The Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for managing acute pain in austere environments, defined as wilderness, remote, or resource-limited settings where access to typical medical resources is limited and evacuation may be challenging. These guidelines, an update to the 2014 version, provide a framework for approaching pain management in these unique contexts.
The initial approach to pain management involves ensuring scene safety, managing immediate threats to life, and conducting primary and secondary surveys to identify the cause and severity of pain. Pain should be managed to provide adequate relief while recognizing limitations imposed by the environment, such as exposure or limited opportunities for monitoring vital signs or injuries. Low-risk treatments should be considered before progressing to higher-risk modalities when appropriate, although multiple simultaneous treatments may be initiated for anticipated severe pain.
Figure 1. Conceptual schematic of escalating pain treatment stratified by risk posed to the patient and the need for monitoring when used. With greater anticipated or reported pain severity, a clinician may elect to use one or more modalities appropriate to that degree of severity. IV, intravenous; IM, intramuscular; IN, intranasal; SL, sublingual; NSAID, nonsteroidal anti-inflammatory drug.
Psychological interventions, such as empathy, reassurance, and distraction, can mitigate pain and are well-suited to austere environments. The ABCDE mnemonic (Table 1) provides a framework for applying psychological first aid techniques.
Table 1: The ABCDE mnemonic for the psychosocial treatment of pain: A suggested mnemonic for the field application of psychological first aid to reduce acute pain.
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A
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Anchoring, Attention & Acknowledgement
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Provide the patient with an attentive provider who identifies themselves as responsible for their comfort and who acknowledges their distress.
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B
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Breathing
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Encourage controlled breathing depth and rate, limiting rapid, shallow breathing or hyperventilation.
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C
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Control and Cognitive Shift
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Provide the patient with a role that allows an element of control over their situation, and which shifts their mindset away from catastrophizing.
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D
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Decrease nociception, Distract, Diffuse.
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Use other pharmacological/ nonpharmacological interventions to treat nociceptive signals. Distract the patient from the source of pain. Diffuse tension using empathy and humor.
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E
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Explanations and Expectations
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Provide the patient with an understanding of what to expect in novel situations, such as technical rescue or vehicle/helicopter transport. Explain procedures to be performed, personnel involved, timelines to be expected, etc.
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For treatment of acute musculoskeletal injuries, the PRICE protocol (Protection, Relative rest, Ice, Compression, Elevation) is recommended, while the MEAT protocol (Movement, Exercise, Analgesics, Treatment/Therapy) may be used for isolated soft tissue injuries when fracture is unlikely.
Oral non-opioid medications, including acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), and their combination, are effective for mild to severe pain. Acetaminophen can be administered orally, rectally, or intravenously, with no significant differences in efficacy between routes. NSAIDs (such as ibuprofen or naproxen) provide anti-inflammatory effects in addition to analgesia but may cause adverse effects with long-term use. Combining acetaminophen and an NSAID can provide superior pain relief compared to either alone.
Oral opioids may be considered for severe pain but carry risks of respiratory depression, sedation, and other significant side effects. Providers administering opioids should be prepared to manage respiratory depression and consider carrying naloxone. Intranasal (fentanyl, sufentanil), transmucosal (oral fentanyl citrate), and sublingual (fentanyl, sufentanil) opioid formulations provide rapid analgesia without the need for intravenous access. Intravenous, intraosseous, and intramuscular opioids offer potent analgesia but require more advanced skills and monitoring.
Ketamine, administered at low doses via intravenous, intramuscular, or intranasal routes, is an effective analgesic for severe pain in austere settings which does not pose the same risk of respiratory depression. Providers should be experienced in its use and avoid higher doses that can cause hallucinations or dissociation.
Local and regional anesthesia techniques, such as topical application and infiltration of local anesthetics like lidocaine, and field-expedient nerve blocks, can provide targeted pain relief with fewer systemic side effects compared to other modalities. Careful attention to maximum doses, equipment, and provider training is necessary to ensure safe and effective use. Intravenous lidocaine infusions are not recommended in austere environments due to the high risk of systemic toxicity and the need for advanced monitoring.
Inhaled analgesics, such as nitrous oxide and methoxyflurane, offer rapid onset and offset of analgesia without the need for intravenous access. However, their use may be limited by available equipment, environmental factors, and altitude. Nitrous oxide/oxygen mixtures can separate if not mixed appropriately at low temperatures, posing a risk of hypoxia, and gas tanks tend to be heavy and bulky. Additionally, administration of nitrous oxide or methoxyflurane at altitude results in delivery of a lower partial pressure of these gasses and may reduce their efficacy.
Benzodiazepines are not recommended for pain management in austere settings due to the lack of evidence supporting their analgesic efficacy and potential for adverse effects, particularly when combined with opioids.
In conclusion, managing acute pain in austere environments requires careful consideration of available resources, provider experience, and patient factors. A stepwise approach utilizing low-risk medications can effectively manage pain while minimizing risks, while more advanced modalities, such as opioids, ketamine, and inhaled anesthetics, may be considered when pain is severe and appropriate resources are available. Further research is needed to refine and optimize pain management strategies in austere settings.