Lung function tests in neonates and infants with chronic lung disease: Lung and chest‐wall mechanics

Abstract

This is the fifth paper in a review series that summarizes available data and critically discusses the potential role of lung function testing in infants and young children with acute neonatal respiratory disorders and chronic lung disease of infancy (CLDI). This review focuses on respiratory mechanics, including chest-wall and tissue mechanics, obtained in the intensive care setting and in infants during unassisted breathing. Following orientation of the reader to the subject area, we focused comments on areas of enquiry proposed in the introductory paper to this series. The quality of the published literature is reviewed critically with respect to relevant methods, equipment and study design, limitations and strengths of different techniques, and availability and appropriateness of reference data. Recommendations to guide future investigations in this field are provided. Numerous different methods have been used to assess respiratory mechanics with the aims of describing pulmonary status in preterm infants and assessing the effect of therapeutic interventions such as surfactant treatment, antenatal or postnatal steroids, or bronchodilator treatment. Interpretation of many of these studies is limited because lung volume was not measured simultaneously. In addition, populations are not comparable, and the number of infants studied has generally been small. Nevertheless, results appear to support the pathophysiological concept that immaturity of the lung leads to impaired lung function, which may improve with growth and development, irrespective of the diagnosis of chronic lung disease. To fully understand the impact of immaturity on the developing lung, it is unlikely that a single parameter such as respiratory compliance or resistance will accurately describe underlying changes. Assessment of respiratory mechanics will have to be supplemented by assessment of lung volume and airway function. New methods such as the low-frequency forced oscillation technique, which differentiate the tissue and airway components of respiratory mechanics, are likely to require further development before they can be of clinical significance.

Lung function in infants and young children with chronic lung disease of infancy: The next steps?

“…[8][9][10][11]13,14 Problems in study design, including failure to recruit sufficient subjects or appropriate controls, ambiguity regarding the definition of CLDI, 3,[19][20][21] or true clinical status at time of testing, 22 use of inappropriate equipment or methods with respect to underlying pathophysiology and lack of data on repeatability with which to interpret what constitutes a clinically significant change, 14,15 have all contributed to contradictory results and difficulties in drawing firm conclusions from many of the published studies in this field. If we are to avoid such problems in the future, there is an urgent need for collaboration between clinicians and physiologists to facilitate optimal use of the exciting technological developments.…”

“…1 During the past year, a series of review articles in Pediatric Pulmonology has responded to this challenge by summarizing the published literature on lung function in infants and young children with acute neonatal respiratory disorders and CLDI. [8][9][10][11][12][13][14] So what have we learnt so far, and what are the next steps?…”

“…As summarized by Gappa et al 9 numerous different methods have been used to assess respiratory mechanics in an attempt to describe pulmonary status and assess the effect of therapeutic interventions both during the neonatal period and follow-up. Results generally support the pathophysiological concept that immaturity of the lung leads to impaired mechanics, with diminished compliance and increased resistance, which may improve with growth and development, irrespective of the diagnosis of CLDI.…”

Lung function measurement in prematurely born preschool children with and without chronic lung disease

“…Lung function tests in neonates and infants with CLD were recently reviewed which showed high resistance and low compliance. 23 Higher airway resistance, measured by plethysmography, was also found in preterm preschool children without CLD. 24 The increased Rint in children with CLD in this study supports the finding of other studies that assessed airways resistance in other ways.…”

Short-term neonatal outcomes following various modes of delivery

“…The raised volume rapid thoracic compression technique [64] is capable of simulating the forced expiratory manoeuvre and it has also been employed in infants; however, it cannot be accomplished without sedation. Moreover, while it may be sensitive to the presence of lung disease, it lacks specificity and is difficult to link to structure.…”