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Updated: May 30, 2026
Conducting Respiratory Oscillometry in an Outpatient Setting
Published on: April 8, 2022
Cardiogenic oscillations in spontaneous breathing airway signal reflect respiratory system mechanics
S Schumann1, F Messmer, M Lichtwarck-Aschoff
1Division for Experimental Anaesthesiology, University Medical Centre, Freiburg, Germany. stefan.schumann@uniklinik-freiburg.de
Background:
Heartbeat-related pressure oscillations appear at the airway opening. We investigated whether these cardiogenic oscillations (COS) - extracted from spontaneous breathing signals - reflect the compliance of the respiratory system.
Methods:
Fifteen volunteers breathed spontaneously at normal or reduced chest wall compliance, i.e. with and without thorax strapping, and at normal or reduced lung compliance, induced by positive end-expiratory pressure (PEEP). COS-related signals were extracted by averaging the flow and pressure curve sections, temporally aligned to the electrocardiogram signal.
Results:
COS-related airway pressure and flow curves correlated closely for each subject (r(2) =0.97 ± 0.02, P<0.0001). At the unstrapped thorax, the oscillation's amplitudes were 0.07 ± 0.03 cm H(2) O (pressure) and 22 ± 10 ml/s (flow). COS-related pressure amplitudes correlated closely with the ratio of tidal volume divided by pressure amplitude (r(2) =0.88, P<0.001) and furthermore increased with either thorax strapping (P<0.001) or with increasing PEEP (P=0.049).
Conclusion:
We conclude that COS extracted from the pressure and flow signal reflect the compliance of the respiratory system and could potentially allow estimating respiratory system mechanics during spontaneous breathing.
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