Developing a multimodal biosensor for remote physiological monitoring

INTRODUCTION

Several UK military expeditions have successfully used physiological sensors to monitor participant's physiological responses to challenging environmental conditions. This article describes the development and trial of a multimodal wearable biosensor that was used during the first all-female unassisted ski crossing of the Antarctic land mass. The project successfully transmitted remote real-time physiological data back to the UK. The ergonomic and technical lessons identified have informed recommendations for future wearable devices.

METHOD

The biosensor devices were designed to be continuously worn against the skin and capture: HR, ECG, body surface temperature, bioimpedance, perspiration pH, sodium, lactate and glucose. The data were transmitted from the devices to an android smartphone using near-field technology. A custom-built App running on an android smartphone managed the secure transmission of the data to a UK research centre, using a commercially available satellite transceiver.

RESULTS

Real-time physiological data, captured by the multimodal device, was successfully transmitted back to a UK research control centre on 6 occasions. Postexpedition feedback from the participants has contributed to the ergonomic and technical refinement of the next generation of devices.

CONCLUSION

The future success of wearable technologies lies in establishing clinical confidence in the quality of the measured data and the accurate interpretation of those data in the context of the individual, the environment and activity being undertaken. In the near future, wearable physiological monitoring could improve point-of-care diagnostic accuracy and inform critical medical and command decisions.

Systematic approach to delivering prolonged field care in a prehospital care environment

BACKGROUND

This article describes a novel patient care algorithm which provides a Role 1 (R1) medic with a structured approach to delivering prolonged field care (PFC) in a resource-limited environment. PFC is a vital component of the operational patient care pathway providing the continuum of care from completion of a primary survey to the delivery to hospital care. Future operational environments are likely to have more fragile or extended lines of communication, potentially delaying evacuation to hospital care. This delay may lead to increases in patient morbidity and mortality. Effective PFC offers an opportunity to improve patient outcomes and help mitigate against this risk.

METHODS

An initial prototype model of a PFC care process was developed using existing hospital-based guidance. A series of medical and trauma vignettes and best available evidence were used to refine the algorithm.

RESULTS

The algorithm has been designed be used in conjunction with patient specific clinical guidance making the approach generalisable for all patient groups. For UK military, clinical guidance is provided by clinical guidelines for operations. The algorithm can be downloaded into a convenient format to be used on mobile devices or printed as an aide memoire.

Epidemiological study of emergency ambulance activation in the British Eastern Sovereign Base Area of Cyprus, September 2013 to August 2016

Objectives

To record the activation and use of the Eastern Sovereign Base Area (ESBA) emergency ambulance service of British Forces Cyprus between 1 September 2013 and 31 August 2016. To reflect on these findings in light of data from 1995 to 1998 to identify current treads and areas of development.

Method

Retrospective epidemiological study of all activations of the ESBA emergency ambulance service within the study period.

Results

812 patients were treated over 3 years, an 80% increase in workload, of which 41% were entitled personnel. Forty-two per cent of activations were for medical complaints compared with 41% for trauma. The number of deaths remained static (n=15). Road traffic incidents (RTI) remain the top activation by type, but accounting for a smaller proportion of workload. RTI mortality has declined by 50%.

Conclusion

The ESBA emergency ambulance service responded to double the activations, when compared with 18 years ago, with a significant shift to medical cases over trauma. This ESBA emergency ambulance provides a varied and vital service for the local community that also benefits Defence Medical Services personnel interested in the Pre-Hospital Emergency Medicine environment in order to maintain clinical skills and currency for the benefit of future deployments, both humanitarian and kinetic in nature.

Unusual case of suspected recurrent scarlet fever in a UK serviceman

The UK prevalence of scarlet fever, a Group A streptococcal infection, is increasing. We present an unusual case of suspected recurrent scarlet fever in a member of the UK Armed Forces. Treatments, occupational implication and public health measures to mitigate the risk of disease spread.

An exertional heat illness triage tool for a jungle training environment

This article introduces a practical triage tool designed to assist commanders, jungle training instructors (JTIs) and medical personnel to identify Defence Personnel (DP) with suspected exertional heat illness (EHI). The challenges of managing suspected EHI in a jungle training environment and the potential advantages to stratifying the urgency of evacuation are discussed. This tool has been designed to be an adjunct to the existing MOD mandated heat illness recognition and first aid training.

Light-emitting nanocasts formed from bio-templates: FESEM and cathodoluminescent imaging studies of butterfly scale replicas

Nanocasts comprising of red-light-emitting cubic Y(2)O(3):Eu phosphors were made from butterfly wing scale bio-templates. We report herein the first cathodoluminescent images made from such nanocasts and show that valuable insights into the nature of the internal structure of the casts can be gained by the use of this technique. The casts faithfully reproduced the fine sub-micrometre size detail of the scales, as was made evident by both FESEM and cathodoluminescent images that were collected from the same sample areas using a hyphenated FESEM-CL instrument. There was excellent agreement between the FESEM and cathodoluminescent images, the image quality of the latter indicating that the Eu(3+) activator ions were evenly dispersed in the Y(2)O(3):Eu phosphor on a sub-micrometre scale. The casts were made by infilling the natural moulds with a Y(2)O(3):Eu precursor solution that was subsequently dried and fired to convert it into the phosphor material. This method provides a simple, low cost route for fabricating nanostructures having feature dimensions as small as 20 nm in size, and it has the potential to be applied to other metal oxide systems for producing nano-and micro-components for electronic, magnetic or photonic integrated systems.

Semi-quantitative analysis of indigo carmine, using silver colloids, by surface enhanced resonance Raman spectroscopy (SERRS)

The application of surface enhanced resonance Raman spectroscopy (SERRS) to the semi-quantitative analysis of the dye, indigo carmine, has been examined using citrate-reduced silver colloids. Good linear correlations are observed for the dye band at 1580 cm(-1) in the concentration range 10(-7)-10(-5) and 10(-9)-10(-5) mol dm(-3), using laser exciting wavelengths of 514.5 [(R=0.9983)] and 632.8 nm [(R=0.9978)], respectively. At concentrations of dye above 10(-6) M the concentration dependence of the SERRS signals is non-linear due to the coverage of the surface of the colloidal particles by the dye being in excess of a full monolayer. At concentrations above 10(-6) M resonance Raman spectroscopy (RRS) can be employed for the quantitative analysis of the dye. An internal standard was used and a good linear correlation (R=0.997) was observed for the dependence of dye signal intensities at 1580 cm(-1) in the concentration range 10(-5)-10(-4) M using a laser exciting wavelength of 514.5 nm. The limits of detection of indigo carmine by SERRS (514.5 nm), SERRS (632.8 nm) and solution RRS (514.5 nm) are found to be 0.9, 1 and 38 ppm, respectively.

Semi-quantitative analysis of indigo by surface enhanced resonance Raman spectroscopy (SERRS) using silver colloids

In this paper we report for the first time semi-quantitative analysis of indigo using surface enhanced Raman spectroscopy (SERS) and surface enhance resonance Raman spectroscopy (SERRS). Indigo, a dye widely used today in the textile industry, has been used, historically, both as a dye and as a pigment; the latter in both paintings and in printed material. The molecule is uncharged and largely insoluble in most solvents. The application of SERS/SERRS to the semi-quantitative analysis of indigo has been examined using aggregated citrate-reduced silver colloids with appropriate modifications to experimental protocols to both obtain and maximise SERRS signal intensities. Good linear correlations are observed for the dependence of the intensities of the SERRS band at 1151 cm(-1) using laser exciting wavelengths of 514.5 nm (R=0.9985) and 632.8 nm (R=0.9963) on the indigo concentration over the range 10(-7)-10(-5) and 10(-8)-10(-5) mol dm(-3), respectively. Band intensities were normalised against an internal standard (silver sol band at 243 cm(-1)). Resonance Raman spectra (RRS) of aqueous solutions of indigo could not be collected because of its low solubility and the presence of strong fluorescence. It was, however, possible to obtain RS and RRS spectra of the solid at each laser excitation wavelength. The limits of detection (L.O.D.) of indigo by SERS and SERRS using 514.5 and 632.8 nm were 9 ppm at both exciting wavelengths. Signal enhancement by SERS and SERRS was highly pH dependent due to the formation of singly protonated and possibly doubly protonated forms of the molecule at acidic pH. The SERS and SERRS data provide evidence to suggest that an excess of monolayer coverage of the dye at the surface of silver colloids is observed at concentrations greater than 7.85x10(-6) mol dm(-3) for each exciting wavelength. The data reported herein also strongly suggest the presence of multiple species of the indigo molecule.

Observations of HIV-1 Genotypic Drug Resistance in a Trial of Four Reverse Transcriptase Inhibitors (Quattro Trial)

The Quattro Trial compared the use of four HIV-1 reverse transcriptase (RT) inhibitors (zidovudine, lamivudine, loviride and zalcitabine), given either as four-drug combination therapy or monotherapy, with 8-week cycles of each drug, with zidovudine/lamivudine dual therapy. Observations of resistance associated and other mutations in the RT gene were made to determine whether therapy failure could be explained by acquisition of these mutations and whether novel mutation patterns developed. As in the intent-to-treat analysis, the use of cyclical monotherapy gave a smaller reduction in plasma virus load at 64 weeks (0.4 log10 copies/ml below baseline) than the quadruple or dual therapy arms (1.3 and 0.8 log10 copies/ml below baseline). Cyclical therapy appeared to generate less genotypic resistance to zidovudine, loviride or zalcitabine than the other arms. Resistance to lamivudine (mutation M184V) developed rapidly in all three arms. Resistance to zidovudine was acquired by a larger proportion of subjects on dual therapy than on quadruple therapy. Resistance to loviride or zalcitabine was rarely observed. During lamivudine monotherapy the M184V mutation was rapidly acquired and viral load rebounded. Zalcitabine monotherapy initially selected M184V mutants, but these were lost as therapy continued. Novel mutations that may have been associated with combination or cyclical quadruple therapy were observed infrequently. There was no clear correlation between changes in response to therapy and the development of previously described resistance mutations or with novel mutations in the RT gene.