63 research outputs found
Effect of tube diameter and capillary number on platelet margination and near-wall dynamics
The effect of tube diameter and capillary number on platelet
margination in blood flow at tube haematocrit is investigated.
The system is modelled as three-dimensional suspension of deformable red blood
cells and nearly rigid platelets using a combination of the lattice-Boltzmann,
immersed boundary and finite element methods. Results show that margination is
facilitated by a non-diffusive radial platelet transport. This effect is
important near the edge of the cell-free layer, but it is only observed for , when red blood cells are tank-treading rather than tumbling. It is also
shown that platelet trapping in the cell-free layer is reversible for . Only for the smallest investigated tube ()
margination is essentially independent of . Once platelets have reached the
cell-free layer, they tend to slide rather than tumble. The tumbling rate is
essentially independent of but increases with . Tumbling is suppressed
by the strong confinement due to the relatively small cell-free layer thickness
at tube haematocrit.Comment: 16 pages, 10 figure
Mathematisches Modell zur Bestimmung des Rotationsfehlwinkels bei der supracondylären Humerusfraktur
Correlation of Comfort Score and Narcotrend Index during Procedural Sedation with Midazolam and Propofol in Children
Background/Objectives: Precise assessment of hypnotic depth in children during procedural sedation with preserved spontaneous breathing is challenging. The Narcotrendindex (NI) offers uninterrupted information by continuous electrocortical monitoring without the need to apply a stimulus with the risk of assessment-induced arousal. This study aimed to explore the correlation between NI and the Comfort Scale (CS) during procedural sedation with midazolam and propofol and to identify an NI target range for deep sedation. Methods: A prospective observational study was conducted on 176 children (6 months to 17.9 years) undergoing procedural sedation with midazolam premedication and continuous propofol infusion. Statistical analyses included Pearson correlation of NI and CS values, logistic regression, and receiver operating curves. Results: Median NI values varied with CS and age. The correlation coefficient between CS and NI was 0.50 and slightly higher in procedure-specific subgroup analyses. The optimal NI cut-off for deep sedation was between 50 and 60 depending on the analyzed subgroup and displayed high positive predictive values for sufficient sedation throughout. Conclusion: Our study found a moderate correlation between NI and CS, demonstrating reliable identification of adequately sedated patients
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