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Lung function
The classic method for the judgement of the breath function is the spirometry. Methods:
1) closed system with bell spirometer
2) open system with breath pipe (Pneumotachograf) and electronic integration of the flow velocity test of:
a) static sizes (e.g. vital capacity)
b) dynamic sizes (e.g. one timed vital capacity)
Measuring of the dynamic lung volumes at respiratory systems obstruction in the normal condition
AZV = breath train volume
IRV = inspiratory reserve volume
ERV = expiratory reserve volume
RV = residual volume
FEV 1 = forced one timed vital capacity, Tiffeneau value
Vital capacity (VC):
Maximally mobilising cash lung volume, measured at a slow inspiration after a slow maximal expiration gone ahead. The rated values are dependent on sex, height and age and are stored in the software of modern spirometry apparatuses. Reduced VC: Obstructive ventilation disorders restrictive ventilation disorders are accompanied by reduction of the VC, (i.e. restricted elasticity of the lung at the breathing) but also strong (i.e. diameter reduced of the respiratory systems and through this breath handicap) be able to a reduction of the VC cause because of an increase of the residual volume (volume which remains after a max. expiration in the lung).
One timed vital capacity FEV1: The amount of air breathed out as quickly as possible in the first second of the expiration with a maximal effort = after a slow deep possible inspiration a forced expiratory volume in the 1st second. The absolute value as well as the relative value (FEV1 & VC) related to the vital capacity are judged.
Reduced FEV1: restriction of the ventilatoric flow reserve causes:
a) endobronchial und exobronchiale Obstruktion
b) reduction of the lung retraction power, weakness of the respiratory musculature
Norm area of the relative FEV1: > 75% (with older people > 70%) the VC. The relative FEV1 (which refers to the actual vital capacity of the patient) may be used for the description of an obstruction only in such a way long as the VC lies in the norm area that is only at a light obstruction. The VC is also reduced at increasing obstruction so that the relative FEV1 value can seem normal. Take in such cases absolutely the absolute one second value which then is reduced into account!
Flow volume diagram:
the following sizes can be derived from the expiratory flow volume curve:
a) PEF: Peak expiratory flow: Expiratory tip flow in l/sec or l/min. dependent on height, sex, age.
b) MEF 25,50,75: maximal expiratory Flow at 25,50,75 % of the forced VC. An isolated reduction of the MEF25 speaks for a peripheral obstruction of the small respiratory systems, typical results among smokers.
Broncholysetest:
reversible obstructions (Bronchospasm e.g. at an allergic asthma) must be distinguished by irreversible respiratory systems obstructions (e.g. at emphysema) (Beta2-Sympathomimetika) by test of FEV1 and breath resistance in front of and approx. 10 minutes after inhalation of bronchospasmolytic substances. A positive test is if the FEV1 by at least 15% improves
These informations may be considered a substitute for a piece of medical advice in no case. The content of health-illness.com doesn't can and may be put into any case to make diagnoses or carry out self medical treatment independently.
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