A pillow-shaped respiration monitor was developed as a vital monitor. A load cell inside the pillow was usedto monitor changes in weight corresponded to respiration precisely. This monitor was evaluated with five different types of mats using standard weights. Thirty-percent smaller signal was obtained from the softest mat compared with the hardest mat. The pillow-shaped respiration monitor was tested for ten healthy subjects with five mats. Head position on the pillow was largely influenced to signal to noise ratio. This monitor was also tested for two bed-ridden patients in total four nights. Respiratory rate and time of body movement, and pillow off condition were monitored from those field tests. Although respiratory rates could not obtained without pillow during sleeping. This monitor can be useful for sleep apnea in bed-ridden patients.

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We developed a smaller-diameter hollow fiber membrane, aiming at improving gas exchange capacity of extracapillary flow type oxy genator. The outer diameter was reduced from225μ m in conventional fiber to205μ m in this smaller fiber. Test oxygenators containing the conventional fibers(Oxy-C)and the smaller fibers(Oxy-S)were manufactured and their performance was compared. Oxy-C and Oxy-S had the identical structure and the same priming volume. Gas exchange capacity was evaluated in in-vivo cardiopulmonary bypass study. Oxygenation efficiency fraction(Qp/Qt)and carbon dioxide removal efficiency index(Δ CO2/PaCO2)were employed as relatively stable parameters against fluctuations in venous gaseous condition and blood hemoglobin concentration. Qp/Qt andΔ CO2/PaCO2 were significantly higher in Oxy-S than those in Oxy-C, especially at higher blood flow rates. We concluded that the newly-developed smaller hollow fiber effectively augmented gas exchange capacity in extracapillary flow type oxygenator.

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A testing apparatus for study and evaluation of the effebcts of fluid dynamic shear stress on hemolytlc property blood under the real Reynolds number conditions for rotary blood pumps has been developed. This paper aims at clarifying the fluid dynamic characteristics of the apparatus that consists of afixed inner cyhnder and a rotating outer container forming a vertical cylindhcal gap and two horizontal conical gaps at the top and the bottom. On the basis of the Rayleigh-Taylor's analytical criterion, it is proved that the fluid driven only by the outer container does not develop centhfugal instabihties in the vertical gap. Therefbre, all the dynamics of the fluid is governed by phenomenon in the hohzontal gaps. As the cone angle is small, a deschption based on the rotating disk theory is apphcable fbr the dynamics in the conical gaps. An experimental investigation utiizing two hquids revealed that the flow sustains simultaneously laminar and turbulent regions and there is a chtical Reynolds number corresponding the spatial boundary that moves with the rotational speed.

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