Abstract
Optimal management of severe pain in a traditional hospital setting can be a challenging process. 1-3 Yet, attempting to manage pain in an out-of-hospital, combat, or austere environment is even more demanding.4-8 Because early intervention in both acute pain9 and chronic pain10 is associated with improved outcomes, timely and aggressive treatment may reduce the prevalence or severity of chronic pain and lead to enduring improvements in patients’ quality of life.11
Optimal management of severe pain in a traditional hospital setting can be a challenging process. 1–3 Yet, attempting to manage pain in an out-of-hospital, combat, or austere environment is even more demanding.4–8 Because early intervention in both acute pain9 and chronic pain10 is associated with improved outcomes, timely and aggressive treatment may reduce the prevalence or severity of chronic pain and lead to enduring improvements in patients’ quality of life.11
Multiple physical challenges in disaster and austere environments exist. Extremes in weather and terrain, difficulties obtaining adequate facilities and equipment, logistical challenges, and personnel safety add to the difficulties of treating pain in disaster situations.12 Natural disasters and terrorist acts have proven the need for health care providers to be properly trained in pain management principles in these environments.13 However, data indicate that in both normal conditions and during major emergencies, the majority of health care providers are culturally and professionally unprepared to adequately treat acute pain conditions.14,15 Unfortunately, there is an inadequate level of training among health care professionals and the source of aid is frequently limited, especially in the immediate aftermath of a disaster.16
No guidelines or validated protocols provide adequate indications for the treatment for pain in case of massive emergencies.16 Unfortunately, most trauma care algorithms, even at major trauma centers, do not include a systematic approach to pain assessment. Furthermore, empirical studies of pain assessment in trauma patients are virtually non-existent.17
The understanding that pain is not just a symptom of disease but at times is a disease process in itself is indicative of a fundamental change occurring in the field of medicine.19 In recent decades, the concept of pain had been outlined as a multifactorial disease that takes into account environmental, personal, physiological, and psychological elements influencing the individual responses.20 The patients’ self-report of pain is a critical component of a comprehensive pain assessment, which includes clinical assessment and pain history and treatment. Pain scores, although imperfect as a stand-alone assessment tool, provide a clinician with an idea of triage priority, of what type of analgesic to use, how well any intervention has worked and what may be required subsequently, the patient’s perception of general quality of care, and alters the patient’s experience of the pain because the pain is recognized as being “real” by another person.18,21–23
Multiple pain assessment tools exist as self-reported forms and scales24, 25. However, the use of these pain assessment tools has not been studied in the disaster setting, and future research should focus on accurate pain assessment during disaster settings to help aid in the diagnosis and adequate treatment of pain. In emergency departments, the intensity of pain is gauged using an 11-point verbal numerical rating scale (VNRS), although few studies support the validity of the VNRS.26–30 The visual analog scale (VAS) is often considered the gold standard in pain research and is more sensitive to changes in pain intensity.31–34 The VAS may be useful in the disaster setting to bypass cultural and language barriers that may exist in these austere settings (Figure 16.1).
Pain inadequately treated may modify the characteristics of the pain itself. Pain is no longer considered just a symptom, but itself becomes an autonomous pathology heavily influencing the social life and psychosocial aspects of a person (Figure 16.2).16 Improved understanding of the pathophysiology of pain and its associated morbidity has only recently begun to alter physician attitudes. There is an evolving appreciation that poorly managed pain can develop into a disease of the nervous system with the potential for lifelong disability and morbidity consequences for the patient.35
Essential Medications
The World Health Organization (WHO) defines essential medicines as those that satisfy the priority health care needs of the population. A list of essential medicines has been devised, and medicines are selected with regard to disease prevalence, evidence on efficacy and safety, and comparative cost-effectiveness. In 1977, WHO devised a Model List of Essential Drugs to use as a guide for the development of national and international essential medicine lists. Since then, the list has been updated and expanded on a regular basis. Essential medicines are one of the most cost-effective elements in modern health care and their potential health impact is remarkable.36
The Model List of Essential Drugs compiled by the World Health Organization may be useful to prepare and treat pain in disaster situations. The Model List medications useful in the treatment of pain include:36
Anesthetics: halothane, isoflurane, nitrous oxide, oxygen, ketamine, propofol, bupivacaine, lidocaine
Analgesics: aspirin, ibuprofen, acetaminophen (paracetamol), codeine, morphine, meperidine, methadone
Psychotropics: midazolam, diazepam, carbamazepine, valproate, phenytoin, amitriptyline.
Anti-infectives: including antibiotic, antifungal, and antiviral medications
Other: dexamethasone, hydrocortisone, fluoxetine, cyclizine, phenobarbital, valproic acid
During a disaster situation, opioids, the mainstay of acute pain management, become less available but are essential for the treatment of patients with acute pain.37,38 Insufficient administration of opioids may be due to difficulties in finding, storing, prescribing, and dispensing these drugs, as many low–middle-income countries lack the funds needed to provide even the most basic health services. Shortage of analgesic drugs after a disaster can be related to difficulties in internal transport and transfer of drugs to and from disaster staging areas. Inconsistent availability of these medications may result in pain that is under-treated and difficult to control, especially in the long term.39 Therefore, opioids should be considered primary and essential medications in a disaster setting.40,41 New formulations of opioids, such as transdermal, sublingual, or transmucosal compositions may facilitate the administration of therapies, act more quickly, and may prove to be more effective overall.42–46 The lack of availability of opioid drugs can seriously compromise the possibility to adequately treat pain, and may lead to subsequent ongoing and costly disability.
The multi-modal approach to pain treatment utilizes multiple analgesic medications with different mechanisms of action and delivery method. For example, opioids, non-steroidal anti-inflammatory drugs, N-methyl-D-aspartate (NMDA) receptor antagonists, alpha-2 antagonists, antineuropathics, and local anesthetics may be used in various combinations to achieve a synergistic effect improving overall pain control while minimizing adverse effects. In cases of primary nerve injury or neuropathic pain, drugs like gabapentin and tricyclic antidepressants may be more fiscally and clinically appropriate than procedural or surgical interventions. In the combat situation, oral opioids, cyclooxygenase (COX)-2 selective non-steroidal anti-inflammatory drugs, and acetaminophen can be self-administered by soldiers who sustain a painful injury.47,48 Ketamine has also been used in the combat setting, partially due to its large margin of safety, and in subanesthetic doses has been shown to provide profound pain relief, potentiate the effects of opioids, and prevent opioid hyperalgesia.49–53 There is substantial evidence for the use of tricyclic antidepressants in the treatment of neuropathic pain.54–59 However, their use may be limited due to side effects. The antiepileptics sodium valproate, phenytoin, and carbamazepine have been successfully used to treat chronic neuropathic pain.60–64 Clonidine, an alpha-2 agonist, acts both as a sedative and an opioid adjunct and has been shown to reduce one-year surgical mortality.65 In addition to the opioid adjuncts, benzodiazepines can significantly calm trauma patients and decrease pain scores, distinct from the sedation and anxiolysis that benzodiazepines provide.68 Utlizing multi-modal therapy may help decrease the incidence of complications of opioid-centered analgesia, including dependence, addiction, ileus, post-operative respiratory depression, and opioid-induced hyperalgesia.66,67
Other Interventions
The use of a multi-modal approach is appropriate for pain management in a disaster setting. Regional analgesia, epidural analgesia, and peripheral nerve blocks, as well as local field blocks, acupuncture, and psychosocial treatments, are available to help treat acute pain as well as decrease the likelihood of the development of chronic pain.
Regional analgesia, epidural analgesia, or peripheral nerve blocks have been used in the polytrauma patient to provide improved analgesia, improved outcomes, and lead to higher patient satisfaction.69–71 Nerve blocks, with and without ultrasound guidance, can also be invaluable as part of a multi-modal approach to pain reduction in disasters. Emergency ultrasound-guided nerve blocks have proven utility in combat and disaster settings72–74 to induce a reversible loss of sensation with minimal central nervous system and cardiovascular adverse effects. The primary goal of emergency ultrasound-guided nerve blocks is pain reduction with a simple, single-injection nerve block that is safe, rapid, and easily learned to provide acute pain reduction. Successful use of ultrasound-guided blocks of the femoral nerve, popliteal block, median, ulnar, and radial nerves (forearm block), and the interscalene brachial plexus has been described in the emergency medicine literature.75–83 Ultrasound guidance for nerve blocks has been shown to be either equivalent to or better than other nerve localization techniques and may decrease complication rates and improve performance time and time to onset of blocks.84,85 In addition, ultrasound guidance prevents the need for potentially painful motor stimulation of injured extremities and can be used across a language barrier. With improved portability, ultrasound is increasingly recognized as a valuable tool in resource-limited and disaster settings for tasks as diverse as triage, surgical decision-making, obstetric care, and procedural efficiency.86–89
The inherent difficulties of disaster settings raise challenges to documentation, sterile technique, and monitoring for adverse effects such as local anesthetic systemic toxicity (LAST) that will require further investigation. This becomes challenging in a setting in which multiple physicians working across language barriers may evaluate the patient in a given period, the basic tools of charting are difficult to procure, and patient condition may necessitate urgent transfer. Detailed training protocols need to be developed for emergency physician providers to ensure proficiency and understanding of the potential complications.90 Patients who have received a block will need to be identified with an unambiguous and universal system that allows clear communication between the multidisciplinary team caring for them and centers to which they may be transferred.
The indication, nerve block(s) performed, technique, approach, sedating medication used, and sedation level achieved (if applicable), local anesthetic and quantity, use of epinephrine, and complications should be carefully documented and reliably stored for later reference.91 The choice of local anesthetic used should be based on the safety profile and accessibility of long- and short-acting agents. The addition of vasoconstrictors, such as epinephrine, to local anesthetics can serve as an early marker of intravascular injection and can significantly slow the systemic absorption, thereby improving the safety profile and prolonging the analgesia. The potential infectious risks of practicing ultrasound-guided nerve blocks in a non-sterile setting, as well as the possible risk of delaying the diagnosis of compartment syndrome, should be further explored, although preliminary data from military operations in Iraq and Afghanistan suggest that the benefits outweigh the risks, despite these challenges.92 Health care providers should be aware of the risks associated with different types of blocks and treatment. Nerve injury is also of concern and known to be exacerbated by high-pressure injection; however, because ultrasound guidance allows good visualization, intraneural injection is usually avoidable, making a rare occurrence even more unlikely. Teams providing blocks should be prepared to recognize and treat LAST, a potential complication that usually occurs within minutes of injection and is most commonly associated with an inadvertent intravascular injection leading to nervous system and cardiovascular system effects, such as agitation, auditory changes, seizures, coma, respiratory arrest, tachycardia, dysrhythmias, cardiovascular collapse, and asystole.93
Ideally, nerve blocks should be performed in a controlled setting with cardiorespiratory monitoring. In a disaster setting, however, this may not be possible. Close clinical monitoring of the patient’s mental status, with vigilance for potential symptoms of toxicity, will allow the early diagnosis of LAST in many patients.94 Monitoring the patient’s pulse rate and oxygen saturation with a pulse oximeter, particularly if epinephrine is used, during and in the immediate 30 minutes after a single injection block may also aid in the early identification of inadvertent intravascular injection, improving the safety of blocks in an austere setting.94–96 Local wound infiltration or basic nerve blocks such as fascia iliacus,97 intercostal, 98 or suprascapular99 blocks can also provide profound analgesia.13
Acupuncture has also been shown to successfully reduce pain in a variety of settings.100,101 Common indications include pain in musculoskeletal disorders,102–104 fatigue,107,108 and depression.109–111 Auricular acupuncture techniques are well-described for acute and chronic pain and anxiolysis after physical and psychological trauma, including amputation and post-traumatic stress disorder (PTSD) in military settings.105,106 There is also evidence in civilians that acupuncture may be effective in the treatment of other complex pain diseases such as irritable bowel syndrome (IBS),112,113 fibromyalgia,114 and post-traumatic stress disorder.115 Studies have shown acupuncture is well tolerated by patients, safe, effective, and cost-effective compared to routine care.116,117
Relationships between disaster events and subsequent psychopathology have been widely established.118 Psychopathology is commonly associated with chronic pain, particularly affective disorders, anxiety disorders, and substance-abuse disorders.119 Psychiatric syndromes such as depression and anxiety disorders, and also somatically mediated complaints, may be exacerbated by the impact of catastrophic events. After disasters, a dramatic rise in pain intensity has been observed. The significant rise in pain was postulated to be due to an acute stress reaction, which could have stimulated a sympathetic-mediated physiological response that resulted in a magnified perception of pain. In addition, these patients may have suffered from post-traumatic stress disorder (PTSD), which caused an exacerbation of symptoms when confronted with media exposure of the event. In addition, women have been noted to experience higher increases in pain scores than men after stressful events.120–122 In a distressed population, there is an increased risk of other musculoskeletal complaints, as manifested by escalating work-related injuries, work absence, and lost productivity.123 Pain and its effects (e.g. disruptions of activities of daily living, such as work and recreation) result in emotional changes.119 These emotional changes can produce significant increases in anxiety, depression, and anger. This emotional distress can then lead to increased psychophysiological stress and tension, which substantially affect pain threshold and exacerbations, ultimately affecting physical functioning and change. This cycle can alter pain threshold and exacerbations, leading to further increases in psychosocial morbidity that can, in turn, produce disruptions in activities of daily living (e.g. anxiety and depression may decrease interest and motivation in getting involved in work and social activities). Disaster or terrorism situations, either as an event or a threat, can interact in or activate this cycle at any point.124 Psychosocial treatment through counseling, antidepressants, anxiolytics, and pain treatment (Table 16.1) should be implemented early to help treat and prevent perpetuation of pain related to psychosocial changes. Because many of the psychological pathologies that manifest after exposure to disaster situations are not diagnosed for months to years after the event, information regarding early intervention with the use of counseling, anxiolytics, and antidepressants is based on retrospective studies in which these interventions are rarely, if ever, instituted and are severely lacking.
Conclusion
Given the evidence that early intervention in both acute pain9 and chronic pain10 is associated with improved outcomes, timely treatment of these problems may lead to enduring improvements in patients’ quality of life and corresponding reductions in the psychosocial sequelae that are closely associated with chronic pain conditions.9,125 Accurate assessment of pain is necessary to adequately treat pain.126 As we improve in our success in the early identification of pain-related problems we also must expect increased demands on pain care resources for acute treatment and prevention of chronic disabling pain. By anticipating the needs of patients with pain in disasters and implementing corresponding changes in health care systems responsible for their care we may be able to minimize suffering while maximizing potential for improvement.127
Related posts:
Chapter 5 – Inhaled Anesthetics and Draw-Over Devices in Disaster Response
Chapter 4 – Total Intravenous Anesthesia in Disaster Medicine
Chapter 14 – Considerations When Working with Children and Families
Chapter 15 – Chemical and Radiologic Exposures in Trauma and Disasters
Chapter 12 – High-Altitude Physiology and Anesthesia
Chapter 21 – Operation Tomodachi: Anesthetic Implications
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