Chapter 9 – Trauma and Musculoskeletal System Dysfunction in the Critically Ill Elderly




Chapter 9 Trauma and Musculoskeletal System Dysfunction in the Critically Ill Elderly


Felix Y. Lui and Kimberly A. Davis



Key Points





  • Unintentional injury was the seventh leading cause of death in the population aged 65 years and older, and geriatric trauma patients consume a disproportionate share of healthcare costs.



  • Patterns of injury differ between younger and older populations, as well as outcomes after traumatic injury.



  • Alterations in cognition, vision, reflexes, muscular strength, and proprioception lead to increased rates of gait instability and subsequent falls, which contribute to an increased propensity for injury.



  • Falls are the leading cause of injury and injury-related mortality for individuals older than age 75 and second only to motor vehicle collisions in those aged 65 to 74.



  • Osteoporosis increases the risk of fractures and subsequent disability.



  • Traumatic brain injuries (TBIs) are a significant contributor of morbidity and mortality in the elderly.



  • Cervical spinal fractures are among the top five fractures in elderly patients.



  • Elderly patients who sustain rib fractures have increased ventilator days, intensive care unit (ICU) and hospital lengths of stay, and rates of pneumonia and twice the mortality and thoracic morbidity than their younger counterparts.



  • The annual mortality of patients older than age 80 with hip fractures is up to three times that of those without hip fractures.



  • Older trauma patients have higher rates of functional impairment because of injury, requiring rehabilitation or placement in skilled care facilities.



Introduction


The aging population of the United States, coupled with increased independence and mobility of these individuals, makes traumatic injury of the elderly a challenging and growing problem in healthcare. The population aged 65 and older comprised 14.5 percent of the overall population in 2014, up from 13.0 percent in 2010, and it represents the fastest-growing segment of the population [1,2]. Accordingly, in 2014, unintentional injury was the seventh leading cause of death in the population aged 65 years and older and resulted in almost 4 million injuries and more than 865,000 hospitalizations [3]. Compared with younger patients, these elderly trauma patients tend to have longer hospital stays, greater medical expenditures, and higher mortality rates [46]. While accounting for one-tenth of the population, geriatric trauma patients consume a disproportionate share of healthcare costs. One-third of healthcare expenditures for trauma went toward trauma in the elderly [7]. Patterns of injury also differ between younger and older populations, as well as outcomes after traumatic injury, due to changes in function and the physiologic consequences of aging. While survival to discharge remains high, older trauma patients have higher rates of functional impairment because of injury, requiring rehabilitation or placement in skilled care facilities [8]. Understanding these challenges enables healthcare practitioners to optimize care and maximize functional outcomes and quality of life for this complex and growing population.



Physiologic Changes with Aging


A myriad of physiologic and anatomic changes occur during aging that influence patterns of injury and the ability of the body to recover from major trauma. Pretrauma frailty, which loosely correlates with age, has been shown to be a major predictor of posttraumatic injury outcomes [9,10]. Diminished reserve and impaired ability to recover from complications after injury result from the normal aging process. Understanding these changes aids in optimizing outcomes in elderly trauma patients, as well as providing guidance in planning of posttrauma rehabilitation and prognosis.


Neurologic function declines in aging, leading to increased rates of gait instability and subsequent falls in the elderly population. Alterations in cognition, vision, reflexes, muscular strength, and proprioception contribute to the propensity for injury. Cortical atrophy results in greater rates of significant brain injury due to increased shear of bridging parasagittal veins leading to subdural and subarachnoid hemorrhage. Increased mobility of the brain within the cranial vault results in higher rates of contusion and countercoup injury after blunt trauma.


Cardiovascular function and reserve also deteriorate over time due to both natural and disease-related factors. Normal aging results in cardiovascular decline due to myocyte loss with a compensatory increase in myocyte volume. The decrease in myocardial compliance results from fat cell infiltration into the ventricular walls and septum, causing decreased diastolic relaxation and slower filling. Decreased maximal cardiac output (due to a decrease in maximal heart rate with preserved stroke volume) and ejection fracture are seen with progressive aging. Loss of myocytes also leads to stiffening of large vessels, which, combined with progressive intimal hyperplasia, increases afterload and impairs early diastolic filling. Deterioration of the conducting system increases rates of arrhythmias in a patient population increasingly dependent on the atrial contribution to maintain end-diastolic volume. The increased use of beta-blockers blunts the body’s response to trauma and stress and confounds evaluation for shock.


Calcification of costal cartilage and muscular atrophy contribute to decreased thoracic compliance over time. Forced vital capacity and forced expiratory volume in 1 second (FEV1) decrease with aging. Oxygen diffusion decreases due to thickening of the alveolar basement membrane. Decreased airway sensitivity and mucociliary clearance leads to higher susceptibility to aspiration and subsequent pneumonia.


Aging is associated with progressive renal cortical loss with glomerulosclerosis and tubular senescence, resulting in decreased glomerular filtration rate and impaired reabsorption and secretion of fluids and electrolytes. Renal reserve decreases, increasing the likelihood of acute kidney injury after trauma due to relative hypoperfusion.


Progressive loss of muscle mass and strength increases the risk of injury in the aging population. Degeneration of myocytes and collagen, combined with cartilaginous and ligamentous stiffening of joints, predisposes patients to accident and injury. Osteoporosis increases the risk of fractures and subsequent disability [11].


Immunologic response to traumatic injury is blunted in the elderly population. Impaired sympathetic response and diminished thermoregulation increase the risk of complications after injury. Aging is associated with decreased immunologic function secondary to decreases in T-lymphocyte response and natural killer cell activity. An increased cytokine response occurs with aging, resulting in an increased incidence of systemic inflammatory response syndrome [12].



Mechanisms and Patterns of Injury


In the elderly, blunt mechanisms of injury predominate. In 2015, motor vehicle collisions (MVCs) were the most common mechanism of injury leading to hospitalization, with greater mortality and severity of injury among patients aged 65 or older compared with their younger counterparts [1315]. As the population ages, the overall number of elderly drivers and passengers will continue to increase, further adding to the growing problem of elderly victims of motor vehicle–related injuries. Behavioral intervention and risk-reduction strategies are encouraging tools in the prevention of these injuries but are poorly studied [16].


Falls are the leading cause of injury and injury-related mortality for individuals over age 75 and second only to MVCs in those aged 65 to 74. Nearly 2.5 million older adults receive treatment yearly in emergency departments for falls, and yet fewer than half of falls are reported to medical personnel [17]. This results in over 700,000 hospital admissions per year, including over 250,000 for hip fractures. While most falls are from ground level, in the elderly population these are still associated with high incidences of morbidity and mortality [18].



Management of Specific Injuries



Neurotrauma


Traumatic brain injuries (TBIs) are a significant contributor of morbidity and mortality in the elderly. In a study by Haring et al. between 2000 and 2010, patients aged 65 to 69 accounted for 13.0 percent of all TBI-related hospitalizations, and patients older than age 85 accounted for 30.3 percent of all admissions. Overall mortality in this population was 11.4 percent over this study period [19]. Common injuries include subarachnoid, subdural, and epidural hemorrhages. This is due to the more adherent dura, cerebral atrophy, and cerebrovascular atherosclerosis seen during the aging process. Confounding these data are the patients who present with intracranial bleeds prior to a traumatic injury (fall, MVC, etc.), which may be mistriaged as TBIs. In addition to age-related physiologic and anatomic factors, a major contributor to TBI outcomes is the use of anticoagulants in this patient population [20]. Further confounding this issue is the rapid adoption of the use of direct oral anticoagulants (DOACs) in the elderly population. The inability to monitor the degree of anticoagulation and limited options for reversal of these agents make the management of TBI patients receiving these agents difficult. Prothrombin complex concentrate (PCC) use for the reversal of warfarin rapidly reverses coagulopathy and decrease the progression of intracranial hemorrhage, but reversal agents for DOACs are still under development and poorly studied [21,22]. Idarcizumab (Praxbind) was approved in 2015 by the Food and Drug Administration (FDA) for the reversal of dabigatran, and other agents such as andexanet alfa show promise in reversing the effects of factor Xa inhibitors [23].



Spinal Trauma


Spine trauma is a significant contributor to morbidity and mortality in the elderly. Cervical spinal fractures are among the top five fractures in elderly patients. Fractures in this population are associated with a significant rate of high cervical fractures with dens involvement. Fortunately, neurologic involvement is still infrequent [24]. Management of these fractures in the elderly is debatable. High rates of surgical complications and mortality with surgical treatment are weighed against the high rate of nonunion in older patients with cervical spine injuries treated nonoperatively with rigid cervical collars [25]. Lower spinal compression fractures are extremely common in the elderly population. Greater than one-fourth of postmenopausal women have vertebral compression fractures due to inadequate accumulation of bone mass in childhood and early adulthood and resorption after menopause. Nonoperative management, including analgesia, bracing, and physical therapy, is effective in the majority of cases, with surgery reserved for chronic, severe pain, instability, or neurologic compromise [26].



Thoracic Trauma


Elderly patients are especially susceptible to pulmonary complications after blunt thoracic trauma. Rib fractures are associated with poor outcomes. Elderly patients who sustain rib fractures have increased ventilator days, intensive care unit (ICU) and hospital lengths of stay, and rates of pneumonia and twice the mortality and thoracic morbidity than their younger counterparts. Each additional rib fracture increases mortality by 19 percent and risk of pneumonia by 27 percent [27]. Additional factors contributing to poorer outcomes in these elderly patients include decreased physiologic reserves and preexisting comorbidities but require further study [28]. Optimal pain control and pulmonary toileting are essential to optimize outcomes in these patients. In elderly patients, use of epidural analgesia over intravenous narcotic analgesia decreases morbidity, as well as hospital length of stays and overall hospital costs, but may be associated with increased deep venous thrombosis [2931]. Frequent treatment with anticoagulants further complicates the placement of epidural and paravertebral catheters for analgesia.



Abdominal Trauma


Most intra-abdominal solid-organ injuries are managed nonoperatively. Specifically, the majority of hepatic and splenic injuries are managed with observation, with angioembolization and surgery reserved for those with active bleeding or hemodynamic instability. Risks of splenectomy include morbidity from laparotomy as well as the risk of postsplenectomy sepsis, although the true risk is unknown. Initial concerns regarding advanced age (defined as older than age 55) being a predictor of failure in nonoperative management of splenic injury have not borne out; therefore, advanced age should not be used as the sole determinant in the decision to pursue nonoperative management [3235]. Improved imaging and interventional techniques have shown good results in the management of both liver and spleen injuries without surgical exploration. However, overall mortality for patients managed both operatively or nonoperatively is elevated compared with their younger counterparts [36]. Therefore, decision making regarding operative versus nonoperative management of solid-organ injury is based on hemodynamic status and transfusion requirements. Patients who are hemodynamically appropriate or respond rapidly to volume resuscitation are appropriate candidates for a trial of nonoperative management. These candidates require close hemodynamic monitoring, serial examinations, and hematocrit determinations. Patient who continue to have hemodynamic instability or have ongoing transfusion requirements should be managed surgically or with angiography and angioembolization.



Thermal Injury


For unclear reasons, elderly patient do particularly poorly after sustaining burn injuries [37]. The LD50 for burn size for patients older than age 65 has remained at 35 percent, whereas gains have in made in younger patients [38,39]. This relationship appears to be linear, however, without a clear inflection point and relates to preexisting conditions as opposed to age alone. Likely higher rates of preexisting pulmonary disease, immobility, and decreased pulmonary reserve contribute to this finding. Elderly patients have longer lengths of stays and higher rates of multisystem organ failure but not infections or sepsis. This may be explained by alterations in the inflammatory response (metabolic, glycemic, immune, wound healing) in the aging population and requires a multimodal approach [40].



Musculoskeletal Trauma


Elderly patients are at particular risk of morbidity and mortality secondary to musculoskeletal trauma. Increased risk of falls, relative skeletal fragility, degenerative joint disease, stress fractures, periprosthetic fractures, and pathologic fractures contribute to increased rates and poorer outcomes. In patients older than age 80, those with hip fractures suffer up to three times the annual mortality compared with those without hip fractures [41]. This difference in outcomes is likely due to preexisting medical comorbidities, lower bone mineral density, and less muscular mass.


Orthopedic injuries should be managed in the safest and most expedient manner. While early operative fixation (<24 hours from injury) has been shown to be beneficial in younger patients, failure to manage preexisting conditions leads to higher mortality in the elderly population [42,43]. Medical consultation, optimization of medications, and stabilization of medical condition prior to repair of orthopedic injuries (up to 72 hours) leads to better outcomes with no increase in 30-day or long-term mortality, infectious complications, myocardial infarction, or thromboembolism. Perioperative antibiotics should address coverage of Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus, and Staphylococcus epidermis in institutions with high rates of colonization. Thromboembolic prophylaxis is an area of controversy, but current American College of Chest Physicians (ACCP) guidelines recommend use of low-molecular-weight heparin, fondaparinux, low-dose unfractionated heparin, a vitamin K antagonist, aspirin, or intermittent leg compression devices in the perioperative period [44]. Ultimately, risk of surgery must be weighed against optimizing the best chance of return to pretrauma functional status and quality of life.



Outcomes


The outcome of trauma patients is associated with the appropriate triage of patients to the appropriate facilities that are best able to manage the complexity and severity of their injuries. Patients younger than age 55 are at an increased risk of undertriage to appropriate trauma centers [4547]. A recent study reviewing the data from the National Trauma Data Bank (NTDB) showed that elderly trauma patients who were triaged to centers that managed a higher proportion of elderly patients had a 34 percent decrease in mortality risk (odds ratio [OR] 0.66, 95 percent confidence interval [CI] 0.54–0.97) [48]. This difference appears to be attributable to the ability of high elderly volume centers to salvage elderly patients after occurrence of complications as opposed to higher initial survival after traumatic injury [49,50].



Resuscitation Goals


Cardiovascular aging contributes to the difficulties in compensating for stress and increased demands after shock and trauma. Diminished cardiac output with decreased maximal heart rate, in addition to common use of antihypertensive and heart rate–controlling medications, makes the diagnosis of shock and hypoperfusion challenging in this population. In a prospective, randomized trial of elderly hip fracture patients, early use of invasive monitoring with pulmonary artery catheters was shown to decrease mortality rates [51]. Increased base deficit (−6 mEq/liter or less) or lactic academia (>2.2 mg/dl) has been shown to be associated with increased mortality [52,53]. Early use of pulmonary artery catheters to guide resuscitation to target cardiac indices or oxygen consumption may be beneficial in optimizing outcomes, but recent intraoperative studies suggest that goal-directed resuscitation appears to be less effective in elderly patients [54,55].



Contribution of Frailty to Outcome


Research involving the geriatric trauma population is difficult to interpret. There is a lack of consensus on the definition and characteristics of geriatric trauma patients and a lack of randomized, prospective, controlled trials examining this age group specifically. The overall mortality rate for elderly trauma patients is approximately 15 percent [56]. This rate increases in a linear fashion with increasing age until age 84, after which rates decline [57]. Research does support that advanced age alone is not a predictor of poor outcomes, and advanced age should not be used as the sole criterion for denying or limiting care [58]. Excellent outcomes are possible because most geriatric trauma patients return home, and up to 85 percent will return to independent function [59,60].


The presence and severity of preexisting conditions are major determinants of outcomes after trauma [61,62]. A combination of factors including preexisting conditions, medications, nutritional status, functional ability, and general state of health contributes to the ability to survive and recover from traumatic injury. Up to 38 percent of geriatric trauma patients are frail, with an increased risk of fractures and discharge to an institution. Increasing frailty is a risk factor for postoperative morbidity, mortality, and hospital length of stay [6366]. In geriatric trauma patients, preinjury frailty assessment, using one of a number of available tools, may be a useful predictor of postinjury functional status and mortality [67]. The Trauma-Specific Frailty Index (TSFI) uses a scale based on 50 variables associated with poorer outcomes, has been validated in a trial of 200 patients, and is a fast and reliable tool for use in trauma patients [68]. Routine assessment of pretrauma status may be a useful tool in early determination of postdischarge needs and functional recovery. While posttrauma ambulation is a significant predictor of outcomes, pretrauma ambulation status is a predictor of long-term survivorship in the elderly with hip fractures [69]. Use of tools such as the Geriatric Trauma Outcome Score {age + [2.5 × Injury Severity Score (ISS)] + 22 (if transfused packed red blood cells)} may provide a more accurate estimation of mortality after trauma [70]. Use of these scores can assist practitioners in discussions with families in determining treatments and goals of care and may help to identify patients in need of early involvement of palliative care services.


While most patients do return to independent living, a significant proportion experiences diminution in quality of life across multiple domains [71]. On average, elderly patients experience the equivalent of loss of one activity of daily living (ADL) 1 year after their injury [72]. This predisposes them to further loss of function, independence, and death. A multidisciplinary approach is required in the management of these complex patients. Early geriatric consultation can improve functional recovery after trauma injury in older patients [73].


Optimal care of these patients requires not only appropriate management of their traumatic injuries but also prevention of further injury and harm. One-third of patients over age 65 suffer a fall annually, and one-third of those either returned to the emergency department or died within 1 year [74,75]. Risk factors for additional falls include prior falls, independent living, use of walking aids, depression, cognitive deficits, and use of greater than six medications. Screening and identification of these risk factors in elderly patients may be an opportunity for intervention to prevent further falls in the future. Targeted educational programs addressing these factors prevent recurrent injury and falls and may benefit long-term outcomes [76].



Special Considerations


Elderly abuse is a common and underreported cause of significant morbidity and mortality in the elderly population. It is estimated that 10 percent of older adults are victims of abuse, but fewer than 1 in 24 cases are ever reported to the authorities [77,78]. Abuse occurs in many forms, including physical, sexual, emotional, psychological, neglect, and financial exploitation. In physical abuse, the most common injuries involve blunt trauma with fists or household objects and are reported as “falls” [79]. Injuries to the upper extremities, face, and neck are uncommon following ground-level falls but are common in victims of elder abuse [80]. Healthcare providers must maintain a low threshold for suspicion of elder abuse in order to intervene early in this vulnerable population.

Only gold members can continue reading. Log In or Register to continue

Oct 24, 2020 | Posted by in CRITICAL CARE | Comments Off on Chapter 9 – Trauma and Musculoskeletal System Dysfunction in the Critically Ill Elderly
Premium Wordpress Themes by UFO Themes