O. John Ma
EPIDEMIOLOGY
While persons over 65 years of age represent 12% of the population, they account for 36% of all ambulance transports, 25% of hospitalizations, and 25% of total trauma costs.
Approximately 28% of deaths due to accidental causes involve persons 65 years and older.
PATHOPHYSIOLOGY
Chronologic age is the actual number of years the individual has lived. Physiologic age describes the actual functional capacity of the patients’ organ systems in a physiologic sense.
Comorbid disease states such as diabetes mellitus, coronary artery disease, renal disease, arthritis, and pulmonary disease can decrease the physiologic reserve of certain patients, which makes it more difficult for them to recover from a traumatic injury.
Physiologic reserve describes the various levels of functioning of the patients’ organ systems that allow them to compensate for traumatic derangement.
Falls are the most common cause of injury in patients over 65 years of age. Falls are reported as the underlying cause of 9500 deaths each year in patients over the age of 65 years. In the >85-year-old age group, 20% of fatal falls occur in nursing homes.
Motor vehicle crashes rank as the second leading mechanism of injury that brings elderly patients to a trauma center in the United States and are the most common mechanism for fatal incidents in elderly persons through 80 years of age.
CLINICAL FEATURES
Following injury, elderly patients have higher admission rates, longer hospital stays, increased long-term morbidity, and higher mortality rates despite lower injury severity.
The clinician should not be led into a false sense of security by “normal” vital signs. In one study of 15 patients initially considered to be hemodynamically “stable,” 8 had cardiac outputs less than 3.5 L/min and none had an adequate response to volume loading. Of seven patients with a normal cardiac output, five had inadequate oxygen delivery.
There is progressive stiffening of the myocardium with age that results in a decreased effectiveness of the pumping mechanism. A normal tachycardic response to pain, hypovolemia, or anxiety may be absent or blunted in the elderly trauma patient. Medications such as β-blockers may mask tachycardia and hinder the evaluation of the elderly patient.
Elderly patients suffer a much lower incidence of epidural hematomas than the general population; however, there is a higher incidence of subdural hematomas. As the brain mass decreases with advancing age, there is greater stretching and tension of the bridging veins that pass from the brain to the dural sinuses.
The incidence of cervical spine injury has been found to be twice as great in geriatric patients as in a younger cohort of blunt trauma patients. Odontoid fractures were particularly common in geriatric patients, accounting for 20% of geriatric cervical spine fractures compared with 5% of non-geriatric fractures.
Severe thoracic injuries, such as hemopneumothorax, pulmonary contusion, flail chest, and cardiac contusion, can quickly lead to decompensation in elderly individuals whose baseline oxygenation status may already be diminished.
Reduction in pulmonary compliance, total lung surface area, and mucociliary clearance of foreign material and bacteria result in an increased risk for elderly patients to develop nosocomial gram-negative pneumonia.
Hip fracture is the single most common diagnosis that leads to hospitalization in all age groups in the United States.
Hip fractures occur primarily in four areas: intertrochanteric, transcervical, subcapital, and subtrochanteric. Intertrochanteric fractures are the most common, followed by transcervical fractures. Emergency physicians must be aware that pelvic and long bone fractures are not infrequently the sole etiology for hypovolemia in elderly patients.
The incidence of humeral head and surgical neck fractures in elderly patients are increased by falls on the outstretched hand or elbow.
DIAGNOSIS AND DIFFERENTIAL
The base deficit and lactate levels provide good initial measures of shock, and serial measurements can guide resuscitation decisions. The base deficit and lactate levels both correlate with systemic hypoperfusion that may be “occult” in patients, and admission levels of these markers correlate with ICU length of stay, hospital length of stay, and mortality.
For older patients, the adhesions associated with previous abdominal surgical procedures increase the risk of performing diagnostic peritoneal lavage.
It is important to ensure adequate hydration and baseline assessment of renal function prior to the contrast load for the CT scan. Some patients may be volume depleted due to medications, such as diuretics. This hypovolemia coupled with contrast administration may exacerbate any underlying renal pathology.
For unstable patients, and especially those with multiple scars on the abdominal wall from previous procedures, the focused assessment with sonography for trauma (FAST) examination is the ideal diagnostic study to detect free intraperitoneal fluid.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Prompt endotracheal intubation and use of mechanical ventilation should be considered in patients with more severe injuries, respiratory rates greater than 40 breaths per minute, or when the Pao2 is <60 mm Hg or Paco2 >50 mm Hg.
Early invasive monitoring has been advocated to help physicians assess the elderly’s hemodynamic status. One study demonstrated that by reducing the time to invasive monitoring in elderly trauma patients from 5.5 to 2.2 hours, and thus recognizing and appropriately treating occult shock, the survival rate of their patients increased from 7% to 53%. Survival was improved because of enhanced oxygen delivery through the use of adequate volume loading and inotropic support.
During the initial resuscitative phase, crystalloid, while the primary option, should be administered judiciously since elderly patients with diminished cardiac compliance are more susceptible to volume overload. Strong consideration should be made for early and more liberal use of packed red blood cell transfusion. Depending on the type of injury and severity of blood loss, switching to blood transfusion after 1 to 2 L of crystalloid resuscitation should be considered.
Despite the multitude of options, there is as yet no true panacea for reversing anticoagulation in the patient with intracranial bleeding. Full reversal with FFP may require administration of up to 4 L of FFP, contributing to fluid overload in some elderly trauma patients. Hematoma expansion appears to occur largely within the first several hours following injury, making sole administration of vitamin K, with its slow onset of action, inadequate.
Among geriatric trauma patients who are hospitalized, the mortality rate has been reported to be between 15% and 30%. These figures far exceed the mortality rate of 4% to 8% found in younger patients. In general, multiple organ failure and sepsis cause more deaths in elderly patients than in younger trauma victims.
Age >75 years, Glasgow Coma Scale score ≤7, presence of shock upon admission, severe head injury, and the development of sepsis are associated with worse outcome and higher mortality figures.
Data demonstrate that immediately after discharge one-third of trauma survivors return to independent living, one-third return to dependent status but living at home, and one-third require nursing home facilities.
For further reading in Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7th ed., see Chapter 252, “Geriatric Trauma,” by O. John Ma, Jennifer H. Edwards, and Stephen W. Meldon.