Venous cannula performance assessment in a realistic caval tree model.

OBJECTIVES: A new caval tree system was designed for realistic in vitro simulation. The objective of our study was to assess cannula performance for virtually wall-less versus standard percutaneous thin-walled venous cannulas in a setting of venous collapse in case of negative pressure. METHODS: For a collapsible caval model, a very flexible plastic material was selected, and a model with nine afferent veins was designed according to the anatomy of the vena cava. A flow bench was built including a lower reservoir holding the caval tree, built by taking into account the main afferent vessels and their flow provided by a reservoir 6 cm above. A cannula was inserted in this caval tree and connected to a centrifugal pump that, in turn, was connected to a reservoir positioned 83 cm above the second lower reservoir (after-load = 60 mmHg). Using the same pre-load, the simulated venous drainage for cardiopulmonary bypass was realized using a 24 F wall-less cannula (Smartcanula) and 25 F percutaneous cannula (Biomedicus), and stepwise increased augmentation (1500 RPM, 2000 and 2500 RPM) of venous drainage. RESULTS: For the thin wall and the wall-less cannulas, 36 pairs of flow and pressure measurements were realized for three different RPM values. The mean Q-values at 1500, 2000 and 2500 RPM were: 3.98 ± 0.01, 6.27 ± 0.02 and 9.81 ± 0.02 l/min for the wall-less cannula (P <0.0001), versus 2.74 ± 0.02, 3.06 ± 0.05, 6.78 ± 0.02 l/min for the thin-wall cannula (P <0.0001). The corresponding inlet pressure values were: -8.88 ± 0.01, -23.69 ± 0.81 and -70.22 ± 0.18 mmHg for the wall-less cannula (P <0.0001), versus -36.69 ± 1.88, -80.85 ± 1.71 and -101.83 ± 0.45 mmHg for the thin-wall cannula (P <0.0001). The thin-wall cannula showed mean Q-values 37% less and mean P values 26% more when compared with the wall-less cannula (P <0.0001). CONCLUSIONS: Our in vitro water test was able to mimic a negative pressure situation, where the wall-less cannula design performs better compared with the traditional thin-wall cannula.

Suomen valkoinen sotilasarkkitehtuuri 1926-1939

Summary: "White" military architecture in Finland, 1926-1939

Keskustajääkäri Aarne Sihvo : näkökulma aseellisen voiman ja yhteiskunnan vuorovaikutukseen itsenäistymisen murroksesta paasikiviläiseen toiseen tasavaltaan

Summary: Middle-of-the-roader : General Aarne Sihvo (1889-1963) and the interaction between the Finnish armed forces and democracy

Nuoren Apollon syöksykierre : sivistyneistö ja kansallisen ideologian murroksia

Päivi Molarius

« L'Art de rethorique », par « maistre JEHAN MOLINET ».

Commençant par : « Pour ce que nouvellement, comme j'entens par voz gracieuses missives, estes tiré soubz l'estandart de Cupido... » et finissant par : «... ja masse, (massa); je Masse (mulier) » .

Sermons pour différentes fêtes de l'année.

Début : « Convertimini ad me in toto corde vestro, Johelis secundo capitulo. Le saint prophete Johel, qui est ung des XII. petis prophetes, voiant la grant tribulacion... »

Suuresta suvusta pieneen perheeseen : itäsuomalainen perhe 1700-luvulla

Summary: From joint family to nuclear family