BACKGROUND: A definite diagnosis of asthma during infancy is difficult. Asthma Predictive Index (API) is used to predict asthma at school age, but does not determine who among these actually have asthma. OBJECTIVES: This study aims to determine the bronchodilator response of infants with recurrent wheezing compared with normal control. METHODOLOGY: This cross sectional study included asymptomatic subjects aged 6-24 months with history of recurrent wheezing and age/sex matched controls. After sedation with chloral hydrate (Odan) at 50-75 mg/kg, a bronchodilator challenge test was performed with single dose 400 mcg salbutamol (Ventolin) MDI inhalation delivered via a spacer (Philips Respironic OptiChamber Diamond). Baseline and 15 minutes after salbutamol inhalation Maximum Flow at Functional Residual Capacity (V‘maxFRC) were determined using MasterScreen Paed/BabyBody Option Squeeze version 8.0. ANOVA and Pearson chi-square were used for the statistical analysis of data. RESULTS: Sixty-nine infants (23 previous wheezers and positive API, 23 previous wheezers with negative API and 23 controls) were included. There was a significant difference in the post bronchodilator challenge test V‘maxFRC between wheezers with positive API and controls (p= 0.047). There was no significant difference in other parameter among groups. CONCLUSION AND RECOMMENDATION Absolute values of V‘maxFRC post bronchodilator challenge using the Tidal Rapid Thoracoabdominal compression technique may be used to identify current asthma among asymptomatic infants with recurrent wheezing. Further studies with patient follow-up are recommended to assess response to treatment.

BACKGROUND: The only lung volume that can be measured reliably in infants is the functional residual capacity (FRC). Published reference values vary, thus, there is a need to determine values for healthy infants using the available equipment. OBJECTIVES: To determine the normal values of FRC in healthy infants using the baby body plethysmogram (CareFusion) and to determine the correlation between FRC and weight, length, age, and gender. METHODS: FRC was measured using the CareFusion MasterScreen baby body plethysmogram in 62 healthy infants aged 1-24 months old. FRC was measured after sedation with Chloral hydrate at 50 mg/kg body weight. Three measurements were performed from which the mean (SD) FRC was calculated. To depict the change in FRC with growth, regression analysis between FRC as dependent variable and weight, length, and age as independent variables was done. CONCLUSION The FRC values obtained in this study is 24.56 ml/kg (4.41). There is a direct correlation of FRC with age, weight, and length. The result of this study was comparable to other studies and may be used as a reference value for healthy infants.