Old Age Flashcards
What is classed as old age?
Above 70
Why do all lung measurements (total lung capacity, FVC, FEV1, vital capacity) decrease as we age?
Because a reduction in elastic support of the airways and leads to increased collapsibility of alveoli and terminal conducting airways/
Why does it matter that elastic support in lungs is lost as we age?
Atelectasis, pulmonary emboli and pneumonia are common post-operative conditions in the elderly.
These complications increased in smokers, patients with chronic chest disease and those undergoing abdominal or thoracic surgery.
What effects does lost of elasticity around the oropharynx have?
Loss of elastic tissue around oropharynx can lead to collapse of the upper airways.
Sleep or sedative states may result in partial or complete obstruction of the airway.
A progressive increase in the number of episodes of arterial desaturation during sleep occurs with advancing age. This gets worse on opiates.
How does ageing affect pharmacokinetics?
Elderly patients have increased sensitivity to CNS depressant drugs and so drug doses need to be modified accordingly.
Patients have reduced hepatic and renal function leading to slower metabolism and elimination of drugs.
How does ageing affect the skin?
Elderly patients tend to have thin skin (thinner dermis) and fragile subcutaneous blood vessels and therefore patients tend to bruise easily.
Achieving and securing venous access can be difficult.
How does ageing affect the cardiovascular system (Blood vessels)?
Large and medium sized vessels become less elastic and therefore become less compliment.
This results in raised systemic vascular resistant and hypertension, which in turn may lead to left ventricular strain and left ventricular hypertrophy.
How does ageing affect the cardiovascular system (conducting cells)?
Cardiac conducting cells decrease in number making heart block, ectopic beats, arrhythmias and atrial fibrillation more prevalent.
Since atrial contraction contributes approximately one third of the volume towards normal ventricular filling, patients with atrial fibrillation suffer a reducing in cardiac output of about 30%.
How does cardiac output change with age and what effect does this have?
Cardiac output falls by about 3% per decade which is due to reduced stroke volume and ventricular contractility.
The reduction on cardiac output with age increases the arm-brain circulation time for drugs which means intravenous anaesthesia is achieved more slowly and with reduced dose of anaesthetic agent.
How does pharmacology change with age?
Reduced cardiac output results in delayed onset of IV anaesthesia.
Reduced total body water and increased adipose tissue leads to an altered volume of distribution of some drugs.
Plasma proteins are reduced resulting in decreased protein binding and increased free drug availability.
How does ageing affect the renal system?
GFR is thought to decrease by 1% per year over the age of 20 due to a progressive loss of renal cortical glomeruli.
A reduction in renal perfusion secondary to reduced cardiac output and atheromatous vascular disease leads to a decrease in renal function.
What is more common is older people and how does this affect the kidney?
DM2 is increasingly common, as is the use of nephrotoxic drugs such as NSAIDs and ACEi
Prostatism in males can lead to obstructive nephropathy and dehydration is common in the elderly, especially during illness.
How does ageing affect the CNS?
Cerebroascular disease is common in the elderly secondary to disuse atherosclerosis and hypertension.
Neuronal density is reduced by 30% by the age of 80yrs old.
How does ageing affect endocrinology and metabolism?
The basal metabolic rate falls by 1% per year after the age of 30. Falls in metabolic activity and reduced muscle mass may cause impaired thermoregulatory control.
Why is dementia so important?
In the UK, at least 1/4 of acute hospital beds are occupied by patients with dementia, with admissions spread across a broad range of specialities.
Dementia care in the community is quality important, given the majority of people with dementia live at home with their care primarily under the auspices of general practise.
