1. Describe the hypermetabolic response in burn patients and the implications for management.

2. Use physical, nutritional, and medical means to mitigate the hypermetabolic response in burn patients.

3. Discuss the impact of medical comorbidities and age-related physiologic changes on assessing and treating older adults after trauma.

4. Detail the challenges involved in receiving, assessing, and treating obese and morbidly obese trauma patients.

5. Participate in a multidisciplinary assessment of an institution’s capacity to adequately manage obese and morbidly obese trauma patients.

Mitigating the Hypermetabolic Response to Burns
David N. Herndon, MD, Jesse H. Jones Distinguished Chair in Burn Surgery and Professor of Surgery, University of Texas Medical Branch, and Chief of Staff, Shriners Burns Hospital, Galveston, TX

Surviving severe burns: 50% of patients <64 yr of age, with burns covering 80% of total body surface (TBS) survive; improvements seen in resuscitation, infection control, support of hypermetabolic response to injury, and environmental control

Hypermetabolic response: tachycardia; increased cardiac output; increased resting energy expenditure (REE); protein catabolism and muscle wasting; hyperpyrexia; increased lipolysis and fatty infiltration of liver; loss of lean body mass—loss of 30% of lean body mass during hospital stay increases risk for pneumonia and pressure ulcers; loss of 40% of lean body mass generally results in death; environmental support—warm environment (31°C in, eg, treatment and operating rooms [ORs] and corridors) decreases hypermetabolic response by 30% to 40%

Nutritional support: early initiation decreases weight loss; caloric supplementation to meet 140% REE maintains total body weight but does not maintain lean body mass; protein catabolism—elevated levels of catecholamines, glucocorticoids, and glucagon; corticosteroids stimulate breakdown of peripheral muscle (for gluconeogenesis); catecholamines stimulate breakdown of peripheral fat, increasing fatty infiltration of liver; total parenteral nutrition (TPN)—associated with increased mortality, compared to maximally tolerated enteral feeding; used only in rare circumstances; nutritional content—prolonged use of high-fat supplements (eg, milk) results in increased fatty infiltration of liver, compared to solutions high in carbohydrates and protein (eg, Vivonex); Vivonex also associated with increased plasma levels of insulin and decreased protein catabolism

Fatty infiltration of liver: at 1 wk after injury, liver size increases 180% in patients with burns \>50% of TBS; postmortem examination reveals uniform fatty infiltration

Protein catabolism: significant loss of lean body mass generally occurs in patients with burns \>40% of TBS; highest rates occur in young men; patients with high proportion of lean body mass at baseline have most significant losses; effect of REE—REE \>170% associated with significant loss in protein mass and associated morbidity

Sepsis: associated with additional increase (≈40%) in hypermetabolic response; hypermetabolism persists beyond period of sepsis, up to 1 yr after injury (unique to burn patients)

Growth and metabolism: inflammatory phase of burn lasts ≥1 yr, during which time, muscle mass does not increase (and may continue to decrease) and liver remains enlarged; growth—stops for up to 2 yr after injury as hypermetabolic response persists; bone formation—stops for ≤1 yr, resulting in osteoporosis in children and adults; heart rate (HR)— 150% to 160% of predicted; elevations persist ≤2 yr; gene regulation—biopsies reveal significant perturbation throughout genome for ≤1 yr

Early excision and grafting: removing burned tissue and covering wound within 48 hr of injury (vs leaving wound intact for \>1 wk) decreases catabolism by ≈30% during first year

Recombinant human growth hormone: effects in children—decreases healing time at donor sites (for skin grafts) by ≈2 days; decreases protein catabolism by ≈66%; associated with increased levels of albumin (by ≈40%); up- regulates production of insulin-like growth factor (IGF)-1 and expression of IGF-1 receptors in skin and bone (significantly improving wound healing); decreases length of stay; improves growth at 1 and 2 yr; improves bone mineral content; reduces need for reconstructive surgeries; improves left ventricular (LV) ejection fraction (EF); effects in adults—associated with increased mortality; increases hyperglycemia, likely resulting in higher infection rates

Insulin: study showed tight glycemic control decreased infection rates among patients in intensive care unit; among burn patients, decreasing blood glucose (BG) levels from 150 to 80 mg/dL decreases healing time at donor sites, increases protein synthesis in muscle and skin, and decreases REE; other agents—fenofibrate and metformin improve BG levels, protein synthesis, and metabolic function of mitochondria

Oxandrolone: anabolic steroid; may be used for ≤1 yr; improves muscle mass; decreases number of reconstructive surgeries; reverses growth arrest; improves bone mineral content; improves strength over time; affects gene regulation

Propranolol: decreases tachycardia and improves LV stroke volume; decreases REE; improves lean body mass through increased protein synthesis; improves insulin response and BG levels; decreases fatty infiltration of liver by preventing peripheral lipolysis; long-term studies in adults and children show decreased infection and mortality rates, decreased HR, and increases in lean body mass and bone mineral content

Hypercortisolemia: studies in progress, looking at cortisol-reducing therapies (eg, ketoconazole)

Exercise: improves patient’s reintegration into society; significantly improves strength over time

Multisystem Geriatric Trauma
Scott P. Zietlow, MD, Associate Professor of Surgery and Chair, Division of Trauma, Critical Care and General Surgery, Mayo Clinic, Rochester, MN

Demographics: growing population of individuals ≥65 yr of age; age group consumes disproportionately large percentage of trauma resources; issues—high prevalence of comorbidities; different patterns and mechanisms of injury

Mechanisms of injury: falls—account for ≈50% of trauma injuries; high risk for repeated falling; continued care often needed after discharge; reason for fall (often medical) must be addressed; fall prevention important; motor vehicle accidents (MVAs)—second-leading cause of hospitalization for multisystem trauma among elderly; decreases in vision, hearing, reaction time, cervical mobility, as well as cognitive impairment and chronic medical conditions, contribute to high rate of MVAs and MVA-associated mortality; for similar type and severity of injury, mortality rates 5- to 6-times higher among elderly patients; pedestrian–MVAs—sensory and cognitive impairments and poor mobility and reaction time leave older adults vulnerable; 30% of fatal accidents occur in crosswalks; violence—assault; elder abuse; suicide; burns—poor survival after severe (\>50% of TBS) burns

Cardiac and circulatory system: decreased cardiac index; increased systemic vascular resistance; decreased EF; decreased chronotropic response (implications for assessing and responding to hypovolemia); common medications— anticoagulants (eg, warfarin [Coumadin], clopidogrel [Plavix], aspirin); β-blockers; calcium channel blockers and other antihypertensive agents; hypotension—poorly tolerated; blood pressure (BP) ≤90 mm Hg generally signals insufficient perfusion; mortality rates increase with duration of hypotension; acidosis—base deficit of -6 mEq/L associated with 60% mortality; even mild acidosis increases mortality rate; resuscitation—patients with signs of hypoperfusion require aggressive resuscitation in monitored setting; short-term use of pulmonary artery catheter may have benefit; dobutamine recommended for patients with adequate preload but impaired myocardial contractility or afterload (avoid pressors in these patients); transfusion trigger—controversial; some evidence supports maintaining hemoglobin levels \>10 g/dL among elderly patients (especially in setting of hypotension, acidosis, and/or known coronary artery disease [CAD])

Respiratory system: decreased alveolar surfaces, diffusion capacity, lung elasticity, chest wall compliance, muscle mass, and mucociliary clearance; high prevalence of chronic obstructive pulmonary disease (COPD); history of tobacco exposure (primary or secondary) common; injuries—rib fractures and pulmonary contusions common; complications—risk for pneumonia after trauma (5-fold that of younger patients); pain control and pulmonary care— critical; epidural catheter recommended if pain control not obtained in ≤24 hr; oxygenation, ventilation, and early intubation, if necessary (eg, for patients struggling with pulmonary secretions)

Renal function: decreased cortical mass; tubular senescence; hypertension, diabetes, and peripheral vascular disease (PVD) further impair glomerular filtration rate and creatinine clearance; assessment—creatinine clearance more accurate than serum creatinine level; use creatinine clearance for calculating dose adjustments; avoid nephrotoxic agents when possible

Central nervous system: cerebral atrophy (≈10% by 75 yr of age); decreased cerebral circulation; decreased vision and hearing; impaired sense of vibration and position; increased reaction time; PVD, stroke, dementia, and many medications increase risk for falls and accidents; subdural hematomas—risk increased, largely due to cerebral atrophy; may result from relatively minor injury; computed tomography (CT) recommended for older adults with abnormal findings on neurologic examination; level of consciousness—Glasgow Coma Scale (GCS) score ≤8 associated with ≥80% mortality

Reversal of anticoagulation therapy: immediate reversal required for patients with head injury; if CT shows operative lesion, activated factor VII recommended

Musculoskeletal system: spine—osteoporosis; degenerative joint disease; falls commonly result in cervical spine fractures (typically proximal; often at level of odontoid process); vertebral compression fractures common; spinal CT recommended over plain radiographs; magnetic resonance imaging (MRI) appropriate in some settings (eg, suspicion of epidural hematoma along spinal cord, acute injury to disc, or central cord syndrome); muscle mass—loss accelerates with age; osteoporosis—present in 50% of men and women by 65 yr of age; falls often result in fractures of proximal hip, femur, humerus, or distal forearm; orthopedic surgery—early mobilization and physical therapy critical for good functional outcome

Skin: thin fragile dermis; thermoregulation—impaired; other contributing factors include CAD, PVD, and diabetes; low metabolism and environmental factors may result in hypothermia; wound healing—impaired; increased risk for infection and pressure ulcers

Liver and spleen: decreased hepatic mass and function; splenectomy may be appropriate in setting of splenic injury

Nutrition and metabolism: decreased metabolic rate; increased glucose intolerance; poor baseline nutritional status; enteral nutrition preferred

Immune system: decreased cell-mediated immunity and antibody response; cancer and chemotherapy may impair febrile response; patients may become neutropenic in response to injury; infections common

Trauma in the Bariatric Patient
Michael D. McGonigal, MD, Assistant Professor of Surgery, University of Minnesota, School of Medicine, and Director of Trauma Services, Regions Hospital, Minneapolis

Obesity: global problem; impact on morbidity and mortality after trauma—mortality rates among obese patients even higher than among elderly patients; extended need for ventilator; prolonged hospital stays; greatly elevated risk for infection; poor functional outcome (eg, mobility); definitions—overweight, body mass index (BMI) of 25 to 29.9; obesity, BMI ≥30; morbid obesity, BMI \>40 or 100 lb above normal weight; BMI based on weight and height (difficult to measure in trauma setting); waist/hip ratio more helpful (\>1.0 signals obesity); practical problems—patient may not fit into equipment (eg, scanners, backboards, cervical collars, BP cuffs); patients difficult to examine; diagnosis and intervention more difficult; studies (eg, plain radiographs) sometimes more difficult to interpret; patterns of injury differ; complications common

Assessment considerations: airway and breathing—weight on chest and abdomen decreases resting lung capacity and increases risk for aspiration; landmarks (eg, for intubation or cricothyroidotomy) difficult to locate; circulation— cardiovascular system impaired at baseline; increased metabolic demand, blood volume, and cardiac workload; decreased ability to tolerate hypotension or hypovolemia; vascular access may require alternative sites; diagnostic peritoneal lavage requires larger incision (consider moving to OR); abdominal adiposity may complicate some studies (eg, focused abdominal sonography for trauma); disability evaluation—cervical immobilization may require improvised collar; patient may not fit in imaging equipment; open-sided MRI scanners provide poorer quality images; environment—obese patients require larger stretchers and beds; patients may require improvised splints

Other issues: drug dosing—avoid subcutaneous doses (uncertain absorption); questionable distribution volume complicates dose calculations; altered drug metabolism; vascular access—inability to visualize landmarks and veins complicates peripheral access; groin often inaccessible and prone to infection; nutrition—patients commonly develop malnutrition (due to preferential mobilization of protein)

Initial management recommendations: airway—use O2 mask; consider providing positive airway pressure; breathing—expect low O2 -saturation levels (even when patients receiving supplemental O2 ) and CO2 retention (PCO2 46-52 mm Hg); consider obtaining baseline arterial blood gas measurements in emergency department (ED); circulation—first attempt standard technique for intravenous (IV) access; consider using longer needle; switch to peripherally inserted central catheter, if necessary; other access points include internal jugular vein and pretibial area (for intraosseous line)

Further assessment: imaging—put patient in reverse Trendelenburg position for chest x-ray (improves visualization; eases breathing); CT best for chest and spine; transesophageal echocardiography recommended for assessing cardiac disease; other issues—access for Foley catheter often problematic; nasogastric tube required to avoid aspiration

Special considerations for massively obese patients: special equipment necessary; sequential compression devices may not fit; prevention of pressure ulcers and infections critical; special dressings often required for soft tissue injury; multidisciplinary approach necessary

Checklist: develop system; consult ED; include emergency medical system; have bariatric equipment available (if renting on as-needed basis, ensure adequate response times); check door sizes; review imaging capabilities; train all staff; involve social workers; develop relationships with referral facilities and home care agencies that can accommodate bariatric patients