الفهرس 
Physiological changes in elderlyOnly 14 pages are availabe for public view
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Abstract
Aging is a progressive, universally prevalent physiologic
process that produces measurable changes in the structure and decremental alteration of the
function of tissues and organs.
Aging is accompanied by alterations in organ functions are manifested as a decreased margin of
reserve; in fact old age can be characterized as a continuation of life with decreasing capacities
for adaptation. For example, cardiovascular changes include left ventricular hypertrophy, decreased
cardiac output and increased peripheral resistance. Nervous system functions show deterioration
with depletion of the neurotransmitters, deafferenation of the peripheral nerves and decreased self
regulation of autonomic functions. The mechanical ventilatory function and the efficiency of gas
exchange deteriorate with aging, making elderly patients more vulnerable for hypoxemia. There is
impaired renal function and any slight increase in the plasma creatinine concentration will
indicate a severe renal impairment. Elderly patient are more liable for intra- and post-operative
hypothermia.
Aging is commonly associated with systemic diseases, which have great implications on the
anesthetic management. Common clinical problems affecting the elderly people include hypertension,
ischemic heart disease and diabetes and the anesthetist must know how to deal with these problems
in his practice. The anesthetist must be aware about the danger of aspiration and postoperative
hypoxemia, as both have increased incidence in elderly patients.
Older patients consume nearly three times as many prescription drugs as younger patients and
therefore are at risk for experiencing significantly more drug-drug interactions and adverse drug
reactions. The pharmacokinetics of most of the drugs used in
anesthesia are altered by aging due to decrease in the drug metabolism and excretion and changes in
protein binding, distribution and fat content of the body. Due to these phannacokinetic changes
with age, elderly patients are vulnerable to the cumulative intravenous drug effects and
increased risk of experiencing adverse drug interaction. Pharmacodynamic properties of the drugs
are also altered due to alteration in the receptor properties and decreased release of the
neurotransmitter substances. In addition, elderly patients may have many diseases, which are
affected greatly with the use of anesthetic drugs. So, the use of anesthetic drugs in the
elderly must be done with great caution and the dosage is mostly decreased.
Elderly patients are in need to be fully investigated as every organ system is mostly affected by
aging and has a narrow margin of reserve. Complete blood picture, chest x-ray, electrocardiography,
renal function tests, liver function tests and blood sugar level all are mandatory to be done
before surgical procedures, but other investigations may be needed according to the clinical state
of the patients.
Elderly patients must be well premedicated, as they are more anxious about the surgery than
young patients. The anesthetic drugs must be given in the minimum calculated dose. The use of
cuffed endotracheal tube is mandatory as they are more liable for aspiration. Mechanical
ventilation is preferred as regard the pulmonary changes that accompany aging. Delayed extubation
is indicated in elderly patients.
The last I 0 to 15 years have seen a considerable increase in the interest in, and use of,
regional anesthetic techniques. The positive features of regional anesthesia mean that its use
may contribute to a successful outcome in ways other than avoidance of general anesthesia.
However, the old may be susceptible to some of the complications and problems of
regional anesthesia than are the young.
The use of day care surgery for older patients IS problematic. While reduction of hospital
admission is theoretically sound. In such patients, it is even more important that the anesthetist
can ensure rapid restoration of an alert, oriented and active patient as soon as after the
anesthetic as possible. For many patients, an inhalation technique with avoidance of all injected
or oral drugs, will prove entirely satisfactory.