Anatomical and Physiological Changes in Elderly
Introduction: Why I Chose This Group
Aging is a process of life. Among the most vulnerable groups of the society is the elderly. These people have special needs and health issues that must be met. They need special attention.
Part of the reason why I chose this particular age group is because of the changes in our society’s demographics. Over the last decades there have been a gradual increase in the number of elder people. It is important that health care professionals give particular attention to this age group in order to ensure their health and well-being and to make them contributing members of the society. The society is graying so fast causing this group to grow. The growth in numbers of the elderly leads to the growth of concern regarding their health and well-being.
Anatomical and Physiological Changes
1. Structure and Posture – According to Jacobs (1981) and Lamb (1996) one loses one and half to 3 inches or 1.2 cm. of height every 20 years as aging occurs. Because of the decrease in stature, long bones appear to be disproportionate in size. 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.
2. Skin, Hair, Nails – The time it takes for epidermal cell renewal becomes longer 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. As a result, wound healing is approximately 50 percent slower than at 35 years of age (Leyden et al 1978). The amount of collagen decreases approximately 1 percent per year, resulting to skin damage (Richey et al 1988). Hair becomes gray because of the decrease in melanin production in hair follicles. Nails of the fingers and toes develop longitudinal striations and grow at a slower rate than in youth. The nail plate may thicken and give the nail a yellow appearance.
3. Facial Change – 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 (Ebersole and Hess 1998).
4. Loss of Tissue Elasticity – One of the most observable changes in the physical appearance of elderly is the loss of tissue elasticity. The aged skin losses resilience and moisture, taking on a characteristic dryness. The face and neck wrinkles reflect life patterns of muscle activity in facial expressions, the pull of gravity on tissue, and diminished elasticity in general. Elasticity affects blood vessel integrity, particularly the arteries. Elastic fibers fray, split, straighten, and fragment. Lung elasticity declines, causing a rigidity in lung tissue (Ebersole and Hess 1998).
5. Body Composition – Due to the decline in lean body mass and loss of water, the body weight drops 54 t0 60 percent in men and 46 to 52 percent in women. Fat tissue increases until 60 years of age; therefore body density is lower in youth because of the density of muscle versus the lightness of fat. From 25 to 75 years of age fat content of the body increases by 16 percent. Cellular solids and bone mass decline (Ebersole and Hess 1998).
1. Heart – There have been studies that revealed that the left ventricle thickens as much as 30 percent between ages 25 to 80 due to the increase in myocyte size. The left atrium increases about 20 percent in size between 18 and 93 years of age. Cardiac mass is estimated to increase 1.5 g in women and 1 g in men per year after 30. By age 60, the maximum coronary artery blood flow provides the cardiovascular system with 35 percent less blood than in earlier years. Under nonstressful conditions the smaller cardiac output is adequate since the mechanisms that determine cardiovascular function depend on the interaction of intrinsic cell performance, heart rate, coronary flow, cardiac filling (preload), and cardiac afterload. Diminished cardiac output becomes significant when the aged person is physically or mentally stressed by illness, worry, or excitement. Sudden demands for more oxygen and energy brought on by various physiologic, psychologic, social, and environmental stress result in poor response of heart function attributed to the limited cardiac reserve, or presbycardia. It takes longer for the heart to accelerate to meet the demands placed on it and to return to a normal level (Ebersole and Hess 1998). General risk factors that can cause stress and strain on the heart include the following:
- Continued intake of high complements of dietary animal fat, salt, and calories
- Obesity and excessive weight
- Long-term cigarette smoking
- Lack of regular exercise
- Internalization of emotions
- Air pollution
- Existing chronic condition
2. Valves – valves may be thicker and stiffer as a result of lipid deposits, collagen degeneration, and fibrosis.
3. Conductivity – during the third and fourth decade of life peacemaker cells decrease in number as myocardial fat, collagen, and elastin fibres increase. This change affects the sinus node, which shows evidence of causing acceleration through the sixth decade (Ebersole and Hess 1998).
4. Vessels – decreased elasticity of arteries and arterioles is responsible for changes that affect blood flow to body organs such as the heart, liver, kidneys, and pituitary gland. The aorta dilates and elongates as collagen and elastin changes and calcium deposition from degenerating elastin occurs. Circulation in the coronary arteries diminishes by approximately 35 percent sixth decade; increased resistance to peripheral blood flow occurs at a rate of about 1percent per year, vessel walls and varicosities can lead to abnormal swelling when subjected to increased pressure (Ebersole and Hess 1998).
Peripheral Vascular Changes
Both arteries and veins exhibit changes as the intima becomes fibrotic and endothelial cell variation increases. The amount of elastin and smooth muscle diminish as collagen and fibrotic tissue increase. The result is loss of flexibility and recoil, an increase in systemic peripheral resistance, and a reduced perfusion to tissues and organs. The stiffening and more rigid structure of the vascular system may lead to the elevation of blood pressure in addition to influencing cardiac and renal changes. Veins lose their elasticity and become less able to store blood volume. Pooling of blood increases the venous pressure, diminishing the effectiveness of peripheral valves and creating tortuous varicosities (Beare and Myers 1994). A form of hypertension seen in elders is isolated systolic hypertension (ISH). This type of hypertension occurs when the diastolic pressure is normal but the systolic pressure is elevated.
Changes in respiratory and pulmonary performance occur gradually, allowing the elderly to continue to breath effortlessly in the absence of pathologic states. When the elderly are confronted with a little exertion or stress, however, dyspnea and other symptoms usually appear. The prominent effect of age-related changes on the respiratory system is reduced efficiency in ventilation and gas exchange. The respiratory system includes the nose, pharynx, larynx, trachea, bronchi, bronchioles, alveolar ducts, and alveoli (Ebersole and Hess 1998).
1. Nose – the nose is a readily visible appendage, which with age elongates downward. It has been suggested that this age related change may account for the mouth breathing that occurs while the elder sleeps and thus the lack of saliva productions (Saxon and Etten 1994).
2. Trachea and Larynx – stiffening of the larynx and tracheal cartilage occurs as a result of calcification. The cilia that line the trachea and help to push up mucus, debris, and dust into the pharynx are less effective. Cilia decrease in number with the resultant decrease in respiratory epithelium and an increase in bronchial mucous gland hypertrophy (Schumann 1995). Voice pitch increases for men and decreases for women, but substantially more so for elders who are in poor health. Breathlessness in speech is the result of less air passing through and incomplete closure of the glottis. Limited mobility of the jaw may also contribute to this (Ebersole and Hess 1998).
3. Chest Wall and Lungs – according to Tockman (1995) during youth the chest wall and lungs grow in proportion to the body and correlate with height. When a person reaches 55, his or her respiratory muscles start to weaken, chest wall compliance begins to decrease, and there is a loss of elastic recoil. As a result, ventilation and gas exchange are affected. Ossification of the costal cartilage and the downward slant of the ribs result in a less compliant, more rigid rib cage, which limits chest expansion. The potential for greater lung expansion exists but cannot be realized because of structural limitations that develop in the thoracic walls. Skeletal defects such as kyphosis and scoliosis and the generally stooped posture of the aged also contribute to restricting chest expansion by further reducing the size of the chest cavity area in which the lungs can expand. The outcome of these changes increase dead space, decrease vital capacity, and decrease expiratory flow (Ebersole and Hess 1998).
Lungs do not shrink in size but do become flabbier and decrease in weight by 20 percent. Total lung capacity is not significantly altered, but rather it is redistributed. Residual capacity increases with the diminished inspiratory and expiratory muscle strength of the thorax. Incomplete lung expansion does not provide for inflation of the lung bases and leads to basilar lung collapse and hyperinflation of the lung apices (Ebersole and Hess 1998).
4. Oxygen Exchange – the aged blood oxygen level is approximately 75 mm Hg, whereas the blood oxygen level for younger adults ranges from 90 mm Hg to 95 mm Hg.
5. Respiratory Problems – according to Tockman (1995) airway problems experienced later in life are due to repeated inflammatory injuries, disruption of inflammatory mediators and humoral protection, neutrophil aggregation, and tissue repair. Diminished immune response, environmental factors, and structural changes are all factors that predispose the aged to respiratory problems. Conditions that affect the respiratory system are among the most common life-threatening disorders experienced by the aged and are considered to be among the leading causes of death.
Kidneys are the primary organs responsible for the regulation of the chemical composition of the body and blood and fluid volume. The age-related loss of as many as half of either kidneys 1 million nephrons leads to little change in the body’s ability to regulate its body fluids and the ability to maintain adequate fluid homeostasis in old age. The size and function of the kidney begins to decrease in the fourth decade and significantly decreases by the middle of the sixth decade, shrinking about 7 percent and by the eight decade by 20 percent to 30 percent (Ebersole and Hess 1998).
Hormones are responsible for and control reproduction, growth and development, maintenance of homeostasis, and energy production.
1. Thyroid Gland – thyroid function remains adequate with age, even though the thyroid gland decreases in mass and becomes fibrotic with an increasing number of colloid nodules. There is also slowing of the metabolic rate and oxygen use by the body (Ebersole and Hess 1998).
2. Pituitary Gland – the pituitary gland, with its diverse functions and central role in the complex hormone feedback system, decrease in volume by 20 percent (Ebersole and Hess 1998).
The digestive system handles are-related changes better than most systems of the body. The primary functions of the gastrointestinal tract are digestion and absorption, which are accomplished by gastrointestinal secretions and motility. Changes in other organ systems affect gastrointestinal structure and function.
1. Mouth and Teeth – Dentition is an important appendage to the gastrointestinal system and can affect digestive activity. Many aged today continue to be edentulous or dependent on dentures. In the presence of few teeth or ill-fitting dentures, the process of preparing the food for swallowing is incomplete with food morsels improperly chewed.
Anaesthesia 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 anaesthesia 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
Anaesthesia should be safe with smooth induction, maintenance and quick reversal without producing any CVS, RS, and CNS complications. The choice of anaesthesia depends on the general condition of the patient, the nature of surgical procedure and the experience of the Anaesthetist.
Types of Anaesthesia
Regional anaesthesia is commonly administered in elective surgeries in the elderly. Regional anaesthesia involves blockade of major nerve trunks which innervates the site of surgery. The two types of regional anaesthesia are spinal and epidural. In spinal anaesthesia the drug is injected into the subarachnoid space and in epidural anaesthesia the durg is injected into epidural space. In elderly surgery, regional anaesthesia 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
- Technically difficult
- Epidural is less reliable
- Supplemental sedation carries great dangers like air way obstruction, pulmonary aspiration and agitation
Causes of Failure to Breath after General Anaesthesia
- Obstruction of the airways
- Central sedation from opiod drugs or anaesthetic agents
- Hypoxia or hyoercarbia of any cause
- Persistent neuromuscular blockade
- Pneumothorax from pleural damage during anaesthesia surgery
- Circulatory failure leading to respiratory arrest
The elderly is a group that is exposed and is vulnerable to health problems. They require special attention and care. Discussed in this paper is the different anatomical and physiological changes that occur as one ages. These changes often lead to health problems and even death. In order to ensure health and well-being of this growing age group it is important that health care professionals, the government, the community, their families and the elderly themselves understand the changes that are happening.
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