Pulmonary Function Tests: From 2 Different Sources
A group of procedures used to evaluate lung function, to confirm the presence of some lung disorders, and to ensure that planned surgery on the lungs will not disable the patient. The tests include spirometry, measurement of lung volume, assessment of the degree of bronchospasm with a peak-flow meter, and a test of blood gases.
Tests to assess how the LUNGS are functioning. They range from simple spirometry (measuring breathing capacity) to sophisticated physiological assessments.
Static lung volumes and capacities can be measured: these include vital capacity – the maximum volume of air that can be exhaled slowly and completely after a maximum deep breath; forced vital capacity is a similar manoeuvre using maximal forceful exhalation and can be measured along with expiratory ?ow rates using simple spirometry; total lung capacity is the total volume of air in the chest after a deep breath in; functional residual capacity is the volume of air in the lungs at the end of a normal expiration, with all respiratory muscles relaxed.
Dynamic lung volumes and ?ow rates re?ect the state of the airways. The forced expiratory volume (FEV) is the amount of air forcefully exhaled during the ?rst second after a full breath – it normally accounts for over 75 per cent of the vital capacity. Maximal voluntary ventilation is calculated by asking the patient to breathe as deeply and quickly as possible for 12 seconds; this test can be used to check the internal consistency of other tests and the extent of co-operation by the patient, important when assessing possible neuromuscular weakness affecting respiration. There are several other more sophisticated tests which may not be necessary when assessing most patients. Measurement of arterial blood gases is also an important part of any assessment of lung function.
Relating to the LUNGS.... pulmonary
The condition in which an embolus (see EMBOLISM), or clot, is lodged in the LUNGS. The source of the clot is usually the veins of the lower abdomen or legs, in which clot formation has occurred as a result of the occurrence of DEEP VEIN THROMBOSIS (DVT) – THROMBOPHLEBITIS (see VEINS, DISEASES OF). Thrombophlebitis, with or without pulmonary embolism, is a not uncommon complication of surgical operations, especially in older patients. This is one reason why nowadays such patients are got up out of bed as quickly as possible, or, alternatively, are encouraged to move and exercise their legs regularly in bed. Long periods of sitting, particularly when travelling, can cause DVT with the risk of pulmonary embolism. The severity of a pulmonary embolism, which is characterised by the sudden onset of pain in the chest, with or without the coughing up of blood, and a varying degree of SHOCK, depends upon the size of the clot. If large enough, it may prove immediately fatal; in other cases, immediate operation may be needed to remove the clot; whilst in less severe cases anticoagulant treatment, in the form of HEPARIN, is given to prevent extension of the clot. For some operations, such as hip-joint replacements, with a high risk of deep-vein thrombosis in the leg, heparin is given for several days postoperatively.... pulmonary embolism
A disorder of the HEART in which obstruction of the out?ow of blood from the right ventricle occurs. Narrowing of the pulmonary valve at the exit of the right ventricle and narrowing of the pulmonary artery may cause obstruction. The condition is usually congenital, although it may be caused by RHEUMATIC FEVER. In the congenital condition, pulmonary stenosis may occur with other heart defects and is then known as Fallot’s tetralogy. Breathlessness and enlargement of the heart and eventual heart failure may be the consequence of pulmonary stenosis. Surgery is usually necessary to remove the obstruction.... pulmonary stenosis
In this condition, increased resistance to the blood ?ow through the LUNGS occurs. This is usually the result of lung disease, and the consequence is an increase in pulmonary artery pressure and in the pressure in the right side of the heart and in the veins bringing blood to the heart. Chronic BRONCHITIS or EMPHYSEMA commonly constrict the small arteries in the lungs, thus causing pulmonary HYPERTENSION. (See also EISENMENGER SYNDROME.)... pulmonary hypertension
Fluid in the small air sacs of the lungs, from inefficient pumping by the heart or leakage of fluid from the blood vessels in the lungs (possibly from envenomation). As it prevents air exchange in the lungs it causes hypoxia and may lead to death.... pulmonary oedema
Most vision tests examine a person’s sharpness of VISION (visual acuity) and often of the ?eld of vision (see VISION, FIELD OF). Refraction tests assess whether a person has an error that can be corrected with glasses such as ASTIGMATISM, HYPERMETROPIA or MYOPIA. Visual acuity is tested using a Snellen chart when the patient tries to read letters of di?ering standard sizes from 6 metres away. The optician will prescribe lenses to correct any defects detected by vision tests.... vision tests
See pulmonary disease, chronic obstructive.... chronic obstructive pulmonary disease
A condition which may develop in both LUNGS (interstitial pulmonary ?brosis) or part of one lung. Scarring and thickening of lung tissues occur as a consequence of previous lung in?ammation, which may have been caused by PNEUMONIA or TUBERCULOSIS. Symptoms include cough and breathlessness and diagnosis is con?rmed with a chest X-ray. The patient’s underlying condition should be treated, but the damage already done to lung tissue is usually irreversible. (See also ALVEOLITIS.)... pulmonary fibrosis
A combination of mouth to mouth resuscitation (E.A.R.) to oxygenate the blood, and external chest compression (E.C.C.) to compress the heart to help pump this artificially oxygenated blood around the body to maintain tissue oxygen concentration and prevent death.... cardio-pulmonary resuscitation
Naturally produced in the LUNGS by cells called pneumocytes, this substance is a mixture of phospholipids (see PHOSPHOLIPID) and LIPOPROTEINS. Present in ?uid lining the alveoli (see ALVEOLUS) in the lungs, their action helps maintain their patency. Premature babies may have a de?ciency of surfactant, a disorder which causes severe breathing diffculties – RESPIRATORY DISTRESS SYNDROME or hyaline membrane disease – and HYPOXIA. They will need urgent respiratory support, which includes oxygen and the administration (via an endotracheal tube) of a specially prepared surfactant such as beractant (bovine lung extract) or edfosceril palmitate.... pulmonary surfactant
One of a large number of tiny, balloon-like sacs at the end of a bronchiole (one of many small air passages in the lungs) where gases are exchanged during respiration.... alveolus, pulmonary
Tests to screen for and diagnose bleeding disorders, usually resulting from deficiencies or abnormalities of blood coagulation factors or of platelets (see blood clotting). Tests are also used to monitor treatment with anticoagulant drugs.... blood-clotting tests
Scarring of lung tissue mainly involving the alveoli. There are a number of causes, including occupational exposure to dusts and fibrosing alveolitis, which is an autoimmune disorder.... interstitial pulmonary fibrosis
This is a term encompassing chronic BRONCHITIS, EMPHYSEMA, and chronic ASTHMA where the air?ow into the lungs is obstructed.
Chronic bronchitis is typi?ed by chronic productive cough for at least three months in two successive years (provided other causes such as TUBERCULOSIS, lung cancer and chronic heart failure have been excluded). The characteristics of emphysema are abnormal and permanent enlargement of the airspaces (alveoli) at the furthermost parts of the lung tissue. Rupture of alveoli occurs, resulting in the creation of air spaces with a gradual breakdown in the lung’s ability to oxygenate the blood and remove carbon dioxide from it (see LUNGS). Asthma results in in?ammation of the airways with the lining of the BRONCHIOLES becoming hypersensitive, causing them to constrict. The obstruction may spontaneously improve or do so in response to bronchodilator drugs. If an asthmatic patient’s airway-obstruction is characterised by incomplete reversibility, he or she is deemed to have a form of COPD called asthmatic bronchitis; sufferers from this disorder cannot always be readily distinguished from those people who have chronic bronchitis and/ or emphysema. Symptoms and signs of emphysema, chronic bronchitis and asthmatic bronchitis overlap, making it di?cult sometimes to make a precise diagnosis. Patients with completely reversible air?ow obstruction without the features of chronic bronchitis or emphysema, however, are considered to be suffering from asthma but not from COPD.
The incidence of COPD has been increasing, as has the death rate. In the UK around 30,000 people with COPD die annually and the disorder makes up 10 per cent of all admissions to hospital medical wards, making it a serious cause of illness and disability. The prevalence, incidence and mortality rates increase with age, and more men than women have the disorder, which is also more common in those who are socially disadvantaged.
Causes The most important cause of COPD is cigarette smoking, though only 15 per cent of smokers are likely to develop clinically signi?cant symptoms of the disorder. Smoking is believed to cause persistent airway in?ammation and upset the normal metabolic activity in the lung. Exposure to chemical impurities and dust in the atmosphere may also cause COPD.
Signs and symptoms Most patients develop in?ammation of the airways, excessive growth of mucus-secreting glands in the airways, and changes to other cells in the airways. The result is that mucus is transported less e?ectively along the airways to eventual evacuation as sputum. Small airways become obstructed and the alveoli lose their elasticity. COPD usually starts with repeated attacks of productive cough, commonly following winter colds; these attacks progressively worsen and eventually the patient develops a permanent cough. Recurrent respiratory infections, breathlessness on exertion, wheezing and tightness of the chest follow. Bloodstained and/or infected sputum are also indicative of established disease. Among the symptoms and signs of patients with advanced obstruction of air?ow in the lungs are:
RHONCHI (abnormal musical sounds heard through a STETHOSCOPE when the patient breathes out).
marked indrawing of the muscles between the ribs and development of a barrel-shaped chest.
loss of weight.
CYANOSIS in which the skin develops a blue tinge because of reduced oxygenation of blood in the blood vessels in the skin.
bounding pulse with changes in heart rhythm.
OEDEMA of the legs and arms.
decreasing mobility.
Some patients with COPD have increased ventilation of the alveoli in their lungs, but the levels of oxygen and carbon dioxide are normal so their skin colour is normal. They are, however, breathless so are dubbed ‘pink pu?ers’. Other patients have reduced alveolar ventilation which lowers their oxygen levels causing cyanosis; they also develop COR PULMONALE, a form of heart failure, and become oedematous, so are called ‘blue bloaters’.
Investigations include various tests of lung function, including the patient’s response to bronchodilator drugs. Exercise tests may help, but radiological assessment is not usually of great diagnostic value in the early stages of the disorder.
Treatment depends on how far COPD has progressed. Smoking must be stopped – also an essential preventive step in healthy individuals. Early stages are treated with bronchodilator drugs to relieve breathing symptoms. The next stage is to introduce steroids (given by inhalation). If symptoms worsen, physiotherapy – breathing exercises and postural drainage – is valuable and annual vaccination against INFLUENZA is strongly advised. If the patient develops breathlessness on mild exertion, has cyanosis, wheezing and permanent cough and tends to HYPERVENTILATION, then oxygen therapy should be considered. Antibiotic treatment is necessary if overt infection of the lungs develops.
Complications Sometimes rupture of the pulmonary bullae (thin-walled airspaces produced by the breakdown of the walls of the alveoli) may cause PNEUMOTHORAX and also exert pressure on functioning lung tissue. Respiratory failure and failure of the right side of the heart (which controls blood supply to the lungs), known as cor pulmonale, are late complications in patients whose primary problem is emphysema.
Prognosis This is related to age and to the extent of the patient’s response to bronchodilator drugs. Patients with COPD who develop raised pressure in the heart/lung circulation and subsequent heart failure (cor pulmonale) have a bad prognosis.... chronic obstructive pulmonary disease (copd)
See LUNGS, DISEASES OF.... pulmonary diseases
Cancer of the lung.
By the blood and lymph cancer may be transferred (metastasised) to the lymph nodes under the arm, liver, brain or lungs. An association has been shown between a low intake of Vitamin A and lung cancer. Causes: occupational hazards, environmental pollution, radiation, keeping of pet birds. Cigarette smoking is a strong risk factor. Studies show that a high Vitamin A/carotene intake is protective against the disease in men. Among women, evidence of a similar protective effect has not been found. Vitamin C reduces cancer risk. The increased prevalence of smoking among women results in more female lung cancer. All smokers should drink freely carrot juice (Vitamin A).
Symptoms. Chronic irritative cough, difficult breathing, pain in the chest, recurrent spitting of blood, clubbing of fingers, weight loss.
Alternatives. Only transient benefit is obtainable, yet it may be sufficient to achieve a measure of relief from distressing symptoms. See: CANCER: GENERAL REMARKS. Mullein tea has its supporters. Bugleweed strengthens lung tissue and supports the action of the heart. Blood root is known to arrest bleeding (haemoptysis).
Tea. Equal parts: Red Clover, Gota Kola, Mullein. 2 teaspoons to each cup boiling water; infuse 5-15 minutes. 1 cup three or more times daily.
Formula No 1. Equal parts: Elecampane, Violet, Red Clover, Echinacea. Mix. Dose: Powders: 750mg (three 00 capsules or half a teaspoon). Liquid extracts: 1-2 teaspoons. Tinctures: 1-3 teaspoons. Thrice daily and, if necessary, at bedtime for relief.
Formula No 2. Tincture Blood root 10 drops; Liquid extract Dogwood 20 drops; Liquid extract Elecampane 200 drops (14ml); Liquid extract Bugleweed (Lycopus europ) 30 drops. Flavour with Liquorice if necessary. Dose: 1-2 teaspoons in water 3 or more times daily. (W. Burns-Lingard MNIMH)
Where accompanied by active inflammation, anti-inflammatories are indicated: Mistletoe, Wild Yam, etc.
Diet. A substance in fish oil has been shown to experimentally prevent cancer of the lung. Mackerel, herring and sardines are among fish with the ingredient. See: DIET – CANCER.
Chinese Herbalism. See: CANCER – CHINESE PRESCRIPTION.
Treatment by a general medical practitioner or hospital oncologist. ... cancer – pulmonary
Analysis of a sample of blood to give information on its cells and proteins and any of the chemicals, antigens, antibodies, and gases that it carries. Such tests can be used to check on the health of major organs, as well as on respiratory function, hormonal balance, the immune system, and metabolism. Blood tests may look at numbers, shape, size, and appearance of blood cells and assess the function of clotting factors. The most important tests are blood count and blood group tests if transfusion is needed. Biochemical tests measure chemicals in the blood (see acid–base balance; kidney function tests; liver function tests). Microbiological tests (see immunoassay) look for microorganisms that are in the blood, as
in septicaemia. Microbiology also looks for antibodies in the blood, which may confirm immunity to an infection. blood transfusion The infusion of large volumes of blood or blood products directly into the bloodstream to remedy severe blood loss or to correct chronic anaemia. In an exchange transfusion, nearly all of the recipient’s blood is replaced by donor blood. Before a transfusion, a sample of the recipient’s blood is taken to identify the blood groups, and it is matched with suitable donor blood. The donor blood is transfused into an arm vein through a plastic cannula. Usually, each unit (about 500 ml) of blood is given over 1–4 hours; in an emergency, 500 ml may be given in a couple of minutes. The blood pressure, temperature, and pulse are monitored during the procedure.
If mismatched blood is accidentally introduced into the circulation, antibodies in the recipient’s blood may cause donor cells to burst, leading to shock or kidney failure. Less severe reactions can produce fever, chills, or a rash. Reactions can also occur as a result of an allergy to transfused blood components. All
blood used for transfusion is carefully screened for a number of infectious agents, including HIV (the AIDS virus) and hepatitis B and hepatitis C.
In elderly or severely anaemic patients, transfusion can overload the circulation, leading to heart failure.
In patients with chronic anaemia who need regular transfusion over many years, excess iron may accumulate (haemosiderosis) and damage organs such as the heart, liver, and pancreas.
Treatment with desferrioxamine to remove excess iron may be needed.... blood tests
See pulmonary function tests.... lung function tests
Questionnaires designed to define various personality traits or types. Tests may be designed to detect psychiatric symptoms, underlying personality traits, how outgoing or reserved a person is, and predisposition to developing neurotic illness.... personality tests
A rare defect of the pulmonary valve at the exit of the heart’s right ventricle. The valve fails to close properly, allowing blood to leak back into the heart. The cause is usually rheumatic fever, endocarditis, or severe pulmonary hypertension.... pulmonary incompetence
See pulmonary function tests.... respiratory function tests
A group of blood tests used to evaluate the function of the thyroid gland and to detect or confirm any thyroid disorder. The thyroid hormones T3 and T4 are measured, as well as thyroid-stimulating hormone (TSH), the pituitary gland hormone that stimulates the thyroid gland.... thyroid-function tests
A combination of chronic bronchitis and emphysema, in which there is persistent disruption of air flow into or out of the lungs. Patients are sometimes described as either pink puffers or blue bloaters, depending on their condition. Pink puffers maintain adequate oxygen in their bloodstream through an increase in their breathing rate, and remain “pink” despite damage to the lungs. However, they suffer from almost constant shortness of breath. Blue bloaters are cyanotic (have a bluish discoloration of the skin and mucous membranes) because of obesity, and sometimes oedema, mainly due to heart failure resulting from the lung damage.... pulmonary disease, chronic obstructive
Skin tests used to determine whether or not a person has been exposed to the bacterium that causes tuberculosis. Tuberculin tests are carried out for diagnosis of tuberculosis, and before BCG vaccination. A small amount of tuberculin (purified protein from the bacteria) is injected into the skin. A few days later, the skin reaction, if any, is noted. A reaction indicates previous exposure.... tuberculin tests
Hearing tests carried out to diagnose conductive deafness. In the Weber test, a vibrating tuning fork is held against the forehead. If there is conductive hearing loss, the sound seems louder in the affected ear. In the Rinne test, a vibrating tuning fork is held first near the ear, and then against the bone behind it. If it sounds louder when held against the bone, there is conductive hearing loss.... tuning fork tests
See urinalysis.... urine tests
a congenital abnormality in which the pulmonary veins enter the right atrium or vena cava instead of draining into the left atrium. The clinical features are those of an *atrial septal defect.... anomalous pulmonary venous drainage
the artery that conveys blood from the heart to the lungs for oxygenation: the only artery in the body containing deoxygenated blood. It leaves the right ventricle and passes upwards for 5 cm before dividing into two, one branch going to each lung. Within the lungs each pulmonary artery divides into many fine branches, which end in capillaries in the alveolar walls. See also pulmonary circulation.... pulmonary artery
(PCWP) an indirect measurement of the pressure of blood in the left atrium of the heart, which indicates the adequacy of left heart function. It is measured using a catheter wedged in the most distal segment of the pulmonary artery. See also Swan-Ganz catheter.... pulmonary capillary wedge pressure
a system of blood vessels effecting transport of blood between the heart and lungs. Deoxygenated blood leaves the right ventricle by the pulmonary artery and is carried to the alveolar capillaries of the lungs. Gaseous exchange occurs, with carbon dioxide leaving the circulation and oxygen entering. The oxygenated blood then passes into small veins leading to the pulmonary veins, which leave the lungs and return blood to the left atrium of the heart. The oxygenated blood can then be pumped around the body via the *systemic circulation.... pulmonary circulation
leakage of the pulmonary valve in the heart. Mild regurgitation is a common normal finding, but severe congenital pulmonary regurgitation may require surgical correction.... pulmonary regurgitation
where clinical *negligence is claimed, tests used to determine the standard of care owed by professionals to those whom they serve, e.g. the standards of care provided to patients by doctors. The 1957 case of Bolam v Friern Hospital Management Committee established that if a doctor acts in accordance with a responsible body of medical opinion, he or she will not be negligent. In 1997 this standard of care test was amended by the case of Bolitho v City and Hackney Health Authority, which requires the doctor’s behaviour to satisfy the judgment not only of responsible medical opinion but also of a court’s own independent logical analysis.... bolam and bolitho tests
(DSTs) tests based on the principle that appropriate doses of *dexamethasone can suppress the output of cortisol from the adrenal glands in the normal state and that this ability is reduced or lost in *Cushing’s syndrome. In the overnight DST 1 mg of dexamethasone is administered at midnight and the serum cortisol level is measured at 9.00 am the next morning. Failure to suppress cortisol output may indicate Cushing’s syndrome but also occurs in patients with obesity and depressive illness. In the low-dose DST (0.5 mg dexamethasone every 6 hours for 48 hours), cortisol suppression occurs in patients with obesity and depression but not in those with Cushing’s syndrome. In the high-dose DST (2 mg dexamethasone every 6 hours for 48 hours), cortisol is suppressed in patients with Cushing’s disease (in which excess amounts of ACTH are secreted by the pituitary gland) but not in those with Cushing’s syndrome due to other causes. Although the low- and high-dose tests are unreliable, all three tests should be performed to aid the diagnosis of Cushing’s syndrome.... dexamethasone suppression tests
(IPF) a serious interstitial lung disease, formerly called cryptogenic fibrosing alveolitis (see alveolitis). It is characterized by progressive fibrous scarring of the lung and increased numbers of inflammatory cells in the alveoli and surrounding tissues. The disease is usually diagnosed on clinical grounds on a basis of worsening breathlessness, inspiratory crackles at the lung bases on auscultation, clubbing of the fingers or toes, bilateral radiographic shadowing predominantly in the lower zones of the chest X-ray, subpleural *honeycomb change on CT scanning of the chest, and restrictive lung function on spirometry. It is also called usual interstitial pneumonia (UIP; see interstitial pneumonia), a term used by lung pathologists for the most common cellular pattern seen on biopsy. Treatment includes *pirfenidone, corticosteroids, and immunosuppressants.... idiopathic pulmonary fibrosis
see tuberculosis.... pulmonary tuberculosis
a valve in the heart lying between the right ventricle and the pulmonary artery. It is a *semilunar valve that prevents blood returning to the ventricle from the pulmonary artery.... pulmonary valve
a vein carrying oxygenated blood from the lung to the left atrium. See pulmonary circulation.... pulmonary vein
tests for assessing the function of the kidneys. These include measurements of the specific gravity of urine, creatinine *clearance time, and blood urea levels; intravenous urography; and renal angiography.... renal function tests
Standard Tests for Young Children and Retardates: tests to detect visual problems in children between the ages of six months and five years. They consist of a series of standardized balls, toys, or letters. The tests were developed by the paediatrician Mary Sheridan.... stycar tests
tests used to assess the ability of the adrenal cortex to produce cortisol. Serum cortisol is measured before and then 30 minutes (or 5 hours) after an intramuscular injection of 250 ?g (or 1 mg) tetracosactide (Synacthen), an analogue of *ACTH. The adrenal glands are considered to be inadequate if there is a low baseline concentration of cortisol or the rise is less than a certain predefined amount.... synacthen tests
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