Whether travelling alone on an expedition or as part of a larger expedition team, pain management on the expedition is a key factor in any medic’s armoury of medical kit. Critical factors in managing pain in the great outdoors are anticipation of incidence, preparation of treatment escalation, and versatility in management.

Pain can be described as having a bi-modal effect on both the psychological and social behaviour of an individual can affect team dynamics and can especially manifest in a dynamic and changeable environment like an expedition. From sore muscles to blisters and injuries, managing pain becomes crucial for ensuring both safety and performance throughout the longevity of an expedition.

In this article, we delve into the prevalence of pain on an expedition, the measurement of pain, the concept of the pain ladder, pain management strategies, proactive measures, improvised techniques, and the various drug and non-drug interventions required to manage pain in any extreme environment.

Understanding Pain in the Expedition Context:

Expeditions inherently subject participants to physical strain due to prolonged periods of walking, carrying heavy loads, and exposure to environmental elements. Consequently, pain manifests in various forms, including musculoskeletal discomfort, joint stiffness, abrasions, and altitude-related symptoms. Recognising the types and triggers of pain is fundamental to devising effective management approaches.

Pain can be categorised into various types based on its underlying causes, location, and characteristics. Two common types of pain on an expedition (not encompassing all types) are somatic pain and musculoskeletal (MSK) pain. While somatic pain primarily encompasses discomfort originating from the skin and musculoskeletal structures, MSK pain extends beyond the surface level to include conditions affecting the joints, bones, and connective tissues.

Both types of pain can coexist and may present concurrently in individuals experiencing musculoskeletal injuries or disorders. Understanding the distinction between somatic and musculoskeletal pain aids in accurate diagnosis, treatment planning, and targeted pain management interventions tailored to the underlying aetiology and anatomical location of the pain.

Cold therapy for MSK injuries:

Ice packs to reduce injury and inflammation have been a longstanding practice supported by clinical experience and expert consensus among healthcare professionals, athletic trainers, and sports medicine practitioners. While anecdotal evidence and historical practice provide some support for the effectiveness of ice pack applications, they do not constitute high-quality scientific evidence.

A prolonged period of cold on the skin was reported to lead to a reduction of blood flow, resulting in tissue death or even permanent nerve damage in some cases. Ice packs and cold therapy are still not directly supported by the literature and could be judged as low-value treatments for MSK injuries.

Preparation and Prevention:

Prevention and preparation serve as the cornerstone for the mitigation of injury on the expedition. Before embarking on any expedition, participants should engage in physical conditioning to enhance strength, endurance, and flexibility, thereby reducing the risk of injuries and minimising discomfort during the expedition.

The evidence overwhelmingly supports the efficacy of conditioning to extreme environments before embarking on expeditions, including physical fitness, adaptation, injury prevention, recovery, and psychological resilience, individuals can optimise their readiness to confront the rigours of extreme environments. Additionally, ensuring proper gear selection, including footwear, backpacks, and clothing, helps mitigate factors contributing to pain, such as blisters and chafing.

The ‘tyranny’ of the blister

Studies conducted among expedition participants, hikers, and military personnel reveal that heel blisters are among the most common foot injuries encountered during extended walking, hiking, or wearing ill-fitting footwear. Risk factors for developing heel blisters include friction from repetitive motion, improper shoe fit, moisture build-up, inadequate foot care, and pre-existing foot deformities.

From a pain and discomfort perspective, research on heel blisters underscores the significance of proactive prevention, prompt intervention, and comprehensive management strategies to mitigate their impact on expedition performance and participant well-being. The management of hot spots before the dermal layer of skin breaks is the best way to prevent the presence of blisters.

Blisters can be trip-ending and the evidence shows a prevalence among inexperienced expedition groups that are naïve to their kit, the terrain and the risks.

The necessity of pain assessment:

Assessing pain accurately on expeditions is essential for ensuring the well-being and performance of participants amidst challenging environments. Deploying an effective pain assessment tool facilitates systematic evaluation, enables timely intervention, and enhances expedition safety. One widely utilised tool in expedition settings is the Numeric Rating Scale (NRS), which involves asking individuals to rate their pain intensity on a scale from 0 to 10, with 0 representing no pain and 10 indicating the worst possible pain.

This simple yet reliable scale allows expedition leaders or medical personnel to gather quantitative data regarding pain severity, aiding in treatment prioritisation and decision-making. Additionally, the Visual Analog Scale (VAS) presents a visual representation of pain intensity, wherein individuals mark their perceived pain level on a line ranging from “no pain” to “worst pain imaginable.” The VAS offers a subjective assessment of pain intensity, complementing the NRS by providing a visual reference for pain perception.

Furthermore, incorporating qualitative assessment techniques such as pain descriptors, location mapping, and functional impact evaluations enhances the comprehensiveness of pain assessment on expeditions.

Pain Management:

It is prudent in any and every extreme environment to know the ceiling of care. Below is a stepwise approach to non-pharmacological and pharmacological approaches to pain management. It is necessary to exercise extreme caution when using benzodiazepines, opiates and NDMA reuptake inhibitors (Ketamine) to have access to monitoring, remain within your scope of practice and have access to resuscitative equipment.

It is also prudent to have access to reversal agents such as Flumazenil and Naloxone should it be required. Most importantly, it is prudent to have experience with these drugs and appreciate your surroundings, availability of other medically trained personnel and longevity of care (it could be a protracted field care situation). These drugs may not be routinely found in expedition medical kits, but good monitoring (NIBP, SP02, ETCO2, ECG) is the cornerstone of safe practice with these drugs therefore in the absence of this equipment it is not always safe to utilise some of the pain medications noted for severe pain.

Non-pharmacologic approaches:

It should be undertaken first in the incidence of stepwise pain management, such as immobilisation, elevation, splinting/wrapping injured extremities, addressing hot spots/blisters, applying cold water to burns for 10 minutes, and reassuring the patient throughout. Also, the use of cling film as a protective layer over the burn, rather than wrapping it around a limb. A clean, clear plastic bag can be used for burns on the hand. All the above are practice steps that can concomitantly mitigate pain and ease the patient’s passage to either continuation or extraction from the expedition.

Pharmacologic Analgesia: Mild to moderate pain:

• Nonsteroidal Anti-inflammatory Drugs (NSAIDs) and acetaminophen should be the starting point for almost every painful condition. Ibuprofen 400 mg with acetaminophen (Paracetamol) 1,000 mg (1 gram) can produce the analgesic effect of common oral opioid/acetaminophen combinations. Meloxicam, diclofenac, and naproxen are alternative NSAIDs.

• Topical Anaesthesia with viscous lidocaine, lidocaine patches/creams/ointments, EMLA (lidocaine + prilocaine), or LET (lidocaine-epinephrine-tetracaine) can provide direct analgesia to superficial wounds or burns.

• Ophthalmic analgesics like tetracaine 0.5% ophthalmic drops and cycloplegics (cyclopentolate 2%, scopolamine patch) can relieve ocular pain from conjunctivitis, corneal abrasions, traumatic iritis, or photokeratitis.

Moderate to severe pain:

• Methoxyflurane (Trade name of Penthrox), is an inhaled analgesic agent used for short-term pain relief, particularly in prehospital and emergency settings. Administered via a hand-held inhaler, Penthrox provides rapid pain relief within minutes, making it valuable for managing acute pain associated with moderate to severe pain, injuries, and medical procedures. Its ease of use, quick onset of action, and minimal sedative effects render it suitable for use in a wide range of painful conditions, including fractures, dislocations, burns, and lacerations. Penthrox’s versatility and portability make it a valuable adjunct in the armamentarium of pain management strategies for expedition patients and accessible pain relief in various clinical scenarios.

• Oral Opioids like Co-codamol are a combination medication containing both an opioid analgesic (codeine) and a non-opioid pain reliever (paracetamol). This blend synergistically enhances pain relief by targeting different pain pathways in the body. Codeine binds to opioid receptors in the brain, reducing pain perception, while paracetamol inhibits pain signalling and reduces fever. Co-codamol is commonly prescribed for moderate to severe pain management. However, caution is advised due to the potential for opioid-related side effects and the risk of dependency or misuse with prolonged use. Close monitoring and adherence to prescribed dosages are essential.

• Parenteral Opioids like fentanyl (25-50 mcg IV/IO, 100-150 mcg IN, or 2-4 mcg/kg nebulised) or morphine (2.5-5 mg IV/IO/SQ or 20 mg nebulised) can be used when oral medications are not tolerated, with fentanyl preferred for rapid onset and morphine for longer duration.

• Ketamine is an alternative therapy for trauma pain control, with sub-dissociative dosing (SDK) of 0.5-1 mg/kg IM, 1 mg/kg IN, or 0.1-0.3 mg/kg IV/IO/SQ for analgesia. At higher doses, it provides sedation through dissociation, allowing management of agitated patients, sedation for painful procedures, or prolonged sedation for evacuation.

• Benzodiazepines like diazepam may be used for muscle relaxation in acute back pain, managing agitation, temporising withdrawal symptoms, and mitigating ketamine’s emergence reaction. However, caution is advised due to the risk of respiratory depression

Penthrox

Methoxyflurane is ideal for moderate to severe pain and has proven its versatility in the expedition environment (14). One of the key reasons for the empirical evidence favouring Penthrox in expedition environments lies in its rapid onset of ac6on and ease of administration. Expeditions often entail unpredictable circumstances and limited access to medical facilities, making timely pain relief crucial.

Penthrox’s portable, hand-held inhaler design allows for immediate use. This feature is particularly advantageous in remote locations where traditional pain management modalities may be impractical or unavailable. Whether it’s MSK injuries from trekking, abrasions from climbing, or burns from cooking over open flames, Penthrox offers effective analgesia for various types of pain commonly experienced in expedition environments.

Its mechanism of action involves inhalation of methoxyflurane vapours, which exert analgesic effects by modulating pain perception pathways in the Central Nervous System (a positive allosteric modulator of GABA). This mechanism enables rapid pain relief while minimising systemic side effects commonly associated with traditional opioid analgesics.

The safety profile of Penthrox further contributes to its empirical effectiveness in expedition settings. Unlike systemic opioids, Penthrox has a lower risk of respiratory depression, sedation, and dependence due to its self-limiting nature and dose-controlled administration. Studies and anecdotal reports from expedition leaders and participants consistently highlight Penthrox’s efficacy in providing rapid and effective pain relief without significant side effects or disruptions to expedition activities.

Its user-friendly design, rapid onset of action, and predictable analgesic effects contribute to high levels of patient acceptance and adherence, fostering trust and confidence in its utility as a primary analgesic option in expedition medicine environments.

Ketamine

Ketamine is used for severe to very severe pain and can be given in pain relief, sedative and anaesthetic doses according to volume. The pharmacokinetic profile of ketamine, lack of respiratory depression, and opioid-sparing qualities make ketamine attractive for expedition medicine where resources are limited. Its versatility allows the management of various painful conditions, agitation, and procedures requiring sedation. Logistical challenges in expeditions amplify the benefits of ketamine.

Its shelf-life, heat stability, and ease of administration via multiple routes (IV, IM, IN, nebulised) are advantageous over typical opioid formula6ons requiring cold chain and IV access. Ketamine’s sympathomimetic properties help maintain blood pressure in hypovolemia.

However, ketamine’s dissociative effects may impair patient mobility required for evacuations over technical terrain. Monitoring capabilities may be limited to manage these effects. Sparing opioid use reduces constipation risk, a considerable issue when evacuating in austere environments without toilet facilities. Avoiding opioid-induced nausea/vomiting is also beneficial with limited personnel to monitor airways. Ketamine’s unique analeptic properties could provide a margin of safety during high-altitude expeditions prone to periodic apnoea or with compromised ventilatory drives. However, caution is still advised at extreme altitudes due to potential exaggerated psychotropic effects.

The evidence supports considering ketamine as a front-line analgesic during expedition medicine over traditional opioids, carefully weighing benefits like opioid-sparing, lack of respiratory depression and versatility against psychological and mobility side effects. Building contingencies like benzodiazepines for emergence reactions is prudent. Comprehensive training, clinical guidance, and risk-mitigation plans should be in place, most administration of ketamine will cause a lack of ability to self-care and self-extricate, and this is a significant consideration when using the agent.

Every decision on an expedition can have significant consequences, not commonly thought of or experienced in-hospital, it is good practice to stay within your scope of practice, have mitigations for the side effects of drugs such as ketamine and have access to monitoring where possible.

Medical Kits

Managing pain in wilderness settings requires careful planning and preparation, as there is no one-size-fits-all solution. Basic medical kits typically contain oral and topical medications, while more advanced kits may include injectable op6ons for escalating care when necessary. Opting for versatile medications and formulations that are lightweight and compact helps minimise the burden on the medical kit.

Prioritising oral, topical, or local/regional administration routes initially allows for conservative management, reserving more invasive routes such as IV, SQ, or IN for situations where alternative options are insufficient. IV/IO administration should be reserved for extreme injuries or scenarios requiring planned evacuations, emphasising the need for prudent resource allocation in austere environments. Anticipation, preparation, and versatility are crucial in effectively managing pain in wilderness settings.

By anticipating potential challenges, and likely pathologies, expedition medics can ensure they have the necessary resources and strategies in place to address pain promptly and effectively. This approach not only enhances patient comfort and safety but also contributes to the overall success and resilience of expeditions in remote and challenging environments.

Each expedition pain management kit must be tailored to the inherent and overt risks that each trip features. One key consideration is checking expiry dates and resilience of inventory should you use or deplete the kit.

Conclusion

Managing pain on expeditions can be complex. It demands a multifaceted approach encompassing proactive preparation, strategic interventions, and psychological resilience. By integrating comprehensive pain management strategies tailored for expedition contexts, adventurers can mitigate discomfort, enhance safety, and optimise performance amidst the rigours of challenging environments.

Adaptability is also key, as expeditions often present unforeseen obstacles and changing conditions. Being prepared to adjust plans, improvise solutions, and support one another fosters resilience and ensures the continuity of the journey despite pain or setbacks. Ultimately, the collective effort of meticulous planning, adaptability, and mutual support enables expedition participants to not only manage pain but also thrive in the face of adversity yielding truly unforgettable experiences.