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With conventional ventilation where tidal volumes (V T) exceed dead space (V DEAD), gas exchange is largely related to bulk flow of gas to the alveoli.With high-frequency ventilation, the tidal volumes used are smaller than anatomical and equipment dead space and therefore alternative mechanisms of gas exchange occur.
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
The partial pressure of oxygen (pO 2) in the pulmonary alveoli is required to calculate both the alveolar-arterial gradient of oxygen and the amount of right-to-left cardiac shunt, which are both clinically useful quantities. However, it is not practical to take a sample of gas from the alveoli in order to directly measure the partial pressure ...
Ventilation rate (V) is the total gas volume that enters and leaves the alveoli in a given amount of time, commonly measured per minute. To calculate the ventilation rate, the tidal volume (inhaled or exhaled gas volume during normal breath) is multiplied by the frequency of breaths per minute, which is represented by the formula:
Therefore it includes, firstly those units that are ventilated but not perfused, and secondly those units which have a ventilation-perfusion ratio greater than one. Alveolar dead space is negligible in healthy individuals, but it can increase dramatically in some lung diseases due to ventilation-perfusion mismatch.
Spirometry (meaning the measuring of breath) is the most common of the pulmonary function tests (PFTs). It measures lung function, specifically the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled.
Microsoft Excel is a spreadsheet editor developed by Microsoft for Windows, macOS, Android, iOS and iPadOS.It features calculation or computation capabilities, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications (VBA).
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. Detect early changes in lung function. Identify narrowing in the airways. Evaluate airway bronchodilator reactivity.