Respiratory Glossary

A

A/C

Assist/Control Mode of Ventilation - Ventilator operation in which a machine breath is delivered when an inspiratory effort by the patient is sensed by the ventilator (Assist), or at set time intervals if the rate of occurrence of inspiratory efforts falls below a set rate (Control).

AACN

American Association of Critical-Care Nurses

AARC

American Association for Respiratory Care

ABG

Arterial blood gas.

AC

Alternating Current having standard frequencies of 60 Hz in North America and possibly other frequencies in other locations internationally

ACCP

American College of Chest Physicians

Adenitis

Inflammation of a lymph node.

Aerosol

Solution that is dispensed in a mist.

Airway Pressure (Paw)

Pressure at a specified point in the patient's airway.

Airway Pressure Release Ventilation

Airway Pressure Release Ventilation (APRV) is a mode of ventilation that provides two levels of CPAP and allows spontaneous ventilation at both levels. APRV is different from other modes of ventilation in that it based on an intermittent decrease in airway pressure, rather than an increase, to provide ventilation. Source: RT Corner, click here for full description.

ALA

American Lung Association

Alarm

A means of alerting the operator that a specified abnormal condition exists; examples: high pressure alarm, apnea alarm.

Alveolar Pressure (PA)

Representative pressure in the alveoli.

Alveolus (p. alveoli)

Termination of the airways in the lungs; primary site of gas exchange with the blood.

Ambu Bag

Ventilating bag.

Analog

Pertaining to data in the form of continuously variable physical qualities in contrast to digital data represented in discrete form.

Anatomical Dead Space

The volume of the airways filled with inspired gas that does not take part in gas exchange with the blood during normal breathing.

Anemometer

A device that measures flow by its cooling of a heated element.

Angioedema

Sudden onset of periodic, recurrent episodes of noninflammatory swelling of skin, mucous membranes, and other tissues, associated with food allergies, urticaria or possibly stress or emotional factors.

Aphonia

Loss of voice.

Apnea Monitor

A machine that sounds an alarm when the infant stops breathing.

Apnea

Temporary stop in breathing.

APRV

(See Airway Pressure Release Ventilation)

Artificial Airway

Another word for tracheostomy tube.

Artificial Nose

See HME.

Asphyxia

Insufficient intake of oxygen.

Aspiration pneumonia

Pneumonia after inhaling foreign matter into the lungs.

Asplenia

Absence of the spleen due to congenital or traumatic cause.

Assist Mode

Ventilator operation in which an machine breath is delivered only when an inspiratory effort by the patient is sensed by the ventilator.

Assist/Control Mode

(See A/C.)

Asthma

Difficulty breathing accompanied by wheezing caused by a spasm of the bronchial tubes or by swelling of the mucous membrane.

ASTM

American Society for Testing and Materials: A scientific and technical organization formed for the development of standards on characteristics and performance of materials, products, systems, and services. The following published ASTM standards pertain to ventilators and mechanical ventilation:

ATC

Automatic Tube Compensation (See Automatic Tube Compensation)

ATS

American Thoracic Society

Auto PEEP

Auto Positive End-Expiratory Pressure (also Inadvertent PEEP) - Residual alveolar pressure above the preset baseline pressure at the end of expiration caused by the occlusion of airways and the consequent trapping of gas behind the occlusions.

Autocycling

Unintended, repeated delivery of machine breaths caused by the dropping of pressure in the patient circuit below the pressure trigger point. This typically occurs if the trigger point (sensitivity) is set too high, or if the circuit cannot hold pressure at the end of exhalation.

AutoFlow

AutoFlow is a ventilator feature pioneered by Draeger Medical that changes the control strategy for a volume-controlled breath to a pressure controlled breath under the constraint that the breath reaches the operator-set volume. It is defined as delivering a volume-targetted, pressure-controlled breath. In AutoFlow, the ventilator uses algorithms to try to determine the right peak pressure that will allow the set volume to be delivered with the minimum pressure. AutoFlow is a registered trademark of Draeger Medical.

Automatic Tube Compensation

A means by which that portion of the work of breathing associated with the movement of gas through an endotracheal or tracheostomy tube (connecting the breathing circuit to the patient's airway) is reduced or eliminated by the ventilator with no, or minimal, intervention by the operator (care giver).

B

Backup Rate

A default controlled breathing rate delivered by the ventilator in the event that its primary control circuits fail. (See Backup Ventilation.)

Backup Ventilation

A default set of ventilator settings activated when the primary control circuits fail. Typically a hardwired analog circuit takes over when a microprocessor in a digitally-controlled system crashes.

Bacteria

Germs.

Barotrauma

Injury to the lungs due to local over-inflation caused by high distending pressure in the intrapulmonary airways.

Base Flow - (also Bias Flow)

A minimum continuous flow introduced into the patient circuit at all times.

Bias Flow

(See Base Flow.)

BiPAP

Bilevel Positive Airway Pressure - A mode of operation in which the breathing circuit from which the patient breathes spontaneously is maintained at one pressure during exhalation and a higher pressure during inspiration.

BPD (bronchopulmonary dysplasia)

Respiratory problem caused by mechanical ventilation.

Branchial cleft cyst

A malformation of the branchial cleft during embryogenesis such that the remnant forms a cyst, usually found in the lateral neck.

Breathing Circuit

(See Patient Circuit.)

Breathing Rate - BR

(See Frequency (of Breathing)).

Bronchiolitis

Inflammation of the bronchioles, often associated with bronchopneumonia. Also known as capillary bronchitis.

Bronchitis

Inflammation of the bronchi.

Bronchodilator

A drug that widens the air passages of the lungs and eases breathing by relaxing bronchial smooth muscle.

Bronchoscope

A device used to look into the intrapulmonary airways; may be flexible utilizing fiber optics to carry the image, or rigid, essentially a narrow metal tube with lenses at each end.

Bronchoscopy

Examination of the bronchi through a scope.

C

C - Celsius (Centigrade)

Temperature scale that assigns 0 to the freezing point of water and 100 to its boiling point.

Cannula

The tube part of the tracheostomy tube.

Carbon Dioxide CO2

Produced by the body's metabolism; transported by the blood to the lungs through which it is eliminated by ventilating of the lungs.

Carina

Area at the end of the trachea, the carina represents the origins of the left and right mainstem bronchi.

Cartilage

The tough tissue rings the wind pipe is made of cartilage.

Catheter

Tube used to remove or inject fluids into the body.

CBC

Complete blood count.

CBVP

Congenital Bilateral Vocal Cord Paralysis.

CCU

Depending on the context, either Critical Care Unit or Cardiac Care Unit.

Cellulitis

Inflammation of the skin.

Circuit

(See Patient Circuit.)

Clark Electrode

Electrochemical device sensitive to PO2 of oxygen contained in blood. cm H2O Centimeters of Water - unit of pressure.

CO2 (carbon dioxide)

Gas that the body eliminates through the lungs.

CO2 monitor

A machine that monitors the amount of carbon dioxide in the blood.

Compliance (C), also called Static Compliance (Cst)

The change of volume divided by the associated change of pressure across a purely elastic structure, or the same ratio measured when a structure that contains resistance and/or inertance is completely static before and after the changes occur. Mathematically, the slope (constant of proportionality) of a linear static pressure difference - volume relation.

Connector

outside edge of the tracheostomy tube which connects to equipment

Control Mode

(See CV-Controlled Ventilation.)

Control Panel

Location of the primary means of directly adjusting the function of a device.

Controlled Ventilation

A mode of ventilator operation in which machine breaths are delivered at preset intervals.

COPD - Chronic Obstructive Pulmonary Disease

Ex.: Emphysema, Asthma

CPAP (Continuous Positive Airway Pressure)

Assisted ventilation that supports the infants own respiratory efforts. Or: A mode of ventilator operation in which the airway pressure remains above ambient during spontaneous breaths.

Continuous positive airway pressure (CPAP)

Continuous positive airway pressure (CPAP) is treatment provided by a machine worn at night or during times of sleep to treat sleep apnea, a sleep disorder in which a person regularly stops breathing during sleep for 10 seconds or longer. A CPAP machine increases air pressure in the throat, keeping tissues in the airway from collapsing when a person inhales.

The CPAP machine delivers air through a mask that covers the nose and mouth, through a mask that covers only the nose (nasal continuous positive airway pressure, NCPAP) or through prongs that fit inside the nose. The mask that covers only the nose is used most frequently.

CPAP is the most widely used treatment for sleep apnea caused by blocked airflow in the throat (obstructive sleep apnea).

CPR (CardioPulmonary Resuscitation)

A method for getting someone to breath again once they have stopped.

CRF - Chronic Respiratory Failure

Long standing inability to eliminate carbon dioxide through the lungs.

Cricothyrotomy

A medical procedure involving an incision being made between the cricoid and thyroid cartilages to maintain patency of the airway.

Croup

Childhood respiratory disease characterized by a barking cough and difficulty breathing. Also known as laryngotracheobronchitis.

Cuff

The inflatable balloon on some tracheostomy tubes.

CV

(See Controlled Ventilation.)

Cyanosis

A blue coloration of the skin and mucous membranes due to deoxygenation of the blood.

Cycling Pressure

That pressure which, when reached in the breathing circuit, causes the ventilator to cycle from one phase to another, e.g., from inhalation to expiration or vice versa.

D

Dead Space

(See Anatomical Dead Space).

Decanulation

The removal of a tube.

Diaphragm

The big muscle below the lungs that controls breathing.

DIC

Disposable inner cannula

Diffusion

The physical process in which a substance moves from areas of higher concentration or pressure to lower concentration or pressure.

Digital

Data represented in discrete, discontinuous form, as contrasted with analog data represented in continuous form.

Dual Control Modes

Modes of ventilator operation in which two variables are controlled by independent feedback loops so that the benefits of each can be realized. (See Pressure Augmentation as an example.)

Dying spells

Episodes of bradycardia, apnea, and cyanosis. Also known as reflex apnea.

Dysphagia

Difficulty in swallowing.

Dyspnea

Labored respiration, difficult breathing, shortness of breath.

E

ECG

A medical test to record the electrical current in the heart. Also known as an electrocardiogram. (also EKG)

Echocardiography

A medical test using ultrasound and Doppler techniques to visualize the structure of the heart.

ED

Emergency Department; Emergency Room

EKG

Electrocardiogram (also ECG).

Emphysema

A condition of the lung characterized by destruction of lung tissue resulting in enlarged terminal bronchioles and reduction of their number.

EMS

Emergency Medical Service.

Encrustation

Hard, crusty, dried mucus.

Endoscopy

A generic medical procedure used to visualize the inside of an organ system. This includes bronchoscopy.

Endotracheal Tube

(See ET Tube.)

ENT Doctor

Ear nose and throat doctor.

EPAP - Expiratory positive airway pressure

Airway pressure remains above ambient during the expiratory phase of the breath.

Epiglottis

A thin leaf-shaped flap that covers to entrance of the airway during swallowing to prevent aspiration into the lungs

Epiglottitis

Inflammation of the epiglottis, This is a medical emergency.

ER

Emergency Room; Emergency Department

ET tube - Endotracheal Tube

A flexible conduit that is inserted through the mouth and the larynx into the trachea to provide an airway to the bronchial tree. It can have, around its distal end, an inflatable cuff which, when inflated, provides a seal between its outside surface and the lumen of the trachea (cuffed), or it may have no such cuff (uncuffed).

Exhale

Breathe out.

Exhalation Valve

A device that closes to direct the gas flowing in the breathing circuit into the patient's lungs during in the inspiratory phase of a machine breath and opens to relieve the pressure in the circuit and permit exhalation of gas through the circuit to the atmosphere.

Expiration

Breathe out.

Expiratory Hold

That portion of the expiratory phase immediately preceding the initiating of the next breath during which flow is continuously zero.

Expiratory Pause Time (TEP)

The time interval between the cessation of expiratory flow to the start of the inspiratory phase of the next breath.

Expiratory Phase

The portion of a breath from the beginning of expiration to the beginning of inspiration of the next breath.

Expiratory Sub-Ambient Pressure

Airway pressure is less than ambient during the expiratory phase of the breath.

Expiratory Time (TE) - (also Expiratory Phase Time)

The time from the start of expiratory flow to the start of inspiratory flow.

Extended Self Test

A set of pre-use tests performed by the ventilator on itself and requiring limited intervention by the operator.

F

Fahrenheit Temperature scale that assigns the value 32 for the freezing temperature of water and 212 for its boiling point.

FDA

United States Food and Drug Administration

Fenestrated

Having openings.

FIO2

Fraction of Inspired Oxygen (See F [Fraction])

Fistula

An abnormal tube-like passage from one body cavity to another.

Flexible Bronchoscope

(See Bronchoscope.)

Flow-By

Flow introduced into the circuit typically for use in triggering the ventilator based on the flow demand of the patient, rather than pressure. The term "Flow-By" was likely introduced in the Puritan Bennett 7200 series ventilators. Flow triggering is usually much more sensitive than pressure triggering (see also Bias Flow).

Flow-Control Mode

A mode of ventilator operation in which the ventilator attempts to deliver a preset flow waveform with a specified peak flow during inspiration.

Fraction

(See F [Fraction])

Frequency (of breathing) (fb)

Number of breath cycles per unit time. Typically, the unit of time is minutes (conventional ventilation) but can be seconds for high frequency ventilation.

G

GAW Airway Conductance

The inverse of airway resistance, Raw.

Glottis

The sound-producing apparatus of the larynx, Also known as the voice box.

Goiter

A chronic enlargement of the thyroid gland not due to neoplasm often seen in endemic areas.

H

Hemorrhage

Bleeding.

HFJV High Frequency Jet Ventilation

A type of high-frequency ventilation in which gas is delivered into the airway as a pulsating stream from a small diameter catheter passed through the endotracheal tube.

HFOV High Frequency Oscillatory Ventilation

A type of high-frequency ventilation in which the applied high frequency expiratory pressure and delivered volume are negative relative to their base line values.

HFV High Frequency Ventilation

A form of ventilatory support characterized by breathing frequencies in excess of 80 breaths per minute and tidal volumes on the order of the anatomical dead space.

High Pressure Relief Valve (safety valve)

A device that prevents the pressure in the patient circuit from exceeding a preset limit by venting excess flow to the atmosphere.

High Priority Alarm

A combination of audible and visual signals indicating that immediate operator response is required.

HME (heat and moisture exchanger)

a filter device that fits onto the end of the tracheostomy tube and warms and moistens the air the child breathes. Or: Heat and Moisture Exchanger - A passive device designed to collect and hold some of the heat and moisture from the patient's exhaled breath, and to return them to the inspired gas mixture during inspiration.

Humidifier

A device that adds water in the form of vapor to a gas mixture

Humidity

Moisture in the air.

Hyaline membrane disease

A disease causing respiratory distress usually in premature newborns in which hyalin, a glassy, eosinophilic material, is seen in the alveoli. Also known as respiratory distress syndrome.

Hydrogen Peroxide> - (H2O2)

Mild antiseptic and cleansing agent.

Hypercapnea

The presence of an abnormally high amount of carbon dioxide in the blood. Also known as hypercarbia.

Hypopharynx

Synonymous with larynx.

Hypoventilation

Reduced rate and depth of breathing.

Hypoxia

The presence of an abnormally low amount of oxygen in the blood.

Hz Hertz

Unit of frequency , cycles per second (cps).

I

ICU

Intensive Care Unit

IMV Intermittent Mandatory Ventilation

A ventilator operating mode that permits spontaneous breathing in the interval between preset ventilator-assisted breaths.

Inertance (I)

The constant of proportionality between the pressure difference across a mass and the acceleration of the volume it displaces as it moves. Typically associated with the mass of the gas in the airways and the mass of the airway walls and surrounding parenchyma, all of which undergo volume accelerations during high frequency ventilation.

Inhale

Breathe in.

Inspiration

Breathe in.

Inspiratory Triggering Response Time

The time delay from the satisfaction of the trigger condition to the initiation of an assisted breath.

Inspiratory (Phase)Time (TI)

The time for the inspiratory phase of a breath.

Inspiratory Pause Time (TIP)

The time interval from the cessation of inspiratory flow to the start of expiratory flow.

Inspiratory Phase

The portion of a breath from the beginning of inspiration to the beginning of expiration.

Inspiratory Pressure

The pressure that is produced in the patient circuit causing inspiratory flow.

Inspiratory Relief Valve

Unidirectional valve that permits air to flow to the patient during a spontaneous breath in which the inspiratory flow available from the ventilator is inadequate.

Inspiratory Triggering Flow

A set level of flow that must be drawn into the patient airway by the patient to initiate the inspiratory phase of a ventilator-assisted breath (See Trigger Flow.)

Inspiratory Triggering Pressure

(See Trigger Pressure.)

Inspiratory Triggering Volume

The volume of gas that must be inspired by the patient to trigger an assisted breath.

Inspiratory Work of Breathing

(See Work of Breathing.)

IPAP Inspiratory Positive Airway Pressure

Airway pressure maintained above ambient during inspiratory phase of the breath.

ISO 9000

Standards dictating the establishment and maintenance of quality systems in the design and manufacture of products.

L

L - Liter

Unit of volume.

Laryngectomy

Removal of the larynx.

Laryngitis (acute infectious)

Inflammation of the mucous membranes of the larynx usually secondary to influenza virus.

Laryngitis (spasmodic)

Inflammation of the mucous membranes of the larynx generally causing stridor. The stridor subsides easily only to return on subsequent nights. Also known as spasmotic croup.

Laryngomalacia

A softening of the structures of the larynx. Also known as chondromalacia of the larynx.

Laryngoplasty

Plastic surgery or reparation of the structures of the larynx.

Laryngoscope

A device used to directly visualize the larynx to aid in the insertion of an endotracheal tube through the vocal cords; often has a battery-powered lamp at its tip.

Laryngoscopy

Examination of the interior of the larynx with a scope.

Laryngotracheobronchitis

Also known as viral croup.

Laryngotracheoplasty (LTP)

Laryngeal and tracheal reconstrutive surgery.

Larynx

The voice box.

Leukocytosis

An elevation of the normal leukocyte blood count.

Low Priority Alarm

A visual signal, or a combination of audible and visual signals indicating that operator awareness is required.

LPS

Liter Per Second (L/s) - unit of flow.

Lumen

Inside part of the tube.

Lung

The organ of external respiration in which gas from the atmosphere is exchanged with the gaseous byproducts of cellular metabolism.

Lymphocytosis

An elevation of the normal lymphocyte blood count.

M

Malacia

A softening of the affected structure.

MAP Mean Airway Pressure

The time-averaged pressure measured in the patient circuit during one or more assisted breath.

Maximum Flow

The highest flow that can be produced in the patient circuit when the ventilator is functioning properly.

Maximum Working Pressure

The highest pressure that can be produced in the patient circuit when the ventilator is functioning properly.

Medium Priority Alarm

A combination of audible and visual signals indicating that prompt operator response is required (ASTM F1463-93).

mm

Millimeter

Modem

Contraction for modulator-demodulator; device that can combine (modulate) and/or separate (demodulate) a signal and a carrier wave. Used to send digital information over telephone lines.

Mole (or Mol)

Gram molecular weight - The mass of a substance divided by the molecular weight of the substance expressed in grams.

Monitor

A device that continuously or intermittently measures a (set of) variable(s) and provides the values in analog and/or digital signals in visual, electrical, hardcopy or other forms. It also includes audible and/or visual alarms.

Musculoskeletal Disease

Ex.: Kyphoscoliosis

Mucus

Slippery fluid that is produced in the lungs and windpipe.

MV - Minute Volume

The volume of gas entering (or leaving) the lungs per minute (L/min).

N

Nasotracheal Tube

A flexible conduit that is inserted through the nose and the larynx into the trachea to provide an airway to the bronchial tree.

Nebulizer

A machine that puts moisture (fine particles) and/or medicine directly into the lungs.

Neck plate

- part of the tracheostomy tube that rests against the neck.

NEEP

Negative End Expiratory Pressure - The pressure in the patient circuit is maintained below ambient at the end of expiration.

Neonatal

The first 6 weeks after birth.

Neoplasm

A tumor or growth.

Neuromuscular Disease

Ex.: Muscular Dystrophy, Amyotrophic Lateral Sclerosis (ALS)

NICU

Neonatal Intensive Care Unit.

Nomograph

A chart relating three or more scales across which a straightedge can be placed to provide a graphical solution for a particular problem.

NPPV

Noninvasive Positive Pressure Ventilation -Mechanical ventilation in which the connection between the patient and the breathing circuit (through which the positive pressure for inspiration is applied to the airways) is a mask over the mouth and/or nose rather than a tube extending into the trachea.

NPV - Negative Pressure Ventilation

A form of ventilation in which inspiratory flow is produced by expanding the lungs by applying a negative pressure (relative to ambient) to the external surface of the chest wall. This can be done by placing a cuirass around the ribcage and abdomen and evacuating it with the negative pressure ventilator.

Nurse Call Output

A signal available from the ventilator that can be connected to a remote device to notify the operator of an alarm condition of the ventilator.

O

O2

Oxygen.

Obturator

The semi-rigid stick you put into the tracheostomy tube to help guide it into the opening in the neck.

Otolyringologist

Ear nose and throat doctor.

Oxygen - O2

The gas required by the body for metabolism; it enters the body and is transferred to the blood by the lungs.

Oxygen Saturation

The ratio of the amount of oxygen carried by blood to the maximum amount that it could carry, expressed as a percent.

Oxygen Saturation Curve

The relation between the amount of oxygen carried by the blood and the partial pressure of oxygen in the blood. It is affected by the partial pressure of carbon dioxide, hematocrit, condition of the red blood cells, and temperature of the blood.

P

Pa - Pascals

Unit of pressure; 1 cm H2O = 98.06 Pa.

Palv

Alveolar Pressure - Representative pressure in the alveoli of the lungs.

Panting

Spontaneous, high frequency (in the range of 3 breaths/second) low tidal volume breathing.

Pao

Pressure at the airway opening, e.g., at the interface between the patient's airways and the end of the patient circuit, or the atmosphere.

Partial Pressure

In a gas mixture: the pressure that a component, X, of a gas mixture would exhibit if X alone occupied the volume that is occupied by the entire mixture at the temperature of the mixture. Symbol: PX. For example: the partial pressure of oxygen is PO2, and the partial pressure of carbon dioxide is PCO2.

Partial Volume

The volume that the amount of a component gas in a gas mixture would occupy if that amount of the component gas existed at the pressure of the total mixture.

Patient Circuit (also Breathing Circuit)

The tubing that carries the gas between the ventilator and the patient. It can include a humidifier, water traps, nebulizer, sensors, and various connectors and valves.

Patient System

Those parts of the ventilator and patient circuit (including attachments) through which gas moves at physiologic pressures during ventilation of the patient.

Patient System Compliance

The effective compliance of the patient system; reflects the distensibility of the patient circuit and the other structures comprising the system as well as the compressibility of the gas within all of these structures.

Patient Wye

The connector that joins the inspiratory and expiratory limbs of a two-limb patient circuit to the patient airway.

Patm

Atmospheric Pressure - Usually the same as ambient, or local, pressure in the vicinity of the patient.

PCV

Pressure-Controlled Ventilation

PEEP

Positive End-Expiratory Pressure - Airway pressure is maintained above ambient during a machine-generated breath.

Peritonsillar abscess

an abscess involving the structures around the tonsil. This is a surgical emergency.

PF

Peak Flow, Peak Inspiratory Flow

pH Electrode

Electrochemical device sensitive to the concentration of H+ ions in solution.

Phase (of a breath)

Various portions of the breathing cycle defined by the direction and sequence of flow; e.g., in the inspiratory phase, flow is either into the lungs or has stopped after the lungs have expanded; during the expiratory phase, flow is either out of the lungs or has stopped after the lungs have deflated.

Phonation

Talking or making sounds with the vocal cords.

PICU

Pediatric Intensive Care Unit.

PIP

Peak Inspiratory Pressure - The maximum value achieved by the pressure in the patient circuit during a machine inspiration.

Plateau Pressure

A pressure value that is maintained constant during a portion of the inspiratory phase of the breath.

Pliable

Soft, flexible.

Pneumatic System

A system in which gas pressure differences and their rates of change are related to gas flows, their integrals and their rates of change.

Pneumonia

An inflammation of the lung parenchyma, often causing consolidation of the affected part with the alveolar air spaces being filled with blood, cells, and fibrin. It has many causes.

Pneumotachometer

A device that measures the flow of gas through it under local conditions of temperature and pressure.

Pneumothorax

The presence of gas or air in the pleural cavity.

Power

The rate of change of energy or, equivalently, the rate of change of work; expressed in units of watts, BTU's or joules.

PPS

(See Proportional Pressure Support).

PPV

Positive Pressure Ventilation - Mechanical ventilation that applies a pressure above ambient to the airways to produce or assist inspiration.

Pressure

Force per unit area; expressed in units such as cm H2O, pascals, kilopascals, or pounds per square inch (psi).

Pressure Augmentation

A combination of pressure control and volume control to provide the fast flow response to patient demand of pressure control. along with the assured volume delivery of volume control. Also called VAPS (Volume-Assured Pressure Support).

Pressure Limited Ventilation

A preset peak pressure is reached and maintained before the end of inspiration. When used in the volume control mode, the delivered volume is limited also since excess flow is vented to the atmosphere.

Pressure-Control Mode

A mode of ventilator operation in which the ventilator attempts to deliver a preset pressure waveform during inspiration. Typically, sufficient flow is provided to achieve and maintain a set pressure in the patient circuit during the inspiratory phase of the breath.

Prioritized Alarms

Alarms that have audible and visible signals that differ according to the severity of the conditions causing the alarm.

Proportional Pressure Support PPS™

Proportional Pressure Support PPS™ compensates for the additional workload due to pathological increased resistance and decreased compliance of the patient. Proportional Pressure Support PPS™ has its origins in Proportional Assist Ventilation PAV which was introduced by Prof. Magdy Younes in the early 90s. The principle is now used under license by Dräger (Source: Dräger Medizintechnik GmbH). The distinctive feature of this mode in comparison to other support modes is that positive pressure delivered at the airway is directly proportional to patient effort.

PSV

Pressure Support Ventilation - A mode supplement that augments the patient's spontaneous inspiratory effort by providing flow sufficient to establish and maintain a preset pressure in the patient circuit throughout inspiration. Expiration begins when the required flow drops below a preset level. PSV may be applied to spontaneous breaths during ventilatory modes such SIMV.

Pulmonary

Pertaining to the lungs.

Pulmonologist

Lung doctor.

Pulse Oximeter

Machine that monitors the oxygen saturation of the blood using an infrared detector placed across a capillary bed such as a digit or ear.

R

Rale

A crackling sound heard on auscultation of the chest.

RAW

Airway Resistance - The ratio of the change in the pressure difference between the airway opening and the alveoli, to the change in flow through the airway, for breathing frequencies up to panting, assuming that the compliance of the airways is normal.

RC

Respiratory Care - A clinical support specialty concerned with the application of treatments for respiratory diseases, trauma and dysfunction.

Relative Humidity

The ratio of the amount of water vapor contained in air to the maximum amount air could hold at the same temperature and pressure, expressed as percent.

Resistance

In a pneumatic system with constant, unidirectional flow, the resistance is the ratio of the pressure difference along a conduit to the flow through it. This same definition can be applied during oscillatory flow, such as breathing, if it can be shown or assumed that the effects of the compliance of the conduit and compressibility and inertance of the gas in it are negligible at the (breathing) frequencies being considered. If these conditions do not hold, then the effects of these factors on the pressure difference must be eliminated either experimentally or mathematically before the ratio is calculated.

Respirator

a machine for artificial breathing. Or: A term that has been used in the past for ventilator

Respiratory Rate - RR

See Frequency (of Breathing).

Resuscitator

A portable device used in emergency situations to ventilate the lungs of individuals to adequately breathe on their own. These devices may be either manually or gas powered.

Retractions

Pulling in at the chest during breathing (intercostal and/or substernal)

Retropharyngeal abscess

An abscess involving the structures in the posterior pharynx. This is a surgical emergency.

Rhinitis

An inflammation of the nasal mucosa.

Rhinorrhea

A discharge from the nasal mucosa.

Rhonchi

A wheezing sound heard on auscultation of the chest.

Rise Time

The time required for a variable to change from its baseline value to a given percentage (usually 90%) of its intended final value.

RSBI

See Rapid Shallow Breathing Index

RT - Respiratory Therapy

(See RC - Respiratory Care.)

S

Safety Valve

A high pressure relief valve.

Saline

(Normal saline or 0.9% sodium chloride) solution similar to water found in the body.

SaO2

Oxygen Saturation of Arterial Blood - (See Oxygen Saturation.)

Saturated Water Vapor

The maximum amount of water vapor that air can hold at a given combination of pressure and temperature.

Saturation Pressure

The partial pressure of saturated water vapor for a given combination of total pressure and temperature.

SCCM

Society of Critical Care Medicine

Secretions

Another word for mucus.

Self Test

A set of pre-use tests performed by the ventilator on itself typically requiring no intervention by the operator.

Sensitivity, Flow Sensitivity, Pressure Sensitivity

(See Trigger Flow, Trigger Pressure.)

Severinghaus Electrode

Electrochemical device sensitive to PCO2 of carbon dioxide in solution.

Sigh

A controlled, substantial increase in the tidal volumes of a small number of successive assisted breaths produced at preset intervals.

SIMV

Synchronized Intermittent Mandatory Ventilation - A ventilator mode of operation in which assisted breaths are delivered at a set frequency with spontaneous breaths permitted in between delivered breaths. The assisted breaths are synchronized with spontaneous efforts when their timing is sufficiently close. If no efforts are detected during the set inter-assisted breath interval, a mandatory breath is delivered.

Sinusitis

An inflammation of the sinus mucosa.

Sinusoidal

Varying as a sine wave.

Sleep apnea

Sleep apnea is a sleep disorder in which a person regularly stops breathing during sleep for 10 seconds or longer. (An occasional stop in breathing is normal.) It can be classified as mild, moderate, or severe, based on the number of times per hour you stop breathing (apnea) or have slowed breathing (hypopnea). Apnea episodes can happen from 5 to 50 times an hour.

There are three types of sleep apnea: obstructive sleep apnea, central sleep apnea, and mixed sleep apnea.

Obstructive sleep apnea is usually caused by a blockage (obstruction) in the nose or mouth that obstructs airflow during sleep. Other factors, such as smoking or obesity, often contribute to OSA. It is most common in overweight, middle-aged men, but it can affect people of any age, including children.

Central sleep apnea result when the brain fails to send electrical signals to the breathing muscles. This type of apnea can occur with conditions such as heart failure, brain tumours, brain infections, and stroke.

Mixed sleep apnea is a combination of obstructive and central sleep apnea.

The most common symptoms of sleep apnea include:

Loud snoring.
Excessive daytime sleepiness.
Restless sleep.
Difficulty breathing during sleep.
Morning headaches.

During an apnea episode, a person's blood oxygen level may drop. Over time low blood oxygen levels can lead to serious health problems and early death. People who have sleep apnea may be at greater risk for developing high blood pressure, depression, irregular heart rhythms, high blood pressure in the lungs (pulmonary hypertension), heart disease, and stroke.

Various treatments are used to relieve the symptoms of sleep apnea, including changes in sleep habits and diet, devices used to assist breathing, and occasionally surgery.

SLP (speech and language pathologist)

A person trained to help with speaking and swallowing problems.

Speaking Valve

A one-way valve that lets air come in through the tracheostomy tube, but then sends it out past the vocal cords and mouth to make talking possible.

Spirometer

A device that continuously measures, at the local temperature and pressure, the volume of gas flowing through, or into and out of, it.

Spontaneous Breathing

Movement of gas into and out of the lungs produced by the patient's respiratory muscles.

Steeple sign

A radiographic sign seen on the anteroposterior endolateral neck x-rays in children with croup. A narrowing of the air column in the hypopharynx is seen resembling a church spire.

Stenosis

The narrowing or constriction of the lumen of a structure. Complete stenosis is also known as atresia.

Sterile

Free from germs.

Stoma

Hole or opening (in the neck where you insert the tracheostomy tube).

Stridor

An inspiratory, high-pitched sound caused by obstruction in the upper airway.

Subglottic stenosis

Stenosis of the structures below the glottis.

Suctioning

Vacuuming up mucus in the tracheostomy tube.

Swaddle

To wrap a baby like a mummy with only his head sticking out.

Swedish Nose

See HME.

Sx

Suction.

T

Tachypnea

Breathing faster than normal.

TC - Tube Compensation

(See Automatic Tube Compensation)

Thermal Humidifying Filter

See HME.

Thermovent T

See HME.

Thumb sign

A radiographic sign seen on lateral endolateral neck x-rays in children with epiglottitis, caused by the marked swelling of aryepiglottic folds and arytenoid cartilages. The swelling resembles the human thumb.

Trach

Short for tracheostomy tube.

Trachea

Wind pipe.

Tracheal Esophageal Fistulas (TEF)

Abnormal opening between the trachea and esophagus. Or: generally a congenital abnormality involving a communication between the trachea and esophagus. It may also be acquired.

Tracheomalacia

Softening of the cartilage of the trachea.

Tracheoplasty

Plastic surgery or reparation of the structures of the trachea.

Tracheostenosis

Contraction or narrowing of the trachea.

Tracheostomy

Opening into the trachea.

Tracheotomy

A medical procedure creating an opening in the trachea.

Trigger Flow

The change in breathing circuit flow required to initiate the ventilator's inspiratory phase.

Trigger Pressure

The change in breathing circuit pressure required to initiate the ventilator's inspiratory phase.

Trigger Response Time

(See Inspiratory Triggering Response Time.)

Trigger Volume

(See Inspiratory Triggering Volume.)

Tube Compensation

(See Automatic Tube Compensation)

TV - Tidal Volume (Exhaled Tidal Volume)

The change of volume of the lungs (estimated by the gas volume entering or leaving the lungs) during either the inspiratory or expiratory phase of a breath.

24x7

Usually applied to the availability of service for equipment: 24 hours a day, seven days a week.

U

URI

Upper respiratory tract infection.

V

Vaporizer

Device designed to evaporate a liquid and add the resulting vapor to a gas mixture.

VAPS

Volume-Assured Pressure Support (See Pressure Augmentation.)

VCV

Volume-Controlled Ventilation

Ventilator

A machine that helps a person breathe. Or: An automatic mechanical/pneumatic device designed to reduce or provide the work required to move gas into and out of the lungs.

Ventilator Expiratory Resistance

The resistance to flow from the point at which the patient circuit is connected to the patient through the exhalation valve to the atmosphere.

Vocal Cords

Two strips of tissue in the voice box in the neck.

Volume

The space occupied by a mass of gas under given conditions of temperature and pressure; the physical space inside a structure.

Volume-Assured Pressure Support

(See Pressure Augmentation.)

Volume-Control Mode

A mode of ventilator operation in which the ventilator attempts to produce a preset volume waveform with a specified tidal volume during inspiration.

W

Water Trap

A device placed in the patient circuit to collect condensed liquids so that it will not collect in the circuit to block flow.

Watt

Unit of power.

Weaning

The process of eliminating a patient's dependence on assisted ventilation provided by a mechanical ventilator. It involves strengthening the patient's respiratory muscles so that they can perform the work required for breathing.

Web

A thin tissue or membrane bridging a space.

WOB

Work of Breathing The work required to accelerate gas in the airways, to overcome airway resistance and to expand the elastic lung tissue so that air can be brought into the lungs and then exhaled. Routinely, just the work of inspiration is of interest.

Pima Lung & Sleep, P.C. does not have an affiliation, connection, or association with any of the third parties referenced above, nor does any of these third parties sponsor, approve, or endorse Pima Lung & Sleep, P.C or its goods, services, or commercial activities. Furthermore, Pima Lung & Sleep, P.C does not sponsor, approve, or endorsement the goods, services, or commercial activities of the above third parties.