Acoustic rhinometry in children: some practical aspects and influence of age and body surface area on results.

Background: Since acoustic rhinometry was described there has been a lack of normal values for minimal cross-sectional area (MCA), especially for children. There has also been debate about factors influencing normal values. The purpose of this study was to find the normal values for children in a Finnish population and whether there is any correlation between age or body surface area (BSA) and MCA.

Methods: We measured 74 children (age, 1-12 years) with an acoustic rhinometer. The values of MCA were compared with age and BSA determined from height and weight.

Results: The mean of unilateral MCA was 0.225 cm2 (SD, 0.041). We found positive correlation between unilateral volume on the left side and age and between MCA from the right side and age or BSA as a constant predictor. As much as 28.4% of the measurements had to be rejected because of acoustic leakage between nostril and nosepiece. Only 6.8% had to be rejected because of a lack of cooperation.

Conclusion: It is possible to find normal values for children. Acoustic rhinometry is well tolerated among children. The method is rapid, reliable and noninvasive, and minimal cooperation is required. The measurements must be performed in a standard way, and some important causes of errors must be kept in mind.