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- Bellner, Johan, et al.
(författare)
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Transkraniell dopplermätning avspeglar intrakraniellt tryck
- 2005
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Ingår i: Läkartidningen. - 0023-7205. ; 102:11, s. 840-844
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Tidskriftsartikel (refereegranskat)abstract
- Vid intrakraniell patologi, speciellt om patienten är medvetslös, är kunskap om det intrakraniella trycket av särskilt värde i neurointensivvård. Intraventrikulär kateter för mätning av intrakraniellt tryck har varit etablerad standard i årtionden. Exakta mätningar är möjliga endast genom invasiva tryckmätare. För att undersöka sambandet mellan intrakraniellt tryck och pulsatilt index, erhållet med transkraniell doppler, har vi genomfört en prospektiv studie. Registreringar av intrakraniellt tryck gjordes parallellt med alla dopplerundersökningar. En stark, signifikant korrelation sågs mellan intrakraniellt tryck och pulsatilt index med en korrelationskoefficient på 0,938. För detektion av ett intrakraniellt tryck >20 mm Hg i en population med intrakraniellt tryck mellan 10 och 40 mm Hg hade metoden – för alla mätningar – en sensitivitet på 0,83 och en specificitet på 0,99. Hos patienter med misstänkt förhöjt intrakraniellt tryck eller hos patienter där förhöjt intrakraniellt tryck måste uteslutas kan mätningar av pulsatilt index vara av stort värde.
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| 4. |
- Engström, Martin, et al.
(författare)
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An in vitro evaluation of standard rotational thromboelastography in monitoring of effects of recombinant factor VIIa on coagulopathy induced by hydroxy ethyl starch
- 2005
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Ingår i: BMC Blood Disorders. - : Springer Science and Business Media LLC. - 1471-2326. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Rotational thromboelastography (ROTEG) has been proposed as a monitoring tool that can be used to monitor treatment of hemophilia with recombinant factor VIIa (rFVIIa). In these studies special non-standard reagents were used as activators of the coagulation. The aim of this study was to evaluate if standard ROTEG analysis could be used for monitoring of effects of recombinant factor VIIa (rFVIIa) on Hydroxy Ethyl Starch-induced dilutional coagulopathy. METHODS: The study was performed in vitro on healthy volunteers. Prothrombin time (PT) and ROTEG analysis were performed after dilution with 33% hydroxy ethyl starch and also after addition of rFVIIa to the diluted blood. RESULTS: PT was impaired with INR changing from 0.9 before dilution to 1.2 after dilution while addition of rFVIIa to diluted blood lead to an overcorrection of the PT to an International Normalized Ratio (INR) value of 0.6 (p = 0.01). ROTEG activated with the contact activator ellagic acid was impaired by hemodilution (p = 0.01) while addition of rFVIIa had no further effects. ROTEG activated with tissue factor (TF) was also impaired by hemodilution (p = 0.01) while addition of rFVIIa lead to further impairment of the coagulation (p = 0.01). CONCLUSIONS: The parameters affected in the ROTEG analysis were Clot Formation Time and Amplitude after 15 minutes while the Clotting Time was unaffected. We believe these effects to be due to methodological problems when using standard activators of the coagulation in the ROTEG analysis in combination with rFVIIa.
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| 5. |
- Engström, Martin, et al.
(författare)
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Ethanol impairs coagulation and fibrinolysis in whole blood: a study performed with rotational thromboelastometry.
- 2006
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Ingår i: Blood Coagulation and Fibrinolysis. - 1473-5733. ; 17:8, s. 661-665
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Tidskriftsartikel (refereegranskat)abstract
- The objective was to study the effects of ethanol on coagulation and fibrinolysis in whole blood. Blood samples from healthy volunteers were analyzed before and after in-vitro addition of ethanol in order to achieve ethanol concentrations of 0, 1, 2 and 4[per mille sign], respectively (0, 22, 44 and 88 mmol/l). Coagulation and fibrinolysis were then assessed using rotational thromboelastometry. We found that increasing ethanol levels increasingly impaired coagulation as evaluated with rotational thromboelastometry, with a maximum prolongation of the clot formation time of 118% at an ethanol level of 4[per mille sign] (P < 0.000001). We also found a very strong impairment of fibrinolysis already at an ethanol level of 1[per mille sign]. This is the first study assessing the effects of ethanol on coagulation and fibrinolysis in a whole blood model. The impairment of coagulation is similar in nature to the impairment found in patients suffering from hypothermia. The impairment is at a level that may be of clinical importance (e.g. in patients suffering from trauma). The inhibition of fibrinolysis is obvious already at an ethanol level of 1[per mille sign] and it may be a contributing factor to the increased amount of coronary and cerebrovascular ischemic events after binge drinking.
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| 10. |
- Engvall, Christian, et al.
(författare)
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Human cerebral blood volume (CBV) measured by dynamic susceptibility contrast MRI and 99mTc-RBC SPECT.
- 2008
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Ingår i: Journal of Neurosurgical Anesthesiology. - 1537-1921. ; 20:1, s. 41-44
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Patients with elevated intracranial pressure risk compromising their cerebral blood flow, resulting in ischemia. Lowering of the raised intracranial pressure, is therefore, mandatory. Reduction of the cerebral blood volume (CBV) might be target. In finding ways to do so, one has to be able to measure CBV. Measurement of CBV is, however, difficult. Radio(99mTc-)labeled erythrocytes (99mTcRBC) single photon emission computer-aided tomography (SPECT) is one established method used for CBV measurement. Recently, dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI), has also been successfully used for this purpose. The aim of this study was to validate the use of DSC-MRI for the measurement of CBV by the investigation of the correlation between the regional distributions of 99mTc-RBC SPECT and DSC-MRI measurement of CBV in humans. If possible, the aim was also to find a conversion constant that will enable the DCS-MRI to be interpreted as CBV (percent of brain volume). METHODS: CBV of 8 volunteers were studied under normocapnic and hypocapnic conditions. CBV was measured with both 99mTc-RBC SPECT and DSC-MRI. RESULTS: There were significant correlations between the regional distributions of CBV measured by 99mTc-RBC SPECT and DSC-MRI (rest: F=4.53, P<0.05; hypocapnia: F=9.61, P<0.005). The derived conversion factor between DSC-MRI voxel values and 99mTc-RBC SPECT CBV (percent of brain volume) at rest was 0.0059+/-0.0013. Global CBV during normocapnia was 4.3%+/-0.6% of brain volume as measured by SPECT of brain volume and 4.5%+/-0.9% as measured by MRI. Decreasing the end-tidal pCO2 by 1.8 kPa by spontaneous hyperventilation reduced the global CBV significantly to 3.9%+/-0.5% in the SPECT group and to 3.5%+/-0.6% in the MRI group. CONCLUSIONS: The comparison of 99mTc-RBC SPECT and DSC-MRI measurements in our study indicates that DSC-MRI can be a useful method to measure CBV as a percent of brain volume.
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