Thomas M. Scalea, M.D., FACS, FCCM
Physician-in-Chief
R Adams Cowley Shock Trauma Center
Professor of Surgery and
Director, Program in Trauma
University of Maryland School of Medicine
Baltimore, Maryland
Over the last 10 years geriatric trauma has become an increasingly important segment of injury. Several principles are important to maximize survival and functional outcome in this special subset of patients.
In general, trauma triage and initial care is based on a step-wide evaluation of both anatomic injury and physiologic stability. This begins in the prehospital phase and then continues when the patient presents to the hospital. Trauma systems must accept a certain rate of over-triage and under-triage. Under triage can be particularly lethal in the geriatric patient. Injuries can often be occult. Symptoms such as confusion or pain may be ascribed to a pre-existing disease. Unfortunately, the margin of error that a geriatric patient will tolerate is relatively small. Most trauma systems currently do not have specialty centers for geriatric injury or different triage protocols for the elderly. Yet, these same systems often sub-segment the pediatric population because of their special needs and the recognition that they will not tolerate shock for a prolonged period of time.
The care of elderly in the prehospital phase should be modified as well. Even a condition as simple as an isolated fracture can be life-threatening in an elderly person. The loss of tissue tugor and the atherosclerosis that affects virtually every elderly person may produce significant blood loss into muscle compartments. The lack of cardiovascular reserve limits the heart’s ability to rapidly accept intravascular volume.’ Cerebral atrophy makes potentially life-threatening traumatic brain injury relatively asymptomatic in the field.2 Patients can become suddenly and profoundly symptomatic hours after injury. Outcome at that point, is likely to be poor particularly if the patient has been under-triaged to a local emergency department.3 We generally advise our paramedics to recognize that occult injuries can kill elderly patients. We recommend IV fluid be given in small boluses such as in 250cc aliquots to avoid precipitating heart failure. Fractures should be splinted and patients transported as rapidly as possible. The suspicion of traumatic brain injury should prompt rapid transport to a trauma center.
Unfortunately, many of the factors affecting long term outcome in elderly patients may not be changed by anything other than trauma prevention strategies. The6physiology of aging limits elderly patients ability to respond to the stresses of injury. This is
perhaps most important in the cardiovascular system. Cardiac output at rest remains relatively stable as patients age, but the ability to augment cardiovascular performance is significantly blunted.6’7 The same is true for heart rate, a compensatory mechanism many people use to maintain peripheral oxygen delivery.8’9 Atherosclerosis affects approximately three-quarters of the American population, age 65 years or older.’0 Autoregulation attempts to hold coronary perfusion stable over a wide range of physiologic variances. This becomes particularly problematic when fixed coronary artery lesions begin to become flow limiting. The coronary circulation is maximally venous extracted even at rest. Increased peripheral oxygen demands following injury precipitate a dangerous set of circumstances. As oxygen demand increases, cardiac output must likewise increase. Blood loss limits peripheral oxygen delivery by robbing valuable preload and diluting hemaglobin concentration. As cardiac output attempts to rise, this can precipitate coronary ischemia which will itself limit cardiac output. This potentially cycles quickly to irreversible shock."
Other organ systems behave similarly, such as the lungs and the kidneys. Ventilation perfusion mismatch normally occurs in about five percent of middle age people. It approaches 15 to 20 percent in the elderly.’2 A drop in cardiac output may itself be sufficient to precipitate hypoxia. A careful resuscitation strategy is necessary to support both the cardiovascular and the respiratory system to avoid the combination of low cardiac output syndrome and hypoxia.
The number of nephrons falls as people age and creatinine clearance falls about 10 percent per decade after midlife. 13,14 However, the loss of circulating muscle mass generally holds serum BUN and creatinine normal.’5 Even relatively dehydrated elderly patients may produce large volumes of relatively dilute urine because of a loss of reabsorptive capacity in distal tubule.2 Finally, diuretics, a common medication in the elderly, may make the average elderly person dehydrated at rest. Thus, these patients often have significant renal impairment, even though their renal function may appear relatively normal at first glance.
The role of occult hypoperfusion and its impact on outcome in elderly patients has recently been recognized as an important determinant of outcome. Occult cardiovascular insufficiency is common in elderly patients who appear relatively stable. Early recognition is extremely important, as delays in therapy can be lethal. High risk patients include patients with traumatic brain injury, multiple long bone fracture, patients who have been struck by an automobile or patients who have an initial systolic blood pressure under 130 mmHg. We have demonstrated that invasive hemodynamic monitoring can be lifesaving in these i’6 Insertion of a pulmonary artery catheter demonstrated occult cardiogenic shock in almost half of these patients. When patients underwent a normal evaluation process, the time from ED admission to monitoring was 5.5 hours. At that point, cardiovascular insufficiency had progressed to the point where mortality was not alterable and approached 100%. However, when the evaluation process was truncated and tailored to address only immediately life-threatening problems, we were able to cut the time to monitoring by over 50%. Mortality was reduced by 50% when the important cardiovascular issues were addressed earlier. Thus, it seems that the degree of
physiologic alteration at the time of admission is not as important as early recognition and treatment. The combination of that data, plus data from the group at Vanderbilt have suggested that the important factors which affect outcome in elderly patients are traumatic brain injury, ED hypotension, sepsis, age and long bone fractures.’7 Of these, age, brain injury, mechanism of injury and long bone fractures can not be altered after injury. The others are cardiovascular parameters which may be treatable with early recognition.
The etiology of this cardiovascular dysfunction has always been thought to be purely pump dysfunction, secondary to factors such as those previously discussed. More recently, however, we have become interested in the possibility of occult acute cardiac ischemia, precipitating pump failure. This unstable angina may go unrecognized by both the patient and the physician. If present, it would mandate a different strategy. Cardiac support for a failing pump involves volume loading and inotropic support to maximize peripheral oxygen delivery. Acute cardiac ischemia, however, would require a strategy aimed at myocardial protection with beta blockade, judicious fluid administration and nitrates. A 12 lead EKG and a single set of cardiac enzymes may well be insufficient to detect acute cardiac ischemia, if present. More work will need to be done in order to determine which patients will benefit from either strategy.
Once admitted, geriatric patients can continue to pose significant challenges. Confusion is extremely common when normal routine is interrupted in an elderly patient’s life. Unfortunately, this often precipitates a polypharmaceutical approach in an attempt to control agitation. These drugs are all relatively long acting in an elderly person and can precipitate worsening of the agitation. Unfortunately, this is often treated with the addition of another drug or physical restraints. Both of these may limit the patient’s ability to get out of bed and have their chest upright, which often produces respiratory failure that worsens over several days. The leading cause of death in hospitalized elderly Americans continues to be pneumonia.’8
The population of America continues to age. Geriatric trauma now accounts for approximately 30% of admissions in our trauma centers. This is likely to continue to rise. Our geriatric trauma patients have special needs which begin in the prehospital phase and continue through discharge. It is important to recognize these needs in order to maximize survival and functional outcome.
Geri:maull
TMS/ema:syllabusKmaull:pointcounterpt:geri
May 2000
REFERENCES
1. DelGuercio LR, Cohn JD: Monitoring operative risk in the elderly. JAMA 243:135, 1980.
2. Scalea TM, Kohl L: Geriatric Trauma, In Feliciano DV, Mattox KL, Moore EE (eds): Trauma 3rd ed. Stamford, Appleton & Lange, 1996.
3. Pennings JL, Bachulis BL, Simons CT, Slazinski T: Survival after severe brain injury in the aged. Arch Surg 128:787, 1993.
4. Schlag G, Krosl P. Heinz R: Cardiopulmonary response of the elderly to traumatic and septic shock. In Perspectives in Shock Research. Vienna: Ludwig Boltzma.nn Institute for Emperimental Traumatology, 1988, p. 223.
5. Davies MJ: Pathology of the aging heart. In Brochlehurst SC, Talus RC, Dillit HM (eds): Textbook of Geriatric Medicine and Gerontology. Edinburgh: Curchill Livingston, 1992, pp. 181-185.
6. Lahatta EG: Age-related alterations in the cardiovascular response to adrenergic mediated stress. Fed Proc 39:3173, 1980.
7. Hossach KF, Bruce RA: Maximal cardiac function in sedentary normal men and women: Comparison of age-related changes. JAppl Physiol: Resp Environ Exer Physiol 53:799, 1982.
8. Kostis JB, Moregra AE, Amendo MT et al: The effect of age on heart rate in subjects free of heart disease. Circulation 65:141, 1982.
9. Darr KC, Bassett DR, Morgan BJ, Thomas DP: Effects of age and training status on heart recovery after peak exercize. Am JPhysiol 254:H340, 1988.
10. Greene HL: Clinical significance and management of arrhythmias in the heart failure patient. Clin Cardiol 15:113, 1992.
11. Braunwald E, Sobel BE: Coronary blood flow and myocardial ischemia. In Braunwald E (ed): Heart Disease: A Textbook of Cardiovascular Medicine. Philadelphia. Saunders, 1988, p. 1191.
12. Jockman MS: Aging of the respiratory system. In Hazzard WR, et al (eds):
Principles of Geriatric Medicine and Gerentology. New York: McGraw-Hill, 1994, p. 555.
13. McLachlan MSF: The aging kidney. Lancet ii:143, 1978.
14. Bick LH: Aging changes in renal function. In Hazzard WR, et al (eds):
Principles of Geriatric Medicine and Gerontology. New York: McGraw-Hill, 1994, p. 615.
15. Tillit H, Rowe J: The aging kidney. In Brochlehurst JC, Tallis RC, Tillit HIM (eds): Textbook of Geriatric Medicine and Gerontology. Edinburgh: Churchill Livingstone, 1992, p. 612.
16. Scalea TM, Simon HM, duncan AO et al: Geriatric blunt multiple trauma: Improved survival with early invasive monitoring. J Trauma 30:129, 1990.
17. van Aalst JA, Morris JA, Yates HK et al: Severely injured geriatric patients return to independent living: A study of factors influencing function and independence. JTrauma 3 1:1096, 1991.
18. Oreskowvich MIR, Howard JD, Copass MK et al: Geriatric trauma: Injury patterns and outcome. J Trauma 24:565, 1984.
 |
|
|
 |
 |
|
 |
|
|
 |
|
|
 |
|
|
 |
|
|
 |
|
|
 |
|
|
 |
|
|
 |
|
|
 |
|