| 1. |
- Dahlberg, Sofia, et al.
(författare)
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The effect of vitamin K on prothrombin time in critically ill patients: an observational registry study.
- 2021
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Ingår i: Journal of Intensive Care. - : Springer Science and Business Media LLC. - 2052-0492. ; 1, s. 11-17
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Tidskriftsartikel (refereegranskat)abstract
- Background Previous studies have indicated that vitamin K deficiency is common in non-bleeding critically ill patients with slightly prolonged prothrombin time-international normalized ratio (PT-INR). It has never been investigated thoroughly whether the administration of vitamin K to these patients could affect their PT-INR. Therefore, the aim of this registry study was to evaluate changes in PT-INR in response to vitamin K in critically ill patients with PT-INR in the range of 1.3–1.9. Methods Patients admitted to a mixed 9-bed general intensive care unit at a University Hospital, between 2013 and 2019 (n = 4541) with a PT-INR between 1.3 and 1.9 at any time during the stay were identified. Patients who received vitamin K with appropriate sampling times for PT-INR and without exclusion criteria were matched with propensity score to patients from the same cohort who did not receive vitamin K (controls). PT-INR was measured at admission, within 12 h before vitamin K administration and 12–36 h following vitamin K administration. Exclusion criteria included pre-existing liver cirrhosis, any plasma or platelet transfusion, or > 1 unit red blood cell transfusion between PT-INR samplings. Results Propensity score matching resulted in two groups of patients with 129 patients in each group. PT-INR decreased in both groups (1.4 [1.3–1.4] in the vitamin K group and 1.4 [1.3–1.6] in the controls, p < 0.001 and p = 0.004, respectively). The decrease in PT-INR was slightly more pronounced in patients who received vitamin K (delta PT-INR − 0.10 [− 0.30 to − 0.10] in the vitamin K group and − 0.10 [− 0.20 to 0.10] in the controls, p = 0.01). Conclusion In critically ill patients with a PT-INR of 1.3–1.9, the administration of vitamin K resulted in a slightly larger decrease of PT-INR 12–36 h after administration compared to controls. Future studies should focus on identifying which patient populations may benefit most from vitamin K administration as well as whether vitamin K could be a better alternative than plasma or prothrombin complex concentrate to improve PT-INR before non-emergent invasive procedures.
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| 2. |
- Kander, Thomas, et al.
(författare)
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ROTEM analyses of low molecular weight heparin effects with vitro induced thrombocythopenia
- 2021
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Ingår i: Women Health Care and Issues. - 2642-9756. ; 4:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Thrombocytopenia is correlated to hemorrhagic complications in patients with low molecular weight heparin (LMWH) thromboprophylaxis. Aims: The aims of our study were to investigate an experimentally induced in vitro thrombocytopenia and then adding 2 types of LMWHs in vitro. Our hypothesis was that a platelet depleted whole blood sample could reflect a stronger synergistic anticoagulative effect of in vitro added LMWH than in the non-manipulated blood. Method: Two venous citrated blood samples were consecutively drawn from 8 patient’s gynaecologic cancer and normal routine coagulation laboratory analyses immediately preopewratively. One of the two samples had its buffy coat pipetted away into a separate tube. Half of the buffy coat was returned to the same sample (treated sample). 3x500 μl of blood from the non-treated sample was added to 3 separate microtubes and corresponding for the treated sample. Thromboprophylactic doses corresponding to an in vivo peak effect 0.5 anti-Xa international units/ml of tinzaparin and enoxaparin were added both to untreated and treated samples – 2 microtubes were unheparinized (treated/untreatedsample).All samples were analysed with rotational thromboelastometry (ROTEM). Results: Wilcoxon matched-pairs signed rank tests of the in-group differences between non-non-treated and treated samples showed no significant differences (p≤0.05) for any of the parameters analysed with the ROTEM-INTEM reagent regardless of heparinization or not. Calculation of non-parametric spearman correlation for clotting time (CT) vs. platelet count (PLC) were not significant for any group. Tinzaparin was clearly observed to prolong CT in the buffy-coat lowered blood from two patients. Conclusions: Our results corroborate previous research that ROTEM cannot detect anticoagulative effects of low dose LMWH in patients with normal PLC. In two patients there was a clear prolongation of clot initiation after tinzaparin that warrants further studies on a more developed in vitro induced thrombocytopenia model.Keywords: thrombocytopenia; thromboprohylaxis; cancer; thromboelastography; low molecular weight heparin
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| 3. |
- Sunnersjö, Lotta, et al.
(författare)
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The precision of ROTEM EXTEM is decreased in hypocoagulable blood : a prospective observational study
- 2023
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Ingår i: Thrombosis Journal. - : Springer Science and Business Media LLC. - 1477-9560. ; 21, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The use of viscoelastic tests is becoming increasingly popular. There is a paucity of validation of the reproducibility of varying coagulation states. Therefore, we aimed to study the coefficient of variation (CV) for the ROTEM EXTEM parameters clotting time (CT), clot formation time (CFT), alpha-angle and maximum clot firmness (MCF) in blood with varying degrees of coagulation strength. The hypothesis was that CV increases in states of hypocoagulability.METHODS: Critically ill patients and patients subjected to neurosurgery at a university hospital during three separate periods were included. Each blood sample was tested in eight parallel channels, yielding the CVs for the tested variables. In 25 patients, the blood samples were analysed both at baseline and after dilution with albumin 5%, as well as after being spiked with fibrinogen, simulating weak and strong coagulation.RESULTS: In total, 225 unique blood samples were collected from 91 patients. All samples were analysed in eight parallel ROTEM channels, resulting in 1,800 measurements. In hypocoagulable samples, defined as those with values outside the normal reference range, the CV of CT was higher (median (interquartile range)) (6.3% (5.1-9.5)) than for normocoagulable samples (5.1% (3.6-7.5)), p < 0.001. CFT showed no difference (p = 0.14), while the CV of alpha-angle was higher in hypocoagulable samples (3.6% (2.5-4.6)) than in normocoagulable samples (1.1% (0.8-1.6), p < 0.001. The CV of MCF was higher in hypocoagulable samples (1.8% (1.3-2.6)) than in normocoagulable samples (1.2% (0.9-1.7)), p < 0.001. The CV ranges for the different variables were as follows: CT: 1.2%-37%, CFT: 1.7%-30%, alpha-angle: 0.0%-17% and MCF: 0.0%-8.1%.CONCLUSIONS: CVs for the EXTEM ROTEM parameters CT, alpha-angle, and MCF increased in hypocoagulable blood compared to blood with normal coagulation, confirming the hypothesis for CT, alpha-angle, and MCF but not for CFT. Furthermore, the CVs for CT and CFT were much higher than those for alpha-angle and MCF. The results demonstrate that EXTEM ROTEM results from patients with weak coagulation should be interpreted with the notion of limited precision and that procoagulative treatment, based only on ROTEM EXTEM, should be given with some caution.
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| 4. |
- Törnudd, Mattias, 1974-
(författare)
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Protamine, Platelet Function and Coagulation in Cardiac Surgery
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bleeding is a serious and common complication in cardiac surgery. Complicated surgery together with alterations in hemostatic conditions from the use of cardiopulmonary bypass (CPB), presents challenges in how to preserve hemostasis in the patient. CPB is thought to affect platelet function and coagulation in many ways. Before connecting the patient to the CPB system, heparin is used as anticoagulation. With the connection between the patient and the CPB tubing there is a dilution of platelets and coagulation proteins and despite anticoagulation there is an activation of coagulation and inflammation resulting in consumption of coagulation factors and triggering of fibrinolysis. After disconnection of the CPB system, protamine is used to reverse the effect of heparin and restore the coagulation capacity of the patient. When protamine binds to heparin, the anticoagulant effect of heparin is removed but protamine is known to affect both platelet function and coagulation. There is uncertainty about how to best dose protamine to limit the negative effects from protamine without risking remaining heparin effect. A lot is known about how and to what extent cardiac surgery with the use of CPB affect the hemostasis in the patient, but there are still many uncertainties. The aims of this thesis were to examine how platelets are affected by CPB and protamine and to investigate if dosing of protamine had an impact on the risk of remaining or reappearing heparin after cardiac surgery. We also wanted to investigate whether sampling site matters when studying platelet function. In paper I, we found that protamine in vitro interacts with platelets by both a direct activating effect and by a secondary impairment of function when exposed to other activators. The impairment of platelet function from protamine could also be seen in vivo and is described in paper III. In paper III, we also conclude that, in contrast to prior studies, there was no increase in activation in platelets, nor net loss of platelets, during moderate CPB times. After CPB we found no impairment of platelet function compared with before surgery. In paper II, we found no differences in platelet aggregability between venous and arterial blood when measured with impedance aggregometry. Also, with flow cytometry most of our parameters showed no differences between venous and arterial blood. However, there were some differences. For example, the level of monocyte-platelet-aggregates was higher in venous- compared with arterial blood, which raises questions whether platelet function changes with oxygenation and flow conditions. In paper IV, we found a dose dependent risk of remaining heparin activity in the first postoperative period. We also found reappearance of heparin activity that was independent of the protamine dose in almost all our patients. We did not find any correlation between remaining or reappearing heparin activity and bleeding. In conclusion, this thesis describes that moderate CPB times do not have the severe impairment on platelet function earlier described in the literature. The thesis also increases the knowledge regarding how protamine affects platelet function and how dosing of protamine does and does not affect the risk of remaining and reappearing heparin activity. Finally, we conclude that in most cases platelet function can be studied in venous and arterial blood interchangeably, but there might be some differences in platelet function depending on whether they are in the venous our arterial system.
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| 5. |
- Wikman, Agneta, et al.
(författare)
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Blood components, special components and whole blood - what and to whom? : Blodkomponenter och helblod – så framställs och används de.
- 2021
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Ingår i: Läkartidningen. - 0023-7205. ; 118:11
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Tidskriftsartikel (refereegranskat)abstract
- Sweden does not have a national blood authority and guidelines for blood transfusions are lacking, leading to varying routines of production and usage of blood in the different regions. The minimum quality requirements are defined in EU Directive 2002/98/EG and in the Swedish SOSFS 2009:28. The standard blood components are red blood cells, plasma and platelets, while special components such as irradiated, washed, frozen-thawed or antigen-matched products are prescribed on certain clinical indications. Thresholds for transfusion of red blood cells and platelets are discussed as well as indications for plasma transfusions. Further, there is evidence that early, balanced blood transfusions in massive bleeding reduce mortality, which has led to requests for blood products in prehospital settings.
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| 6. |
- Åkesson, Alexander, et al.
(författare)
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Biomarkers of complement and platelet activation are not correlated with the one or twenty-four hours corrected count increments in prophylactically platelet transfused hematological patients : a prospective cohort study
- 2022
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Ingår i: Platelets. - : Informa UK Limited. - 1369-1635 .- 0953-7104. ; 33:3, s. 350-359
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Tidskriftsartikel (refereegranskat)abstract
- Platelet transfusion refractoriness is a serious clinical concern that complicates the management of thrombocytopenic patients. Previous studies have suggested a potential role for both complement and platelet activation based on in vitro analyses of platelet concentrates. In this study, the post-transfusion platelet response, as indicated by the corrected count increment at 1 and 24 h after prophylactic platelet transfusions, respectively, was correlated with the 1 h post-transfusion Δconcentration (1 h post-transfusion - pretransfusion) of complement and platelet activation biomarkers. The study was registered as a clinical trial at ClinicalTrials.gov (identifier: NCT02601131) and patients were recruited during inpatient care in the hematological department. Soluble terminal complement complexes, soluble P-selectin and soluble CD40 ligand were analyzed. Confirmed alloimmunized patients were excluded. Included subjects were either given platelet transfusions (n = 43) and categorized into four clinical study groups or included in a non-transfused control group (n = 10). In total, 54 transfusions were included. No transfusion-mediated complement activation was observed. The transfusions were associated with a significant increase in the concentration of soluble P-selectin (p < .001), primarily corresponding to the passive infusion of soluble P-selectin-containing plasma residuals. The Δconcentration of soluble P-selectin was, however, not significantly correlated with the corrected count increments. Thus, significant correlations between biomarkers of complement and platelet activation and the post-transfusion platelet response could not be demonstrated in this study.
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| 7. |
- Ölander, Filippa, et al.
(författare)
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Monitoring of Low Molecular Weight Heparin Thromboprophylaxis with Alternative Methods to Anti-Factor Xa
- 2021
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Ingår i: Anesthesia and Medical Practice Journal. - : Gavin Publishers. - 2637-9953. ; 5:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Initiating low molecular weight heparin (LMWH) thromboprophylaxis too early in patients with traumatic braininjury increases the risk of intracranial bleeding. Therefore, it is important to monitor LMWH and asses when it is safe to initiate.The aim of this research was to study alternative monitoring methods for LMWH than the standard method anti-factor Xa (antiFXa), and to investigate the peak anti-FXa level. We hoped to answer “How do rotational thromboelastometry (ROTEM) andSonoclot change at different LMWH concentrations added in vitro to blood from intensive care patients? How do point of careparameters change after subcutaneous LMWH administration on healthy volunteers with consecutive measurements to catch thepeak effect?”.Methods: Different concentrations of enoxaparin were added in vitro to citrated whole blood from fifteen intensive care patients.The first ten patients’ coagulation was analysed with ROTEM using the INTEM and NATEM assays, and the last five withSonoclot with a kaolin activator and ROTEM INTEM. Previously collected data was used from nine healthy volunteers that hadreceived subcutaneous enoxaparin. Citrated blood samples were collected before and after LMWH initiation and analysed withSonoclot kaolin and a chromogenic anti-FXa-assay. Friedman test, Dunn’s multiple comparison test and Spearman’s correlationtest were performed.Results: ROTEM INTEM CT, CFT, A10 and MCF were significantly affected with increasing in vitro enoxaparin from 0.4anti-FXa concentration. ROTEM NATEM CT was also prolonged at this LMWH concentration. Sonoclot’s parameters didn’tsignificantly change with increasing in vitro enoxaparin. The peak of in vivo LMWH was reached after 2 to 4 hours with avariation of peak anti-FXa between 0.3-0.5 IU/mL.Conclusions: ROTEM INTEM CT performed best and was prolonged at anti-FXa from 0.4-0.6 IU/mL. ROTEM INTEM shouldbe tested in neurointensive care to increase the safety of LMWH thromboprophylaxis and possibly to individualize the dosage.
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