Contents
- Introduction and Collaborators
- Expedition and Wilderness Medicine Section
- Global Health and Humanitarian Medicine Section
- Want to get involved?
We are changing the publication schedule of the Evidence Explorer from now on. Instead of quarterly, we will be producing an article biannually, with all the best research the wilderness and global health medicine.
Thank you to our contributors and a particular shout out to Dr Murdoch for providing the accompanying images.
Wilderness and Expedition Medicine
In this evidence explorer, we start by reviewing the role of tranexamic acid, and note that women and the elderly were less likely to be given the drug compared to men in the study. Tranexamic acid is often used in pre-hospital settings, yet it is less likely to be present in most expedition doctors kit bags. Time and more evidence may change that. Next up is a systematic review looking at the efficacy of expired anti-venom, which was largely positive, however, more evidence is needed. An article looking at the role of rashes in decompression sickness shows that any rash should be taken seriously and may indicate concurrent neurological effects. Ever wondered what a plane medical kit bag may contain? An American article outlines the kit list which has not been updated since 2006 and argues that there should be some important additions. Finally, a systematic review outlines a likely positive predictive relationship between pulse oximetry and acute mountain sickness.
Evaluation of the prehospital administration of tranexamic acid for injured patients: a state-wide observational study with sex and age-disaggregated analysis
Girardello C, Carron P, Dami F, et al. EMJ. August 2024
Tranexamic acid is an antifibrinolytic which has been shown to reduce mortality in trauma patients. It is not routinely available in expedition medicine kit bags but this may change in the future. This study was a retrospective observational study in Switzerland between 2018 and 2021. The study looked at all patients who had an ambulance/helicopter dispatched who should have received tranexamic acid according to their BATT score – Bleeding Audit for Trauma and Triage. A total of 2401 patients were identified to be at risk of death from bleeding, however, only 11% received tranexamic acid. It was more likely to be given with higher BATT scores. However, women and elderly were significantly less likely to be given tranexamic acid.
The study had a large sample size, although it was carried out in Switzerland rather than the United Kingdom so it is unclear if the research is applicable to our population. Statistical analysis was clear and the confidence intervals were statistically significant. The study calls for qualitative research to understand why there was a difference in tranexamic acid administration between women and men.
Preclinical testing of expired antivenoms and its uses in real-world experience: a systematic review
Sutinee Soopairin, Chanthawat Patikorn, Suthira Taychakhoonavudh. EMJ. September 2024
Managing a patient with a suspected venomous snake bite relies upon prompt availability of anti-venom. This paper wished to assess whether the quality, efficacy and safety was degraded with expired anti-venom. They approached the study question by undertaking a systematic review in 2023 using four databases (PubMed, Scopus, Web of Science and Embase). A total of 15 studies were included, which was made up from 10 pre-clinical studies and five articles which described their use in the real world. The storage time ranged from two months to twenty years.
One of the studies assessed the quality of expired anti-venom and found it comparable to unexpired anti-venom. Five of the studies looked at the venom binding capacity and found this was comparable, with the caveat that efficacy declines with time from expiration. The evidence for the systematic review was poor with small sample sizes and anecdotal evidence. The authors concluded that their findings are ‘inconclusive’ and more research is required in the future.
Potet responded to the article succinctly commenting that the ‘data, although incomplete, could also be helpful for national regulatory drug authorities to conduct a benefit-risk analysis and make informed decisions on a case-by-case basis about exceptional off-label use of expired vials, when non-expired antivenoms are unavailable. Obviously, use of expired antivenoms should be ‘the exception, not the rule’.
Clinical Significance of Mottling Rashes in Diving Decompression Sickness
Breen, Ilana D.; Stepanek, Jan; Marks, Lisa; Yale, Katerina; Mesinkovska, Natasha; Swanson, David. Aerospace Medicine and Human Performance. September 2024
Decompression sickness in divers occurs during ascent when the inert gas nitrogen enters tissues. The mechanism is poorly understood with the thought that the primary effect of nitrogen damages tissues by occlusion and the secondary effect is an inflammatory response causing further damage. Symptoms can include joint pain, chest pain, neurological deficit, headache, fatigue and a rash. (Decompression illness, RCEM learning)
This article carried out a systematic review to understand the relationship of the rash in decompression sickness and two outcomes – (1) paradoxical embolism across a right to left shunt (RLS) and (2) neurological effects. Four databases were searched over a sixty year period with a total of 31 articles meeting the inclusion criteria. Of the 128 pooled patients, 63 had neurological deficits and 76 had RLS. The majority recovered with hyperbaric oxygen treatment (84%) and there were four deaths.
Positively, the systematic review looked at a range of databases over a long period of time. However, there is a small sample size and the included studies were of varying quality. There was no mention of the limitations of the study or statistical analysis.
Clinicians should be aware that a rash in the context of suspected decompression sickness should be taken seriously and it should be a trigger for investigating for any other signs and symptoms.
Recommendations for Updates to Emergency Medical Kits for Commercial Aviation
Alaina Brinley Rajagopal, Adam Pissaris, Katharine Clark, Andrea Merrill, Robert Glatter, Amy Ho, Daryn C Towle, Justin Yanuck, Sari Lahham, Lindsey Ulin, Chanel Fischetti, Luke Apisa. Aerospace Medicine and Human Performance. October 2024
Have you ever been concerned when boarding a plane that they will call for a doctor to assist with a medical emergency? You’ve left your seat and wandered down the aisle apprehensively. You are given the on board medical bag and expected to assess the passenger.
There is a lot of planning involved in deciding what equipment and medications you will take on an expedition. You would expect the same level of planning for medical kits on commercial flights. This American article comments that the medical kits, although standardised by the Federal Aviation Administration, have not updated the contents list since 2006. You may notice that an automated blood pressure cuff, pulse oximeter, glucose meter and epipen are not included. The authors advocate for their inclusion in the article and for the introduction of a centralised data collection of all medical emergencies on commercial flights.
Next time you board a flight, you may need to remember how to draw up the correct dose of adrenaline and dig out the manual blood pressure skills from medical school.
Pulse oximetry for the prediction of acute mountain sickness: A systematic review
Johnathan S. L. Goves, Kelsey E. Joyce, Sophie Broughton, Julian Greig, Kimberly Ashdown, Arthur R. Bradwell, Samuel J. E. Lucas. Experimental Physiology. September 2024
Any individual at high altitudes is at risk of acute mountain sickness. The diagnosis is mainly a clinical one using a scoring system. This article carried out a systematic review using 7 databases to include any studies which involved human participants from lowland locations and monitored oxygen saturations to high altitude. The primary research question was ‘Is there a predictive relationship between oxygen saturation and subsequent development of AMS?’.
The study found ‘a predictive relationship between decreased resting 𝑆pO2 measured around 3500 to 4000 m and the risk of developing AMS at higher camps’. Therefore, measuring oxygen saturations may be a useful tool with your clinical assessment when deciding if a participant should continue on a high altitude expedition.
There was an assessment for bias (low for six and moderate for one study), heterogeneity and there were transparent research methods outlined. It is noted that the times for when the measurement was taken varied between all the studies and this was raised as a limiting factor.
Heat Alert! These Medications May Influence the Risk of Heat Illness
Ashley Hedges, PharmD, BCPS, BCCCP. Wilderness Medicine Magazine. July 2024.
Finally, we came across this handy table to remind expedition doctors of medications which may affect heat illness. Further details available in the full article above.
| Medications That influence Heat Illness Risk | |
| Effect | Medications |
| Alter volume status | diuretics (e.g., furosemide, hydrochlorothiazide) anti-hypertensives (e.g., losartan, lisinopril) |
| Adjusts electrolyte balances | diuretics (e.g., furosemide, hydrochlorothiazide) calcium channel blocks (e.g., amlodipine, nifedipine) lithium |
| Decreased thirst | diuretics (e.g., furosemide, hydrochlorothiazide) opiates |
| Decreased sweating | antipsychotics (e.g., olanzapine, quetiapine, risperidone) tricyclic antidepressants (e.g., amitriptyline) anti-seizure medications (e.g., topiramate) hallucinogens (e.g., MDMA) cocaine |
| Increased sweating | antidepressants (e.g., sertraline, fluoxetine, duloxetine, venlafaxine) antiseizure medications (e.g., oxcarbamazepine) thyroid replacement (e.g., levothyroxine) alcohol |
| Reduced superficial vasodilation | antiplatelets (e.g., clopidogrel, aspirin) |
| Increased kidney injury risk with dehydration | antibiotics (e.g., Bactrim) NSAIDS (e.g., ibuprofen, naproxen) aspirin antivirals (e.g., indavir) |
| Affects central thermoregulation | anticholinergic antihistamines (promethazine, diphenhydramine) stimulants (e.g., dextroamphetamine, amphetamine, methylphenidate) |
| Heightened risk of toxicity with dehydration | apixaban carbamazepine lithium |
| Increased sun sensitivity | doxycycline |
| Increased degradation possible with sun exposure | epinephrine inhalers (e.g., albuterol) insulin |
Global Health Section
This section looked at six papers in total. The first explores perceptions of cancer in Ethiopia. We assessed the role of strong caregiver relationships in reducing post-conflict trauma in Congolese Youth. We reviewed two papers which used predictive technologies to identify patterns of disease. We reviewed strategies used to decrease sex-workers’ risk of HIV/AIDS in Zimbabwe. Finally we discuss how up-skilling medical workers in rural areas in Nepal can improve obstetric care.
Perceived causes of cancer in a rural community of Ethiopia: a qualitative study
A.Wondimagegnehu, M.Gizaw, L.Abebe, et al. Global Health Action. September 2024.
Cancer incidence is increasing worldwide and is projected to reach 30.2 million cases over the next two decades, with two-thirds occurring in low- and middle-income countries. In 2020, Ethiopia was estimated to have over 77,000 new cancer cases and more than 50,000 cancer-related deaths, with breast and cervical cancers being the most common. Community-based studies in southern Ethiopia have shown that cancer knowledge is approximately 11%, with rural residents displaying lower overall awareness—likely due to limited education and access to basic healthcare services. This is reflected in the frequent late presentations of cancer and the continued reliance on traditional healers and religious leaders.
This study aimed to fill a gap in qualitative data regarding perceptions of cancer, with the goal of improving early identification and treatment. Researchers surveyed 58 participants from four remote villages located 135 km from the capital. The participants included a diverse group, ranging from health professionals to community members. Each participant took part in two semi-structured interviews exploring their perceptions of cancer, including its causes, signs and symptoms, transmission, treatment, and prognosis.
Data were collected through focus group discussions and in-depth interviews conducted in various configurations to ensure participants could freely express their views—for example, within maternal and child health groups, and in gender-specific sessions. Data collection continued until saturation was reached, meaning no new themes emerged. The findings were categorized into four areas within each broad theme: (1) desirable and beneficial, (2) undesirable and harmful, (3) non-existent or incomplete, and (4) benign perceptions.
Many participants described cancer as a very dangerous disease that is difficult to treat, often referring to it by the local term “Nekersa.” Most recognized weight loss as a significant symptom of cancer. While there was general awareness of breast and uterine cancers, few participants mentioned cancers of the brain, neck, lungs, abdominal organs, bones, or legs. Participants believed cancer could be caused by “bad air,” but also expressed several other misconceptions, categorized as undesirable and harmful—for example, exposure to sunlight during breastfeeding, and transmission through sharp objects or breastfeeding.
Benign perceptions included beliefs such as cancer being caused by exposure to bad air, sunlight after preparing traditional alcohol, storing coins under the bra, or urinating in the direction of the sun or moon, or on dirty ground. A recurring belief was that urinating on contaminated soil would allow dust or ash to enter the uterus, causing cancer. Cancer was most often associated with the appearance of a visible wound as the first sign of disease. Additionally, there was confusion between cervical cancer and other conditions such as menstrual bleeding, hemorrhoids, fistulas, and sexually transmitted infections, due to overlapping symptoms.
This study will contribute to the design of more effective public health campaigns by addressing and correcting community misconceptions about cancer.
Close relationships with caregivers as protective factor for the mental health and functioning of war-affected Congolese youth
F.Scharpf, R.Haer, T.Hecker. Conflict and Health. October 2024.
Conflict-affected youth face significant risks to their well-being due to high levels of trauma exposure and, in many cases, involvement in violent acts as members of armed groups. This regression study examined the association between the quality of caregiver relationships and the protective effect these may have on the link between traumatic experiences and various indicators of adjustment—specifically, post-traumatic stress symptoms (PTSS), emotional problems, behavioural issues, and criminal behaviour.
As of 2022, over one in six children globally were estimated to live in conflict-affected areas, alongside a rise in child soldier recruitment. War-related trauma is a well-known risk factor for poor mental health, with greater exposure correlating with a higher likelihood of aggressive and violent behaviour.
The study assessed 268 war-affected youth in the Democratic Republic of Congo, around half of whom were former members of armed groups. Participants were recruited through local child protection organisations using convenience sampling. Data were gathered via individual, structured quantitative interviews, and participants received $5 compensation. Mental health referrals were provided as needed. The questionnaire evaluated socioeconomic characteristics, war-related trauma exposure and violence perpetration, perceived caregiver relationship quality, PTSS, emotional and behavioural problems, and criminal behaviour.
As expected, higher trauma exposure was significantly associated with increased PTSS and emotional problems. Greater perpetration of violence was linked to higher rates of PTSS, behavioural issues, and criminal behaviour.
A better-quality caregiver relationship was associated with lower levels of these problems, especially in cases of high exposure. The findings show that perceived caregiver relationship quality moderates the link between war-related trauma and youth adjustment. This reinforces the importance of a supportive home environment as a key protective factor for mental health and functional recovery.
Youth rated caregiver relationships highly when they were emotionally warm and supportive, helping them process and cope with trauma. Maladjustment was partly linked to community and family stigma. Caregivers who showed forgiveness and acted as mediators in their communities helped reduce stigma and support reintegration, aiding the healing process.
Use of Open-Source Epidemic Intelligence for Infectious Disease Outbreaks, Ukraine, 2022
A.Kannan, R.Chen, Z.Akhtar, et al. Emerging Infectious Diseases. September 2024.
During conflict, public health surveillance is often disrupted, hindering epidemic tracking and increasing outbreak risks. Even before Russia’s invasion in early 2022, Ukraine had some of the world’s lowest vaccination rates (for COVID-19, polio, and measles) and high rates of TB and HIV/AIDS—partly due to ongoing conflict since 2014. The invasion worsened these issues by disrupting vaccination programs, limiting testing, and causing displacement and overcrowding.
The conflict also damaged access to clean water, housing, nutrition, hygiene, and sanitation. Formal disease surveillance largely ceased post-invasion. This study explored the use of open-source data—including news, social media, and medical reports—combined with AI to generate early warning signals and provide epidemiological data over two years, spanning before and after the invasion.
Researchers used EPIWATCH, a system that scans 200 disease-related terms in 46 languages; 70% of data came from non-English sources within Ukraine. Reports were included only if they involved confirmed, probable, or suspected infectious or zoonotic diseases. The top eight most reported diseases were compared to official surveillance data from the same period.
Between February–July in 2021 and 2022, outbreak reports increased by 447%. Gastroenteritis cases, including cholera and dysentery, rose notably. A meningitis report from July 31, 2021, indicated a rise in viral and bacterial meningitis cases since pre-invasion.
The disease profile shifted post-invasion—from COVID-19, influenza, and polio, to COVID-19, cholera, botulism, TB, HIV/AIDS, salmonellosis, and diphtheria. Cholera had not been reported before the conflict. Most diseases were not formally reported during the invasion, except for botulism, TB, and diphtheria. Botulism was more prevalent in formal reports than EPIWATCH, while TB was vastly underreported (5,647 cases in EPIWATCH vs. 113 officially reported). Both sources recorded two diphtheria cases.
The study also underscored how worsening hygiene and sanitation contributed to outbreaks like cholera and gastroenteritis. Ultimately, this study demonstrated the utility of combining AI with open-source intelligence to detect and monitor disease outbreaks during conflict, especially when formal surveillance is compromised.
Cost-effectiveness and health impact of screening and treatment of Mycobacterium tuberculosisinfection among formerly incarcerated individuals in Brazil: a Markov modelling study
A.Titan, F.Klaassen, D.Pelissari et al. The Lancet Global Health. September 2024.
This study modelled the health impact and cost-effectiveness of TB screening and treatment among previously incarcerated individuals in Brazil—a group currently ineligible for TB prevention despite their high incidence rates. The aim was to evaluate whether implementing a TB screening and preventive treatment (TPT) program in this population could reduce disease burden and be cost-effective.
Prisons act as TB amplifiers due to overcrowding, poor ventilation, and higher baseline disease prevalence. Incarcerated individuals also face increased TB risk due to malnutrition, untreated comorbidities, smoking, and drug use. In Brazil, TB notification rates are 40 times higher among incarcerated individuals. Brazil has committed to the WHO’s End TB Strategy, aiming to eliminate TB by 2030.
Using a Markov state-transition model, the study simulated TB-related health outcomes and costs in the previously incarcerated population. It compared several infection tests and TPT regimens against a no-screening scenario. Outcomes included reductions in TB cases, deaths, and disability-adjusted life years (DALYs) per 1,000 people. Costs (in USD) were estimated by comparing intervention and baseline scenarios, and results were expressed as the incremental cost per DALY averted. The model population had a mean age of 30, had been incarcerated for at least two years, and had been released three months before the intervention.
All TPT strategies were found to be cost-effective compared to no intervention. TB incidence dropped from 225 to 184 per 100,000 with intervention. DALYs averted were greatest among younger individuals and those tested soon after release, particularly if incarcerated for two years or less. Any combination of testing and treatment was more beneficial than no screening. IGRA testing offered greater health benefits than TST, and shorter TPT regimens were more effective than longer ones.
Limitations included not accounting for reincarceration, a wide range of uncertainty due to limited data, and omission of TB drug resistance. However, these did not significantly affect the cost-effectiveness estimates. The study concluded that resources should be directed toward TB screening and treatment in formerly incarcerated populations.
A risk-differentiated, community-led intervention to strengthen uptake and engagement with HIV prevention and care cascades among female sex workers in Zimbabwe (AMETHIST): a cluster randomised trial
Prof F.Cowan, F.Machingura, M.Ali et al. The Lancent Global Health. September 2024.
Female sex workers are disproportionately affected by HIV. This study assessed the effectiveness of peer support for female sex workers in Zimbabwe in reducing their risk of acquiring or transmitting HIV over just over two years (May 2019 to December 2021). It was a cluster-randomised, open-label, controlled trial involving 22 clinics dedicated to female sex workers, each within a government health facility, randomized to either standard care or the AMETHIST intervention.
Standard care included HIV testing, pre-exposure prophylaxis (PrEP), referral to government antiretroviral therapy (ART) services, contraception, condoms, syndromic management of sexually transmitted infections, health education, legal advice, and peer support. The AMETHIST intervention added peer-led microplanning tailored to individual risk and self-help groups. Data reviewers were blinded to intervention status, although program implementers were aware.
Participants were followed up after 28 months via survey to assess the primary outcome: the proportion of sex workers at risk of acquiring or transmitting HIV. Risk of transmission was defined as HIV-positive individuals who were not virally suppressed and inconsistently used condoms. Risk of acquisition was defined as HIV-negative individuals who inconsistently used condoms or PrEP.
The study found no overall reduction in combined risk of transmission or acquisition from the intervention. However, viral load suppression improved in the AMETHIST group, suggesting better ART adherence.
Successful task shifting: a mixed-methods cross-sectional evaluation of an emergency obstetric care program to increase access to caesarean sections in rural Nepal
R.Budhathoki, A.Knoble, S.Tamang, Et Al. Global Health Action. December 2024.
In 2020, an estimated 800 women died daily worldwide from preventable childbirth-related causes, mostly in low- and middle-income countries (LMICs). Approximately 86% of these deaths were due to obstetric complications. Nepal’s maternal mortality ratio (MMR) remains high, with 12% of deaths among women of reproductive age attributed to preventable obstetric causes and a shortage of doctors. Improved access to medical interventions like cesarean sections (CS) could reduce MMR by 63% in low-income countries. The WHO recommends CS rates of 10–15%, but Nepal’s rate was only 5.9% in 2020, partly due to uneven distribution of skilled healthcare workers.
To address this, a Nepalese NGO and the National Health Training Centre developed a 70-day Advanced Skilled Birth Attendant (ASBA) program in 2013 to train non-specialist medical officers (MOs) to perform safe CS and manage obstetric emergencies. Graduates were placed in facilities with emergency obstetric care and operating theaters. This mixed-methods study used surveys, interviews, and focus groups to assess the program’s effectiveness and barriers to CS availability.
Of 234 ASBA graduates surveyed, 93 responses were analyzed. Over 90% performed CS after training, 75% did so unsupervised, and 65% continued performing CS up to 10 years later. Factors supporting ongoing CS practice included temporary contracts, presence of another ASBA, and longer facility tenure. Where CS was not performed, over half cited the lack of a functional operating theater. The presence of ASBAs increased patient presentations and reduced referrals, especially in rural areas and where multiple ASBAs worked.
Barriers included presence of specialist teams, hospital level, and lack of infrastructure such as blood banks. Participants suggested adding abortion care and emergency hysterectomy training to the curriculum, along with follow-up and refresher courses.
This study supports training MOs through ASBA-style programs to fill human resource gaps, improve safe obstetric care, and enhance rural hospital conditions in LMICs.
That’s all folks! We will be coming back at you better than ever in the next few months with a new edition of the Evidence Explorer.
We love to hear from our readers. If there is anything you think should be amended or if you’d like to get involved with the next issue, please contact: constance@theadventuremedic.com.