Anatomical and Physiological Changes
Structure and Posture
According to (1981) and (1996) one loses one and half to 3 inches or 1.2 cm. of height every 20 years as aging occurs. Obvious manifestations, which are an interaction of many factors such as age, sex, race, and environment, occur in the fifth decade of life. Long bones take on the appearance of disproportionate size because the stature decreases. Vertebral disks become thin due to dehydration, causing a shortening of the trunk. Many aged persons assume a stooped, forward-bent posture, with hips and knees somewhat flexed and arms bent at the elbows, raising the level of the arms. Posture and structural changes occur primarily because of calcium loss from bone and as a result of atrophic processes of cartilage and muscle. Excessive leaching of calcium from the bone matrix creates the condition called osteoporosis. This type of degeneration is four times more prevalent in women ( 1985), becoming apparent as estrogen declines in older women.
Skin, Hair, and Nails
Epidermal cell renewal time increases by one third after 50 years of age. The normal young adult renews epithelium every 20 days, whereas an older person requires 30 or more days because of diminished mitotic epidermal activity. Because of this slow replacement of epidermal cells, wound healing is approximately 50% slower than at 35 years of age ( 1978). The amount of collagen decreases approximately 1% per year, causing the skin to “give” less under stress and tear more easily ( 1988). The dermis becomes thinner in the absence of subcutaneous fat ( 1983).
Hair becomes gray because of the decrease in melanin production in hair follicles. Regardless of sex, 50% of the population over 50 years of age has gray or partly gray scalp hair. Body and facial hair becomes gray later. Hair loss is prominent in men, beginning in the second decade for some.
Facial Changes
Facial changes occur as a result of altered subcutaneous fat, dermal thickness, decreased elasticity, and lateral surface compression of underlying muscle contractions. Loss of bone mass, particularly the mandibular bone, accentuates the size of the upper mouth, nose, and forehead. Indented “loss of lip” appearance of the mouth occurs with tooth loss when uncorrected by dentures or other oral prostheses. Eyelids appear swollen as a result of the redistribution of fat deposits. Conversely, eyes that look sunken are the result of the loss of orbital subcutaneous fat. Loss of elasticity accentuates jowls and elongated ears and contributes to the formation of a “double” chin.
Loss of Tissue Elasticity
Tissue elasticity is most easily observed in skin integrity and reflects the progressive, universal, and intrinsic nature of age changes. The aged skin loses resilience and moisture, taking on a characteristic dryness.
Anesthesia in the Elderly
Many geriatric surgeries are performed as a result of increasing longevity. In geriatric patients there is reduction of cardiovascular, respiratory, renal and liver functions, These in very little functional reserve which is safety margin available to the patient during anesthesia and the post-operative period and contributes to the increased morbidity and mortality. The major risk factors in the elderly are:
Poor general condition
Severity of co-morbid conditions
Major surgery
Emergency surgery
Anesthesia should be safe with smooth induction, maintenance and quick reversal without producing any CVS, RS, and CNS complications. The choice of anesthesia depends on the general condition of the patient, the nature of surgical procedure and the experience of the Anesthetist.
Type of Anesthesia
Regional Anesthesia
Regional anesthesia is commonly administered in elective surgeries in the elderly. Regional anesthesia involves blockade of major nerve trunks which innervates the site of surgery. The two types of regional anesthesia are spinal and epidural. In spinal anesthesia the drug is injected into the subarachnoid space and in epidural anesthesia the drug is injected into epidural space. In elderly surgery, regional anesthesia is preferred for the following reasons:
Advantageous in debilitating respiratory disease patients
Reduces bleeding, postoperative respiratory problems and deep vein thrombosis
Diminishes stress response and CNS complications
Decreases convalescence time and facilities early ambulation
Minimizes requirements of postoperative analgesia
Reduces mortality
Disadvantages include:
Technically difficult
Epidural is less reliable
Supplemental sedation carries great dangers like air way obstruction, pulmonary aspiration and agitation
General Anesthesia
Causes of Failure to Breath after General Anesthesia
Obstruction of the airways
Central sedation from opium drugs or anesthetic agents
Hypoxia or hyoercarbia of any cause
Persistent neuromuscular blockade
Pneumothorax from pleural damage during anesthesia surgery
Circulatory failure leading to respiratory arrest
Credit:ivythesis.typepad.com
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