Current pre-hospital traumatic brain injury management in China

BACKGROUND: Traumatic brain injury(TBI) is associated with most trauma-related deaths. Secondary brain injury is the leading cause of in-hospital deaths after traumatic brain injury. By early prevention and slowing of the initial pathophysiological mechanism of secondary brain injury, prehospital service can signifi cantly reduce case-fatality rates of TBI. In China, the incidence of TBI is increasing and the proportion of severe TBI is much higher than that in other countries. The objective of this paper is to review the pre-hospital management of TBI in China.DATA SOURCES: A literature search was conducted in January 2014 using the China National Knowledge Infrastructure(CNKI). Articles on the assessment and treatment of TBI in pre-hospital settings practiced by Chinese doctors were identified. The information on the assessment and treatment of hypoxemia, hypotension, and brain herniation was extracted from the identifi ed articles.RESULTS: Of the 471 articles identified, 65 met the selection criteria. The existing literature indicated that current practices of pre-hospital TBI management in China were sub-optimal and varied considerably across different regions.CONCLUSION: Since pre-hospital care is the weakest part of Chinese emergency care, appropriate training programs on pre-hospital TBI management are urgently needed in China.

Responsivity and noise characteristics of AlGaN/GaN-HEMTterahertz detectors at elevated temperatures

The responsivity and the noise of a detector determine the sensitivity. Thermal energy usually affects both the responsivity and the noise spectral density. In this work, the noise characteristics and responsivity of an antenna-coupled AlGaN/GaN high-electron-mobility-transistor(HEMT) terahertz detector are evaluated at temperatures elevated from 300 K to 473 K. Noise spectrum measurement and a simultaneous measurement of the source–drain conductance and the terahertz photocurrent allow for detailed analysis of the electrical characteristics, the photoresponse, and the noise behavior. The responsivity is reduced from 59 mA/W to 11 mA/W by increasing the detector temperature from 300 K to 473 K. However,the noise spectral density maintains rather constantly around 1–2 pA/Hz^(1/2) at temperatures below 448 K, above which the noise spectrum abruptly shifts from Johnson-noise type into flicker-noise type and the noise density is increased up to one order of magnitude. The noise-equivalent power(NEP) is increased from 22 pW/Hz^(1/2) at 300 K to 60 pW/Hz^(1/2) at 448 K mainly due to the reduction in mobility. Above 448 K, the NEP is increased up to 1000 pW/Hz^(1/2) due to the strongly enhanced noise. The sensitivity can be recovered by cooling the detector back to room temperature.

The origin of distorted intensity pattern sensed by a lens and antenna coupled AlGaN/GaN-HEMT terahertz detector

Antenna-coupled field-effect-transistors(FETs) offer high sensitivity for terahertz detection. Both the magnitude and the polarity of the response signal are sensitive to the localized terahertz field under the gate. The ability of accurate sensing the intensity pattern is required for terahertz imaging systems. Here, we report artefacts in the intensity pattern of a focused terahertz beam around 1 THz by scanning a silicon-lens and antenna coupled AlGaN/GaN high-electron-mobility-transistor(HEMT) detector. The origin of the image distortion is found to be connected with one of the antenna blocks by probing the localized photocurrents as a function of the beam location and the frequency. Although the exact distortion is found with our specific antenna design, we believe similar artefacts could be commonplace in antenna-coupled FET terahertz detectors when the beam spot becomes comparable with the antenna size. To eliminate such artefacts, new antenna designs are welcomed to achieve strong asymmetry in the terahertz field distribution under the gate while maintaining a more symmetric radiation pattern for the whole antenna.

Integration of a field-effect-transistor terahertz detector with a diagonal horn antenna

Efficient coupling of terahertz electromagnetic wave with the active region in a terahertz detector is required to enhance the optical sensitivity. In this work, we demonstrate direct integration of a field-effect-transistor（FET） terahertz detector chip at the waveguide port of a horn antenna. Although the integration without a proper backshot is rather preliminary, the noise-equivalent power is greatly reduced from 2.7 nW/Hz^（1/2） for the bare detector chip to 76 pW/Hz^（1/2） at340 GHz. The enhancement factor of about 30 is confirmed by simulations revealing the effective increase in the energy flux density seen by the detector. The simulation further confirms the frequency response of the horn antenna and the onchip antennas. A design with the detector chip fully embedded within a waveguide cavity could be made to further enhance the coupling efficiency.

Emergency department use among patients from residential aged care facilities under a Hospital in the Nursing Home scheme in public hospitals in Queensland Australia

BACKGROUND: Hospital emergency department(ED) use by patients from residential aged care facilities(RACFs) is not always appropriate, and this calls for interventions to avoid some unnecessary uses. This study aims to compare patterns of ED use by RACF patients with and without a Hospital in the Nursing Home(Hi NH) program.METHODS: RACF patients presenting to EDs of a hospital with and a hospital without this program during pre- and post-intervention periods were included. Data on patient demographics and ED presentation characteristics were obtained from the Emergency Department Information System database, and were analysed by descriptive and comparative statistics.RESULTS: In both hospitals, most RACF residents presenting to EDs were aged between 75–94 years, female, triaged at scale 3 to 5, and transferred on weekdays and during working hours. Almost half of them were subsequently admitted to hospitals. In accordance with the ICD-10-AM diagnostic coding system, diagnoses that consistently ranked among the top three reasons for visiting the two hospitals before and after intervention included Chapter XIX: injury and poisoning and Chapter X: respiratory diseases. Associated with the intervention, significant decreases in the numbers of presentations per 1 000 RACF beds were identified among patients diagnosed with Chapter XI: digestive diseases [rate ratio(95%CI): 0.09(0.04, 0.22); P<0.0001] and Chapter XXI: factors influencing health status and contact with health services [rate ratio(95%CI): 0.22(0.07, 0.66); P=0.007].CONCLUSION: The Hi NH program may reduce the incidence of RACF residents visiting EDs for diagnoses of Chapter XI and Chapter XXI.