See “healthy ageing”.
The effects of ageing include: cessation of MENSTRUATION in females; wrinkling of the skin due to a loss of elastic tissue; failing memory (especially short term) and a reduced ability to learn new skills, along with slowed responses
– changes caused by the loss of or less e?cient working of nerve cells; the senses become less acute; the lungs become less e?cient, as does heart muscle, both causing a fall in exercise tolerance; arteries harden, resulting in a rise in blood pressure and poor blood circulation; joints are less mobile, bones beome more brittle (OSTEOPOROSIS) and muscle bulk and strength are reduced; the lens of the EYE becomes less elastic, resulting in poorer sight, and it may also become opaque (CATARACT).
In developed countries people are living longer, in part because infant and child mortality rates have dropped dramatically over the past 100 years or so. Improved standards of living and more e?ective health care have also contributed to greater longevity: the proportion of people over 65 years of age has greatly increased, and that of the over-75s is still rising. The 2001 census found 336,000 people in the UK aged over 90 and there are 36,000 centenarians in the US. This extreme longevity is attributed to a particular gene (see GENES) slowing the ageing process. Interestingly, those living to 100 often retain the mental faculties of people in their 60s, and examination of centenarians’ brains show that these are similar to those of 60-year-olds. (See MEDICINE OF AGEING; CLIMACTERIC.)
Help and advice can be obtained from Age
Concern and Help the Aged. See www.helpthaged.org.uk www.ageconcern.org.uk... ageing
For more prolonged arti?cial ventilation it is usual to use a specially designed machine or ventilator to perform the task. The ventilators used in operating theatres when patients are anaesthetised and paralysed are relatively simple devices.They often consist of bellows which ?ll with fresh gas and which are then mechanically emptied (by means of a weight, piston, or compressed gas) via a circuit or tubes attached to an endotracheal tube into the patient’s lungs. Adjustments can be made to the volume of fresh gas given with each breath and to the length of inspiration and expiration. Expiration is usually passive back to the atmosphere of the room via a scavenging system to avoid pollution.
In intensive-care units, where patients are not usually paralysed, the ventilators are more complex. They have electronic controls which allow the user to programme a variety of pressure waveforms for inspiration and expiration. There are also programmes that allow the patient to breathe between ventilated breaths or to trigger ventilated breaths, or inhibit ventilation when the patient is breathing.
Indications for arti?cial ventilation are when patients are unable to achieve adequate respiratory function even if they can still breathe on their own. This may be due to injury or disease of the central nervous, cardiovascular, or respiratory systems, or to drug overdose. Arti?cial ventilation is performed to allow time for healing and recovery. Sometimes the patient is able to breathe but it is considered advisable to control ventilation – for example, in severe head injury. Some operations require the patient to be paralysed for better or safer surgical access and this may require ventilation. With lung operations or very unwell patients, ventilation is also indicated.
Arti?cial ventilation usually bypasses the physiological mechanisms for humidi?cation of inspired air, so care must be taken to humidify inspired gases. It is important to monitor the e?cacy of ventilation – for example, by using blood gas measurement, pulse oximetry, and tidal carbon dioxide, and airways pressures.
Arti?cial ventilation is not without its hazards. The use of positive pressure raises the mean intrathoracic pressure. This can decrease venous return to the heart and cause a fall in CARDIAC OUTPUT and blood pressure. Positive-pressure ventilation may also cause PNEUMOTHORAX, but this is rare. While patients are ventilated, they are unable to breathe and so accidental disconnection from the ventilator may cause HYPOXIA and death.
Negative-pressure ventilation is seldom used nowadays. The chest or whole body, apart from the head, is placed inside an airtight box. A vacuum lowers the pressure within the box, causing the chest to expand. Air is drawn into the lungs through the mouth and nose. At the end of inspiration the vacuum is stopped, the pressure in the box returns to atmospheric, and the patient exhales passively. This is the principle of the ‘iron lung’ which saved many lives during the polio epidemics of the 1950s. These machines are cumbersome and make access to the patient di?cult. In addition, complex manipulation of ventilation is impossible.
Jet ventilation is a relatively modern form of ventilation which utilises very small tidal volumes (see LUNGS) from a high-pressure source at high frequencies (20–200/min). First developed by physiologists to produce low stable intrathoracic pressures whilst studying CAROTID BODY re?exes, it is sometimes now used in intensive-therapy units for patients who do not achieve adequate gas exchange with conventional ventilation. Its advantages are lower intrathoracic pressures (and therefore less risk of pneumothorax and impaired venous return) and better gas mixing within the lungs.... intermittent positive pressure (ipp)
Lifestyle While this may change as people grow older – for instance, physical activity is commonly reduced – some lifestyle factors are unchanged: for example, cigarette smoking, commonly started in adolescence, may be continued as an adult, resulting in smoker’s cough and eventually chronic BRONCHITIS and EMPHYSEMA; widespread ATHEROSCLEROSIS causing heart attacks and STROKE; osteoporosis (see BONE, DISORDERS OF) producing bony fractures; and cancer affecting the lungs and bladder.
Genetic factors can cause sickle cell disease (see ANAEMIA), HUNTINGTON’S CHOREA and polycystic disease of the kidney.
Ageing process This is associated with the MENOPAUSE in women and, in both sexes, with a reduction in the body’s tissue elasticity and often a deterioration in mental and physical capabilities. When compared with illnesses described in much younger people, similar illnesses in old age present in an atypical manner
– for example, confusion and changed behaviour due to otherwise asymptomatic heart failure, causing a reduced supply of oxygen to the brain. Social adversity in old age may result from the combined effects of reduced body reserve, atypical presentation of illness, multiple disorders and POLYPHARMACY.
Age-related change in the presentation of illnesses This was ?rst recognised by the specialty of geriatric medicine (also called the medicine of ageing) which is concerned with the medical and social management of advanced age. The aim is to assess, treat and rehabilitate such patients. The number of institutional beds has been steadily cut, while availability of day-treatment centres and respite facilities has been boosted – although still inadequate to cope with the growing number of people over 65.
These developments, along with day social centres, provide relatives and carers with a break from the often demanding task of looking after the frail or ill elderly. As the proportion of elderly people in the population rises, along with the cost of hospital inpatient care, close cooperation between hospitals, COMMUNITY CARE services and primary care trusts (see under GENERAL PRACTITIONER (GP)) becomes increasingly important if senior citizens are not to suffer from the consequences of the tight operating budgets of the various medical and social agencies with responsibilities for the care of the elderly. Private or voluntary nursing and residential homes have expanded in the past 15 years and now care for many elderly people who previously would have been occupying NHS facilities. This trend has been accelerated by a tightening of the bene?t rules for funding such care. Local authorities are now responsible for assessing the needs of elderly people in the community and deciding whether they are eligible for ?nancial support (in full or in part) for nursing-home care.
With a substantial proportion of hospital inpatients in the United Kingdom being over 60, it is sometimes argued that all health professionals should be skilled in the care of the elderly; thus the need for doctors and nurses trained in the specialty of geriatrics is diminishing. Even so, as more people are reaching their 80s, there seems to be a reasonable case for training sta? in the type of care these individuals need and to facilitate research into illness at this stage of life.... medicine of ageing
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