Diurnal Effects of Respiratory Resistance using an Airflow Perturbation Device

Background: The purpose of this study was to demonstrate possible changes in respiratory resistance throughout a 24-hour period using an Airflow Perturbation Device. The working hypothesis was that there was a significant difference in the respiratory resistance that can be attributed to changes throughout the day.

Methods: The research tested 25 healthy subjects sitting upright while utilizing the Airflow Perturbation Device (APD) to measure respiratory resistances at different times during the 24-hour day. The Airflow Perturbation Device (APD) is a noninvasive medical instrument (still under development) designed to measure respiratory resistance. In addition, factors that could influence differences in respiratory resistance, such as gender, height, weight, and other medical information, were recorded to facilitate understanding of the results.

Results: The data revealed that there was no significant change in respiratory resistance due to diurnal effects.

Conclusion: There was no evidence in the data pointing towards a diurnal change in respiratory resistance. If significant diurnal changes had been noted during this research, then future pulmonary measurements taken in a hospital or clinic would have to be interpreted differently during different times of the day. These results suggested that those adjustments are not required.

Keywords: Respiratory resistance, diurnal changes, pulmonary function tests.