Morphine is the gold standard analgesic used for battlefield pain control, having been first administered orally in the War of 1812 and parenterally in the U.S. Civil War. Intramuscular (IM) morphine can be given on the battlefield or battalion aid station (BAS), ideally by a medical corpsman, or alternatively by a buddy, or the soldier himself. Although IM administration generally provides rapid and reliable analgesia, the liabilities of this delivery mode include variable absorption during shock and with lower extremity wounds, and the risk of infection. Intravenous administration is more reliable than IM use, but is often impractical and requires specialized equipment and trained personnel (Jowitt and Knight 1983). The U.S. military is currently investigating the feasibility of providing transmucosal fentanyl citrate in “wound packs” to small, highly disciplined units that tend to operate independently without the benefit of an organized, medical support system (e.g. Special Forces) (Black and Mcmanus 2009). The pharmacokinetics of transmucosal delivery are comparable to IM administration, with therapeutic blood levels being reached within 10–15 min, and peak plasma concentration occurring about 20 min after administration (Fine and Streisand 1998). Depending on the formulation, between 25 and 50% of transmucosal fentanyl is absorbed via the oral or buccal mucosa, with another 15–25% being slowly absorbed through the gastrointestinal tract. The pharmacokinetics of transmucosal fentanyl also appear to be independent of age, unaffected by multiple dose regimens, and less prone to hemodynamic variations (Egan et al. 2000; Kharasch et al. 2004). This may make it an ideal agent for battlefield analgesia. Kotwal et al. recently reported using high dose (1,600 μg) oral transmucosal fentanyl citrate to treat 27 soldiers with acute orthopedic injuries in an out-of-hospital setting in OIF (Kotwal et al. 2004). Excellent pain relief without the need for additional analgesia was reported in 19 patients, with minor, self-limiting side effects occurring in eight soldiers. In one patient who received a repeat dose of fentanyl followed by subsequent intravenous opioids, hypoventilation requiring reversal with naloxone occurred 4 h postadministration. Other rapidly acting analgesics that may someday be used in lieu of parenteral opioids include intranasal butorphanol, intranasal ketamine, and fentanyl buccal tablets (Davis 2010).

Second echelon medical treatment facilities include mobile field surgical teams and forward surgical teams (FST), whose providers include surgeons, anesthetists, and nurses. The primary functions of FSTs are resuscitation and stabilization. Pain control at this level of care generally involves oral opioids, nonopioid analgesics, and intravenous opioids, which can be safely monitored by nurses and other trained personnel. Patient-controlled analgesia may also be used at these facilities as resources dictate.

Combat support hospitals (CSH), which have fully replaced mobile army surgical hospitals or MASH units in the U.S. military, represent the backbone of forward-deployed medical care. Care at these units generally includes a wide array of medical and surgical specialists some of whom may possess training in pain management. Since the U.S. and allied militaries do not currently classify anesthesiologists and most other physicians by subspecialty training, having a pain management specialist serving downrange in a forward-deployed area is a serendipitous endeavor. However, this may soon change, as both the U.S. Army and Navy have appointed pain management consultants to their respective Surgeon Generals. Recommendations from the Army Surgeon General’s (2010) pain medicine task force stated that a provider trained in pain management should be assigned to each CSHs. However, at the present time, these recommendations have not been adopted.

Care at third echelon military treatment facilities includes intensive care units and medical wards, which may administer continuous infusions of opioid and nonopioid (e.g. ketamine and epidural infusions of local anesthetics) analgesics for acute and subacute injuries. When pain management-trained anesthesiologists are deployed to CSH, more advanced interventions such as sympathetic and paravertebral blocks may be performed. Recently, anesthesiologists have also begun to employ peripheral nerve catheters for intermediate-term pain control (Buckenmaier et al. 2005, 2006). In addition to providing safe and titratable pain relief, peripheral nerve catheters also can be used for anesthesia in patients requiring repeat surgery or wound debridement (Table 14.2). With proper maintenance and monitoring, tunneled peripheral nerve catheters can be reliably used for up to 3 weeks or longer postplacement. The main factors limiting the routine use of peripheral nerve block catheters are the speed of evacuation, variability in training levels of medical personnel, and theoretical concerns about masking compartment syndrome. Compartment syndrome may result in permanent nerve and muscle damage (Wall et al. 2010).

To a lesser degree, care at this level focuses on reducing the long-term sequelae of acute injury. Recently, the U.S. military has attempted to reduce the incidence of chronic pain following trauma or surgery by the preventive use of neuropathic pain medications such as gabapentin. When used preemptively before surgical procedures associated with a high incidence of severe acute and chronic postsurgical pain, gabapentin, pregabalin, and similar drugs used to treat neuropathic pain have been shown to reduce perioperative pain and opioid requirements, and decrease the incidence of chronic postsurgical pain (Fassoulaki et al. 2001, 2002; Hurley et al. 2006). At fourth and fifth echelon treatment centers, acute and chronic pain management is also similar to the care received in civilian trauma centers and pain management clinics, respectively.

Emerging developments in the acute pain management of combat casualties, especially the polytrauma patient, also require additional evaluation (Malchow and Black 2008). There is a lack of randomized, controlled studies with long-term outcomes. That said, there is a growing body of evidence that suggests that early and effective use of analgesia is associated with improved short-term outcomes including a decreased incidence of thromboembolic events (Tuman et al. 1991; Sorenson and Pace 1992), decreased pulmonary complications (Wu et al. 2006), shortened ICU and hospital stays (Liu et al. 1995), and a diminished catabolic stress response marked by absent tachycardia, decreased oxygen consumption, and the avoidance of immunosuppression (Desborough 2000; Schricker et al. 2004). Whether these short-term effects will actually translate into better long-term benefits is yet another area ripe for clinical investigation.