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Remote physiological monitoring in an austere environment: a future for battlefield care provision?
  1. Matthew J Smyth1,
  2. J A Round2,3 and
  3. A J Mellor1
  1. 1 Defence Medical Group (North), South Tees Hospitals NHS Foundation Trust, Middlesbrough, UK
  2. 2 34 Field Hospital, Queen Elizabeth Barracks, York, UK
  3. 3 James Cook University Hospital, Middlesbrough, UK
  1. Correspondence to J A Round, James Cook University Hospital, Middlesbrough TS4 3BW, UK; Jonathan.Round1{at}nhs.net

Abstract

Wearable technologies are making considerable advances into the mainstream as they become smaller and more user friendly. The global market for such devices is forecasted to be worth over US$5 billion in 2018, with one in six people owning a device. Many professional sporting teams use self-monitoring to assess physiological parameters and work rate on the pitch, highlighting the potential utility for military command chains. As size of device reduces and sensitivity improves, coupled with remote connectivity technology, integration into the military environment could be relatively seamless. Remote monitoring of personnel on the ground, giving live updates on their physiological status, would allow commanders or medical officers the ability to manage their soldiers appropriately and improve combat effectiveness. This paper explores a proof of concept for the use of a self-monitoring system in the austere high altitude environment of the Nepalese Himalayas, akin to those experienced by modern militaries fighting in remote locations. It also reviews, in part, the historical development of remote monitoring technologies. The system allowed for physiological recordings, plotted against GPS position, to be remotely monitored in Italy. Examples of the data recorded are given and the performance of the system is discussed, including limitations, potential areas of development and how systems like this one could be integrated into the military environment.

  • biotechnology & bioinformatics
  • altitude medicine
  • physiology

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Key messages

  • Wearable technologies are becoming more mainstream in everyday life, within both the social and professional markets.

  • Wearable technologies have the potential to be integrated into the modern battlefield to provide real-time updates to commanders on the health of their soldiers.

  • Basic physiological parameters, HR and oxygen saturations, can be interpreted to provide a simplified clinical picture.

  • Coupling this with geotagging can facilitate in the generation of real-time location and physiological status of a soldier as demonstrated by the INMM self-monitoring kit.

  • We successfully tested the INMM self-monitoring kit in an austere environment, thus proving such systems have a future in enabling effective command of medical support.

Introduction

Modern warfare has developed extensively over the last century through advancements in technology. Improvements in remotely piloted systems, use of satellite imagery and overhead surveillance have improved commanders’ understanding of the battlefield. The recent conflicts in Afghanistan and Iraq highlighted the importance of technological advances in personnel protective equipment and machinery to defend the lives of the soldiers on the ground from the combative enemy and roadside explosives. These changes have been popularly credited in decreasing the morbidity and mortality of service personnel from ballistic injury.1 2 However, environmental conditions continue to pose a threat to service personnel as highlighted by recent deaths on training in the UK.3

The significant effects of fatigue during conflict and the importance of managing this in order to prevent non-combat casualties is well documented and discussed.4 The UK Armed Forces have for many years had detailed policy for the prevention and management of climatic injuries; despite this, these injuries continue to occur. Many soldiers do not realise, nor are they willing to acknowledge, that their physical performance and the performance of others are deteriorating as fatigue takes over the body. Physical fatigue in a hostile environment, hot or cold, will significantly raise the risk of climatic injury. During warfighting, soldiers not only have to contend with hostile environmental conditions and physical fatigue, they may be placed under considerable psychological stress that can be compounded by sleep deprivation. For a commander to have the ability to remotely monitor a soldier’s physical performance and well-being could provide an effective tool in optimising the deployed force, physically and mentally, reducing climatic injury and maintaining combat effectiveness.

Clinical use of ambulatory monitoring is established as a diagnostic tool and is used in the monitoring of long-term medical conditions. These devices have also been used to monitor patients in more isolated clinical environments where medical expertise may not be immediately available. A prime example of where such monitoring has been invaluable is the Space environment. During the Space Race of the 1960s, the Gemini Programme was designed to develop techniques that would allow for advanced, long duration space travel, of which physiological monitoring devices would be the key devices. Spacelabs Medical pioneered the use of medical telemetry as a direct output of developments during the space programme.5

As extraterrestrial monitoring developed, so did the aspirations to introduce biotelemetry to the battlefield. In the 1980s, a US Army scientist named Tacker6 started to develop early concept designs focusing on a method of determining whether or not a casualty, in full chemical protective gear, was dead or alive without violating the integrity of the protective gear. To facilitate this, Tacker designed a wrist-worn sensor system that could detect motion, HR and respiration. His early prototypes were effective in providing the required information; however, the monitors had limited practical use due to their size.

Current developments

The area of advanced combat wearable electronics is currently being developed by different militaries in collaboration with industry. Lockheed Martin is developing an adhesive transdermal patch that analyses electrolyte levels in perspiration.7 The US Air Force Research Laboratory, working with several partner universities, is developing a system of wireless sensors that can be used in emergency response operations to aide triage of patients through vital sign monitoring.8 An Italian based company, In Manibus Meis - known as INMM,9 currently supplies remote monitoring information technology systems for medical assistance to manage rescue operations and disaster relief but have aspirations to introduce their technology into military operations. We were given the opportunity to test an example of this technology, INMM self-monitoring kit (Figure 1), now known as TRAMA during a remote and high altitude trek in Nepal. This demonstrated a proof of concept for the use of intelligent sensors to assess the real-time physiological status of the soldiers in a hostile environment. This information could enable military commanders and their medical advisors to maximise their soldiers’ combat effectiveness.

Figure 1

INMM self-monitoring kit with cold weather beanie.

INMM self-monitoring kit (TRAMA)

The proof of concept took place using personnel from the British Services Dhaulagiri Medical Research Expedition 2016 (BSDMRE 2016). This evaluation took place at high altitude in the remote mountain environment of the Nepalese Himalayas and involved personnel on the BSDMRE 2016 during periods of extreme physiological stress at high altitude. Ethical approval was not sought, as this was a service evaluation by two individuals (MS and JAR) with an interest in wearable technologies. No medical analysis of the data took place. The monitoring systems were attached to two members of the team for periods of at least 2 hours daily (excluding three rest days taken for acclimatisation) as they undertook a trek of the Dhaulagiri circuit ascending from lowland terrain to cross two high passes at around 5300 m (an overview of this expedition has been published in this journal10). During the 15-day expedition, the first two components of the self-monitoring kit were evaluated.

The INMM system is broken down into three constituent parts:

  1. Nonin Wrist Ox2 oximetry probe (Figure 2).

  2. Samsung smartphone and bespoke INMM App.

  3. Base receiver programme.

Figure 2

Nonin Wrist Ox2 information display.

The INMM system is a customisable device designed to be adjustable to fit comfortably to the user; it can also be adjusted to the environment and generate a reliable alert based around the personalised settings. The system uses a probe in skin contact with the forehead to detect the flow of blood through the capillaries, thereby determining HR and oxygen saturation. On our evaluation devices, this was sewn into the headband of a baseball cap or cold weather beanie (Figures 1 and 3) to allow the system to be adaptable to the changing environmental conditions, facilitating continuous recording of parameters.

Figure 3

Self-monitoring kit at 2500 m.

Overall, the system was effective and straightforward to use once initial connectivity issues were resolved (which are discussed later). The measured parameters, oxygen saturation and pulse, were accurate and gave identical readings to other SpO2 devices (Nonin Onyx II) and HR monitors (Garmin Fenix 3 hour) that were being used by the team members for other medical research projects. Figure 4 shows HR and SpO2 data collected on 3 May 2016 over a period of 5 hours and 30 min. It shows the measured vital signs of one of the expedition participants as they moved from Italian Base camp at 4600 m to Hidden Valley Base Camp at 5200 m over a 5400 m pass (Figures 4 and 5).

Figure 4

Data set collected at 5300 m.

The collected data was sent via Bluetooth to the portable handheld receiver, which during the trial period was a Samsung smartphone. The battery life of this system allowed for up to 8 hours (4×2 hour) of data collection before needing to be charged. The smartphone collected the data and buffered a data packet every 4 s, displaying the information through a specifically designed app while also storing it on the internal memory. The smartphone’s GPS provided this system with an accelerometer and route ‘Geo-Health’9 tracking allowing the user to be tracked on a map. This provided accurate geo-tagging of the collected medical data. While the wearer is able to see their HR and oxygen saturation at any given time through the app, they are not exposed to the trend graph or to their location.

The INMM personal systems used different frequencies to prevent other devices in close proximity picking up the wrong Bluetooth data. The handheld receivers used Global System for Mobile Communications (GSM) to connect and send the data packets to the base receiver programme. GSM uses data encryption; however, as packets of data are sent over the ‘air’, it can be susceptible to interference and/or eavesdropping. When not in areas of GSM coverage, the data was stored locally before being sent off to the base receiver. This transmission of data allowed geographical progress and physiological readings to be tracked by the INMM Team in Italy. This mimicked the command team, observing the physiological changes remotely, maintaining overall situation awareness without being directly on the ground.

Discussion

Overall, the devices proved very capable of providing real-time measurements of pulse rate and SpO2 during exercise in a challenging and remote environment. The physiological parameters recorded by the current INMM system provide useful data in identifying the degree of exertion exhibited by the wearer. A significantly elevated HR for a prolonged period of time is known to have impacts on levels of fatigue and therefore efficiency and effectiveness. An increased HR can also be an indicator of pain, injury and potential blood loss. Combining the physiological data with the GPS ‘Geo-Health’ tracker could facilitate interventions from a command team remotely monitoring this information. A static soldier with a persistent tachycardia can be identified as being possibly incapacitated and requiring medical assistance. The same can be said of the oxygen saturations; decreasing saturations in an immobile soldier may indicate airway obstruction or a chest wall injury. This information can be used to effectively direct medical aid and triage.

The ergonomics of such devices is an important factor when considering their potential use on military deployment. The modern soldier now carries an array of equipment and interoperability between systems is essential. This system as tested is configured with the saturation probe resting on the forehead, limiting the user to having to wear a hat. Some issues were encountered with the probe not getting continuous readings as the probe was not in constant contact with the skin. Tightening of the headband allowed for a better contact but made it uncomfortable to wear for prolonged periods. The intention is to incorporate the sensor within the structure of a combat helmet, thus improving the comfort of the system. The latest prototype now known as TRAMA is shown in Figure 6.

Figure 6

Redesigned prototype of self-monitoring kit.

The use of Bluetooth to connect the Nonin Probe to the phone reduces the need for wires and therefore making the system more portable and adaptable to the equipment worn by the user. Unfortunately, the use of wireless technology has the disadvantage of a significant power drain on battery. The battery life of the Samsung smartphone limited the continuous use of the system, using ∼11% battery per hour. Such issues should not be overlooked when trying to integrate further electronic systems into the modern soldier’s equipment. It is very easy for everyday users to get access to a charging point but during times of conflict and/or in remote environments, this can become extremely challenging. One solution is to rely on charging off compatible solar panels, a technology that is still rather cumbersome.

Furthermore, although large areas of the world now have GSM coverage, it would not be implausible for military personnel be deployed to environments where such coverage is limited, as it was in the Dhaulagiri region. One of the battlefield limitations of the current system is that it requires GSM signal to send the data packets to the base receiver, which, if limited by signal will be of no use for real-time updates. This could be solved by integration with military closed communication systems that, coupled with the GPS capability, would be able to provide commanders with the ability to identify and locate personnel in a wide range of scenarios. This could prove particularly useful in an evade and escape scenario or incapacitation/death on a rolling battlefield. There may be considerable security issues in such an integration. Effective security measures would be needed to prevent any data from being intercepted by enemy forces. GPS signals and geotagged data could also be used by the enemy to locate harbour areas or analyse tactical movements of a unit. While GSM does use data encryption, it has the potential to be intercepted. The use of military grade data encryption within secure communications systems would negate the cyber threat.

Future development of such systems should focus on what physiological parameters should be monitored. Heart/respiratory rate, saturations and blood pressure are essential from a trauma perspective but could be further enhanced by measuring temperature, lactate, electrolytes and blood glucose. We know that changes in temperature and lactate can impact on coagulation in massive haemorrhage and therefore knowing these parameters could help triage medical care. Monitoring of temperature could also be used to mitigate any risk and prevent casualties from occurring secondary to environmental injury; whether that be hypothermia or heat stroke/injury in a training setting where the risk versus benefits must be closely managed.

The INMM self-monitoring system has highlighted that it is feasible to have continuous monitoring in the challenging and remote high altitude environment. In its current state, it is very adaptable and could be used by the military and other services to provide ‘live’ feedback to the individual and an overseer. Its use is not limited to battlefield monitoring but could be used during training exercises to protect the wearer from environmental challenges. Given that the system monitors key vital signs, the information displayed could be integrated into a medical early warning system or enhance casualty evacuation by providing continuous monitoring without radio communications.

Physiological monitoring systems can provide useful information, but they must also be comfortable, easy to use and work reliably in the military environment. Such military environments pose unique demands and certainly differ from civilian home health monitoring settings. The system needs to be small, lightweight, unencumbering and compatible with other military equipment and clothing worn. Not only that but also easy to clean, capable of functioning on low power consumption, ensure security of the data and be of reasonable cost. As electronics and battery technologies develop, making them smaller and more efficient, we may see devices such as the INMM self-monitoring kit (TRAMA) being integrated into the next generation of combat equipment.

Acknowledgments

Photography: Flt Lt Karl Cooper.

References

Footnotes

  • Contributors All authors contributed equally to the preparation of the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests INMM provided the loan equipment free of charge and at no obligation. After the expedition, INMM supported the postexpedition lecture with an unconditional grant.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.