Purpose: To estimate the form of pressure generated by respiratory muscles (Pmus).
Methods: 8 spontaneously breathing patients with Chronic Obstructive Pulmonary Disease were included. Respiratory system compliance and resistance were first preset to reasonable values. The Kalman filter with Rauch-Tung-Striebel smoother was applied to assess the Pmus. The results were compared to the esophageal pressure (Pes).
Results: High correlation was found between estimated Pmus signals and measured Pes signals (-0.828 ± 0.083, mean ± standard diviation).
Conclusions: The form of Pmus can be well estimated with Kalman filter, which provides an insight of the pulmonary system in patients with spontaneous breathing. The lung in such patients may therefore be better supported by e.g. the PSV mode.