To make US-guided peripheral venipuncture widely acceptable across Japan, we developed a device to hold an US probe. The aim of this study was to identity the utility of the probe holder to perform simple and accurate US-guided peripheral venipuncture. Forty-eight nursing students were allocated to 3 groups：group A performed traditional peripheral venipuncture, group B performed conventional US-guided peripheral venipuncture, and group C performed US-guided peripheral venipuncture with the probe holder. All participants performed the specific venipuncture procedure assigned to the group using a venipuncture training aid model including a simulated invisible venous model. The success rate of peripheral venipuncture within three attempts was 56%（n=9）in group A, 75%（n=12）in group B, and 100%（n=16）in group C, with a significant difference between group A and C. Subjective difficulty of IV cannulation was evaluated significantly lower in groups B and C compared with group A. Our findings suggest that the novel probe holder enables easy and accurate US-guided venipuncture in veins that are not or hardly visible.

In this study, we evaluated the influence of multi-task conditions on walking balance, by investigating the variation of hip acceleration. We employed an inertial measurement unit（IMU）sensor attached to the hips of subjects, and measured the hip acceleration during normal walking and walking under multi-task conditions. The hip acceleration with respect to the base frame was derived by Kalman filter, and we defined the increase rate of acceleration during walking under multi-task conditions to the one during normal walking. The results suggested that the auditory task and the combination of auditory and calculation tasks influence walking balance, and the acceleration in the left and right directions with respect to traveling direction were mainly deviated by the tasks. Moreover, we showed that walking balance is capable to be evaluated by a simple system utilizing only one IMU sensor.

Patients feel much pain during epidural needle insertion, due to deformation of the skin before puncturing. In order to develop a painless epidural insertion needle, purpose of the current study was quantification of pain by calculation of strain derivative inside the skin with finite element analysis（FEM）. A mimicked skin for epidural insertion training was employed. Epidural needle insertion experiment against the mimicked skin showed actual insertion force and skin deformation. Results of the FEM matched with the experimental data satisfactory. When the epidural needle was inserted 0.8 mm into the mimicked skin, strain derivative was calculated as 0.49/mm in the location of 0.5 mm from the surface. The strain derivative with the epidural needle showed 1.5 times value as large as the strain derivative with an indenter for rubber stiffness. Thus, pain intensity could compare not only by visual analogue scale method, but also by the calculated strain derivative inside skin.