcontinental air ambulances are prohibitively expensive and many American and European commercial airlines ban travel by seriously ill patients. Transit intensive care on board commercial airline flights poses complex physiological and logistic challenges. We have transported hundreds of critically ill patients and report on 10 episodes of aero-intensive care with IPPV on board scheduled passenger services. These were from the Philippines, the USA, the United Kingdom, Thailand, France, Norway and Austria on Qantas, Singapore Airlines, Thai Airways and Malaysia Airlines. The aviation environment imposes a bewildering array of electronic, safety and security related issues to be overcome. The entire mobile ICU weighs 100 kg. A vacuum-mattress on a stretcher fitted to the cabin floor at the rear of the economy-class cabin and screened off from the other passengers ensures patient privacy (Fig. ​(Fig.1).1). Oxygen is scarce and extremely expensive during flight. We employed the 'circle system' with a CO2 absorber and in-line oxygen analyser. Mobile suction, infusion pumps, transit-care monitors and portable blood gas analysers were all adapted for use in commercial aircraft. Figure 1 Australia and New Zealand lead the world in transit care of the critically ill in commercial airliners.

Influence of pericardial suction blood retransfusion on memory function and release of protein S100B

To study the influence of pericardial suction blood (PSB) on postoperative memory disturbances and release patterns of protein S100B during and after cardiopulmonary bypass (CPB). Sixty male patients admitted for coronary artery bypass surgery were prospectively randomized to receive PSB either by using conventional cardiotomy suction retransfusion or after cell-saver processing. The concentration of S100B rose during the period of CPB from 0.065 +/- 0.004 to 0.24 +/- 0.001 microg/L (p < 0.001). PSB contained 18.0 +/- 1.7 microg/L of S100B. Direct retransfusion from the cardiotomy reservoir made the systemic level increase to 1.42 +/- 0.19 microg/L compared to 0.25 +/- 0.02 microg/L using a cell-saver. Signs of postoperative memory dysfunction ( > 1 SD) were discovered in one of three tests, but were unrelated to technique of retransfusion. No associations were found between serum concentrations of S100B and memory function. In this study, retransfusion of PSB during cardiac surgery appeared not to cause memory disturbances. PSB contained high concentrations of protein S100B making its use as a marker of cerebral injury unsuitable.

Coronary surgery without cardiotomy suction and autotransfusion reduces the postoperative systemic inflammatory response

BackgroundCardiotomy suction and autotransfusion of mediastinal shed blood may contribute to the inflammatory response after cardiac surgery. We compared inflammatory activation, myocardial injury, bleeding, and hemoglobin levels in patients undergoing coronary surgery with or without retransfusion of cardiotomy suction blood and mediastinal shed blood. MethodsTwenty-nine patients were included in a prospective randomized study. Cardiotomy suction blood and mediastinal shed blood were either retransfused or discarded. Plasma concentrations of the cytokines tumor necrosis factor-α and interleukin-6 and complement factor C3a were measured preoperatively and 10 minutes, 2 hours, and 24 hours after cardiopulmonary bypass. C-reactive protein, erythrocyte sedimentation rate, troponin-T, and hemoglobin levels were analyzed preoperatively, and 24 and 48 hours after cardiopulmonary bypass. Postoperative bleeding the first 12 hours was registered. ResultsBaseline data did not differ between the groups. Plasma concentrations of tumor necrosis factor-α, interleukin-6, and C3a increased after surgery in both groups but significantly less in the group without cardiotomy suction and autotransfusion. The peak delta values in the no-retransfusion group was 36% (tumor necrosis factor-α), 47% (interleukin-6), and 75% (C3a) of the values in the retransfusion group. C-reactive protein, erythrocyte sedimentation rate, and troponin-T increased after surgery in both groups without intergroup differences. Postoperative bleeding and hemoglobin levels did not differ between the groups. No patient received homologous blood transfusion. ConclusionsCoronary surgery without retransfusion of cardiotomy suction blood and mediastinal shed blood reduces the postoperative systemic inflammatory response.

Contaminating fat in pericardial suction blood: a clinical, technical and scientific challenge.

Stroke and diffuse brain damage after cardiac surgery are too common. It is important to find means to reduce the incidence in view of future competition to surgery from less invasive procedures. Stroke is fairly well defined in clinical terms and with several identified mechanisms. Diffuse brain damage is less well defined and more complex in nature. One suggested mechanism is from cerebral fat microembolization of retrieved pericardial suction blood (PSB). The present study aimed to describe a simple method to measure fat content of PSB, how experimental artefacts interfere with the results, and how the unstable character of a fat-blood suspension can be used to design a simple fat-separation system. The quantity of small amounts of fat can be amplified by centrifugation to the tapered tip of a standard glass pipette. The coefficient of variation after repeated experiments was 9.5%. PSB after coronary bypass surgery contained 0.22 +/- 0.04% fat of which 15 +/- 3% was bound to the surface of the plastic collecting bag. Experimentation requires standardized routines. Static incubation, blood-fat mixing routines, and transfer steps of blood samples between syringes induce substantial artefacts from spontaneous density separation and surface-adhesion of fat. Soya oil is a common reference substance replacing human fat in technical laboratory science, but is associated with artefacts of its own. These artefacts cause problems during experimentation but the oil is a good resource in the design of a simple fat-separation system.

Maximizing a transport platform through computer technology.

One of the most recent innovations coalescing computer technology and medical care is the further development of integrated medical component technology coupled with a computer subsystem. One such example is the self-contained patient transport system known as the Life Support for Trauma and Transport (LSTAT(tm)). The LSTAT creates a new transport platform that integrates the most current medical monitoring and therapeutic capabilities with computer processing capacity, creating the first "smart litter". The LSTAT is built around a computer system that is network capable and acts as the data hub for multiple medical devices and utilities, including data, power, and oxygen systems. The system logs patient and device data in a simultaneous, time-synchronized, continuous format, allowing electronic transmission, storage, and electronic documentation. The third-generation LSTAT includes an oxygen system, ventilator, clinical point-of-care blood analyzer, suction, defibrillator, infusion pump, and physiologic monitor, as well as on-board power and oxygen systems. The developers of LSTAT and other developers have the ability to further expand integrative component technology by developing and integrating clinical decision support systems.

The inflammatory response to recycled pericardial suction blood and the influence of cell-saving

Objective--To investigate the inflammatory and cellular response attributed to conventional cardiotomy suction vs cell-saver during cardiac surgery. Design--Thirty-three (n = 33) low-risk patients admitted for routine coronary artery bypass grafting were randomly assigned to two groups: cardiotomy suction or cell-saver for salvage of pericardial blood. The groups were compared with reference to proinflammatory cytokines, complement activation, leukocyte pattern, and haemolysis during and after cardiopulmonary bypass. Results--Pericardial suction blood contained significantly increased concentrations of free plasma haemoglobin, C3a, IL-6, IL-8, TNF-α, eosinophils and basophils compared with the systemic circulation. No differences were found for the terminal complement complex and lymphocytes, whereas overall concentrations of leukocytes, platelets and haemoglobin were decreased. Recycling of pericardial suction blood gave no systemic effects except from that of free plasma haemoglobin, which increased significantly. The cell-saver eliminated plasma haemoglobin, but no other effects could be demonstrated. Conclusion--Cardiotomy suction is a major cause of haemolysis, but contributes insignificantly to the systemic inflammatory response. Treatment of shed mediastinal blood with a cell-saver reduces haemolysis and may lower the dose load of inflammatory components.

Fat reduction in pericardial suction blood by spontaneous density separation: an experimental model on human liquid fat versus soya oil.

Pericardial suction blood (PSB) contains mediastinal liquid wound fat with an embolic potential to cause brain damage after cardiopulmonary bypass (CPB). The aims were to measure how fat separates spontaneously from blood by density and how temperature and fat surface adhesion affect the results under experimental conditions. Human liquid fat was heat-extracted from retrieved pericardial fat tissue of coronary artery bypass graft (CABG) patients (n = 10). Human fat or soya oil, 5% and 10%, respectively, were mixed with postoperatively shed mediastinal blood (n = 20). The mixture was loaded into a temperature-controlled (37 degrees C, 20 degrees C, 10 degrees C) vertical separation column. At 1, 2.5, 5 and 10 minutes, the blood was collected in five fractions, representing layers of density separation, followed by centrifugation. Human fat solidified at 8 degrees C. Soya oil remained liquid below 0 degrees C. Soya oil separated fast in water, but was slower in blood. At 10 minutes and 37 degrees C 73 +/- 6% of added soya oil was found in the top 20% fraction. Human fat at 37 degrees C behaved similarly to soya oil, with 58 +/- 2% separation at 10 minutes. However, at lower temperatures the density separation became less efficient (p < 0.001), whereas human fat more effectively adhered to the walls of the column, which added to the removal. In total, 66%-78% of the human fat was removed, depending on temperature. In conclusion, fat in PSB can be reduced by simple density separation and surface adhesion while it is temporarily retained from the CPB circuit.

Surface Modified Cardiopulmonary Bypass Circuits: Modifying the Inflammatory Response

As a consequence of an aging population demographic, now more than ever, researchers in cardiac surgery must focus on means to improve the methods and technologies related to cardiopulmonary bypass. This review presents a classification of the currently available options for biomaterial modification for cardiopulmonary bypass circuits. Hypotheses are given relating the mechanism of action by which some of these surfaces afford improved biocompatibility. Finally, nonpharmacologic biomaterial-independent strategies for minimizing the effects of cardiopulmonary bypass, such as the use of hemofiltration and leukocyte filtration, and the minimization of the use of cardiotomy suction blood are outlined.

Circulation extracorporelle contre cœur battant en chirurgie coronaire de l'adulte

This study is comparing in adult coronary patients the clinical and biological criteria between two types of extra corporeal circulation (ECC) practiced (open and closed venous reservoirs system) and the coronary surgery on beating heart. Cell saving device of cardiotomy suction blood and reduction of air/blood interface during ECC obtained in closed circuit technique must reduce the phenomenon accompanying per operative inflammatory reaction induced by ECC. The conventional open circuit ECC (rigid venous reservoir) is the most deleterious technique according to clinical and biological criteria. For these patients, the stagnant mediastinal blood is mixed with venous return. Coronary surgery using closed circuit ECC gives the same advantages of the surgery on beating heart principally as regard postoperative bleeding and reduction of hemodilution.

Fat contamination of pericardial suction blood and its influence on in vitro capillary-pore flow properties in patients undergoing routine coronary artery bypass grafting

Objective: Neurologic dysfunction after cardiopulmonary bypass might be due to arterial microembolization. Pericardial suction blood is a possible source of embolic material. Our aim was to determine the capillary-pore flow ability of pericardial suction blood. Methods: Pericardial suction blood from patients undergoing coronary bypass was collected, and pericardial suction blood and venous blood were sampled at the end of cardiopulmonary bypass and before reinfusion of pericardial suction blood. Pericardial suction blood was (n = 10) or was not (n = 10) prefiltered through a 30-μm cardiotomy screen filter before capillary in vitro analysis. Additionally, in 8 patients the plasma viscosity was measured, and in 5 of these patients, pericardial suction blood capillary deposits were evaluated by using a microscopy-imprint method and fat staining. Capillary flow was tested through 5-μm pore membranes. Tested components were plasma, plasma-eliminated whole-blood resuspension, and leukocyte/plasma-eliminated erythrocyte resuspension. Initial filtration rate and clogging slope expressed the blood-to-capillary interaction. Results: The plasma-flow profile of pericardial suction blood was highly impaired, with a 47% reduction in initial filtration rate (P <.001) and a 142% steeper clogging slope flow deceleration (P <.01). This difference was not due to a change in pericardial suction blood viscosity, such as by free hemoglobin, which corresponded to 5.7% of the erythrocytes. There were no differences in resuspended whole blood or erythrocytes. The cardiotomy filter had no effect. Microscopy suggested the presence of capillary fat deposits in pericardial suction blood that were not seen with venous plasma (P <.05). The pericardial suction blood volume was 458 ± 42 mL and contained 95.6 ± 9.3 g/L hemoglobin. Conclusions: The pericardial suction blood plasma capillary flow function was highly impaired by liquid fat. Pericardial suction blood hemoglobin appears worth recovering after fat removal, despite profound hemolysis.J Thorac Cardiovasc Surg 2002;124:377-86

The rationale for fat filtration during cardiac surgery

Improved filter technology may enable the removal of specific substances such as lipids from the blood. Lipids form a heterogeneous group of compounds, but during surgery, the main interest is focussed on triglycerides, glycerol and free fatty acids. Fat emboli have been demonstrated in the brain after cardiac surgery and are associated with ischaemic brain injury. Fat emboli have also been demonstrated in lung and kidney tissue. Lung tissue and leucocytes are especially vulnerable to the effects of free fatty acids. The surgical wound suction blood during cardiac surgery contains a considerable quantity of microemboli. Therefore, as a first step to determining the place of fat filtration during cardiac surgery, the use of a fat removal filter for surgical wound suction blood is advocated.

Effects of cardiopulmonary bypass on narrow-pore flow behavior of blood

The Journal of Thoracic and Cardiovascular Surgery • Volume 123, Number 2 381 T he possible link with cognitive changes caused by arterial microembolization during cardiopulmonary bypass (CPB) drives cardiac surgery toward off-pump procedures. One of these CPB effects is blood trauma. CPB indeed causes hemolysis, but in terms of erythrocyte flow function, some conflicting results exist.1,2 With regard to CPB, the focus of science has been on leukocytes and systemic inflammatory response,3,4 whereas the capillary flow function of blood remains an unexplored field. Of great interest are new observations about fat deposits in brain capillaries versus the reinfusion of pericardial suction blood.5 The possible role of activated leukocytes and platelets has also been discussed.6 We aimed at investigating the embolic potential of the different blood subcomponents. This was accomplished by using an in vitro narrow-pore flow model with diameter approximating the size of human capillaries.