Respiratory quotient Health Dictionary

Respiratory Quotient: From 1 Different Sources

(RQ) the ratio of the volume of carbon dioxide transferred from the blood into the alveoli to the volume of oxygen absorbed into the alveoli. The RQ is usually about 0.8 because more oxygen is taken up than carbon dioxide excreted.

Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Respiratory Arrest

Cessation of breathing, often caused by envenomation (or poisoning).... respiratory arrest

Respiratory System

All the organs and tissues associated with the act of RESPIRATION or breathing. The term includes the nasal cavity (see NOSE) and PHARYNX, along with the LARYNX, TRACHEA, bronchi (see BRONCHUS), BRONCHIOLES and LUNGS. The DIAPHRAGM and other muscles, such as those between the RIBS, are also part of the respiratory system which is responsible for oxygenating the blood and removing carbon dioxide from it.... respiratory system

Respiratory Distress Syndrome

This may occur in adults as ACUTE RESPIRATORY DISTRESS SYNDROME (ARDS), or in newborn children, when it is also known as HYALINE MEMBRANE DISEASE. The adult syndrome consists of PULMONARY OEDEMA of non-cardiac origin. The process begins when tissue damage stimulates the autonomic nervous system, releases vasoactive substances, precipitates complement activation, and produces abnormalities of the clotting cascade – the serial process that leads to clotting of the blood (see COAGULATION). The activation of complement causes white cells to lodge in the pulmonary capillaries where they release substances which damage the pulmonary endothelium.

Respiratory distress syndrome is a complication of SHOCK, systemic SEPSIS and viral respiratory infections. It was ?rst described in 1967, and – despite advances with assisted ventilation

– remains a serious disease with a mortality of more than 50 per cent. The maintenance of adequate circulating blood volume, peripheral PERFUSION, acid-base balance and arterial oxygenation is important, and assisted ventilation should be instituted early.

In newborns the mechanism is diferent, being provoked by an inability of the lungs to manufacture SURFACTANT.... respiratory distress syndrome

Acute Respiratory Distress Syndrome (ards)

Formerly known as adult respiratory distress syndrome. A form of acute respiratory failure in which a variety of di?erent disorders give rise to lung injury by what is thought to be a common pathway. The condition has a high mortality rate (about 70 per cent); it is a complex clinical problem in which a disproportionate immunological response plays a major role. (See IMMUNITY.)

The exact trigger is unknown, but it is thought that, whatever the stimulus, chemical mediators produced by cells of the immune system or elsewhere in the body spread and sustain an in?ammatory reaction. Cascade mechanisms with multiple interactions are provoked. CYTOTOXIC substances (which damage or kill cells) such as oxygen-free radicals and PROTEASE damage the alveolar capillary membranes (see ALVEOLUS). Once this happens, protein-rich ?uid leaks into the alveoli and interstitial spaces. SURFACTANT is also lost. This impairs the exchange of oxygen and carbon dioxide in the lungs and gives rise to the clinical and pathological picture of acute respiratory failure.

The typical patient with ARDS has rapidly worsening hypoxaemia (lack of oxygen in the blood), often requiring mechanical ventilation. There are all the signs of respiratory failure (see TACHYPNOEA; TACHYCARDIA; CYANOSIS), although the chest may be clear apart from a few crackles. Radiographs show bilateral, patchy, peripheral shadowing. Blood gases will show a low PaO2 (concentration of oxygen in arterial blood) and usually a high PaCO2 (concentration of carbon dioxide in arterial blood). The lungs are ‘sti?’ – they are less e?ective because of the loss of surfactant and the PULMONARY OEDEMA.

Causes The causes of ARDS may be broadly divided into the following:... acute respiratory distress syndrome (ards)

Intelligence Quotient (iq)

This is the ratio between the mental age and chronological age multiplied by 100. Thus, if a boy of 10 years of age is found to have a mental age of 12 years, his IQ will be 120. On the other hand, if he is found to have a mental age of 8 years, his IQ will be 80.

The mental age is established by various tests, the most widely used of which are the Stanford-Binet Scale, the Wechsler Adult Intelligence Scale, and the Mill Hill Vocabulary Test.

Average intelligence is represented by an IQ of 100, with a range of 85 to 115. For practical purposes it is taken that the intellectual level reached by the average 15-year-old is indistinguishable from that of an adult.... intelligence quotient (iq)

Respiratory Syncytial Virus (rsv)

Usually known as RSV, this is one of the MYXOVIRUSES. It is among the major causes of BRONCHIOLITIS and PNEUMONIA among infants aged under 6 months; its incidence has been increasing, possibly due to atmospheric pollution.... respiratory syncytial virus (rsv)

Respiratory Therapy

The diagnostic evaluation, management and treatment of the care of older persons with deficiencies and abnormalities of the cardiopulmonary (heart lung) system.... respiratory therapy

Severe Acute Respiratory Syndrome (sars)

See SARS.... severe acute respiratory syndrome (sars)

Respiratory Failure

A condition in which there is a buildup of carbon dioxide and a fall in the level of oxygen in the blood (see hypoxia). Causes include lung disorders, such as severe asthma, emphysema, or chronic bronchitis (see pulmonary disease, chronic obstructive), or damage to the respiratory centre in the brain due to, for example, an overdose of opioid drugs, a stroke, or serious head injury.

Treatment is with ventilation and oxygen for the underlying cause.... respiratory failure

Respiratory Function Tests

See pulmonary function tests.... respiratory function tests

Respiratory Tract Infection

Infection of the breathing passages, which extend from the nose to the alveoli. This type of infection is divided into upper and lower respiratory tract infections. Upper respiratory tract infections affect the nose, throat, sinuses, and larynx. They include the common cold, pharyngitis, tonsillitis, sinusitis, laryngitis, and croup. Lower respiratory tract infections, which affect the trachea, bronchi, and lungs, include acute bronchitis, acute bronchiolitis, and pneumonia.... respiratory tract infection

Acute Respiratory Distress Syndrome

see adult respiratory distress syndrome.... acute respiratory distress syndrome

Acute Respiratory Failure

(ARF) a primary disorder of gaseous exchange (as distinct from failure of the mechanical process of breathing). The prototype of ARF is *adult respiratory distress syndrome, but the term sometimes also refers to disruption of any other part of the respiratory system, including the respiratory control centre in the brain with its *efferent and *afferent pathways.... acute respiratory failure

Adult Respiratory Distress Syndrome

(acute respiratory distress syndrome, ARDS) a form of *acute respiratory failure that occurs after a precipitating event, such as trauma, aspiration, or inhalation of a toxic substance; it is particularly associated with septic shock. Lung injury is characterized by reduced oxygen in the arteries, reduced lung volume, and decreased lung compliance, and diffuse infiltrates are seen on a chest X-ray. Treatment is correction of the original cause, volume replacement, diuretics, oxygen, and mechanical ventilation.... adult respiratory distress syndrome

Intelligence Quotient

(IQ) an index of intellectual development. In childhood and adult life it represents intellectual ability relative to the rest of the population; in children it can also represent rate of development (*mental age as a percentage of chronological age). The population’s IQ follows almost a normal distribution curve. Most *intelligence tests are constructed so that the resulting intelligence quotients in the general population have a *mean of about 100 and a *standard deviation of about 15. An IQ of below 80 is considered to be indicative of *learning disability.... intelligence quotient

Middle East Respiratory Syndrome

(MERS) a viral respiratory infection that was first identified in 2012. Humans seem to be infected most easily by contact with dromedary camels (hence the informal name camel flu), although human-to-human infection also occurs. Symptoms include fever, cough, and shortness of breath. Although the syndrome is often mild, death occurs in about a third of diagnosed cases. Most reported cases have been in the Arabian Peninsula, although there was a major outbreak in South Korea in 2015. At present there is no vaccine or treatment.... middle east respiratory syndrome

Respiratory Distress

severe difficulty in achieving adequate oxygenation in spite of significant efforts to breathe: it is usually associated with increased *respiratory rate and the use of *accessory muscles in the chest wall. It can occur in both obstructive and nonobstructive lung conditions. See adult respiratory distress syndrome; airway obstruction; dyspnoea; respiratory distress syndrome; stridor.

respiratory distress syndrome (RDS; hyaline membrane disease) the condition of a newborn infant in which the lungs are imperfectly expanded. Initial inflation and normal expansion of the lungs requires the presence of a substance (*surfactant) that reduces the surface tension of the air sacs (alveoli) and prevents collapse of the small airways. Without surfactant the airways collapse, leading to inefficient and ‘stiff’ lungs. The condition is most common and serious among preterm infants, in whom surfactant may be deficient. It lasts 5–10 days, with worsening on days 2–3. Breathing is rapid, laboured, and shallow, and microscopic examinations of lung tissue in fatal cases has revealed the presence of *hyalin material in the collapsed air sacs. The condition is treated by careful nursing, intravenous fluids, and oxygen, with or without positive-pressure ventilation (see noninvasive ventilation). Early surfactant replacement therapy has been shown to reduce the severity of RDS and when given prophylactically it has been demonstrated to improve clinical outcome. See also adult respiratory distress syndrome.... respiratory distress

Respiratory Rate

(RR) breathing rate: the number of breaths per minute. Normally between 6 and 12, it increases after exercise and in cases of *respiratory distress and decreases after head injury and opioid overdosage.... respiratory rate

Respiratory Syncytial Virus

(RSV) a paramyxovirus (see myxovirus) that causes infections of the nose and throat. It is a major cause of bronchiolitis and pneumonia in young children. In tissue cultures infected with the virus, cells merge together to form a conglomerate (syncytium). RSV is thought to have a role in *sudden infant death syndrome. Vulnerable children can be treated with *ribavirin, but most children just require supportive measures.... respiratory syncytial virus

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Respiratory quotient Health Dictionary

Respiratory Quotient: From 1 Different Sources

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