Background: Unlike spirometry, impulse oscillometry (IOS) may provide more particular data on respiratory tract's resistive and elastic features. This study aimed to create our reference equations of IOS parameters of healthy children collected from AL-Sharkia governorate, Egypt, as this has not been found till now.

Methods: This cross-sectional investigation was performed on 249 healthy children aged 3 to 15 years in Pediatric Chest, Allergy, and Immunology units in Zagazig University Hospitals. All subjects underwent full history taking, and their body weight, height, and body mass index (BMI) were calculated, as well as a thorough clinical and pulmonary examination. IOS method was performed for all cases, and each case had three attempts with less than 10% variability.

Results: All IOS factors had a substantial negative connection with weight, height, and age, except pred X 5Hz, which had a positive relationship (P < 0.05). For girls, all IOS factors had a notable negative connection with age and weight, except for X5 Hz, which had a positive relationship (P< 0.05). Results of various linear regression equations were reported, with standard error of estimate (SEE), modified R2, coefficients of determination (R2) for all IOS components in both girls and boys. Height was greatest predictive indicator for modeling all IOS characteristics in boys and most of factors in girls.

Conclusions: Our research revealed that weight, height, age were substantially associated with IOS values, as a remarkable negative association was found between all IOS factors and height, age, weight, while Reactance (X) had a positive association.