What do environment-related illnesses tell us about the character of military medicine and future clinical requirements?

Extreme environments present medical and occupational challenges that extend beyond generic resuscitation, to formulating bespoke diagnoses and prognoses and embarking on management pathways rarely encountered in civilian practice. Pathophysiological complexity and clinical uncertainty call for military physicians of all kinds to balance intuition with pragmatism, adapting according to the predominant patterns of care required. In an era of smaller operational footprints and less concentrated clinical experience, proposals aimed at improving the systematic care of Service Personnel incapacitated at environmental extremes must not be lost to corporate memory. These general issues are explored in the particular context of thermal stress and metabolic disruption. Specific focus is given to the accounts of military physicians who served on large-scale deployments into the heat of Iraq and Kuwait (Operation TELIC) and Oman (Exercise SAIF SAREEA). Generalisable insights into the enduring character of military medicine and future clinical requirements result.

Reflex syncope in the UK Armed Forces

INTRODUCTION

Reflex syncope is the most common subtype of syncope and, despite not being associated with increased mortality, often results in significant morbidity and costly diagnostics. Reflex syncope can be of concern for certain occupational groups and may be exacerbated by some occupations. Reflex syncope in the military is anecdotally common but the extent in the UK Armed Forces (UKAF) is unknown. The aim of this study was to assess the incidence and prevalence of reflex syncope in the UKAF.

METHODS

A retrospective search of the Defence Medical Information Capability Programme using prespecified read-codes was performed at defence primary healthcare centres over the period of 1 January 2019 to 1 January 2020. Data were obtained on 76 103 service personnel (SP) (53% of the UKAF).

RESULTS

The overall syncope case rate for the UKAF was 10.5 per 1000 person-years (p-yrs). In comparing services there was a significantly increased risk of syncope in the British Army (10.7 per 1000 p-yrs) compared with the Royal Air Force (8.6 per 1000 p-yrs) (p=0.0365), SP who served overseas (16.7 per 1000 p-yrs) in comparison with UK medical centres (10.3 per 1000 p-yrs) (p<0.0001), and British Army units that regularly took part in State Ceremonial and Public Duties (15.8 per 1000 p-yrs vs 10.2 per 1000 p-yrs) (p=0.0035). Army training units conferred a significantly reduced risk of syncope (p<0.0001).

CONCLUSIONS

These data are the first to define the incidence and prevalence of syncope in the UKAF. Orthostasis and heat are probable triggers, although recruits are potentially protected. These data offer opportunities to improve the health and well-being of SP, with economic, logistical and reputational benefits for the UKAF. Further research to identify personnel at risk of future syncopal events may allow for targeted use of countermeasures.

Procedure for assessing patients referred to the UK's military Heat Illness Clinic: a case series

INTRODUCTION

The UK military operates a Heat Illness Clinic (HIC) to aid the return to exercise, training and occupational duty recommendations for individuals who have suffered exertional heat illness or heatstroke. This paper describes the process of assessment and reports representative data from n=22 patients referred to the HIC.

METHOD

The assessment included clinical consultation, and measurement of maximal oxygen consumption (V̇O2max) and a heat tolerance test (HTT) conducted on a treadmill in an environmental chamber with an air temperature of 34°C and 44% relative humidity. Patients began the HTT wearing military clothing, carrying a rucksack (mass 15 kg) and walking at 60% V̇O2max, at 30 min the rucksack and jacket were removed and the T-shirt at 45 min, individuals continued walking for 60-90 min. Patients were considered heat tolerant if rectal temperature achieved a plateau.

RESULTS

N=14 patients were heat tolerant on the first assessment and of the n=8 patients required to return for repeat assessment, five were heat tolerant on the second assessment and the remaining three on the third assessment.

CONCLUSIONS

In conjunction with patient history and clinical evaluation, the HTT provides a physiological basis to assist with decisions concerning patient management and return to duty following an episode of heat illness.

Validation of dried blood spot sampling for detecting SARS-CoV-2 antibodies and total immunoglobulins in a large cohort of asymptomatic young adults

BACKGROUND

Detecting antibody responses following infection with SARS-CoV-2 is necessary for sero-epidemiological studies and assessing the role of specific antibodies in disease, but serum or plasma sampling is not always viable due to logistical challenges. Dried blood spot sampling (DBS) is a cheaper, simpler alternative and samples can be self-collected and returned by post, reducing risk for SARS-CoV-2 exposure from direct patient contact. The value of large-scale DBS sampling for the assessment of serological responses to SARS-CoV-2 has not been assessed in depth and provides a model for examining the logistics of using this approach to other infectious diseases. The ability to measure specific antigens is attractive for remote outbreak situations where testing may be limited or for patients who require sampling after remote consultation.

METHODS

We compared the performance of SARS-CoV-2 anti-spike and anti-nucleocapsid antibody detection from DBS samples with matched serum collected by venepuncture in a large population of asymptomatic young adults (N = 1070) living and working in congregate settings (military recruits, N = 625); university students, N = 445). We also compared the effect of self-sampling (ssDBS) with investigator-collected samples (labDBS) on assay performance, and the quantitative measurement of total IgA, IgG and IgM between DBS eluates and serum.

RESULTS

Baseline seropositivity for anti-Spike IgGAM antibody was significantly higher among university students than military recruits. Strong correlations were observed between matched DBS and serum samples in both university students and recruits for the anti-spike IgGAM assay. Minimal differences were found in results by ssDBS and labDBS and serum by Bland Altman and Cohen kappa analyses. LabDBS achieved 82.0% sensitivity and 98.2% specificity and ssDBS samples 86.1% sensitivity and 96.7% specificity for detecting anti-Spike IgGAM antibodies relative to serum samples. For anti-SARS-CoV-2 nucleocapsid IgG there was qualitatively 100% agreement between serum and DBS samples and weak correlation in ratio measurements. Strong correlations were observed between serum and DBS-derived total IgG, IgA, and IgM.

CONCLUSIONS

This is the largest validation of DBS against paired serum for SARS-CoV-2 specific antibody measurement and we have shown that DBS retains performance from prior smaller studies. There were no significant differences regarding DBS collection methods, suggesting that self-collected samples are a viable sampling collection method. These data offer confidence that DBS can be employed more widely as an alternative to classical serology.

Optimising the use of physiotherapy resources after manipulation under anaesthetic for frozen shoulder

INTRODUCTION

Manipulation under anaesthetic (MUA) is a successful treatment for frozen shoulder (FS), and the recovery period and recurrence rates may be reduced by postoperative physiotherapy. This study evaluates two physiotherapy pathways for patients undergoing MUA for FS.

METHODS

Between 2016 and 2018, 248 age- and sex-matched patients presented to either a NHS secondary care upper limb service or the lead author's independent practice with a diagnosis of FS. The patients had differential access to postprocedure physiotherapy based on which service they presented to. In Group 1, physiotherapy advice only was given to the patient. In Group 2, supervised hydrotherapy and physiotherapy occurred postoperatively. Pre- and postprocedure Oxford Shoulder Scores (OSS) were collected for each group. Analysis of covariance (ANCOVA) was used to measure the effect of physiotherapy on postoperative OSS.

RESULTS

Group 2 showed a significantly greater improvement in postprocedure OSS when compared with Group 1 (18.2 vs 16.7) p<0.001). The estimated maximum effect of physiotherapy on postoperative OSS was an increase of 3.2.

CONCLUSION

Following MUA for FS, a statistically significant increase in OSS was detected in patients receiving postprocedure physiotherapy compared with advice alone. There was no difference in recurrence rates. The increase in OSS (3.2) is below the minimal clinically important difference, raising questions regarding the relative importance of postprocedure physiotherapy in a resource-limited environment.

Nonmyopic and pseudo-nonmyopic approaches to optimal sequential design in the presence of covariates

In sequential experiments, subjects become available for the study over a period of time, and covariates are often measured at the time of arrival. We consider the setting where the sample size is fixed but covariate values are unknown until subjects enrol. Given a model for the outcome, a sequential optimal design approach can be used to allocate treatments to minimize the variance of the estimator of the treatment effect. We extend existing optimal design methodology so it can be used within a nonmyopic framework, where treatment allocation for the current subject depends not only on the treatments and covariates of the subjects already enrolled in the study, but also the impact of possible future treatment assignments within a specified horizon. The nonmyopic approach requires recursive formulae and suffers from the curse of dimensionality. We propose a pseudo-nonmyopic approach which has a similar aim to the nonmyopic approach, but does not involve recursion and instead relies on simulating trajectories of future possible decisions. Our simulation studies show that, for the simple case of a logistic regression with a single binary covariate and a binary treatment, and a more realistic case with four binary covariates, binary treatment and treatment-covariate interactions, the nonmyopic and pseudo-nonmyopic approaches provide no competitive advantage over the myopic approach, both in terms of the size of the estimated treatment effect and also the efficiency of the designs. Results are robust to the size of the horizon used in the nonmyopic approach, and the number of simulated trajectories used in the pseudo-nonmyopic approach.

Skills2Care: An innovative, cooperative learning programme for community health workers in South Africa

Background

Community health workers (CHWs) hold potential to support universal health coverage and better health for vulnerable communities. They are integral to the re-engineered Primary Health Care (PHC) strategy, introduced in South Africa in 2011. This study focussed on how to train CHWs in large numbers, especially in resource-limited, rural settings. Skills2Care, a method of cooperative learning for CHWS, has been pioneered in the Eastern Cape of South Africa.

Aim

To determine whether Skills2Care could improve the cognitive knowledge of CHWs; to understand their response and attitude to the programme; to explore factors that enabled and inhibited learning and to consider its viability as a training method.

Setting

Research was conducted in 2019 in the Ngqeleni subdistrict of the O.R. Tambo district, in rural Eastern Cape.

Methods

A group-learning model using specifically tailored study modules in booklet format, addressing mother and baby care, was used. A facilitator promoted learning. Knowledge assessment was conducted by pre- and post-study testing using multiple choice questions. Focus group discussions and interviews explored the appropriateness and acceptability of this method, and factors enabling and inhibiting the learning.

Results

This method of peer group cooperative learning can significantly increase the cognitive knowledge of CHWs. Test scores indicated a significant (13%) improvement. Focus group discussions indicated that participants valued this method as it increased knowledge and boosted their confidence.

Conclusion

This innovative approach to district-based, continuing education suggests that CHWs could be trained in large numbers without the need for additional resources.

793 Orthopaedic Surgical Training in The Independent Sector During the COVID 19 Pandemic

Introduction

The COVID pandemic had led to the cancellation of elective Orthopaedics in the NHS. The aim of this study was to investigate the effect of the independent sector on orthopaedic training and the effect of the COVID pandemic on training locally.

Method

A retrospective review of trauma and elective operations was made between April and September of 2019 and 2020 to compare the effects of COVID on training opportunities and the additional capacity provided by the private sector.

Results

The impact of COVID on Surgical training at GWH has been no decrease in trauma operating experience, but a 53% decrease in elective operating experience and a 74% decrease in joint replacement operative experience during an equivalent six-month period. Use of the independent hospital has enabled 6% of the total elective surgery experience, and 11% of the joint replacement surgery experience.

Discussion

The private sector has provided additional capacity but a productivity of 66 cases from 48 half day lists is low (1.4 cases per list) has proved disappointing. There has been a low impact on elective training. The challenges have been faced on the elective side as trauma cases have remained consistent during the pandemic.

Conclusions

Use of the alliance between the private sector and NHS as a resource to provide additional training opportunities needs to be developed further in the future with incentivised guidance. Orthopaedic training will inevitably adapt to the challenges presented for the next generations of surgeons.

1419 Targeted Use of Physiotherapy Resources in The COVID Era: How Does Face to Face Physiotherapy Compare with Simple Advice Sheets After Manipulation Under Anaesthetic for Frozen Shoulder?

Introduction

This study compares two pathways for patients undergoing MUA for FS, one where physiotherapy advice is only given to the patient (Group 1), and the other where supervised hydrotherapy and physiotherapy occur post operatively (Group 2).

Method

A descriptive analysis of pre- and post-operative Oxford Shoulder Scores and change scores were performed. Analysis of covariance (ANCOVA) was used to measure the effect of physiotherapy on post-operative OSS, with pre-operative OSS as the only covariate.

Results

The results for post-operative OSS were significantly greater for Group 2 than for Group 1 (40.7 for NHS and 44.7 for private, improvement of 17.32 for NHS and 18.23 for Private). The effect of physiotherapy was significant (p &lt; 0.001). The estimated effect of physiotherapy on postoperative OSS was an increase of 3.2 (95% confidence interval 1.5 – 4.8).

Conclusions

We detected a statistically significant increase in post-operative OSS in patients treated for frozen shoulder with MUA + physiotherapy compared with patients receiving MUA plus advice alone. These results suggest that physiotherapy does confer a real benefit, however the increased OSS is below the clinically significant level. Therefore, in a resource poor environment, such as may exist during and after COVID in many health care systems, MUA plus physio advice alone gives an excellent outcome for the treatment of FS.

18 Manipulation Under Anaesthetic for Frozen Shoulder: Does Post-Operative Supervised Physiotherapy Affect the Outcome?

Introduction

This study compares two pathways for patients undergoing MUA for FS, one where physiotherapy advice is only given to the patient (Group 1), and the other where supervised hydrotherapy and physiotherapy occur post operatively (Group 2).

Method

A descriptive analysis of pre- and post-operative Oxford Shoulder Scores and change scores were performed.

Analysis of covariance (ANCOVA) was used to measure the effect of physiotherapy on post-operative OSS, with pre-operative OSS as the only covariate.

Results

The results for post-operative OSS were significantly greater for Group 2 than for Group 1 (40.7 for NHS and 44.7 for private, improvement of 17.32 for NHS and 18.23 for Private). The estimated effect of physiotherapy on postoperative OSS was an increase of 3.2 (95% confidence interval 1.5 – 4.8).

Conclusions

We detected a statistically significant increase in post-operative OSS in patients treated for frozen shoulder with MUA + physiotherapy compared with patients receiving MUA plus advice alone. These results suggest that physiotherapy does confer a real benefit, however the increased OSS is below the clinically significant level. Therefore, in a resource poor environment, such as may exist after COVID in many health care systems, MUA plus physio advice alone gives an excellent outcome for the treatment of FS.

Case series of non-freezing cold injury: the modern clinical syndrome

BACKGROUND

Non-freezing cold injury (NFCI) occurs when peripheral tissue is damaged by cold exposure but not to the extent of freezing. Historically, the phenotype of NFCIs sustained was severe, whereas today the spectrum of injury represented in the UK military predominantly comprises subtler injuries. The diagnostic challenge of recognising these injuries, both in the acute and chronic settings, can lead to mismanagement and subsequent morbidity.

METHODS

We characterised a recent case series of 100 UK Service Personnel referred with suspected NFCI to a Military UK NFCI clinic. We characterised the acute and chronic phenotype of those diagnosed with NFCI (n=76) and made comparison to those who received alternate diagnoses (n=24), to find discriminatory symptoms and signs.

RESULTS

The most common acute symptoms of NFCI were the extremities becoming cold to the point of loss of feeling for more than 30 min (sensitivity 96%, specificity 90%, p<0.001), followed by a period of painful rewarming (sensitivity 81%, specificity 67%, p<0.001). In-field foot/hand inspections took place in half of the NFCI cases. Importantly, remaining in the field and undergoing multiple cycles of cooling and rewarming after an initial NFCI was associated with having double the risk of the NFCI persisting for more than a week. The most common and discriminant chronic symptoms and signs of NFCI were having extremities that behave differently during cold exposures (sensitivity 81%, specificity 75%, p<0.001) and having abnormal pinprick sensation in the affected extremity (sensitivity 88%, specificity 88%, p<0.001).

CONCLUSIONS

A small collection of symptoms and signs characterise acute and chronic NFCIs and distinguish this vasoneuropathy from NFCI mimics.

Case series of non-freezing cold injury: epidemiology and risk factors

Background

Non-freezing cold injury (NFCI) occurs when the peripheral tissue is cooled sufficiently that damage occurs, but not to the point of tissue freezing. Historically, the phenotype of the injuries studied was often severe, and it is unclear whether knowledge gained from these cases is entirely relevant to the frequently subtle injuries seen today.

Methods

We therefore sought to characterise a recent case series of 100 patients referred with suspected NFCI to a military UK NFCI clinic. Their demographics, medical history and situational risk factors leading to their injuries were analysed, and comparison was made between those subsequently diagnosed with NFCI (n=76) and those receiving alternate diagnoses (n=24).

Results

Statistically significant predisposing factors for NFCI in the UK service personnel (SP) were being of African-Caribbean ethnicity and having a short duration of service in the Armed Forces. Past or current smoking was not identified as a risk factor. Injuries were almost always suffered on training exercises (most commonly in the UK); being generally cold and being on static duties were statistically significant situational risk factors. Non-significant trends of risk were also found for having wet clothing, wet boots and immersion. Self-reported dehydration was not found to be a risk factor for NFCI.

Conclusions

Our demographic findings are in general agreement with those of previous studies. Our situational risk factor findings, however, highlight a pattern of NFCI risk factors to the modern UK SP: winter training exercises, when troops are generally cold and extremities often wet, with static duties frequently implicated in the disease mechanism.

A Database Built Upon the Medical Event Vector

PHAMIS is an automated medical information system designed to provide long-term storage and retrieval of clinical information about Public Health Service patients. The patient database is composed of clinical events stored in compact format as multidimensional vectors in a write-once, read-only file to minimize file maintenance. Clinical observations are recorded as pointers to a large and expandable dictionary, rather than as text, to reduce storage requirements. The database design includes both within-patient-record and between-patient-recorcl indexes to speed data retrieval and facilitate report generation.

Power supplies and equipment for military field research: lessons from the British Service Dhaulagiri Research Expedition 2016

INTRODUCTION

The British Service Dhaulagiri Research Expedition (BSDMRE) took place from 27 March to 31 May 2016. The expedition involved 129 personnel, with voluntary participation in nine different study protocols. Studies were conducted in three research camps established at 3600, 4600 and 5140 m and involved taking and storing blood samples, cardiac echocardiography and investigations involving a balance plate. Research in this remote environment requires careful planning in order to provide a robust and resilient power plan. In this paper we aim to report the rationale for the choices we made in terms of power supply, the equipment used and potential military applicability.

METHODS

This is a descriptive account from the expedition members involved in planning and conducting the medical research.

RESULTS

Power calculations were used to determine estimates of requirement prior to the expedition. The primary sources used to generate power were internal combustion engine (via petrol fuelled electric generators) and solar panels. Having been generated, power was stored using lithium-ion batteries. Special consideration was given to the storage of samples taken in the field, for which electric freezers and dry shippers were used. All equipment used functioned well during the expedition, with the challenges of altitude, temperature and transport all overcome due to extensive prior planning.

CONCLUSIONS

Power was successfully generated, stored and delivered during the BSDMRE, allowing extensive medical research to be undertaken. The challenges faced and overcome are directly applicable to delivering military medical care in austere environments, and lessons learnt can help with the planning and delivery of future operations, training exercises or expeditions.

Physiological monitoring for healthy military personnel

Military employment commonly exposes personnel to strenuous physical exertion. The resulting interaction between occupational stress and individual susceptibility to illness demands careful management. This could extend to prospective identification of high physiological strain in healthy personnel, in addition to recognition and protection of vulnerable individuals. The emergence and ubiquitous uptake of ‘wearable’ physiological and medical monitoring devices might help to address this challenge, but requires that the right questions are asked in sourcing, developing, validating and applying such technologies. Issues that must be addressed include system requirements, such as the likelihood of end users deploying and using technology as intended; interpretation of data in relation to pretest probability, including the potential for false-positive results; differentiation of pathological states from normal physiology; responsibility for and consequences of acting on abnormal or unexpected results and cost-effectiveness. Ultimately, the performance of a single monitoring system, in isolation or alongside other measures, should be judged by whether any improvement is offered versus existing capabilities and at what cost to mission effectiveness.

The Adrenocortical Response to Synthetic ACTH Following a Trek to High Altitude

Gradual ascent to high altitude is typically associated with reduced resting aldosterone and unchanged cortisol, features that may facilitate acclimatization but are poorly understood. The aim of the study was to investigate the cortisol and aldosterone response to adrenocorticotrophic hormone at altitude. Eleven subjects underwent a 250 μg short synacthen test at sea-level and again after trekking to 3 600 m in Nepal. Cortisol and aldosterone were measured by conventional assay from blood samples taken immediately prior to the administration of synacthen (T0) and then 30 (T30) and 60 (T60) min later. At 3 600 m resting basal cortisol and aldosterone levels were both significantly lower than they were at sea-level (p=0.004, p=0.003, respectively). Cortisol values at T30 and T60 were not different between sea-level and 3 600 m but the increment after synacthen was significantly greater (p=0.041) at 3 600 m due to a lower basal value. Aldosterone at T30 and T60 was significantly lower (p=0.003 for both) at 3 600 m than at sea-level and the increment following synacthen was also significantly less (p=0.003) at 3 600 m. At 3 600 m there appears to be a divergent adrenal response to synthetic adrenocorticotrophic hormone with an intact cortisol response but a reduced aldosterone response, relative to sea-level. This may reflect a specific effect of hypoxia on aldosterone synthesis and may be beneficial to acclimatization.

Assay for Ubiquitin Ligase Activity: High-Throughput Screen for Inhibitors of HDM2

An assay for the autoubiquitination activity of the E3 ligaseHDM2 (Mdm2) was developed and adapted to a high-throughput format to identify inhibitors of this activity. The assay can also be used tomeasure the activity of other E3s andmay be useful in finding both inhibitors and activators of a wide range of different ubiquitin ligases.

Missing voices: Profile and extent of acquired communication disorders in Aboriginal and non-Aboriginal adult stroke survivors in Western Australia using linked administrative records

Background

Limited data exist on the extent of specific functional sequelae, including acquired communication disorder, among Aboriginal stroke survivors, making planning of multidisciplinary services difficult.

Aims

To obtain estimates of the extent and profile of acquired communication disorder in Aboriginal and non-Aboriginal adult stroke survivors in Western Australia and investigate potential disparities in receiving in-hospital speech pathology services among survivors with acquired communication disorder.

Methods

Stroke cases surviving their first stroke episode during 2002–2011 were identified using Western Australia-wide person-based linked hospital and mortality data, and their five-year comorbidity profiles determined. The mid-year prevalence of stroke cases with acquired communication disorder was estimated for 2011. Regression methods were used to investigate determinants of receiving speech pathology services among acquired communication disorder cases.

Results

Of 14,757 stroke survivors aged 15–79 years admitted in 2002–2011, 33% had acquired communication disorder (22% aphasia/dysphasia) and 777 (5.3%) were Aboriginal. Aboriginal patients were more likely to be younger, live remotely, and have comorbidities. A diagnosis of aphasia was more common in Aboriginal than non-Aboriginal patients 15–44 years (p = 0.003). A minimum of 107 Aboriginal and 2324 non-Aboriginal stroke patients with acquired communication disorder lived in Western Australia in 2011. Aboriginal status was not associated with receiving in-hospital speech services among acquired communication disorder patients in unadjusted or adjusted models.

Conclusions

The relative youth, geographical distribution, high comorbidity prevalence, and cultural needs of Aboriginal stroke patients with acquired communication disorder should inform appropriate service design for speech pathology and rehabilitation. Innovative models are required to address workforce issues, given low patient volumes.

Case ascertainment of heat illness in the British Army: evidence of under-reporting from analysis of Medical and Command notifications, 2009-2013

Background

Heat illness in the Armed Forces is considered preventable. The UK military relies upon dual Command and Medical reporting for case ascertainment, investigation of serious incidents and improvement of preventive practices and policy. This process could be vulnerable to under-reporting.

Objectives

To establish whether heat illness in the British Army has been under-reported, by reviewing concordance of reporting to the Army Incident Notification Cell (AINC) and the Army Health Unit (AHU) and to characterise the burden of heat illness reported by these means.

Methods

Analysis of anonymised reporting databases held by the AHU and AINC, for the period 2009–2013.

Results

565 unique cases of heat illness were identified. Annual concordance of reporting ranged from 9.6% to 16.5%. The overall rate was 13.3%. July was the month with the greatest number of heat illness reports (24.4% of total reporting) and the highest concordance rate (30%). Reports of heat illness from the UK (n=343) exceeded overseas notifications (n=221) and showed better concordance (17.1% vs 12.8%). The annual rate of reported heat illness varied widely, being greater in full-time than reservist personnel (87 vs 23 per100 000) and highest in full-time untrained personnel (223 per100 000).

Conclusions

The risk of heat illness was global, year-round and showed dynamic local variation. Failure to dual-report casualties impaired case ascertainment of heat illness across Command and Medical chains. Current preventive guidance, as applied in training and on operations, should be critically evaluated to ensure that risk of heat illness is reduced as low as possible. Clear procedures for casualty notification and surveillance are required in support of this and should incorporate communication within and between the two reporting chains.

Physiology studies at high altitude; why and how

The military has always had an important role in high altitude research. This is due to the fact that mountainous regions often span borders and provide a safe haven to enemies. Deploying troops rapidly into high altitude environments presents major problems in terms of the development of high altitude illness. This paper examines the rationale for carrying out research at high altitude and the opportunities within the UK Defence Medical Services for carrying out this research.

Where do pulse oximeter probes break?

Pulse oximetry, a non-invasive method for accurate assessment of blood oxygen saturation (SPO2), is an important monitoring tool in health care facilities. However, it is often not available in many low-resource settings, due to expense, overly sophisticated design, a lack of organised procurement systems and inadequate medical device management and maintenance structures. Furthermore medical devices are often fragile and not designed to withstand the conditions of low-resource settings. In order to design a probe, better suited to the needs of health care facilities in low-resource settings this study aimed to document the site and nature of pulse oximeter probe breakages in a range of different probe designs in a low to middle income country. A retrospective review of job cards relating to the assessment and repair of damaged or faulty pulse oximeter probes was conducted at a medical device repair company based in Cape Town, South Africa, specializing in pulse oximeter probe repairs. 1,840 job cards relating to the assessment and repair of pulse oximeter probes were reviewed. 60.2 % of probes sent for assessment were finger-clip probes. For all probes, excluding the neonatal wrap probes, the most common point of failure was the probe wiring (>50 %). The neonatal wrap most commonly failed at the strap (51.5 %). The total cost for quoting on the broken pulse oximeter probes and for the subsequent repair of devices, excluding replacement components, amounted to an estimated ZAR 738,810 (USD $98,508). Improving the probe wiring would increase the life span of pulse oximeter probes. Increasing the life span of probes will make pulse oximetry more affordable and accessible. This is of high priority in low-resource settings where frequent repair or replacement of probes is unaffordable or impossible.

Heat illness in military populations: asking the right questions for research

Reports of death and injury in military populations due to exertional heat illness (EHI) and its most severe form, exertional heat stroke, date from antiquity. Yet, understanding of why one soldier may succumb to EHI, while those around him do not, is incomplete. This paper sets out research questions in support of the health of military populations who may experience exertional heat stress. The mechanisms by which excess body heat arises and is dissipated are outlined and the significance of core temperature measurement during exercise is discussed. Known risk factors for EHI are highlighted and new approaches for identifying individual vulnerability to EHI are introduced. A better understanding of the underlying pathophysiology may allow the effective use of biomarkers in future risk stratification and identification of EHI, allied to emerging genetic technologies. The thermal burden associated with states of dress and personal protection of Service personnel in their worldwide duties should be a focus of research as new equipment is introduced. At all times, the discerning use of existing guidance by Commanders on the ground will remain a mainstay of preventing EHI.

Technique for high axial shielding factor performance of large-scale, thin, open-ended, cylindrical Metglas magnetic shields

Metglas 2705M is a low-cost commercially available, high-permeability cobalt-based magnetic alloy, provided as a 5.08-cm wide and 20.3-μm thick ribbon foil. We present an optimized construction technique for single-shell, large-scale (human-size), thin, open-ended cylindrical Metglas magnetic shields. The measured dc axial and transverse magnetic shielding factors of our 0.61-m diameter and 1.83-m long shields in the Earth's magnetic field were 267 and 1500, for material thicknesses of only 122 μm (i.e., 6 foil layers). The axial shielding performance of our single-shell Metglas magnetic shields, obtained without the use of magnetic shaking techniques, is comparable to the performance of significantly thicker, multiple-shell, open-ended Metglas magnetic shields in comparable-magnitude, low-frequency applied external fields reported previously in the literature.