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.     

Inflammatory response after coronary revascularization: off-pump versus on-pump (heparin-coated circuits and poly2methoxyethylacrylate-coated circuits).

OBJECTIVE: Off-pump coronary artery bypass grafting (OPCAB) may reduce the inflammatory response associated with cardiopulmonary bypass (CPB) and contribute to minimizing postoperative complications. Heparin-coated circuits and poly2methoxyethylacrylate (PMEA)-coated circuits were developed to reduce such complications. We compared the postoperative inflammatory response with or without CPB. METHODS: Eighteen consecutive patients undergoing isolated coronary artery bypass grafting (CABG) were divided into three groups: OPCAB group (n=6), heparin-coated circuits group (n=6), PMEA-coated circuits group (n=6). The plasma concentrations of the following inflammatory markers were measured: cytokines [interleukin (IL-10)], polymorphonuclear elastase (PMNE), coagulofibrinolytic factor [thrombin-antithrombin III complex (TAT)], complement factor (C3a). RESULTS: At the end of CPB, IL-10 and TAT concentrations were significantly different among the three groups (OPCAB group < PMEA-coated group < heparin-coated group). The PMNE concentration was significantly lower in the OPCAB group and the heparin-coated group as compared to the PMEA-coated group both at the end of CPB and 4 hours after CPB. C3a concentration was significantly lower in the OPCAB group than in the CPB groups at the end of CPB. Clinical variables did not differ significantly among the three groups. CONCLUSION: Off-pump CABG is associated with a reduction in the inflammatory response when compared with on-pump CABG, using either PMEA-coated or heparin-coated circuits.     

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.     

Biocompatibility of poly2methoxyethylacrylate coating for cardiopulmonary bypass.

The systemic inflammatory response to cardiopulmonary bypass (CPB) may contribute to the development of postoperative complications. Heparin-coated circuits and poly2methoxyethylacrylate (PMEA)-coated circuits have been developed to reduce the risk of such complications. We compared the biocompatibility of these circuits. Twelve patients scheduled to undergo elective coronary artery bypass grafting (CABG) with CPB were assigned to CPB with a PMEA-coated circuit (PMEA-coated group, n=6) or a heparin-coated circuit (heparin-coated group, n=6). The plasma concentrations of the following inflammatory markers were measured before CPB and just after, 4 hours after, and 24 hours after the termination of CPB: cytokines (interleukin [IL]-6, IL-8, IL-10), complement factor (C3a), polymorphonuclear elastase (PMNE), and coagulofibrinolytic factors (thrombin-antithrombin III complex [TAT], D-dimer). Postoperative clinical response was evaluated on the basis of respiratory index, blood loss, and the postoperative and preoperative body-weight percent ratio. There were no significant differences between the groups in the plasma concentrations of IL-6, IL-10, C3a, PMNE, TAT, or D-dimer. Plasma IL-8 concentrations were below the assay detection limits at all time points in both groups. Clinical variables did not differ significantly between the groups. In conclusion, PMEA-coated CPB circuits are as biocompatible as heparin-coated CPB circuits and prevent postoperative organ dysfunction in patients undergoing elective CABG with CPB.     

A new poly-2-methoxyethylacrylate-coated cardiopulmonary bypass circuit possesses superior platelet preservation and inflammatory suppression efficacy

BACKGROUND: Poly-2-methoxyethylacrylate (PMEA) is a new coating material, and several studies have revealed that PMEA-coated cardiopulmonary bypass (CPB) circuits have good biocompatibility. This study sought to compare this biocompatibility with those of heparin-coated and noncoated circuits. METHODS: Forty-five patients undergoing coronary artery bypass grafting were randomly assigned to PMEA-coated (group P, n = 15), heparin-coated (group H, n = 15), or noncoated (group N, n = 15) circuit groups. Clinical data and the following markers were analyzed: (1) platelet preservation by number of platelets; (2) complement (C) activation by C3a and C4a levels; (3) inflammatory response by interleukin-6 (IL-6) and interleukin-8 (IL-8) levels. RESULTS: Platelet numbers were significantly preserved in group P compared with groups N and H. Postoperative blood loss did not differ among the groups. During CPB, C3a values were significantly lower in group H (536 +/- 145 ng/mL) than in group P (1,458 +/- 433 ng/mL, p < 0.01) and group N (1,815 +/- 845 ng/mL, p < 0.01). The C4a values did not differ 60 minutes after CPB initiation among the groups. The IL-6 and IL-8 levels were significantly lower in group P and group H than in group N. CONCLUSIONS: The PMEA coating was superior to heparin coating and noncoating in preserving platelets, and was equivalent to heparin coating in terms of the perioperative clinical course and inhibition of inflammatory cytokines, but slightly inferior in reducing complement activation.     

Biocompatibility of heparin-coated cardiopulmonary bypass circuits in coronary patients with left ventricular dysfunction is superior to PMEA-coated circuits

BACKGROUND: Several coating techniques for extracorporeal circulation have been developed to diminish the systemic inflammatory response during cardiopulmonary bypass (CPB). The aim of this study was to evaluate the clinical effectiveness and biocompatibility of heparin-coated and poly-2-methoxyethylacrylate (PMEA)-coated CPB circuits on coronary patients with left ventricular systolic dysfunction. METHODS: Thirty-six patients who underwent elective coronary artery bypass grafting were divided into two equal groups: group H (n = 18), heparin-coated; group P (n = 18), PMEA coated. Clinical outcomes, hematologic variables, cardiac enzymes, malondialdehyde (MDA), and acute phase inflammatory response (including myeloperoxidase (MPO), catalase, hsCRP, and IL-8) were analyzed perioperatively. RESULTS: Demographic, CPB, and clinical outcome data were similar for both groups. Plasma fibrinogen, total protein, albumin, and platelet count decreased, neutrophil count, MDA, IL-8, MPO, and catalase levels increased during CPB. During CPB, MPO and catalase values were significantly higher in group P (p = 0.02 and p = 0.01) and postoperative MDA concentration was lower in group H (p = 0.03). Platelet counts were better preserved in group H during and after CPB but neutrophil count and IL-8 level did not differ between the groups. Postoperative total protein, albumin, and fibrinogen levels were higher in group H (p < 0.05). The postoperative first day levels of troponin-I, CK-MB, and CRP increased in both groups without any significant differences between the groups. CONCLUSIONS: Heparin-coated circuit provided better suppression of perioperative inflammatory markers and exhibited more favorable effects on hematologic variables than PMEA-coated circuit.     

Influence of PMEA-coated bypass circuits on perioperative inflammatory response

BACKGROUND: Poly(2-methoxyethylacrylate) (PMEA) is a new coating material, and several experimental studies have revealed excellent biocompatibility of PMEA-coated cardiopulmonary bypass circuits. The clinical utility of the PMEA-coated circuits was compared with that of uncoated circuits, focusing on perioperative inflammatory response. METHODS: Twenty-two patients were randomized to PMEA-coated (group P; Capiox RX25; n = 11) or uncoated (group U; Capiox SX10; n = 11) circuit group, and underwent coronary artery bypass grafting and/or valve operations. The following markers, as well as clinical outcomes, were analyzed perioperatively: (a) complement activation by C3a (including C3a-desArg) concentrations; (b) leukocyte activation by polymorphonuclear-elastase concentrations; (c) acute phase inflammatory response by interleukin-6 concentrations; and (d) platelet preservation by number of platelets. RESULTS: The maximal values of C3a and polymorphonuclear-elastase were significantly lower in group P than in group U. The intergroup difference of interleukin-6 was not significant. Although preservation of platelets was significantly better in group P until 1 hour after initiating cardiopulmonary bypass, no significant intergroup difference was observed thereafter. The duration of postoperative mechanical ventilation revealed no significant intergroup difference. CONCLUSIONS: The PMEA-coated circuits exhibited better suppression of perioperative complement and leukocyte activation than the uncoated circuits. In addition, the price of the PMEA-coated circuits is the same as that of the uncoated circuits. Therefore, we judged that the clinical utility of the PMEA-coated circuits is superior to those of the uncoated circuits.     

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 beta-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.     

Ventilation during Cardiopulmonary Bypass: Impact on Neutrophil Activation and Pulmonary Sequestration

Background: Cardiopulmonary bypass (CPB) is associated with neutrophil activation, pulmonary sequestration, and release of inflammatory mediators leading to pulmonary dysfunction. We investigate the effect of continuous ventilation during cardiopulmonary bypass on neutrophil activation and pulmonary sequestration. Methods: Forty-six patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were prospectively randomized to continuous ventilation and nonventilation groups. Blood samples were collected, and bronchoalveolar lavage (BAL) was performed following induction of anesthesia and at 4 hr after aortic declamping. Differential white cell count was measured, and flow cytometry to determine cell count numbers and quantify CD45 and CD11b leukocyte cell surface adhesion molecule expression was performed on the blood and BAL samples. Results: Twenty-three patients were randomized to standard nonventilated CPB and 23 patients to ventilation throughout CPB. Significant increases in blood and BAL neutrophil numbers were detected at 4 hr following aortic declamping in both groups (Blood: NV p <. 0001, V p <. 0001; BAL: NV p =. 017, V p =. 0007). No significant inter-group differences in BAL and blood neutrophil numbers were found. Significantly higher blood neutrophil CD11b mean fluorescent intensity levels were present 4 hr following declamping compared with baseline in both groups (NV Blood, p =. 021; V Blood p <. 0001). No significant inter- or intragroup differences in BAL neutrophil CD11b mean fluorescent intensity levels were found. There was no death or major complication. Conclusions: Cardiopulmonary bypass during coronary artery bypass grafting is associated with increased neutrophil pulmonary sequestration, and blood neutrophil CD11b activation. Continuous ventilation during cardiopulmonary bypass does not significantly reduce neutrophil pulmonary sequestration or activation.     

Off-pump coronary artery bypass grafting attenuates proinflammatory markers

Objective: Cardiac surgery with cardiopulmonary bypass (CPB) has been considered the main causative factors of postoperative inflammatory reactions. The aim of this study was to compare surrogate markers of the proinflammatory response in patients who underwent coronary artery bypass grafting (CABG) with or without CPB. Methods and Results: Twenty patients undergoing first-time CABG were enrolled in the study, 10 with and 10 without CPB. Blood samples were drawn at the following times: at the anesthetic induction, the end of surgery, and thereafter at 12 and 24 hours postoperatively. Neutrophil elastase, interleukin (IL)-6 , and serum soluble Fas were chosen to evaluate the extent of the systemic inflammatory response. The groups were similar in terms of age, gender ratio, number of grafts per patient. There were no operative mortality or serious postoperative complications. Two of each group received blood transfusion postoperatively. Neutrophil elastase showed a significantly higher value in the on-pump group compared with the off-pump group at the end of surgery. Soluble Fas level showed a higher value at the end of surgery compared with baseline, while it had no significant changes in the off-pump patients. IL-6 levels in the on-pump group were consistently higher compared to the off-pump group but showed no statistically significant differences between the groups. Conclusion: Compared with off-pump CABG, on pump CABG induced higher serum levels of proinflammatory markers including neutrophil elastase and soluble Fas.     

Off-pump surgery does not eliminate microalbuminuria or other markers of systemic inflammatory response to coronary artery bypass surgery

Objective. To evaluate whether off-pump surgery attenuates microalbuminuria and other markers of systemic inflammatory response to coronary artery bypass surgery as compared to surgery performed using cardiopulmonary bypass. Design. Forty-three adult patients undergoing elective coronary artery bypass grafting surgery were operated on with or without cardiopulmonary bypass (CPB). Microalbuminuria, serum C-reactive protein, and oxygenation and lung function parameters were measured at several time points until the first postoperative morning. Results. The urinary albumin/creatinine ratio was low in both groups before surgery, but reached a maximum level at the end of CPB or just after opening the last coronary artery clamp in the off-pump group (p?<?0.05). The urinary albumin/creatinine ratio remained slightly elevated in both groups until the morning after the operation (p?<?0.05). There were no statistical differences between groups. Serum C-reactive protein remained at the initial level the evening after the operation, but increased by the first postoperative morning in both groups (p?<?0.001). The alveolar-arterial gradient for oxygen partial pressure rose significantly after the operation in the intensive care unit in both groups (p?<?0.0001). The shunt fraction of the pulmonary circulation did not change in either group. Conclusions. Off-pump coronary artery surgery did not prevent the acute phase inflammatory response measured in the present study. The acute phase inflammatory response after coronary artery bypass surgery is more likely a response to the surgical trauma itself rather than to CPB.     

The rewarming rate and increased peak temperature alter neurocognitive outcome after cardiac surgery.

Neurocognitive dysfunction is a common complication after cardiac surgery. We evaluated in this prospective study the effect of rewarming rate on neurocognitive outcome after hypothermic cardiopulmonary bypass (CPB). After IRB approval and informed consent, 165 coronary artery bypass graft surgery patients were studied. Patients received similar surgical and anesthetic management until rewarming from hypothermic (28 degrees -32 degrees C) CPB. Group 1 (control; n = 100) was warmed in a conventional manner (4 degrees -6 degrees C gradient between nasopharyngeal and CPB perfusate temperature) whereas Group 2 (slow rewarm; n = 65) was warmed at a slower rate, maintaining no more than 2 degrees C difference between nasopharyngeal and CPB perfusate temperature. Neurocognitive function was assessed at baseline and 6 wk after coronary artery bypass graft surgery. Univariable analysis revealed no significant differences between the Control and Slow Rewarming groups in the stroke rate. Multivariable linear regression analysis, examining treatment group, diabetes, baseline cognitive function, and cross-clamp time revealed a significant association between change in cognitive function and rate of rewarming (P = 0.05). IMPLICATIONS: Slower rewarming during cardiopulmonary bypass (CPB) was associated with better cognitive performance at 6 wk. These results suggest that a slower rewarming rate with lower peak temperatures during CPB may be an important factor in the prevention of neurocognitive decline after hypothermic CPB.     

Cardiotomy Suction: A Major Source of Brain Lipid Emboli During Cardiopulmonary Bypass

Background. Brain injury remains a significant problem in patients undergoing cardiac surgery assisted by cardiopulmonary bypass (CPB). Autopsy brain specimens of patients after cardiac operations with CPB reveal numerous acellular lipid deposits (10 to 70 μm) in the microvasculature. We hypothesize that these small capillary and arterial dilatations result from a diffuse inflammatory response to CPB or from emboli delivered by the bypass circuit. This study was undertaken to determine which aspect of CPB is most clearly associated with these dilatations.

Methods. Thirteen dogs were studied in four groups: group I (n = 3), right-heart CPB; group II (n = 2), lower-extremity CPB; group III (n = 3), hypothermic CPB; and group IV (n = 5), hypothermic CPB with cardiotomy suction. All dogs in all groups were maintained on CPB for 60 minutes and then euthanized. Brain specimens were harvested, fixed in ethanol, embedded in celloidin, and stained with the alkaline phosphate histochemical technique so that dilatations could be counted.

Results. All dogs completed the protocol. The mean density of dilatations per square centimeter for each group was as follows: group I, 1.77 ± 0.77; group II, 4.17 ± 1.65; group III, 4.54 ± 1.69; and group IV, 46.5 ± 14.5. In group IV (cardiotomy suction), dilatation density was significantly higher than in group III (hypothermic cardiopulmonary bypass) (p = 0.04) and all other groups (p = 0.04).

Conclusions. Blood aspirated from the surgical field and subsequently reinfused into dogs undergoing CPB produces a greater density of small capillary and arterial dilatations than CPB without cardiotomy suction, presumably because of lipid microembolization.     

Efficacy of a new coating material, PMEA, for cardiopulmonary bypass circuits in a porcine model

BACKGROUND: A new coating material, poly-2-methoxyethyl acrylate (PMEA), was developed to improve the biocompatibility of cardiopulmonary bypass (CPB) circuits. METHODS: To investigate the efficacy of the PMEA coating for CPB circuits, we compared PMEA-coated circuits (group P, n = 6) with uncoated circuits (group C, n = 6) and heparin (covalent-bonded heparin, Hepaface)-coated circuits (group H, n = 6) in a porcine CPB model. RESULTS: Platelet counts were significantly preserved in groups P and H compared with those in group C (P versus C, p < 0.05). The plasma levels of thrombin-antithrombin complex and bradykinin were significantly lower at 120 minutes in groups P and H than in group C (thrombin-antithrombin: P versus C, p < 0.05; bradykinin: P versus C, p < 0.05). The amount of fibrinogen adsorbed onto the hollow fibers was markedly less in group P than in groups C and H. CONCLUSIONS: The PMEA coating was equal to heparin coating in preventing reactions induced by CPB circuits, and might be superior to heparin coating in suppressing the adsorption of plasma proteins such as fibrinogen. Thus, PMEA coating may be a suitable means for improving the biocompatibility of CPB circuits.     

Heparin-coated cardiopulmonary bypass circuits reduce blood cell trauma. Experiments in the pig

Blood cell trauma and postoperative bleeding remain important problems in cardiopulmonary bypass (CPB). We compared heparin-coated with non-coated circuits in the pig. Twenty animals were perfused for 2 h at normothermia using membrane oxygenators (Bentley Bos 50). Two groups were studied. In the non-coated group (NC, n = 11) the CPB circuits used were without a heparin coating. This group had systemic heparinization of 400 IU/kg to maintain an ACT (activated clotting time) of over 400 s during CPB. In the coated group (C, n = 9), all surfaces exposed to blood in the CPB circuits were heparin-coated. This group had the heparin dose reduced to 25% (100 IU/kg) without further administration regardless of ACT. During CPB, group C displayed shorter ACT (per definition), higher platelet count, platelet adhesion and lower fibrinolysis and haemolysis (P less than 0.05) as compared to group NC. No thromboembolic events were detected during CPB. Three animals in group NC and 4 animals in group C were weaned from CPB and protaminized. Four hours postoperatively, the leucocyte consumption was two-fold greater and blood loss about four-fold greater in group NC as compared with group C (P less than 0.05). Perfusion with heparin-coated surfaces reduces blood cell trauma. The decreased postoperative blood loss observed in group C is probably explained by the reduced dosages of heparin and protamine.     

Effects of new polymer-coated extracorporeal circuits on biocompatibility during cardiopulmonary bypass

An inflammatory response due to bioincompatibility of extracorporeal circuits is a major clinical issue during cardiopulmonary bypass (CPB). By using a swine model, we determined whether new polymer-coated circuits, the blood-contacting surfaces of which are coated with poly(2-methoxyethylacrylate) (PMEA), would reduce the inflammatory response during CPB. Plasma bradykinin levels and the percentages of CD35-positive monocytes in PMEA-coated circuits were significantly lower than those in uncoated circuits during CPB. The amount of proteins adsorbed on the PMEA-coated circuits was significantly lower than that on the uncoated circuits (0.30 microg/cm2 versus 3.42 microg/ cm2). Almost no IgG, IgM, or C3c/d was detected in proteins adsorbed on the PMEA-coated circuits although these proteins were clearly detected in proteins adsorbed on the uncoated circuits. We concluded that PMEA coating could reduce complement activation during CPB by suppressing the adsorption of IgG and IgM, which activate C3 via the classical pathway, on the surface of the circuits.     

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

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

Zero‐Balance Ultrafiltration of Priming Blood Attenuates Procalcitonin and Improves the Respiratory Function in Infants After Cardiopulmonary Bypass: A Randomized Controlled Trial

Blood priming is needed for cardiopulmonary bypass (CPB) in neonates and infants to avoid exceeding hemodilution; however, transfusion‐related inflammation affects post‐CPB outcomes in infant open‐heart surgery. Procalcitonin, a newly detected inflammatory moderator and a sensitive parameter for predicting pulmonary dysfunction secondary to CPB, rises after CPB. We hypothesized that the hemofiltration of priming blood before CPB might decrease inflammatory mediators in the blood and post‐CPB inflammatory replications, thereby improving the respiratory function after CPB in infants. Sixty infants with a weight below 10 kg were divided randomly into two equal groups of CPB with the zero‐balance ultrafiltration (Z‐BUF) of priming blood and CPB without it. The procalcitonin level was measured before anesthesia, after admission to the intensive care unit (ICU), and 24 h afterward. The respiratory index and pulmonary compliance were measured after anesthesia, at the end of CPB, and 2 h after admission to the ICU. Additionally, time to extubation was recorded. The Z‐BUF of priming blood maintained electrolytes within a physiologic level, and procalcitonin had a slighter rise in the Z‐BUF Group at 24 h after admission to the ICU (P = 0.05). The respiratory index was decreased in the Z‐BUF Group, but the difference with the control group did not reach statistical significance (P > 0.05). The change in pulmonary compliance was significantly increased in the cyanotic patients in the intervention group, but there was no significant difference between the two groups. The time to extubation and the ICU stay were shorter in the Z‐BUF Group (P < 0.05). A positive correlation was found between the peak procalcitonin concentration and the time to extubation directly and pulmonary compliance reversely. These results suggest that the Z‐BUF of priming blood may have some beneficial clinical effects such as improved respiratory function and attenuated procalcitonin.     

The influence of heparin-coated and uncoated extracorporeal circuits on blood rheology during cardiac surgery

The effect of heparin-coated perfusion circuits on blood trauma during clinical cardiopulmonary bypass (CPB) was studied in order to find out if traumatic changes in the blood could be minimized. Twenty-four patients undergoing coronary artery bypass surgery were randomized prospectively to CPB with heparin-coated circuits (HCC) or non-coated circuits (NCC). The trauma to blood was assessed by measuring damage to blood cells by estimating red and white cell rheology changes. These were measured as red cell filtration rate (RFR) and white cell filtration rate (WFR) using standard microfiltration methods. Furthermore, changes in plasma hemoglobin (P-Hb), whole blood and plasma viscosity were simultaneously assessed. The RFR was significantly reduced in both groups during CPB by 10% in the HCC and 32% in the NCC groups (p less than 0.01). When comparing the HCC and NCC groups, a significant difference was first seen after 30 minutes of bypass (p less than 0.05) and increased at the end of CPB (p less than 0.01). Similar results were seen regarding WFR (15% and 36%, p less than 0.01). After 30 minutes of bypass, a significant difference was seen between HCC and NCC groups (p less than 0.05). Furthermore, a significant increase in P-Hb levels were seen during CPB in both patient groups. At the end of CPB, there was a significant difference in P-Hb levels (HCC 305+/-90 mg/L; NCC 455+/-78 mg/L, p less than 0.01) when comparing the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

体外循环对大鼠体内白介素．6的释放、大脑NF-κB的表达及神经认知功能的影响

背景心外科手术中,体外循环（cardiopulmonary bypass,CPB）术后发生的神经认知功能障碍一直影响着患者的生活质量。炎症反应可能是其中的因素之一。本实验中我们检测了年轻大鼠围术期体内IL-6的浓度,海马NF-κB的表达含量和神经认知功能,同时评估了氧合器的大小对上述指标的影响。方法将大鼠随机分为4组：空白对照组（n=7）,假手术组（n=10,麻醉、置管、不连接体外循环）和两组体外循环实验组,CPB组大鼠在麻醉、置管后行90分钟的体外循环,分别使用小容量的大鼠氧合器（n=10）和新生儿氧合器（n=10）。在术前、CPB结束时和CPB结束后2小时采集血样检测IL-6的含量。在术后第21天采用免疫组化的方法检测海马NF—κB的表达含量。在术前和术后的21天内对神经功能采用改良孔板实验进行评估。结果CPB组与假手术组相比,IL-6的水平明显升高,新生儿氧合器组在CPB结束后2小时与大鼠氧合器组相比IL-6的水平更高[CPB／大鼠氧合器组：220pg／ml（16～415）;CPB／新生儿氧合器组：1400pg／ml（592～5812）]（P〈0．05）。3组实验组中海马NF—KB的表达含量与对照组（10±4）相比明显升高。CPB组与假手术组（173±24）相比NF．KB表达含量更高（CPB／新生儿氧合器组：271±57;CPB／大鼠氧合器组：269±72）。神经认知功能和行为学的评估结果显示组间没有差异。结论CPB引发显著的全身性炎症反应并伴随着海马中NF-κB蛋白表达的增多并没有导致神经认知功能的损伤。由此可推断,排除体外循环和炎症反应这两个因素,可能有其他因素最终导致了患者CPB术后神经认知功能的障碍。