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The measurement of peak expiratory flow was pioneered by Martin Wright, who produced the first meter specifically designed to measure this index of lung function. Since the original design of instrument was introduced in the late 1950s, and the subsequent development of a more portable, lower cost version (the "Mini-Wright" peak flow meter ...
It can be measured with devices such as a Wright respirometer or can be calculated from other known respiratory parameters. Although minute volume can be viewed as a unit of volume, it is usually treated in practice as a flow rate (given that it represents a volume change over time). Typical units involved are (in metric) 0.5 L × 12 breaths ...
Forced expiratory flow (FEF) is the flow (or speed) of air coming out of the lung during the middle portion of a forced expiration. It can be given at discrete times, generally defined by what fraction of the forced vital capacity (FVC) has been exhaled. The usual discrete intervals are 25%, 50% and 75% (FEF25, FEF50 and FEF75), or 25% and 50% ...
Pulmonary function testing is a diagnostic and management tool used for a variety of reasons, such as: Diagnose lung disease. Monitor the effect of chronic diseases like asthma, chronic obstructive lung disease, or cystic fibrosis.
In respiratory physiology, the ventilation/perfusion ratio (V/Q ratio) is a ratio used to assess the efficiency and adequacy of the ventilation-perfusion coupling and thus the matching of two variables: V – ventilation – the air that reaches the alveoli; Q – perfusion – the blood that reaches the alveoli via the capillaries
Any process that increases the CC by increasing the closing volume (CV) can increase an individual's risk of hypoxemia, as the small airways may collapse during exhalation, leading to air trapping and atelectasis. A mnemonic for factors increasing closing capacity is ACLS-S: Age, Chronic bronchitis, LV failure, Smoking, Surgery.
A pulmonary ventilation-perfusion scan (lung V/Q scan) can be used to diagnose the V/Q mismatch. A ventilation scan is used to measure airflow spread and a perfusion scan for blood flow distribution in the lungs. A radioactive tracer is used to scan the whole lung and the ventilation and perfusion function. [21]
A pulse oximeter probe applied to a person's finger. A pulse oximeter is a medical device that indirectly monitors the oxygen saturation of a patient's blood (as opposed to measuring oxygen saturation directly through a blood sample) and changes in blood volume in the skin, producing a photoplethysmogram that may be further processed into other measurements. [4]