Oscillometry of the respiratory system: a translational opportunity not to be missed

Abstract

Airway oscillometry has become the de facto standard for quality assessment of lung physiology in laboratory animals and has demonstrated its usefulness in understanding diseases of small airways. Nowadays, it is seeing extensive use in daily clinical practice and research, however, a question that remains unanswered is how well physiological findings in animals and humans correlate? Methodological and device differences are obvious between animal and human studies. However, all devices deliver an oscillated airflow test signal and output respiratory impedance. In addition, despite analysis differences, there are ways to interpret animal and human oscillometry data to allow suitable comparisons. The potential with oscillometry is its ability to reveal universal features of the respiratory system across species, making translational extrapolation likely to be predictive. This means that oscillometry can thus help determine if an animal model displays the same physiological characteristics as the human disease. Perhaps more importantly, it can also be useful to determine whether an intervention is effective as well as to understand if it affects the desired region of the respiratory system e.g., the periphery of the lung. Finally, findings in humans can also inform preclinical scientists and give indications as to what type of physiological changes should be observed in animal models to make them relevant as models of human disease. The present article will attempt to demonstrate the potential of oscillometry in respiratory research, an area where the development of novel therapies is plagued with a failure rate higher than in other disease areas.

Evaluation of Impulse Oscillometry in Respiratory Airway Casts with Varying Obstruction Phenotypes, Locations, and Complexities

“…By contrast, both the experiment and CFD quantify the flow resistance using the pressure difference at two points. Another possible reason is that IOS R20Hz is a cumulative result of transient returning pressures over several breathing cycles, while the experiment and CFD both use steady inhalation flows [42][43][44]. For a sinusoidal waveform, the peak inhalation and exhalation velocities are approximately 1.414 times the mean, presumably leading to more intensified turbulences.…”

Lung Mechanics Over the Century: From Bench to Bedside and Back to Bench

“…On the other hand, new lung mechanics techniques evolving from experimental physiology can be used in spontaneously ventilated patients. Notably, forced oscillation technique, or oscillometry, has contributed to a better understanding of lung function in clinical routine and in research, particularly in patients with obstructive disease ( Peterson-Carmichael et al, 2016 ; Hantos, 2021 ; Lundblad and Robichaud, 2021 ).…”

“…The constant-phase model (see section ‘Respiratory mechanics in animal models’ and Figure 1 ) applied in small rodents is not suitable for patients because of the low frequency broadband excitation needed ( Lundblad and Robichaud, 2021 ). So, the analysis of the human respiratory impedance is based mostly on the frequency response behaviour of impedance, a complex mathematical function with real and imaginary components.…”

Small Airway Dysfunction Measured by Impulse Oscillometry and Fractional Exhaled Nitric Oxide Is Associated With Asthma Control in Children

“…The Global Initiative for Asthma (GINA) has made recommendations for early diagnosis and good control based on symptoms and conventional spirometry to improve asthma outcomes (6). Impulse oscillometry (IOS) is an effort-independent method for measuring respiratory system resistance (R) and reactance (X), which is suitable for younger children unable to receive spirometry (7)(8)(9). Increasing evidence shows that IOS indicator with R5 (resistance at 5 Hz) may better predict asthma exacerbations or loss of control in children with asthma (8).…”