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Biomedical subjects

Atsuo Murata

Publications and source records attributed to Atsuo Murata.

At least 19 recordsLinked to original sources
PubMed2007

Applicability of location compatibility to the arrangement of display and control in human - vehicle systems: comparison between young and older adults.

The effects of age on applicability of the location compatibility principle to the design of display and control systems were discussed. A dual-task experiment was conducted, in which the primary task was first-order tracking. The secondary tasks included control of an air conditioner, the operation of a radio and the operation of a CD/MD, by means of either a steering wheel-mounted switch or a console-mounted switch. The display was arranged either in front of or on the left side of a participant. Performance of the young group did not completely follow predictions of the compatibility principle. In particular, the principle did not apply to the left-side display condition. The steering wheel-mounted switch was more effective than the left-side switch even for the left-side display. The compatibility principle was applicable to both front and left-side displays for the older adults. For the front display, the steering wheel-mounted switch was more effective. Such differences should be taken into account when designing display and control systems in man - vehicle systems.

Adult↗
PubMed2006

A multicenter, prospective validation of disseminated intravascular coagulation diagnostic criteria for critically ill patients: comparing current criteria.

OBJECTIVES: To validate scoring algorithm criteria established by the Japanese Association for Acute Medicine (JAAM) for disseminated intravascular coagulation (DIC) and to evaluate its diagnostic property by comparing the two leading scoring systems for DIC, from the Japanese Ministry of Health and Welfare (JMHW) and International Society on Thrombosis and Haemostasis (ISTH). DESIGN: Prospective, multicenter study during a 3-month period. SETTING: General critical care center in a tertiary care hospital. PATIENTS: Two hundred seventy-three patients with platelet counts<150x109/L were enrolled. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: The JAAM, JMHW, and ISTH DIC scoring algorithms were prospectively applied within 12 hrs of patients meeting the inclusion criteria (day 0) to days 1-3, by global coagulation tests. The numbers of systemic inflammatory response syndrome (SIRS) criteria and Sequential Organ Failure Assessment (SOFA) scores were determined simultaneously. Mortality associated with any cause was also assessed 28 days after the enrollment. All global coagulation tests and SIRS criteria adopted in the JAAM criteria and their cutoff points were validated with use of SOFA scores and mortality rate. DIC diagnostic rate of the JAAM DIC scoring system was significantly higher than that of the other two criteria (p<.001). The JAAM DIC algorithm was the most sensitive for early diagnosis of DIC (p<.001). PATIENTS who fulfilled the JAAM DIC criteria included almost all those whose DIC was diagnosed by the JMHW and ISTH scoring systems. The JAAM DIC scores showed significant correlation with SOFA scores ([rho]=0.499; p<.001). SOFA score and mortality rate worsened in accordance with an increase in the JAAM DIC score. Fibrinogen criteria had little effect in predicting outcome for the DIC patients, and a total score of 4 points in the JAAM scoring system without fibrinogen was closely related to poor prognosis. According to the results, we revised the JAAM criteria by excluding fibrinogen and confirmed that the DIC diagnostic properties of original criteria remained unchanged in the revised JAAM criteria. CONCLUSIONS: The JAAM scoring system has an acceptable property for the diagnosis of DIC. The scoring system identified most of the patients diagnosed by the JMHW and ISTH criteria. Revised JAAM DIC criteria preserved all properties of the original criteria for DIC diagnosis. The revised scoring system can be useful for selecting DIC patients for early treatment in a critical care setting.

Algorithms↗
PubMed2005

Blunt splenic injury: usefulness of transcatheter arterial embolization in patients with a transient response to fluid resuscitation.

PURPOSE: To evaluate the use of transcatheter arterial embolization (TAE) in hemodynamically unstable patients with blunt splenic injury in whom there is a transient response to initial fluid resuscitation. MATERIALS AND METHODS: Human subject committee approval and informed consent were obtained. Angiography was performed in patients with contrast material extravasation and/or splenic injury of grade III or higher (American Association for the Surgery of Trauma criteria) at computed tomography (CT). TAE was performed when angiograms showed disruption of terminal splenic branches or arterial extravasation. Among 104 patients with splenic injury, the 15 patients (10 male, five female; mean age, 36.2 years) with a transient response to fluid resuscitation were the subjects of this study. A post hoc analysis was performed for CT grades, angiographic findings, associated injuries, and hemodynamic status in the subjects. RESULTS: Among 15 patients with a transient response, two had grade III, 11 had grade IV, and two had grade V injuries at CT. Six patients had associated injuries that required TAE. TAE of the spleen and associated injuries was successfully performed in all patients. The mean systolic blood pressure and shock index at the start of TAE were 84.2 mm Hg +/- 9.2 (standard deviation) and 1.46 +/- 0.30, respectively, and those at the completion of TAE were 132.1 mm Hg +/- 18.7 and 0.77 +/- 0.21, respectively (P < .001). The fluid infusion rate within 24 hours after the completion of TAE (132.1 mL/h +/- 71.1) was lower than that from the completion of the initial fluid resuscitation until the completion of TAE (1230.6 mL/h +/- 264.8) (P < .001). CONCLUSION: TAE for blunt splenic injury can be performed successfully even in hemodynamically unstable patients with a transient response to initial fluid resuscitation.

Adolescent↗
PubMed2005

Relationship between pseudoaneurysm formation and biloma after successful transarterial embolization for severe hepatic injury: permanent embolization using stainless steel coils prevents pseudoaneurysm formation.

OBJECTIVE: The purpose of this study was to determine the association between bilomas and pseudoaneurysm complications after severe hepatic injury. METHODS: Angiography was performed in patients with American Association for the Surgery of Trauma grade > or = III hepatic injury on contrast-enhanced computed tomographic scanning. When contrast extravasation was observed, transarterial embolization (TAE) was performed. After TAE, technetium-99m pyridoxyl-5-methyl-tryptophan cholescintigraphy was performed to detect the coexistence of bilomas. Follow-up angiography was performed when a biloma was detected. Eighty consecutive patients underwent angiography; after angiography, five patients died. The remaining 75 patients who underwent cholescintigraphy were included in this study. RESULTS: All 11 patients who had bilomas had angiographic evidence of contrast extravasation. The biloma frequency was higher in patients with grades IV and V injuries than in those with grade III injury (p = 0.024). Follow-up angiography revealed pseudoaneurysms in 7 of these 11 patients. All six patients in whom only gelatin sponge pledget injection was used to embolize had pseudoaneurysms. Among them, two patients had computed tomographic evidence of massive intra-abdominal fluid collection. In contrast, only one of five patients who received the combination of gelatin sponge pledget injection and stainless steel coils to permanently embolize injured arteries had a pseudoaneurysm. In this patient, the pseudoaneurysm was found in the peripheral part of the collateral vessels. All patients with pseudoaneurysms underwent repeat TAE and were discharged from the hospital uneventfully. CONCLUSION: In patients with high-grade hepatic injury and arterial bleeding who developed biloma, use of a gelatin sponge, an absorbable embolic material, is associated with a risk of pseudoaneurysm formation. Permanent arterial embolization using stainless steel coils is indicated to decrease this risk.

Adolescent↗
PubMed2005

Evaluation of new Japanese diagnostic criteria for disseminated intravascular coagulation in critically ill patients.

New Japanese diagnostic criteria were prepared for disseminated intravascular coagulation (DIC) in critically ill patients and their usefulness was compared with the criteria of the International Society of Thrombosis and Haemostasis (ISTH) and those of the Japan Ministry of Health and Welfare (JMHW). In a retrospective study of patients with platelet counts of less than 150 x10(3)/mL, 52 cases (33.3%), 66 cases (42.3%), and 101 cases (64.7%) were diagnosed as DIC by the ISTH, JMHW, and new Japanese DIC criteria, respectively. The DIC state as diagnosed by the new Japanese DIC criteria included both DIC states as diagnosed by ISTH or JMHW criteria. Some DIC states diagnosed by the JMHW criteria included those diagnosed by ISHT criteria but this was not universal. The mortality of DIC as diagnosed by the ISTH or JMHW criteria was markedly high, compared to that for DIC diagnosed by the new Japanese criteria. The mortality of patients without DIC by ISTH was also high when they were diagnosed as DIC by the new Japanese criteria. The frequency of DIC by each set of diagnostic criteria was significantly higher in patients with infection than in those without infection. The mortality of DIC by each set of diagnostic criteria was significantly higher in patients with infection than in those without infection, and the mortality of overt-DIC by ISTH diagnostic criteria was also high in patients without infection.

Critical Illness↗
PubMed2005

Relationships among display features, eye movement characteristics, and reaction time in visual search.

The relative contribution of number of fixations and fixation duration to reaction time in visual search was investigated. Ten participants (age 20-24 years) took part in each of two experiments. In Experiment 1, the experimental factors were display type (icon and file name), organization (arrangements with and without grouping), and number of stimuli presented (4, 8, and 16). In Experiment 2, a search task for a target stimulus (three prespecified random letters) was conducted, and the experimental factor was the display's layout complexity. Multiple regression analysis was used to examine whether reaction time was explained by a mediational model in which reaction time is mediated by eye movements and display features are not directly related to reaction time. The mediational model was not supported, and the effects of display features on reaction time were not attributable solely to eye movements. The interaction between number of fixations and fixation duration was also explored as a function of display features. As the display feature changed and the task became more difficult, the contribution of the number of fixations to explain the variation in reaction time became dominant for both experiments. Potential applications include measurements of cognitive ability, eye muscle balance disorders, and binocular fusion ability.

Adult↗
PubMed2005

An attempt to evaluate mental workload using wavelet transform of EEG.

An attempt was made to evaluate mental workload using a wavelet transform of electroencephalographic (EEG) signals. Participants performed a continuous matching task at three levels of task difficulty. EEG signals during the task were recorded continuously from Fz, Cz, and Pz. The reaction time increased as the difficulty of the task increased. The percentage correct decreased as the task became more difficult. In accordance with this, the rating score on the NASA-Task Load Index tended to increase with increased task difficulty. The EEG signals were analyzed using wavelet transform to investigate time-frequency characteristics. The total power at theta, alpha, and beta frequency bands and the time that the maximum power appeared for the three frequency bands were extracted from the scalogram. Increasing cognitive task difficulty seems to delay the time at which the central nervous system works most actively. These measures were found to be sensitive indicators of mental workload and could differentiate three cognitive task loads (low, moderate, and high) with high precision. Actual or potential applications of this research include a method that is relatively quick and accurate, compared with traditional methods, for the evaluation of mental workload.

Adult↗
PubMed2005

Usability of touch-panel interfaces for older adults.

The usability of a touch-panel interface was compared among young, middle-aged, and older adults. In addition, a performance model of a touch panel was developed so that pointing time could be predicted with higher accuracy. Moreover, the target location to which a participant could point most quickly was determined. The pointing time with a PC mouse was longer for the older adults than for the other age groups, whereas there were no significant differences in pointing time among the three age groups when a touch-panel interface was used. Pointing to the center of a square target led to the fastest pointing time among nine target locations. Based on these results, we offer some guidelines for the design of touch-panel interfaces and show implications for users of different age groups. Actual or potential applications of this research include designing touch-panel interfaces to make them accessible for older adults and predicting movement times when users operate such devices.

Adult↗
PubMed2004

Brain death due to abdominal compartment syndrome caused by massive venous bleeding in a patient with a stable pelvic fracture: report of a case.

We report a rare case in which abdominal compartment syndrome resulting from venous hemorrhaging developed in a patient with stable pelvic fractures, resulting in a fatal outcome. An 84-year-old man with mild pelvic fractures developed hypovolemic shock and underwent transcatheter arterial embolization. He became hemodynamically stable after the procedure, but became hypotensive for the second time 11 h after admission. Urinary bladder pressure rose to 32 mmHg from 4-7 mmHg. Rebleeding from the pelvis with the development of abdominal compartment syndrome was suspected. Repeated transcatheter arterial embolization and laparotomy were performed; however, 1 min into the procedure, both pupils symmetrically dilated and the light reflex disappeared. This case suggests that brain death can sometimes occur due to abdominal compartment syndrome.

Accidental Falls↗
PubMed2004

The usefulness of transcatheter arterial embolization for patients with blunt polytrauma showing transient response to fluid resuscitation.

BACKGROUND: This study aimed to determine whether nonsurgical management using transcatheter arterial embolization (TAE) is safe for patients with blunt multiple trauma who transiently respond to the initial fluid resuscitation. METHODS: Contrast computed tomography was performed for patients with blunt abdominal injuries, excluding those who did not respond to initial fluid resuscitation. Angiography was performed for patients with injuries showing contrast extravasation or solid organ injury classified, according to the American Association for the Surgery of Trauma, as grade 3 or higher on computed tomography. Transcatheter arterial embolization was performed when angiography showed arterial extravasation. The protocol was abandoned for any patients who became profoundly hypotensive (with systolic blood pressure 60 mm Hg or lower) during computed tomography or angiography. RESULTS: Between January 2000 and December 2002, 269 patients with blunt abdominal injuries underwent TAE immediately after admission. Of these patients, 41 had injuries in at least two regions and underwent TAE for these regions. Among them, 22 patients were hemodynamically stable or showed rapid response to fluid resuscitation. The nonsurgical treatment was successful in all these cases. The remaining 19 patients (Injury Severity Score, 37.3 +/- 8.2), who showed a transient response, were the subjects of this study. Of these patients, 15 underwent TAE for injuries in two regions (13 pelvic fractures, 7 splenic injuries, 6 hepatic injuries, 3 facial bleeding, and 1 renal injury), and 4 patients underwent TAE for injuries in three regions (4 had splenic injuries, 3 hepatic injuries, 2 renal injuries, 2 pelvic fractures, and 1 facial bleeding). For all these patients, TAE was successfully performed. Before TAE, the systolic blood pressure was 79.9 +/- 8.4 mm Hg, and the shock index was 1.45 +/- 0.25 mm Hg. After TAE, the corresponding values were 120.6 +/- 19.3 mm Hg and 0.87 +/- 0.16 mm Hg, respectively (p < 0.001). The rate of fluid administration required after TAE (214.2 +/- 139.3 mL/hour) was significantly less than that required before TAE (1244.2 +/- 347.1 mL/hour; range, 632-1,728 mL/hour) (p < 0.001). The deaths of two patients were classified as nonpreventable on the basis of the Trauma and Injury Severity Score (TRISS), and their respective probabilities of survival were determined to be 0.13 and 0.03. CONCLUSION: Nonsurgical management using TAE can be performed safely even for patients with blunt multiple trauma who are in hemorrhagic hypotension if their hemodynamics are improved by resuscitation with 2 L of fluid.

Abdominal Injuries↗
PubMed2004

Foveal task complexity and visual funneling.

The current study was designed to examine whether increasing foveal task complexity would cause the functional field to shrink as a result of a visual funneling effect. Using 8 male participants, the study examined whether the effects of foveal task complexity on peripheral performance was most pronounced at the far periphery. The response time to an addition task using foveal vision tended to increase with the increase of the visual angle. The percentage correct, however, did not differ among 3 levels of task complexity or among 4 levels of visual angle. The miss rate in the peripheral vision task tended to increase with the increase in not only the complexity of the foveal task but also the visual angle. This is indicative of visual funneling. However, greater funneling was not necessarily observed for response time. In this study, response time was not a sensitive measure of visual funneling. Actual or potential applications of this research include safe driving and other vigilance tasks.

Adolescent↗