Heparin bonding of the extracorporeal circuit reduces thrombosis during prolonged lung assist in goats

This study investigated whether an artificial membrane lung of nonmicroporous polyolefin hollow fibers bonded with heparin could prolong venoarterial extracorporeal lung assist (ECLA) with low dose systemic heparin in goats. We compared heparin bonded circuits (Carmeda Bioactive Surface, "HB" group, n = 5) with non heparin bonded circuits ("NHB" group, n = 5) in venoarterial ECLA (V-A ECLA) for 7 days. Activated coagulation time (ACT) was maintained at approximately 130 sec by systemic infusion of small doses of heparin in the HB group, and at 200-230 sec in the NHB group. Thrombus formation was assessed by visual examination of the circuit, and possible cerebral embolization of thrombi was observed from behavioral abnormalities of the animals. The mean heparin dose given during ECLA was 20.4 +/- 3.6 U/kg per hr in HB, and 50.9 +/- 14.2 U/kg per hr in NHB, significantly less in HB than NHB (p < 0.01). Blood gas changes across the oxygenator, bypass flow rate, platelet aggregation activity, platelet counts, fibrin monomer (FM) test, and antithrombin-III (AT-III) activity did not differ between the two groups. In HB, thrombi were fewer and no abnormal neurologic symptoms were observed during ECLA. Numerous thrombi were observed in all oxygenators with NHB. One NHB goat developed convulsions and cerebral hemorrhage on the 6th day of ECLA. Nonmicroporous polyolefin hollow fibers can be bonded with heparin. An artificial membrane lung constructed of these fibers showed good anticoagulation by decreased thrombus formation with a small dose of infused heparin.     

Activation of coagulation and fibrinogen loss after using an extracorporeal circulation

Alterations of the coagulation potential of heparinized blood after using an extracorporeal circulation have been studied by means of a toluidine blue-calcium chloride reagent. This technique was originally used to detect the effect of activation by contact on the coagulation mechanism in heparinized blood. It has been shown that it also detects, in the presence of heparin, the clotpotentiating effect of blood cell contents liberated in vitro by mechanical trauma to blood.     

Synthesis and characterisation of phosphorylcholine-based polymers useful for coating blood filtration devices

Copolymers of 2-methacryloyloxyethylphosphorylcholine (MPC) and lauryl methacrylate (LMA) of molar ratios MPC: LMAX where x = 1, 2 or 4, have been synthesised by two different free-radical polymerisation techniques. The solubility characteristics of the resulting materials were investigated in a variety of water: alcohol solvent mixtures and found to be influenced not only by the molar ratio of MPC: LMA, but also the method of synthesis. A window of solubility was observed for certain copolymers and the alcohol used in the solvent mixture was also found to have a profound influence on the solubility profile of the polymers. These materials were soluble in a wider range of aqueous methanol mixtures compared to aqueous mixtures of higher aliphatic alcohols, such as ethanol or isopropyl alcohol, which was rationalised in terms of the affinity of the phosphorylcholine headgroup for the various alcohols relative to water. 1H nuclear magnetic resonance spectroscopy was used to further examine the solution properties of the copolymers in various solvents. The copolymer MPC: LMA2 was coated onto a variety of substrates from both alcohol-only and water: alcohol solvent systems and the surface properties of the films compared by static and dynamic contact angle, atomic force microscopy (AFM) and attenuated internal reflectance Fourier transform infrared spectroscopy (ATR-IR). The coating formed from the water: alcohol solvent was found to be hydrophilic in nature, possessing spontaneous wettability, whereas films formed from alcohol-only solvents were hydrophobic, and only on conditioning with water were more wettable surfaces attained. This phenomenon was applied in the coating of leukocyte filtration material, where the aqueous-based systems demonstrated lower critical wetting surface tension (CWST) and shorter wetting times relative to both uncoated filters and those coated from alcohol-only systems. The haemocompatibility of the coated filters was equivalent for both coating solvent systems. employed, and far superior when compared to the uncoated control.     

Responses of microvasculature in the paired cheek pouches of hamsters to blood loss and blood substitution

Comparison of arteriolar and venular responses in the left and right cheek pouches of hamsters to blood loss and blood substitution showed that blood loss led to a greater constriction of arterioles and venules in the right pouch than in the left and that blood substitution decreased arteriolar constriction and restored venular size in the right pouch, but resulted in a more marked constriction of both arterioles and venules in the left pouch. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 1, pp. 30–32, January, 1996 Presented by V. V. Kupriyanov, Member of the Russian Academy of Medical Sciences     

Effects of low-density lipoproteins on blood coagulation and fibrinolytic activity

In vitro experiments showed that copper-oxidized low-density lipoproteins activate factors of the prothrombin complex in the whole blood and inhibit fibrin generation in both blood and plasma. Moreover, oxidized low-density lipoproteins inhibit fibrinolysis and impair the structure of fibrin clot, which results in hypercoagulation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 6, pp. 637–639, June, 2000     

Use of a miniaturized cardiopulmonary bypass circuit in neonates and infants is associated with fewer blood product transfusions

Miniaturized bypass circuits, including the Kids D100 oxygenator and the D130 arterial filter, were specially designed to reduce blood transfusions in small infants undergoing cardiac surgery. This study compared the number of blood product transfusions and short-term outcome between patients younger than 1 year undergoing cardiac surgery with a conventional and a miniaturized bypass circuit, after controlling for baseline characteristics and surgical complexity by 1:1 matching. Adjusted odds ratios (ORs) and 95% confidence intervals for exposure to transfusions and to any additional transfusion were estimated from binary and polytomous regression models. Of the 804 patients enrolled retrospectively, 246 were analyzed after matching. The use of the miniaturized circuit required a lower priming volume, 265.5 vs. 432.4 mL, p < 0.001, fewer packed red blood cell (PRBC) transfusions, 1.4 vs. 2.0 U, p < 0.001, and fewer platelet transfusions on the day of surgery, 57.7% vs. 76.4%, p < 0.001. After adjustment for the use of antifibrinolytics, the ultrafiltration rate, and the year of surgery, the use of the miniaturized circuit was independently related to a reduced risk of additional PRBC transfusions, OR 0.04 (0.01, 0.13), and exposure to platelet transfusions, OR 0.78 (0.63, 0.96). Short-term outcome was similar.     

Use of bone wax reduces blood loss and transfusion rates after total knee arthroplasty

BackgroundUnnecessary costs and complications can be reduced by minimizing blood loss and allogeneic blood transfusion in cases of total knee arthroplasty (TKA). This study evaluated the effectiveness of bone wax in reducing blood loss and transfusion rates after TKA.MethodsA total of 674 consecutive TKAs performed for degenerative osteoarthritis were retrospectively reviewed. Propensity score-matching and inverse probability of treatment weighting analyses were performed for demographics, comorbidities, use of medications, preoperative laboratory findings and radiologic prosthetic coverage of osteotomy surface. In the bone wax group, bone wax (2.5 g) was applied to the uncovered bone section around the prostheses along with the topical administration of tranexamic acid, whereas hemostasis was achieved in the control group with the topical administration of tranexamic acid. Intergroup comparisons of estimated blood loss, decreases in hemoglobin (Hb) levels, and transfusion rates were performed.ResultsThe mean estimated blood loss and volume of postoperative drainage were reduced in the bone wax group. The maximum decreases in Hb levels on postoperative days 1, 3, 5, and 7 were 1.8 ± 0.7 ml, 2.5 ± 0.8 ml, 2.7 ± 0.8 ml, and 2.8 ± 0.8 ml in the bone wax group and 2.1 ± 1.0 ml, 3.0 ± 1.2 ml, 3.1 ± 1.1 ml, and 3.2 ± 1.1 ml in the control group, respectively. The postoperative transfusion rates decreased markedly from 8.8% to 2.0% when bone wax was used.ConclusionsThe use of bone wax significantly reduced blood loss, decreased Hb levels, and the risk of transfusion.Level of evidence: Level III, Therapeutic studies.     

氨甲环酸关节腔给药联合静脉给药可有效减少全膝关节置换后出血

BACKGROUND: Studies have shown that tranexamic acid can effectively reduce postoperative blood loss in patients with total knee arthroplasty. There are many means to inject tranexamic acid (intra-articular injection, intravenous injection and their combination). Which is the best way has no conclusion.     

Changes in blood pressure, fluid volumes and glomerular filtration rate during long-term treatment with prizidilol, an antihypertensive drug with combined vasodilatator and beta-adrenoceptor blocking actions

The long term effects on blood pressure, body fluid volumes, glomerular filtration rate and plasma renin concentration were studied in 11 patients with essential hypertension during treatment with prizidilol, which is an antihypertensive compound with combined vasodilatator and beta-adrenoceptor blocking actions. After the patients had been treated for four weeks with placebo, the active treatment was given for 12 weeks. Prizidilol reduced both supine and erect blood pressure by 26/14 mmHg (p less than 0.01) and 24/16 mmHg (p less than 0.01) respectively, without inducing significant changes in heart rate. Plasma volume increased significantly by eight percent (p less than 0.02), whereas the increase in extracellular fluid volume was insignificant. Glomerular filtration rate decreased by 4 ml/min./1.73 m2 (p less than 0.02). Plasma renin concentration was unchanged. Prizidilol was tolerated well, but six patients developed oedema and gained weight, which necessitated addition of diuretics in three patients.     

Cortical and subcortical electrical activity during the development of hypoxia from blood loss

It was shown previously that in some cases during the development of hypoxia polymorphic waves are replaced by synchronous standardized waves, also in the band, which have been called standardized slow complexes (SSC). In the present investigation discharges of the neuron pool were observed during SSC in the caudate nucleus, lateral and medial thalamus, hypothalamus, hippocampus, amygdaloid nucleus, and mesencephalic reticular formation. The highest firing rate of the neurons correlated (P<0.01) with the second half of the negative phase of SSC. Bursts of discharges of the neuron pool during SSC indicate that it reflects physiological processes taking place in these structures.Laboratory of Experimental Physiology of Resuscitation, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. A. Negovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 6, pp. 658–661, June, 1978.