Welcome to the MBW Glossary :
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The ending of a tiny airway in the lung, where the alveoli (air sacs) are located.
Area Under the Curve (AUC)
That is the ability of measures to determine the true positive rate and the true negative rate. Area under the receiver operating curves (AUCROC) were assessed (1.0 = perfect discrimination considering sensitivity and specificity).
Bias flow block
A block delivering a supply of washin and/or washout gas in one direction.
Body temperature and pressure saturations (BTPS)
A gas volume has been expressed as if it were saturated with water vapour at body temperature (37°C) and at the ambient barometric pressure; used for measurements of lung volumes.
Permanently dilated airways caused by chronic bronchial inflammation secondary to inappropriate clearance of various micro-organisms and recurrent infections in the airways.
The activity of checking, by comparison with a standard, the accuracy of a measuring instrument of any type.
CO2 airway adapter / capnostat / CO2 cuvette and senor
Equipment parts making up the C02 sensor in the Exhalyzer D device.
Coefficient of variation
A measure of the spread of a set of data as a proportion of its mean. It is often expressed as a percentage.
The zone of the respiratory system that conducts the air into the lungs (nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles).
Convective gas mixing
The transfer of heat by the circulation or movement of the heated parts of a liquid or gas.
The process of establishing a relationship or connection between two or more things.
An equipment part that will reduce the equipment space the patient has to breath through to reach the fresh gas supply.
Diffusive gas mixing
The net movement of a gas from a region of high concentration to a region of low concentration.
A diagram of an expired gas over volume.
The degree of being easily or conveniently done.
Forced expiratory flow at 25-75% of the pulmonary volume.
Forced Expiratory Volume in the first second. The volume of air that can be forced out in one second after taking a deep breath.
Flow gas delay
Delay-times between flow and gas signals.
The degree of flow gas delay can depend on a number of factors: the gas transport-times from the flow sensor near the patients mouth to the gas analyzer(s) as well as on the response-times of the gas analyzer(s).
Flow past circuit
The parts of washout system delivering the supply of washin and/or washout gas.
Flow volume loop
A graphical depiction of the rate of airflow on the Y-axis and the total volume inspired or expired on the X-axis.
Instrument measuring flows and volumes.
The accuracy of the flow measurements over the full range of the flowmeter.
Functional Residual Capacity (FRC)
The volume of gas contained in the lung after a normal expiration.
The FRC as measured by the MBW device
FRC is calculated as follows
FRC = net volume of inert gas exhaled / Cetstart – Cetend
where Cet is the concentration at end-tidal volume of the
inert gas, at the start (Cet start ) and end (Cet end) of the
A gas that does not react with many substances- neither absorbed nor excreted by the body to any significant degree.
Minimal clinically important difference
The smallest change in a treatment outcome that a patient would identify as important.
Tubing for gas sampling sensors.
The equipment making up the parts of the washout system through which the patient breathes.
Airways that are less than 2 mm in diameter and consist of small membranous, terminal and respiratory bronchioles, as well as alveolar ducts.
Photo-acoustic gas analyser
The measurement of the effect of absorbed electromagnetic energy on matter by means of acoustic detection.
Post sampling gas point equipment deadspace volume
The equipment deadspace volume between the gas sampling point and the bias flow supply.
Pre-sampling gas point equipment deadspace volume
The equipment deadspace volume between the patient and the gas sampling point.
Degree to which a measurement is consistent and free from error.
A bag in the washout system circuit containing a reservoir of washin and/or washout gas.
The ratio of carbon dioxide to oxygen.
Degree to which a test changes in response to an intervention .
The contribution of inhomogeneity arising in the acinar airway zone- derived from the analysis of the progression phase III slope (alveolar inert gas in a breath).
The contribution of inhomogeneity arising in the conductive airway zone- derived from the analysis of the progression phase III slope (alveolar inert gas in a breath).
Simple Washout software
A software programme to analyse data files generated by the Innocor™ gas analyser during multiple breath washouts, to generate indices of ventilation inhomogeneity including lung clearance index.
Single use disposable breathing tubes.
The lung volume moved into and out of the lungs during quiet breathing.
The causal effect of a intervention on an outcome variable.
Degree to which a test correlates with a “gold standard” criterion test which has been established as a valid test of the attribute of interest.
Ventilation Inhomogeneity (VI)
Differences in ventilation arising between lung regions.
MBW systems using exogenous gases (e.g. SF6) require a washin phase, to allow the inspired gas to reach equilibrium within the lungs.
Clearance of a gas from the lungs is measured during the washout phase.