There are many ways of estimating neonatal lung function, but only infant spirometry provides volume anchored measurements, which can be reliably related to spirometry assessments later in childhood. We conducted infant spirometry by forced flow-volume measurements applying the Raised Volume Rapid Thoracic Compression Technique during chloral hydrate 90 mg/kg sedation in agreement with the American Thoracic Society (ATS) and European Respiratory Society (ERS) standards.
A non-expandable outer coat is wrapped around the infant’s chest and abdomen with an inflatable “balloon” inside. The infant’s lung volume is raised above the tidal range by inflating air through the pneumotachograph to a transrespiratory pressure of 2 kPa mimicking a full inspiration before a compression force is applied via the squeeze-jacket causing a full forced expiratory maneuver during which the flow was measured by a pneumotachograph with an aircushion facemask.
The software identified the Forced Vital Capacity (FVC) as the first plateau on the volume-time curve; only measurements with FVC appearing after 0.5 second and with the Forced Expiratory Volume at 0.5 seconds (FEV0.5) being smaller than or equal to FVC were accepted. Three to five acceptable curves were obtained at each measurement; the curve containing the median value of FEV0.5 was used for the analyses of both volume (FEV0.5) and flow (Forced Expiratory Flow at 50% of FVC; FEF50) parameters.
This is a non-invasive technique for sampling of undisturbed mucosal lining fluid from the upper airways, by which quantification of in situ levels of protein mediators such as cytokines and chemokines can be performed in subjects of all ages.
The mucosal lining fluid is sampled on a strips of filter paper (fibrous hydroxylatedpolyester sheets from Accuwik Ultra (cat no. SPR0730, Pall Life Sciences, Portsmouth, Hampshire, UK). One filter paper is inserted in each nostril, placed at the anterior part of the inferior turbinate, and left for 2 min of absorption. Analytes are eluted from the filter papers after addition of identical volumes of buffer to all samples. Thereafter, the extracted protein-based eluates are analyzed by an electro-chemoluminescence-
We have measured in situ levels of 20 pre-selected immune mediators related to specific immune signaling pathways in the upper airway mucosa, but the technique is not limited to that specific panel or sampling site.
COPSAC has developed a computer program assisting the child to achieve the correct breathing frequency during hyperventilation with dry or cold air. The method is particularly useful in young children.
Exercise induced bronchoconstriction (EIB) is a hallmark of asthma and particularly it is a key-symptom in pediatric asthma. EIB reflects uncontrolled disease, but a history of EIB in children is of limited accuracy and subject to recall bias by parents. EIB testing is therefore useful to diagnose and monitor asthma in children and has a fair sensitivity, specificity and repeatability.
COPSAC has contributed substantially to develop whole-body plethysmography for measurement of lung function in preschool children from 2 years of age.
Specific airway resistance (sRaw) is measured as the ratio between the pressure (P) generated by the thoracic and abdominal excortions during tidal breathing and the resulting air flow (V’). sRaw is determined in a whole-body plethysmograph, where a transducer measures pressure changes in the sealed box and a pneumotachograph simultaneously measures the flow swing at the mouth. Flow and volume measurements are corrected to body temperature and pressure, saturated with water vapour (BTPS) conditions.
The software calculates sRaw as (delta P/ delta V’) x (Pamb – PH2O).
MasterScreen Body Unit. (E. JAEGER GmbH, Wuerzburg, Germany), which is calibrated once daily.
We recommend a facemask with a large cushion, which ensures a good seal and stabilizes the cheeks and chin. A built-in flexible tube ensures that the mouth remains open to avoid nasal breathing.