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1. the process or act of supplying a house or room continuously with fresh air.
2. in respiratory physiology, the process of exchange of air between the lungs and the ambient air; see alveolar ventilation and pulmonary ventilation. See also respiration (def. 1). Called also breathing.
3. in psychiatry, verbalization of one's problems, emotions, or feelings.
alveolar ventilation a fraction of the pulmonary ventilation, being the amount of air that reaches the alveoli and is available for gas exchange with the blood.
assist/control mode ventilation positive pressure ventilation in the assist-control mode; if the spontaneous ventilation rate falls below a preset level, the ventilator enters the control mode.
assisted ventilation artificial respiration.
assist mode ventilation positive pressure ventilation in which the ventilator is in the assist-control mode; see also control mode ventilation and assist/control mode ventilation.
controlled ventilation (control mode ventilation) positive pressure ventilation in which the ventilator is in control mode, with its cycle entirely controlled by the apparatus and not influenced by the patient's efforts at spontaneous ventilation.
high-frequency ventilation a technique of mechanical ventilation that uses very high rates (over 80 breaths per minute) and small tidal volumes (equal to or less than dead space); it may either be positive pressure ventilation or be delivered in the form of frequent jets of air. It is used to lower the peak airway pressure applied to the lung, thus decreasing the risk of barotrauma.
high-frequency jet ventilation a type of high-frequency ventilation characterized by delivery of gas through a small catheter in the endotracheal tube.
high-frequency percussive ventilation a type of high-frequency ventilation characterized by delivery of pressure-limited breaths in short bursts of gas from a venturi mask.
high-frequency positive pressure ventilation a type of high-frequency ventilation characterized by low compressible volume circuit and tidal volume delivery of 3 to 4 mL per kg.
impaired spontaneous ventilation a nursing diagnosis accepted by the North American Nursing Diagnosis Association, defined as a state in which an individual's decreased energy reserves result in inability to maintain breathing adequate to support life. See also spontaneous ventilation.
intermittent mandatory ventilation (IMV) a type of control mode ventilation in which the patient breathes spontaneously while the ventilator delivers a prescribed tidal volume at specified intervals and allows the patient to breathe spontaneously between cycles. The ventilator rate is set to maintain the patient's PaCO2 at desired levels and is reduced gradually to zero as the patient's condition improves. See also intermittent positive-pressure breathing.
intermittent mandatory ventilation, synchronized (SIMV) positive pressure ventilation in which the patient breathes spontaneously while the ventilator delivers a positive-pressure breath at intervals that are predetermined but synchronized with the patient's breathing.
intermittent positive pressure ventilation (IPPV) intermittent positive pressure breathing.
maximal voluntary ventilation (maximum voluntary ventilation (MVV)) the maximum volume that can be exhaled per minute by the patient breathing as rapidly and deeply as possible. Called also maximal breathing capacity.
mechanical ventilation
1. ventilation accomplished by extrinsic means, usually distinguished as either negative pressure or positive pressure ventilation. See also spontaneous ventilation.
2. in the nursing interventions classification, a nursing intervention defined as the use of an artificial device to assist a patient to breathe.
minute ventilation the total volume of gas in liters expelled from the lungs per minute. See also minute volume. Called also total ventilation.
negative pressure ventilation a type of mechanical ventilation in which negative pressure is generated on the outside of the patient's chest and transmitted to the interior of the thorax in order to expand the lungs and allow air to flow in; used primarily with patients having paralysis of the chest muscles. See also ventilator.
noninvasive ventilation mechanical ventilation that does not use an artificial airway, such as positive pressure ventilation with a nasal or face mask.
partial liquid ventilation ventilatory support in which the lungs are filled to the level of the functional residual capacity with a liquid perfluorocarbon; mechanical ventilation is then superimposed and oxygen and carbon dioxide are transferred through the liquid.
positive pressure ventilation any of numerous types of mechanical ventilation in which gas is delivered into the airways and lungs under positive pressure, producing positive airway pressure during inspiration; it may be done via either an endotracheal tube or a nasal mask. See also ventilator.
pressure control ventilation positive pressure ventilation in which breaths are augmented by air at a fixed rate and amount of pressure, with tidal volume not being fixed; used particularly for patients with acute respiratory distress syndrome.
pressure support ventilation positive pressure ventilation in which the patient breathes spontaneously and breathing is augmented with air at a preset amount of pressure, with tidal volume not being fixed.
proportional assist ventilation positive pressure ventilation in which the ventilator can sense the patient's level of inspiratory flow and deliver pressure support to achieve a given tidal volume.
pulmonary ventilation a measure of the rate of ventilation, referring to the total exchange of air between the lungs and the ambient air, usually in liters per minute.
spontaneous ventilation term used to denote breathing accomplished naturally, without any artificial aids, as opposed to mechanical ventilation and other forms of artificial respiration.
total ventilation minute ventilation.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


1. Replacement of air or other gas in a space by fresh air or gas.
See also: respiration.
2. Movement of gas(es) into and out of the lungs.
See also: respiration. Synonym(s): oxidative metabolism, respiration (2)
3. In physiology, the tidal exchange of air between the lungs and the atmosphere that occurs in breathing.
See also: respiration.
[see ventilate]
Farlex Partner Medical Dictionary © Farlex 2012


a. The replacement of stale or noxious air with fresh air.
b. The mechanical system or equipment used to circulate air or to replace stale air with fresh air.
a. The maintenance of breathing by artificial means.
b. A breath that is induced by artificial means.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


Pulmonology The exchange of air between the lungs and the outside air. See Dead space, High-frequency ventilation, Jet ventilation, Maximum voluntary ventilation, Mechanical ventilation, Noninvasive positive pressure ventilation, Partial ventilation, Staircase ventilation Public health The circulation of air from one space to another, usually understood to mean the replacement of ambient air with fresh air from another source. See General exhaust, Local exhaust, Mechanical exhaust.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


1. Replacement of air or other gas in a space by fresh air or gas.
2. Movement of gases into and out of the lungs.
Synonym(s): respiration (2) .
3. physiology The tidal exchange of air between the lungs and the atmosphere that occurs in breathing.
See also: respiration
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


(vent?i-la'shon) [ ventilatio, an airing]
1. The movement of air into and out of the lungs.
2. Circulation of fresh air in a room and withdrawal of foul air.
3. In physiology, the amount of air inhaled per day. This can be estimated by spirometry, multiplying the tidal air by the number of respirations per day. An average figure is 10,000 L. This must not be confused with the total amount of oxygen consumed, which is on the average only 360 L/day. These volumes are more than doubled during hard physical labor.

abdominal displacement ventilation

A noninvasive type of artificial ventilation that relies on displacement of the abdominal contents to move the patient's diaphragm.

adaptive support ventilation

Abbreviation: ASV
A mode of mechanical ventilation in which the minute ventilation is not allowed to fall below a set threshold (e.g., in adults, below 100 ml/kg/min), but the inspiratory pressure, inspiratory time, and tidal volume are all adjusted by the ventilator to the patient's needs.

airway pressure release ventilation

A type of mechanical ventilation in which patients breathe spontaneously at any phase of the ventilator's duty cycle at high continuous positive airway pressures (CPAP). Periodically, the level of CPAP is lowered to eliminate waste gases from the circuit.

alveolar ventilation

The movement of air into and out of the alveoli. It is a function of the size of the tidal volume, the rate of ventilation, and the amount of dead space present in the respiratory system. It is determined by subtracting the dead space volume from the tidal volume and multiplying the result by the respiratory rate.

assist-control ventilation

A type of mechanical ventilation with a minimum frequency of respirations determined by ventilator settings. It also permits the patient to initiate ventilation at the same tidal volume or pressure as set on the ventilator.

asynchronous ventilation

In emergency cardiac or critical care, the administration of artificial breaths to a patient that are timed independently of chest compressions.

continuous positive-pressure ventilation

A method of mechanically assisted pulmonary ventilation. A device administers air or oxygen to the lungs under a continuous pressure that never returns to zero.

differential lung ventilation

The use of different ventilatory strategies in each lung in a patient with focal lung disease, e.g., a patient undergoing surgery to remove a tumor in one lobe of a lung but not another, or a patient with more severe COPD on one side of the chest than another. This technique requires a double-lumen endotracheal tube.

dual control ventilation

Mechanical ventilation initiated by either a change in airway pressures or by a change in gas flowing through the ventilator circuit. Dual control is asserted when pressure limited breaths are delivered and the pressure changes from breath to breath to meet a desired delivered tidal volume. It improves the coordination between the patient's respiratory efforts and machine-generated breaths.

high-frequency jet ventilation

A type of ventilation that continuously ventilates at 100 to 150 cycles/min. It is used in respiratory failure to provide continuous ventilation without the side effects of positive-pressure ventilation.

high-frequency oscillatory ventilation

Abbreviation: HFOV
Pulmonary ventilation with multiple rapid breaths given at small tidal volumes. It limits the stretching and collapse of the alveoli that occur in conventional mechanical ventilation.

high-frequency percussive ventilation

Mechanical ventilation that decreases peak and end-expiratory pressure by delivering hundreds of shallow (low tidal volume) breaths per minute. It is a time-cycled, pressure-limited mode of ventilation.

intermittent mandatory ventilation

Abbreviation: IMV
Machine ventilation that delivers pressurized breaths at intervals while allowing for spontaneous breathing.

intermittent positive-pressure ventilation

A mechanical method of assisting pulmonary ventilation, using a device that inflates the lungs under positive pressure. Exhalation is usually passive.
Synonym: breathing, intermittent positive-pressure

inverse ratio ventilation

Abbreviation: IRV
Mechanical ventilation in which the normal temporal relationship between inspiration and expiration is reversed (the inspiration time is longer than the expiratory time). It is sometimes used in severely hypoxemic patients who have not responded to other ventilatory maneuvers. Because it is uncomfortable for patients, paralysis and sedation are needed.

liquid ventilation

A ventilatory technique used to treat both premature infants with surfactant-deficient lungs and adults with acute respiratory distress syndrome.

mandatory minute ventilation

Ventilatory support that provides mechanical breaths when the patient's spontaneous breathing does not achieve the preset mechanical ventilatory rate.

maximum sustainable ventilation

The normal maximum breathing pattern that can be maintained for 15 min (usually approx. 60% of maximum voluntary ventilation).

maximum voluntary ventilation

The maximum amount of gas that can be ventilated into and out of the lungs in a voluntary effort in a given time, measured in liters per minute.

mechanical ventilation

Any form of artificially supplied ventilation.

minute ventilation

Abbreviation: MV
The volume of air inhaled and exhaled in 60 sec. See: minute volume
Enlarge picture

noninvasive ventilation

The use of airway support administered through a face (nasal) mask instead of an endotracheal tube. Inhaled gases are given with positive end-expiratory pressure often with pressure support or with assist control ventilation at a set tidal volume and rate. Numerous studies have shown this technique to be as effective as, and better tolerated than, intubation and mechanical ventilation in patients with exacerbations of COPD.
See: illustration

positive-pressure mechanical ventilation

Mechanical ventilatory support that applies positive pressure to the airway. The objectives include improving pulmonary gas exchange, relieving acute respiratory acidosis, relieving respiratory distress, preventing and reversing atelectasis, improving pulmonary compliance, preventing further lung injury, and avoiding complications. Positive-pressure ventilation can be life saving, but complications such as toxic effects of oxygen, laryngeal injury, tracheal stenosis, alveolar injury, barotrauma, pneumonia, and psychological problems may occur.
See: pressure, positive end-expiratory

pressure support ventilation

A type of assisted ventilation that supplements a spontaneous breath. The patient controls the frequency and the duration and flow of inspiration from the ventilator.

protective ventilation

A type of mechanical ventilation in which tidal volumes are set to avoid overstretching the alveoli, and pressures at the end of an inhaled breath are set to avoid alveolar collapse.

pulmonary ventilation

The inspiration and expiration of air from the lungs.

reduced ventilation

Respiratory depression.

synchronized intermittent mandatory ventilation

Abbreviation: SIMV
Periodic assisted ventilation with positive pressure initiated by the patient and coordinated with spontaneous patient breaths.
See: intermittent mandatory ventilation

transtracheal catheter ventilation

An emergency procedure in which a catheter is placed percutaneously through the cricothyroid membrane and attached to a high-pressure, high-flow jet ventilator. This form of ventilation is used for patients with an upper airway obstruction who cannot be intubated.

volume-controlled ventilation

A form of mechanical ventilation in which the peak inspiratory flow rate, fraction of inspired oxygen, positive end-expiratory pressure, respiratory rate, and tidal volume are preset and delivered to the patient.
Synonym: volume-cycled ventilation; volume-limited ventilation

volume-cycled ventilation

Volume-controlled ventilation.

volume-limited ventilation

Volume-controlled ventilation.
Medical Dictionary, © 2009 Farlex and Partners


1. Replacement of air or other gas in a space by fresh air or gas.
2. Movement of gas(es) into and out of the lungs.
Synonym(s): respiration (2) .
Medical Dictionary for the Dental Professions © Farlex 2012

Patient discussion about ventilation

Q. Help her to breathe. My sixteen year old cousin (girl) who is wondering if she is suffering from asthma, anxiety or both. She is thin, healthy girl and have been very worried She have asthma and have been thinking about it constantly. When she exercise, she get more out of breath, more worn out, and her heart beats faster than other people. Sometimes her chest hurts, but people tell me that is from my chest muscles being worked. She get a little dizzy also. When she go to bed at night sometimes it seems hard to breathe. She can take a deep breath and everything but it seems hard or something. I know there isn't anything wrong with my heart because she had an EKG done recently and chest x-rays. That was fine. When it is hot humid and muggy outside she find it hard to breath. Do you think she have asthma. She don't have any coughing or any known wheezing. Could thinking about every breath she take seem like she have asthma? She really want to know and me too, what is going on! Please help her to breathe!!!!

A. PS--alcohol and cigarettes can cause this problem to(drugs)mrfoot56.

Q. What causes bad breath? I have bad breath for a long time. What causes it?

A. Here are some causes of bad breath:
A Dry mouth- Saliva helps cleanse and moisten your mouth. A dry mouth enables dead cells to accumulate on your tongue, gums and cheeks. These cells then decompose and cause odor. Dry mouth naturally occurs during sleep. It's what causes "morning breath." Dry mouth is even more of a problem if you sleep with your mouth open. Some medications as well as smoking can lead to a chronic dry mouth, as can a problem with your salivary glands.
Some Diseases can also cause bad breath- Chronic lung infections and lung abscesses can produce very foul-smelling breath. Other illnesses, such as some cancers and certain metabolic disorders, can cause a distinctive breath odor. Kidney failure can cause a urine-like odor, and liver failure may cause an odor described as "fishy." People with uncontrolled diabetes often have a fruity breath odor. Chronic reflux of stomach acids from your stomach (gastroesophageal reflux disease, or GERD)

Q. How to get rid of bad breath? My wife complains that I have bad breath. How can I get rid of it?

A. Consider that candida infection can make your breath worse. You might try cutting down on sugar and carbs.

"Bad breath can also be caused by a candida (yeast infection), you may have a constant white furry tongue. Look at cutting down your intake of sugars and processed foods, as well as those containing yeast. - Search for Anti-Candida diet on a search engine for more info"

More discussions about ventilation
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References in periodicals archive ?
Until 2001, ASHRAE standards indicated outdoor air ventilation at 15-30cfm/person (8-15 L/s-person) to be sufficient.
A recent review reported that forced-air warmers contaminate ultraclean air ventilation systems (10).
We investigated a hypothesis that higher concentrations of C[O.sub.2], within the range found in buildings, and without changes in outdoor air ventilation rate, have detrimental effects on occupants' decision-making.
"The air ventilation louvres will basically operate as heat evacuation mechanisms that will allow fresh air to enter the shop floor leading to cooling down of surrounding temperatures," he said.
The temperature settings for space heating within the various rooms show general trends that can be used for energetic optimization with air ventilation.
Outside air ventilation can account for 20% of the air circulated in a building and 30 to 50% of the heating and cooling load.
Among those factors are sleeping on the stomach and soft bedding, both of which limit air ventilation around an infant's breathing pathway and thus increase the chance of re-breathing exhaled carbon dioxide, said the researchers.
Some of the measures NYMEX instituted include: improving recycling and waste reductions practices, including composting of all organic kitchen waste; purchasing renewable energy credits for 100% wind power at its facility; installing new carbon dioxide and humidity sensors around the building, allowing NYMEX to control the outside air ventilation system based on occupancy and space demand instead of constant volume.
It also has electric lights, an air ventilation system, and a pulley system to facilitate the transport of drugs and other contraband.
F Shaw has progressed from humble origins as a general tinsmith supplying textile firms to become a leading designer, maker and installer of sophisticated air ventilation systems.
A fully adjustable air ventilation system allows production of a soft and thick product with high resilience for insulation or automotive applications, or thin and rigid for mattresses or undercarpets.