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October 16-20, 2010 San Diego, CA Home Abstract Archive Search Abstracts 2010 Session Grid 2010 Meeting Website Policy Statements ASA Website Feedback 
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A933
October 19, 2009 2:00 PM - 4:00 PM Room Area M |
| Design and Evaluation of a Head-Mounted Display System for Ultrasound Guided Regional Anesthesia |
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Hiroshi Sekiyama, M.D., Masaaki Asamoto, M.D., Yuichiro Saito, M.D., Masahiko Sumitani, Ph.D., M.D., Yoshitsugu Yamada, M.D., Ph.D. Department of Anesthesiology, University of Tokyo, Bunkyo-ku, Tokyo, Japan |
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INTRODUCTION:
In recent years, use of ultrasound-guided nerve block (USNB) has increased because of its higher efficacy and safety. Generally, USNB practitioners look at a display on the ultrasonograph machine itself and not at the manipulation on the patient's body surface. To perceive visual information during real-time manipulation on the patient's body surface, practitioners must transfer their gaze to the patient's body surface from the display. Simultaneous perception of visual information on both the machine monitor and manipulation of the needle would ensure safer USNB. Recently, we developed a new device for simultaneous perception that uses a head-mounted display (HMD). In this study, we present the design of our system and the effects of wearing it on the procedure.
METHODS: (1) The setup consists of a 12-MHz linear transducer, ultrasonograph machine body (LOGIQe, GE Healthcare), down-scan converter (TVC-XGA2,IO Data), PC, and HMD (Data Glass 2/A, Shimadzu Co.). The HMD has a compact eyeglass design with a see-through liquid crystal display that provides an image equivalent to a 13-inch screen at 60 cm. When the practitioner wearing this HMD system performs the manipulation in a phantom with one hand holding the probe and the other hand the insulated needle, the system enables a look at the gross manipulation while showing the ultrasonographic observation though a 13-inch screen at 60 cm in the third quadrant of the visual field. (2) This HMD system may encumber manipulations during USNB due to unfamiliarity. To determine whether the HMD encumbers the procedure, six experienced anesthesiologists were enrolled. Each practitioner performed needle-insertions using in-plain technique for 30 seconds to generate a “doughnut sign” around the target phantom, under ultrasound-guidance. USNB was done once with the conventional method and once with the HMD system. A squid arm-embedded chicken model was used as the phantom. Each video image of the procedure was recorded and stored. After the trial, comments about merits, demerits, and ease of use were obtained from the subjects. (3) All video images were divided into a conventional group and an HMD group and played back to estimate the needle-visualization time out of 60 seconds. Data were analyzed with the unpaired t-test and p values less than 0.05 were considered statistically significant. RESULTS : Average needle-visualization time of the conventional group was 40.3 ± 12.7 s, whereas that of the HMD group was 3.15 ± 11.9 s. There were no significant differences between the groups (p=0.243). With HMD, subjects liked the continuous perception of visual information on ultrasonographic observation and the manipulation of the needle and the fact that it was not necessary to move one's head; whereas they disliked the time-lag of approximately 1s, the poor image quality, and the difficult focal shift between the puncture site and HMD within the same visual field. CONCLUSIONS :We developed a HMD system for USNB, which allows for simultaneous visual perception of both ultrasonographic observation and manipulation of the needle. The HMD system may not encumber the manipulations of USNB. Practical application ofthis system will require further improvement of hardware. From Proceedings of the 2009 Annual Meeting of the American Society Anesthesiologists. |