Introduction

The quality of life in developed countries has improved over the past 50 years, increasing the average lifespan by nearly 30 years.¹ Individuals aged 65 years and over account for 13% of the US population. This ‘elderly’ population is projected to double from 40.2 million in 2010 to 88.5 million by 2050. Such population aging is unprecedented.² By 2050, the number of elderly persons in the world is expected to exceed the number of young for the first time in history.³ This trend presents a special challenge, as the elderly will constitute an ever-growing segment of the average surgeon’s practice and will influence clinical decisions, ethical decisions, and healthcare costs.

A multicenter study conducted in Tokyo found that 25% of burned patients were over 65 years old.⁴ A systematic review of over 186 500 patients in Europe showed that 10–16% were in this age range.⁵ In the US, geriatric patients constitute about 10% of the major burn population. The anticipated rise in the geriatric population makes understanding age-related physiological and metabolic changes even more important for the burn care professional.⁶^–⁸ The elderly and the very young are most likely to die from severe burns.⁹^–¹² Nearly 12 deaths per day result from residential fires, with infants, toddlers, and the elderly representing the high-mortality population.^10,¹¹ Adults over 65 years old have a mortality from burns that is six times the national average.⁹ Treatment of these patients remains a greater challenge than treatment of middle-aged and younger patients, as lower physiological reserves and higher underlying comorbidities reduce the margin for error.

Epidemiology

Contact with flame is the main (50%) cause of burn injury. One-third of injuries result from cooking accidents: scalds in 20% of cases and contact with hot objects in about 9% of cases.⁶^–⁸ ^,13 ^,14 The latter cause is more prevalent in the elderly, reflecting increased psychological and physical disability. This fact is also reflected in the rate of fire-related deaths in individuals over 75 years old, which is four times the national average. The male-to-female ratio decreases progressively as age increases, with women exceeding the number of men in the 75 years and older group (compared to the 5 : 1 male-to-female ratio for young adult burn victims).¹⁴ This ratio is explained by the fact that 95% of burns in elderly people occur at home, compared to less than half in younger adults. Therefore, prevention must be focused on the home.¹⁵ Prevention should also focus on the fact that 30% of geriatric patients are the victims of self-neglect, and at least 10% are the victims of elder abuse.¹³

Outcome

Mortality has diminished among all age groups in recent decades.^5,^14,¹⁶ Technological progress as well as advances in fluid resuscitation, early burn wound excision, skin grafting, and pharmacotherapy have improved survival. As expected, mortality and morbidity are higher in geriatric burn patients.^1,^2,¹⁰^–¹² ^,14 ^,17 Mortality is 50% in young adults with a burn covering 80% of the total body surface area (TBSA) and in individuals aged 60 and older with burns covering only 35% TBSA.^6,¹² Pereira et al.¹⁶ analyzed 1674 patients admitted to the Shriners Burn Hospital, Galveston, Texas, between 1989 and 2005 as well as 179 autopsies conducted during this period to study mortality trends and primary causes of death in the entire age spectrum over time. They found that mortality has indeed been reduced in all age groups, including the elderly (>65), over the last decade. Lung injury and sepsis were the commonest primary causes of death noted at autopsy. An increase in the weights of heart, lung, spleen, and liver was noted in all age groups post mortem. Fogerty et al. reported an 83% reduction in the odds of death and a 50% reduction in the odds of sepsis in elderly patients treated with a statin before injury.¹⁸ Pomahac et al. reported that increased levels of creatinine at the time of admission were associated with increased mortality.¹⁹

Gender dimorphism exists in mortality rates of patients over 65 years old. The National Burn Repository 2009 reported an overall greater mortality in women than in men, but a lower disparity during recent years. Age, TBSA burned, and inhalation injury are associated with increased mortality. The mortality rate is 9.7% for patients aged 60–69 years, 17% for patients aged 70–79 years, and 28.6% for patients over 80 years of age. ¹⁴

Geriatric patients also experience greater long-term disability following burn injury. Only about 50% of elderly patients with a major burn return home within the first year,^7,^16,²⁰ whereas 90% of young adults return home. The increased risk factors present in this population explain these statistics. The increased complications seen in elderly burn patients may also result from more cautious and less aggressive treatments. This is due to existing beliefs that elderly burn patients cannot tolerate eschar excision as well as their younger counterparts, resulting in a greater delay in the excision of burned tissue.²¹ However, despite these risk factors, elderly patients have repeatedly been shown to tolerate multiple, early surgical procedures, and early wound closure corresponds to a better outcome in these patients.²²^–²⁴

Risk factors

A number of well-recognized risk factors are present in elderly people. Increased risk of infections, pulmonary diseases, and sepsis as well as the variability of comorbidities present in these patients will increase morbidity after a burn. Some of the more prominent factors are shown in Box 36.1.

Box 36.1 Risk factors in elderly people

• Chronic illness, e.g., adult diabetes

• Effects of aging, e.g., presbyphagia

• Cardiovascular disease, e.g., previous infarct

• Pulmonary reserve decreased with age

• Infections, e.g., pneumonia and UTI

• Unintentional weight loss

• Decrease in lean body mass

• Impaired nutrition with presence of deficiency states in energy, protein, and macronutrients

• Decreased endogenous anabolic hormones

• Skin aging (thin, decreased synthesis)

Decreased cardiopulmonary reserve

Aging reduces pulmonary reserve for both gas exchange and lung mechanics.²⁵ Elderly people are more prone to pulmonary failure, the major cause of burn-related death. The presence of atherosclerosis, coronary artery disease, and previous myocardial infarcts is also common.

Chronic illness including malnutrition

Numerous diseases are common in the elderly. Some of these, such as swallowing disorders (presbyphagia), can lead to malnutrition.²⁶ Some degree of protein–energy malnutrition is found in over 50% of elderly burn patients on admission.²⁷ This, in combination with burn-induced hypermetabolic responses and protein catabolism, can substantially reduce lean body mass in just a few weeks. Daily protein requirements are higher in the elderly than in the younger population.²⁸

Malnutrition increases morbidity and mortality after a burn and may increase the risk of burn injury in the elderly.²⁷^–²⁹ Nutritional support is a critical in improving the clinical outcome of these patients. Use of a screening tool at admission to assess the nutritional status of elderly patients is necessary.³⁰

Infections

Pneumonia and urinary tract infections are the most prevalent complications in elderly burn patients.¹⁴ The development of pneumonia seems to correlate with the male gender, TBSA burned, and presence of inhalation injury.¹⁷ Pneumonia contributes to increase mortality, especially in the elderly.

Decreased lean body mass

Aging leads to progressive decreases in lean body mass.³¹ The lean mass or body protein compartment is responsible for all the physiological and metabolic activity needed for survival, and any significant decrease is detrimental. Any pre-existing loss will result in increased morbidity, early onset of immune deficiency, organ dysfunction, weakness, and impaired wound healing.^29,^32,³³ Losses are caused by multiple factors, including impaired nutrition, reduced mobility, and age-related decreases in endogenous anabolic hormones, human growth hormone, and testosterone.^25,²⁹

Decreased anabolic activity prolongs recovery time and greatly delays restoration of muscle. Importantly, elderly people respond to exogenous anabolic stimuli such as testosterone analogs, human growth hormone, and resistance exercise similarly to the younger population. Therefore, exercise, high-protein nutrition, and anabolic agents are essential for recovery.³⁴^–³⁶

Aging skin and wound healing

Aging produces significant changes in the skin. Because of these changes, more deep burns occur in the elderly than in younger patients.^24,^37,³⁸ After the age of 65 the turnover rate of the epidermis decreases by 50%. A flattening of the rete pegs and fewer epidermal-lined skin appendages are present. These properties significantly delay healing of partial-thickness burns.^24,^37,³⁸

In addition to the above-mentioned changes, a progressive thinning of the dermis occurs, along with a decrease in both collagen content and matrix, especially glycosaminoglycan. The latter is responsible for loss of skin turgor. There is also a decrease in vascularity, macrophages, and fibroblasts. The thinner dermis with less blood flow explains the greater amount of deep burn, and the decreased cellularity explains the decrease in all phases of healing (Box 36.2).^37,³⁸

Box 36.2 Aging of skin

• Decreased epidermal turnover

• Decrease in skin appendages

• Thinning of dermis

• Decreased vascularity

• Decreased collagen and matrix

• Decreased fibroblasts and macrophages

Treatment

In general, elderly patients are treated identically to younger patients, except that massive burns are more commonly managed expectantly. Some differences exist in responses to burn injury between children and adults; however, no evidence supports changing the treatment protocol. Current differences in burn management among patient groups are related to comorbid conditions and adversities that may arise.

Initial resuscitation

Improved fluid resuscitation over time is one of the factors associated with decreased mortality. Compared to younger patients, more fluid is required to resuscitate elderly patients with the same burn size to avoid hypovolemia.³⁹ This is likely attributable to decreased skin turgor, which reduces resistance to fluid accumulation or edema production. Another possible factor is impaired cardiac function. Burn depth, inhalation injury, and delayed resuscitation can influence fluid requirements.⁴⁰ Benicke et al. developed a multifactorial resuscitation formula with a compensating factor for advanced age that promises to help in the initial assessment of fluid resuscitation.⁴¹ Early ventilatory support is more commonly required because of decreased lung reserve and earlier fatigue.

Wound management

Early removal of the burn wound and rapid closure with skin grafts are essential for survival.²²^–²⁴ Because the elderly have thin skin, thermal injuries often create full-thickness wounds, and skin grafts cannot always be obtained. In fact, they might create a new wound.²⁴ Thinner skin grafts are necessary because of the thinner dermis, and healing time is prolonged.³⁷ Gore found that donor site healing time decreased substantially in elderly patients undergoing AlloDerm skin grafting, allowing more patients to undergo operative wound closure.²⁴ Because older patients do tolerate operative procedures, a conservative approach is not warranted. Because multiple residual problems persist for years after injury, patient orientation is crucial to understand the long-term outcome of wound healing.

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