Pulmonary Ventilation in Infants Under One Year of Age

Measurement of pulmonary ventilation in infants has been performed by a number of investigators.1-8In the last three decades plethysmographic methods have been used by most groups, although it has recently been demonstrated that the mask-and-bag technique is possible in small infants.7,8Observations have been chiefly limited to the newborn period, although one study has included a few infants up to 3 months of age.2 None of the studies to date have included data on flow rates. The purpose of this paper is to describe a method which permits direct measurement of ventilation. In addition, observations which have been extended to infants up to 8.9 months of age are included. Methods The apparatus (Fig. 1) employs the bag-in-box principle. The box is constructed of Lucite, is airtight, and has a 27 liter capacity. Within the box is a Neoprene balloon of 6 liter capacity. The box and the