Lung Structure and Function of Infants with Recurrent Wheeze when Asymptomatic

¹ Depts of paediatric Pulmonology and Critical Care; and Paediatric Pulmonology Dept, Hospital del Niño Jesús, Cátedra de Metodología de la Investigación, Facultad de Medicina, Universidad Nacional de Tucumán, Tucumán, Argentina
² Depts of paediatric Pulmonology and Critical Care
³ Biostatistics
⁴ Radiology, Indiana University Medical Center, Indianapolis, Indiana
⁵ Dept of Radiology, Vancouver General Hospital and James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, St Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada

^* To whom correspondence should be addressed. E-mail: rtepper{at}iupui.edu.

	Abstract

Infants with recurrent wheeze have repeated episodes of airways obstruction; however, relatively little is known about the structure and function of their lungs when not symptomatic.

We evaluated whether infants with recurrent wheeze have smaller airway lumens or thickened airway walls, as well as decreased airway function.

1-mm thick high resolution computed tomography images were obtained at three anatomic locations at an elevated lung volume and at functional residual capacity. Forced expiratory flows were also measured in Recurrent Wheeze subjects.

Airway lumen, wall areas, and lung tissue density were not significantly different for Recurrent Wheeze (N=17) and Control (N=14) subjects; however, subjects with Recurrent Wheeze had lower forced expiratory flows than predicted. Similar findings were obtained when subjects were grouped by exposure to tobacco smoke.

These findings indicate that infants with Recurrent Wheeze, as well exposure to tobacco smoke have lower airway function when not symptomatic. The lower forced expiratory flows may result from a degree of airway narrowing that could not be resolved with the methodology employed or from other mechanisms, such as more collapsible airways or decreased pulmonary elastic recoil.