Daniel J. Weiner, MD

Abstract: As in adults and older children, pulmonary function testing in infants may help detect certain obstructive or restrictive diseases. However, different techniques and equipment must be used. The most commonly performed noninvasive tidal breathing test involves use of a face mask with a pneumotachograph; an alternative method is respiratory inductive plethysmography. Ratios derived from volume-time and flow-time tracings can help identify patients with obstructive lung disease, who have a shorter time to peak expiratory flow:expiratory time ratio than do healthy persons. Instead of spirometry, the rapid thoracic compression technique can be used to measure expiratory flow and construct a flow-volume curve. This method, which is performed with the patient under sedation, increases flow rates over tidal flow values and enhances the ability to detect abnormal airway function. (J Respir Dis. 2006;27(4):158-166)