Lung function measurements in children - copsac
Lung function measurements in children - copsac Lung function measurements in children - copsac
pulmonary function test obtained by clinicians caring for children with respiratory diseases and invaluable as a screening test of general respiratory health. Younger children can rarely perform a maximal inspiration followed by a forced expiration sufficiently (29). Most schoolchildren are able to perform acceptable and repeatable spirometry that conforms to standard criteria (30, 31). Bronchial hyperresponsiveness Bronchial hyperreactivity (BHR) is a characteristic phenomenon in asthma, defined as an abnormal fall (FEV 1 ) in lung function (or rise in airway resistance) after direct or indirect airway challenge test with stimuli which induce increased airflow limitation. Test of BHR contributes to the asthma diagnose (32). Direct airway challenge tests (e.g. methacholine, histamine) cause airway narrowing by acting directly on their respective receptors on the bronchial smooth muscles. Methacholine challenge test are well established (33, 34) and guidelines have been published by the American Thoracic Society (35). The subject inhale increasing dose of methacholine until the FEV 1 falls by 20% or more and the provocative dose causing a 20% fall (PD 20 ) is calculated. A low PD 20 suggests severe bronchial responsiveness. Indirect airway challenge tests (e.g. exercise, hypertonic saline, cold air, mannitol, and adenosine) use non-allergic irritants that have no direct effect on the smooth airway muscles. Hyperventilation leads to dehydration of the cells in the airways, which induces release of bronchoconstricting mediators. Dry/cold air hyperventilation testing has a similar mechanism of osmotic dehydration. School children and adults traditionally use exercise test. This is applicable from the age of 7-8 years where adequate cooperation may be expected. For younger children Danish paediatricians developed a simple test, cold air provocation. The method is documented and has shown good predictive value and repeatability for asthma or ongoing asthma in preschool children. The test is positive if sRaw increases ≥3SD corresponding 20% or more (18, 36-38). Nitric oxide as an inflammatory marker Direct monitoring airway inflammation in respiratory diseases with bronchoscope taking biopsies or making broncho alveolar lavage (BAL) is limited in children because 8
of the invasive nature. In the last decade fractional exhaled nitric oxide (F E NO) has been studied as a non-invasive marker of eosinophilic airway inflammation (39, 40). F E NO has been correlated with BAL fluid and bronchial biopsies (41, 42). Studies have found higher concentration in subjects with asthma compared to healthy (43-46). Especially atopy seems to be a significant factor associated with a raised exhaled NO. In general F E NO has not correlated with lung function but positively associated with bronchial hyperresponsiveness (47, 48) and sensitive to changes in anti-inflammatory treatment (49). F E NO is now applied in the clinical setting as a supplement to the traditional lung function testing. 9
- Page 1: Lung function measurements in child
- Page 4 and 5: Contents Acknowledgements .........
- Page 6 and 7: Acknowledgements The thesis was wri
- Page 8 and 9: Introduction Symptoms of chronic re
- Page 12 and 13: I. Accuracy of Wholebody Plethysmog
- Page 14 and 15: Methods Designs Study I: Six center
- Page 16 and 17: "Loops" on the screen showed the re
- Page 18 and 19: We included age in the analysis of
- Page 20 and 21: Normative data (study I) Mean sRaw
- Page 22 and 23: Additional results sRaw measurement
- Page 24 and 25: After correcting the factory settin
- Page 26 and 27: Normative data In the second part o
- Page 28 and 29: II. -III. Lung function measurement
- Page 30 and 31: of a diagnosis of asthma: Frequent
- Page 32 and 33: Figure 8: Familial predisposition t
- Page 34 and 35: Total twins 12.349 twin pairs Born
- Page 36 and 37: Methods Designs Study II: Hospital
- Page 38 and 39: Children less than 7 years were tes
- Page 40 and 41: Ethics The two studies were approve
- Page 42 and 43: FEV 0.5 (ml) Table 4: Baseline char
- Page 44 and 45: lung symptoms, 19% said it was the
- Page 46 and 47: symptoms in response to verified RS
- Page 48 and 49: epigenetic factors. Acute environme
- Page 50 and 51: detection changes in lung function
- Page 52 and 53: that small airways were not the dis
- Page 54 and 55: onciolitis. There is an increasing
- Page 56 and 57: further studies are needed to inves
- Page 58 and 59: Summary The Ph.D. thesis is based o
pulmonary <strong>function</strong> test obta<strong>in</strong>ed by cl<strong>in</strong>icians car<strong>in</strong>g for <strong>children</strong> with respiratory<br />
diseases and <strong>in</strong>valuable as a screen<strong>in</strong>g test of general respiratory health. Younger<br />
<strong>children</strong> can rarely perform a maximal <strong>in</strong>spiration followed by a forced expiration<br />
sufficiently (29). Most school<strong>children</strong> are able to perform acceptable and repeatable<br />
spirometry that conforms to standard criteria (30, 31).<br />
Bronchial hyperresponsiveness<br />
Bronchial hyperreactivity (BHR) is a characteristic phenomenon <strong>in</strong> asthma, def<strong>in</strong>ed as<br />
an abnormal fall (FEV 1 ) <strong>in</strong> lung <strong>function</strong> (or rise <strong>in</strong> airway resistance) after direct or<br />
<strong>in</strong>direct airway challenge test with stimuli which <strong>in</strong>duce <strong>in</strong>creased airflow limitation.<br />
Test of BHR contributes to the asthma diagnose (32).<br />
Direct airway challenge tests (e.g. methachol<strong>in</strong>e, histam<strong>in</strong>e) cause airway narrow<strong>in</strong>g by<br />
act<strong>in</strong>g directly on their respective receptors on the bronchial smooth muscles.<br />
Methachol<strong>in</strong>e challenge test are well established (33, 34) and guidel<strong>in</strong>es have been<br />
published by the American Thoracic Society (35). The subject <strong>in</strong>hale <strong>in</strong>creas<strong>in</strong>g dose of<br />
methachol<strong>in</strong>e until the FEV 1 falls by 20% or more and the provocative dose caus<strong>in</strong>g a<br />
20% fall (PD 20 ) is calculated. A low PD 20 suggests severe bronchial responsiveness.<br />
Indirect airway challenge tests (e.g. exercise, hypertonic sal<strong>in</strong>e, cold air, mannitol, and<br />
adenos<strong>in</strong>e) use non-allergic irritants that have no direct effect on the smooth airway<br />
muscles. Hyperventilation leads to dehydration of the cells <strong>in</strong> the airways, which<br />
<strong>in</strong>duces release of bronchoconstrict<strong>in</strong>g mediators. Dry/cold air hyperventilation test<strong>in</strong>g<br />
has a similar mechanism of osmotic dehydration. School <strong>children</strong> and adults<br />
traditionally use exercise test. This is applicable from the age of 7-8 years where<br />
adequate cooperation may be expected. For younger <strong>children</strong> Danish paediatricians<br />
developed a simple test, cold air provocation. The method is documented and has shown<br />
good predictive value and repeatability for asthma or ongo<strong>in</strong>g asthma <strong>in</strong> preschool<br />
<strong>children</strong>. The test is positive if sRaw <strong>in</strong>creases ≥3SD correspond<strong>in</strong>g 20% or more (18,<br />
36-38).<br />
Nitric oxide as an <strong>in</strong>flammatory marker<br />
Direct monitor<strong>in</strong>g airway <strong>in</strong>flammation <strong>in</strong> respiratory diseases with bronchoscope<br />
tak<strong>in</strong>g biopsies or mak<strong>in</strong>g broncho alveolar lavage (BAL) is limited <strong>in</strong> <strong>children</strong> because<br />
8
Change language