Acute or Intermediate Phase of Burn Care: Pain Management, Nutritional Support

Pain Management

Pain is inevitable during recovery from any burn injury. Pain in the burn patient has been described as a tormenting consequence of burn injury and wound healing (Jonsson, Holmsten, Dahlstrom & Jonsson, 1998). Burn pain is thought to have both nociceptive and neuropathic pain components. Management of the often-severe pain is one of the most difficult challenges facing the burn team. Many factors contribute to the burn patient’s pain experience. These factors include but are not limited to the severity of the pain, the adequacy of the health care provider’s assessment of the pain, the appropriateness and adequacy of pharmacologic treatment of pain, the multiple procedures involved in burn care (ie, wound care, rehabilitative exercises), and appropriate evaluation of the effectiveness of pain relief measures. The outstanding features of burn pain are its intensity and long duration. Further, necessary wound care carries with it the anticipation of pain and anxiety.

In partial-thickness burns, the nerve endings are exposed, re-sulting in excruciating pain with exposure to air currents. Although nerve endings are destroyed in full-thickness burns, the margins of the burn wound are hypersensitive to pain, and there is pain in adjacent structures. Healing of full-thickness burns creates signif-icant discomfort as regenerating nerve endings become entrapped in scar formation. Most severe burns are a combination of partial-thickness and full-thickness burns.

Burn patients have been described as having three types of pain: background or resting pain, procedural pain, and break-through pain. Background pain is pain that exists on a 24-hour basis. Procedural pain is pain caused by procedures such as burn wound care or range of motion exercises. Breakthrough pain oc-curs when blood levels of analgesic agents fall below the level re-quired to control background pain. The patient’s pain level must be assessed throughout the day because each type of pain is dif-ferent and various pain management strategies may be needed to address different types of pain (McCaffrey & Pasaro, 1999).

The primary pain from the burn itself is intense in the initial acute postburn phase. In the next few weeks thereafter, until the skin heals or skin grafts are applied and heal, the pain intensity re-mains high because of treatment-induced pain. Wound cleaning, dressing changes, débridement, and physical therapy can all cause intense pain. Donor sites may be intensely painful for several days. Discomfort related to tissue healing, such as itching, tingling, and tightness of contracting skin and joints, adds to the duration, if not the intensity, of pain over weeks or months. Because pain can-not be eliminated short of complete anesthesia, the goal is to min-imize the pain with analgesic agents to an acceptable goal set by the patient.

Opioid administration via the intravenous (IV) route, partic-ularly in the emergent and acute phases of burn management, re-mains the mainstay for pharmacologic management of burn pain. Use of opioids is complicated by the fluctuation in the bioavail-ability of drugs, protein binding of the drug, and the drug clear-ance related to the hemodynamic and fluid volume shifts that occur with a burn injury. Absorption of the opioid also may be affected. Titrating analgesic agents to obtain pain relief while minimizing side effects is crucial. The burn patient’s require-ments for analgesia are often high, but fear of addiction on the part of the patient and health care provider hamper adequate opioid administration.

Morphine sulfate remains the analgesic of choice for treat-ment of acute burn pain. It is titrated to obtain pain relief based on the patient’s self-report of pain using a standardized pain rating scale.

Fentanyl is another useful opioid for burn pain, particularly procedural burn pain. It has been shown to be effective for man-agement of intense pain of short duration. Fentanyl has a rapid onset, high potency, and short duration, all of which make it effective for use with burn wound procedures. Appropriate car-diac and respiratory monitoring must be carried out during its administration.

Patient-controlled analgesia (PCA), in which a pump is used to administer a continuous infusion of an opioid, maintains a steady level of opioid for pain relief. Use of continuous infusion requires close monitoring of the patient’s responses.

Sustained-release opioids, such as MS Contin or oxycodone (OxyContin), have also been used successfully in the treatment of burn pain. These medications can effectively treat the resting pain that is often associated with burn injury. Additional med-ications must be prescribed with these medications to cover breakthrough pain.

Some burn units use self-administered nitrous oxide during burn wound procedures. Proper ventilation and monitoring equipment and availability of qualified personnel to administer nitrous oxide limit its use.

Anxiety and pain go hand in hand for burn patients. The entire burn experience can produce severe anxiety, which can, in turn, exacerbate pain. Therefore, the ideal pain management regimen must incorporate the treatment of pain and anxiety and must be individualized for each patient. Sedation with anxiolytic medica-tions such as lorazepam (Ativan) and midazolam (Versed) may be indicated in addition to the administration of opioids.

The use of nonpharmacologic measures has also proven effec-tive in the management of burn pain. These measures include re-laxation techniques, deep breathing exercises, distraction, guided imagery, hypnosis, therapeutic touch, humor, information giving, and music therapy (McCaffrey & Pasaro, 1999).

Music therapy has gained interest recently in the treatment of pain. Researchers have found that music affects both the physio-logic and psychological aspects of the pain experience. Music di-verts the patient’s attention from the painful stimulus; provides reality orientation, distraction, and sensory stimulation; and allows for patient self-expression (Fratianne et al., 2001; Prensner et al., 2001).

Nutritional Support

Burn injuries produce profound metabolic abnormalities fueled by the exaggerated stress response to the injury. The body’s re-sponse has been classified as hyperdynamic, hypermetabolic, and hypercatabolic. Hypermetabolism can affect morbidity and mor-tality by increasing the risk of infection and slowing the healing rate. Patients’ metabolic demands vary with the extent of the burn injury. Hypermetabolism is evident immediately after a burn in-jury. The degree of the response depends on the size of the burn and the patient’s age, body composition, size, and genetic response to insult. Persistent hypermetabolism may last up to 1 year after burn injury (Hart et al., 2000).

Major metabolic abnormalities seen after a burn injury include increased catabolic hormones (cortisol and catechols); decreased anabolic hormones (human growth factor and testosterone); a marked increase in the metabolic rate; a sustained increase in body temperature; a marked increase in glucose demands; rapid skeletal muscle breakdown with amino acids serving as the energy source; lack of ketosis, indicating that fat is not a major source of calories; and catabolism that does not respond to nutrient intake (DemlingSeigne, 2000). Therefore, it is essential to control the stress re-sponse by increasing the anabolic process through adequate nutri-tion and increased muscle activity, decreasing heat loss from wounds, and maintaining a warm environment. Controlling sec-ondary stress, such as pain and anxiety, also helps to control the stress response.

The most important of these interventions is to provide adequate nutrition and calories to decrease catabolism. Nutritional support with optimized protein intake can decrease protein losses by approximately 50% (Cioffi, 2000). Healing of the burn wound consumes large quantities of energy. Effective nutrition man-agement depends on how well the energy expenditure due to the burn injury can be estimated and matched with appropriate amounts of micronutrients, carbohydrates, lipids, and protein. The goal of nutritional support is to promote a state of positive nitro-gen balance by optimizing nutrition to match nutrient utilization. The nutritional support required is based on the patient’s preburn status and the TBSA burned.

Several formulas exist for estimating the daily metabolic ex-penditure and caloric requirements of patients with burn injuries. The most commonly used formulas include the Curreiri formula, which uses body weight and percent burn, and a variation of the Harris-Bennedict equation, which determines basal energy re-quirements based on stress and burn size (Demling & Seigne, 2000). Protein requirements may range from 1.5 to 4.0 g of pro-tein per kilogram of body weight every 24 hours. Lipids are in-cluded in the nutritional support of every burn patient because of their importance for wound healing, cellular integrity, and ab-sorption of fat-soluble vitamins. Carbohydrates are included to meet caloric requirements as high as 5,000 calories per day and to spare protein, which is essential for wound healing. The pa-tient also needs adequate vitamins and minerals. Existing for-mulas may underestimate the daily metabolic expenditures associated with burns. The formulas fail to account for added stressors such as pain, anxiety, daily dressing changes, and de-creased activity levels. These must be considered when estimat-ing appropriate nutritional support. Research findings have brought about changes in specific guidelines for estimating en-ergy expenditure during the various phases of postburn recovery. The proportions of fat, protein, and carbohydrate must be care-fully planned for maximal use (Demling & Seigne, 2000).

The enteral route of feeding is far superior to the parenteral route. Enteral feedings preserve the intestinal barrier function and absorption of peptides and amino acids, which leads to higher nitrogen retention. Feedings are started as soon as possible. If a feeding tube is used, placement into the duodenum is ideal to prevent aspiration and to allow for continuous, uninterrupted feedings during surgical procedures. If the oral route is used, high-protein, high-calorie meals and supplements are given. Dietary consultations are useful in helping patients meet their nutritional needs. Daily calorie counts aid in assessing the ade-quacy of nutritional intake. Overfeeding must be avoided because it increases metabolism, O₂ consumption, and CO₂ production.

Patients lose a great deal of weight during recovery from se-vere burns. Reserve fat deposits are catabolized, fluids are lost, and caloric intake may be limited. Because a burn injury lowers the patient’s resistance to infection and disease, the nutritional status must be improved and maintained although the patient has a poor appetite and is weak.

Indications for parenteral nutrition include weight loss greater than 10% of normal body weight, inadequate intake of enteral nutrition due to clinical status, prolonged wound exposure, and malnutrition or debilitated condition before injury. The risk of infection at the site of the central venous catheter required for parenteral nutrition must be considered. Moreover, the risk of Curling’s ulcer continues in the acute phase.