TRALULALA

Tracheomalacia in Focus

LUNGEFUNKTIONSUNDERSØGELSER


Lungefunktionsundersøgelser er et meget værdifuldt værktøj til hyppig vurdering af lungers tilstand. 

Ved tracheomalaci er det dog en udfordring at lave den mest almindelige lungefunktionsundesøgelse, såkaldt spirometri. Det skyldes at patienten ved spirometri skal ekspirere fuldt og forceret, hvilket får luftvejene til at klappe sammen, og resultatet siger derfor ikke altid noget om lungerne. 

Vi ønsker derfor at finde ud af hvilke andre lungefunktionsundersøgelser, som er gode til at sige noget om sygdom i lungerne og som ligeledes kan udføres af børn med tracheomalaci. 


Multiple Breath Washout (MBW)

The Multiple Breath Washout (MBW) test is a sensitive lung function test used to assess how evenly air is distributed in the lungs. It involves breathing a tracer gas in and then washing it out by breathing room air. The key outcome is the Lung Clearance Index (LCI), which reflects ventilation inhomogeneity—an early sign of small airway disease. MBW is gentle, requires only normal breathing, and is especially useful in children or patients with early lung disease such as cystic fibrosis.

 


Impulse Oscillometry (IOS)

Impulse Oscillometry (IOS) is a non-invasive lung function test that measures airway resistance and reactance during normal tidal breathing. By applying small pressure oscillations through the airways, IOS assesses mechanical properties of the respiratory system across different frequencies. It is particularly useful for detecting small airway dysfunction and is well suited for young children or patients unable to perform forced spirometry. Key parameters include R5 (total airway resistance), R20 (central airway resistance), and AX (reactance area), which can provide early markers of obstructive lung disease.


Body Plethysmograhy

Body plethysmography is an advanced lung function test that measures absolute lung volumes, including total lung capacity (TLC) and residual volume (RV). The patient sits in an airtight chamber and breathes against a closed shutter; pressure and volume changes allow calculation of intrathoracic gas volume using Boyle’s Law. Unlike spirometry, plethysmography accurately captures trapped gas and is essential for diagnosing restrictive and obstructive lung diseases, particularly when small airway closure is suspected.


Static Spirometry

Static spirometry measures lung volumes during slow, non-forced breathing. Key parameters include vital capacity (VC), inspiratory reserve volume (IRV), and expiratory reserve volume (ERV). It provides information on lung volumes without the influence of airflow or effort, and is useful for evaluating restrictive lung disease and assessing lung capacity at rest.


Dynamic Spirometry

Dynamic spirometry assesses airflow over time during forced respiratory maneuvers. The most common parameters are forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁). This test is essential for diagnosing and grading obstructive lung diseases, such as asthma and COPD, by evaluating how quickly air can be exhaled from the lungs.


Cardiopulmonary exercise testing (CPET)

Cardiopulmonary exercise testing (CPET) is a comprehensive, non-invasive assessment of the integrated function of the cardiovascular, pulmonary, and muscular systems during graded physical exertion. The primary parameter, maximal oxygen uptake (VO₂ max), reflects the body's capacity to transport and utilize oxygen at peak exercise. The test is typically performed on a treadmill or cycle ergometer while continuously measuring respiratory gas exchange (VO₂, VCO₂), heart rate, and ventilation.

 


PRMC

Dit barn skal her indånde en luftart med en radioaktivt mærket tung partikel i 20 vejrtrækninger efterfulgt af fuld udånding. Herefter måler vi på radioaktivitet i lungerne ved at dit barn ligger ned ovenpå et kamera der måler på radioaktivitet først 0 min. efter indåndingerne, derpå 60 min. og 120 min. Dagen efter tages et sidste billede af lungernes radioaktivitet. Undersøgelsen viser lungernes egenskab til at komme af med partikler over en vis størrelse.

 


(C) 2023 Marika Rønne, marika.nathalie.roenne@regionh.dk

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