The vascular structure in skin consists of standard arteriole-capillary-venule loops and arteriovenous anastomoses (AVA). Regulation of the blood flow in these two regions is different, and it is physiologically important to measure each blood flow separately. The theory of using laser blood flowmetry to separately measure the blood flow through superficial vessels, predominantly capillaries, and deeper vessels, arterioles, venules and AVA's, in the skin is discussed. In addition, results obtained by performing these measurements using probes with different optic fiber separations are reported. The real time recordings showed a different pattern of changes in blood flow for the two regions, as the body was warmed, confirming that changes in deeper AVA, and more superficial capillary blood flow, respond differently to thermal stimulation in the human finger. The proposed method of examination may be useful for assessing physiological functions and to estimate warm-hot environments.
A lot of monitors and medical electronic apparatus are used in criticalill patients. The chances of MRI examination in such patients are increased. Some troubles of infusion pump due to interference from the electrosurgical unit were reported. We thought that there was the possibility of malfunction in MRI examination as same as that situation .Therefore, we investigated malfunction of infusion pumps and precision of infusion rate. We made 7m circuit using X-2 extension tubes. We decided that the group we used infusion pump in normal situation was 7 m group and another group we used infusion pump in MRI examination was 7m-MRI group. In low infusion rate less than 20ml/hr, errors in 7m group were more increased than in 7m-MRI group. However, in high infusion rate more than 30ml/hr, errors in 7m-MRI group were more increased than in 7m group. We didn't observe the malfunction of infusion pumps during MRI examination. In conclusion, it seemed that we could use infusion pumps safely during MRI examination, if we placed them at 7m distance from MRI.