Reliability and reproducibility of the DICART device to assess capillary refill time: a bench and in-silico study.

Capillary refill time (CRT) is an important indicator of peripheral perfusion with a strong prognostic value, but it is sensitive to environmental factors and numerous measurement methods are reported in the litterature. DiCARTECH has developed a device that assesses CRT. We sought to investigate the robustness of the device and the reproducibility of the algorithm in a bench and in-silico study. We used the video acquired from a previous clinical study on healthy volunteers. For the bench study, the measurement process was performed by a robotic system piloted by a computer that analyzed 250 times nine previously acquired videos. For the in-silico study, we used 222 videos to test the algorithm's robustness. We created 30 videos from each video with a large blind spot and used the "color jitter" function to create a hundred videos from each video. In the bench study, the coefficient of variation was 11% (95%CI: 9-13). The correlation with human-measured CRT was good (R2 = 0.91, P < 0.001). In the in-silico study, for the blind spotted video, the coefficient of variation was 13% (95%CI: 10-17). For the color-jitter modified video the coefficient of variation was 62% (95%CI: 55-70). We confirmed the ability of the DiCART™ II device to perform multiple measurements without mechanical or electronic dysfunction. The precision and reproducibility of the algorithm are compatible with the assessment of clinical small changes in CRT.

Spinning of hydroalcoholic chitosan solutions.

We investigated the spinning of hydroalcoholic chitosan solutions. The dope composition was optimized in order to obtain a continuous alcogel fiber by water evaporation on heating the extruded hydroalcoholic solution. This alcogel fiber was then neutralized in aqueous alkali baths and washed in water to eliminate the residual alcohol and salts before final drying. Depending on the alcohol content in the filament at the neutralization step, on specific alcohol-chitosan interactions and on the nature and concentration of the coagulation base, the process yielded semicrystalline chitosan fibers with different proportions of anhydrous and hydrated allomorphs. Contrarily to the classical annealing method, the formation of mainly anhydrous crystals was obtained without significant molecular weight decrease by neutralizing the polymer in hydrophobic conditions. The control of allomorph content was shown to be related to the hydrophobicity of the solvent (alcohol fraction) at the neutralization step.