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Highly sensitive infrared photodetectors are needed in numerous sensing and imaging applications. In this paper, we report on extended short-wave infrared (e-SWIR) avalanche photodiodes (APDs) capable of operating at room temperature (RT). To extend the detection wavelength, the e-SWIR APD utilizes a higher indium (In) composition, specifically In0.3Ga0.7As0.25Sb0.75/GaSb heterostructures. The detection cut-off wavelength is successfully extended to 2.6 µm at RT, as verified by the Fourier Transform Infrared Spectrometer (FTIR) detection spectrum measurement at RT. The In0.3Ga0.7As0.25Sb0.75/GaSb heterostructures are lattice-matched to GaSb substrates, ensuring high material quality. The noise current at RT is analyzed and found to be the shot noise-limited at RT. The e-SWIR APD achieves a high multiplication gain of M~190 at a low bias of Vbias=- 2.5 V under illumination of a distributed feedback laser (DFB) with an emission wavelength of 2.3 µm. A high photoresponsivity of R>140 A/W is also achieved at the low bias of Vbias=-2.5 V. This type of highly sensitive e-SWIR APD, with a high internal gain capable of RT operation, provides enabling technology for e-SWIR sensing and imaging while significantly reducing size, weight, and power consumption (SWaP).

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BACKGROUND: The use of supraglottic airways has been recommended in combat trauma airway management. To ensure an adequate airway management on the battlefield, suitable training concepts are sought to efficiently teach as many soldiers as possible. Our aim was to compare three approaches of teaching laypersons in the handling of supraglottic airways in a mannequin model. METHODS: In this prospective randomized blinded study, 285 military service men without any medical background were divided into three groups and trained in the use of the Laryngeal Mask Airway Supreme (LMA) and the Laryngeal Tube Disposable (LT-D). The first group received a theoretical lecture, the second group was shown an instruction video, and the third group underwent a practical training. Immediately after instruction participants were asked to place the supraglottic airway and ventilate the mannequin within 60 seconds. The entire test was repeated 3 months later. Test results were evaluated with regard to success rate, insertion time, ability to judge the correct placement, and degree of difficulty. RESULTS: Practical training showed the highest success rate when placing supraglottic airways immediately after the instruction (lecture: 68%, video: 74%, training: 94%); (training vs. lecture and training vs. video, p < 0.001) as well as 3 months later (lecture: 63%, video: 66%, training: 78%); (training vs. lecture, p = 0.019 and training vs. video, p = 0.025). Immediately after the instruction practical training was also superior in terms of insertion time, ability to judge the correct placement, and the self-rated degree of difficulty (p < 0.001). These effects were significantly reduced 3 months after the instruction. In comparison between supraglottic airways LT-D was superior to LMA regarding all the outcome parameters mentioned above (p < 0.001). DISCUSSION: In this study, performed with personnel of the German Armed Forces, we have shown that persons without any medical and paramedical background are able to successfully place a supraglottic airway immediately following minimal instruction and after 3 months as well. Study participants achieved the best results after practical training followed by video presentation and finally lecture regardless of the airway device used. There are two possible reasons why practical training is the superior method. Firstly, the success is tied to more time spent with the learners. Secondly, practical training seems to be the best teaching method for various types of learners such as visual, auditory, reading/writing, and kinesthetic type. In addition the results of our study show that the LT-D is an ideal supraglottic airway in the hands of people inexperienced in airway management. In conclusion, our results show that practical training is the superior instruction method compared to theoretical lecture and presentation of an instruction video. Nevertheless, the presentation of an instruction video is a promising approach of teaching a maximum number of laypersons with minimal effort to correctly place supraglottic airways. To optimize the success rate of such a concept LT-Ds instead of LMAs should be used for airway management. The presented concepts hold promise for combat as well as for civilian emergency medicine.

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The treatment of patients in mass casualties generally requires a high level of organisational understanding. The delivery of medical care to one patient should not cause delays in helping all other patients. Therefore triage and a prioritisation of treatment and transport is necessary. Military triage has developed over centuries and forms the basis of civilian triage. The differences between both systems include established military triage performed by paramedics and care under fire. These characteristics have led to the development of separate algorithms.

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