A direct relationship of increasing age and mortality is seen with gunshot injury in the elderly (Fig. 31.2) [1]. In addition, elderly patients with penetrating trauma present with higher rates of comorbidities and have been found to have longer hospital and ICU length of stay [1, 3, 4]. Significant physiologic changes occur with aging, which may affect the clinical presentation, hospital course, and outcomes of elderly trauma patients.

In a comparison study between younger (age 15–40) and older (age 65 and older) penetrating trauma patients, the older patients were found to have significantly more comorbidities on admission, primarily cardiac and endocrine comorbidities including hypertension, coronary artery disease, and diabetes [3]. These comorbidities result in a diminished ability to compensate for acute blood loss and increased risk of peri-traumatic cardiac events. In the respiratory system, increased dead space and decreased compliance are often associated with increased age as is a reduction in kidney mass and glomerular filtration rate. For these reasons, early aggressive invasive monitoring and treatment of elderly patients has been shown to improve outcomes [5].

In addition to the physiologic changes noted in the elderly population, pharmacologic differences can influence outcome. In a 2005 report, 48.5 % of adults in the USA age 65 and older reported taking aspirin (Agency for Healthcare Research and Quality). Aspirin, clopidogrel, warfarin, and the newer Xa inhibitors and antithrombin agents are becoming increasingly common in the aging population and have significant effect on trauma outcomes. These medications are often unknown at the time of presentation and can complicate management in the bleeding trauma patient and lead to increased mortality [6]. Elderly patients on these medications require urgent reversal and aggressive monitoring with liberal use of imaging, angioembolization, and operative intervention.

Cardiac medications are also common in the elderly population including medications that block the response to endogenous catecholamines after trauma. These medications may dampen the physiologic response to bleeding resulting in earlier hypotension and shock. Further exacerbating this response is the common use of diuretics resulting in an earlier state of dehydration and sensitivity to acute blood loss.

Clear guidelines have been established to allow for prehospital identification of the most injured patients and effectively triage these patients to trauma centers with a graded level of activation based on the suspected level of injury. Patients with the highest level activation receive priority for triage, imaging, intervention, and overall care. Given the known diminished physiologic reserve and effect of cormorbid conditions and medications on outcome in the elderly population, there is concern that level of injury is underestimated using standard parameters applicable for a younger population.

Of particular concern is the use of vital sign criteria for activation as the baseline physiology and potential alterations due to medications in the elderly patient may be misleading. This can potentially result in significant undertriage in this population. In a study of 883 patients >70 years meeting trauma center criteria at Los Angeles County Medical Center, only 25 % of patients met criteria for the highest level of activation. In those that did not meet hemodynamic criteria for highest level activation, 63 % had an ISS >15, and 25 % had an ISS >30 signifying a significant rate of undertriage. In this group, 24 % required ICU admission, 19 % required a non-orthopedic operation, and mortality was 16 % [7]. These findings support the concern for high mortality in this population and underscore the importance of modified hemodynamic criteria in the elderly population. As a result of this study, the activation criteria were altered to include age >70 as an automatic activation of the highest level trauma. This change resulted in improved overall mortality as well as improved mortality in patients with higher ISS [5].

The vital sign criteria suggestive of increased mortality risk differ in the geriatric population. In the young trauma patient, SBP less than 90 mmHg and heart rate greater than 120–130 are considered physiologic indicators of shock or near shock state. These findings were supported in a young population (age 17–35) in a study out of Rhode Island, with an increased mortality noted at SBP less than 95 mmHg and heart rate greater than 130 [8]. These results differ significantly in the elderly population (age 65 and older), with a mortality increase identified at SBP less than 110 mmHg and significant mortality increases with even mild tachycardia. With the recognition that an SBP of less than 110 in the elderly may represent shock, Brown et al. used the National Trauma Data Bank to determine that increasing the SBP criterion from less than 90 mmHg to less than 110 mmHg in the elderly resulted improved rates of undertriage [9]. These results further validate the need for early and aggressive triage and monitoring of the elderly trauma patient.