Pre/Postbronchodilator Interrupter Resistance in Former Preterm Children During Preschool Age

The primary aims of this study were to determine the pulmonary out­come of very low birth weight (VLBW) infants and to use interrupter resistance (Rint) measurements in testing bronchoreactivity at pre­school age. The study group (n=15) was composed of preschool children who were born at less than 32 weeks gestation who were all mechanically ventilated during the newborn period. The control group (n=15) consisted of healthy children who were born at term and had not experienced any acute or chronic respiratory problems. A detailed history and physical examination were completed at the time of Rint testing. Rint measurement, reversibility to salbutamol and skin prick tests were performed. Resistance measurements made with the inter­rupter technique were subdivided into inspiratory (Rint insp) and ex­piratory (Rint exp) values. Eighty-five percent of all preschool children were able to perform Rint measurement. Median Rint insp value was significantly higher in the study group than the controls (0.74 and 0.53 Kpa.L-1 .sec, respectively). Median Rint exp values of the study group (0.64 Kpa.L-1 .sec) were not statistically significantly different than those of the control group (0.49 Kpa.L-1 .sec). Pre-/post-bronchodila- tor Rint insp values of the study group were significantly different as well (0.74 and 0.64 Kpa.L-1 .sec, respectively, p=0.01). Children born before 32 weeks of gestation had higher Rint insp values at preschool age. The interrupter technique is a noninvasive test and can be used to assess airway obstruction in young children who fail to cooperate with forced expiratory measurements.