Simultaneous estimation of respiratory parameters by regional fitting of respiratory parameters

Abstract

A medical ventilator (10) performs a method including: receiving measurements of pressure of air inspired by or expired from a ventilated patient (12) operatively connected with the medical ventilator;receiving measurements of air flow into or out of the ventilated patient operatively connected with the medical ventilator;dividing a breath time interval into a plurality of fitting regions (60); and simultaneously estimating respiratory system's resistance and compliance or elastance, and respiratory muscle pressure in each fitting region by fitting to a time series of pressure and air flow samples in that fitting region. In one approach, the fitting includes parameterizing the respiratory muscle pressure by a continuous differentiable function, such as a polynomial function, over the fitting region.In another approach, the fitting is to an equation of motion of the lungs in each fitting region, while monotonicity constraints and inequalities bounding at least the respiratory muscle pressure P mus (t) and respiratory system's resistence R and compliance C are applied to the respiratory muscle pressure in each region.

Description

technical field [0001] The following relates to the field of respiratory therapy, the field of respiratory monitoring and related fields. Background technique [0002] All types of respiratory therapy use mechanical ventilators. In passive patient therapy, the patient is unable to breathe, and the ventilator operates in a pressure-controlled mode, wherein the ventilator performs the entire work of breathing (WoB). In active patient therapy, the patient can perform some necessary work, but cannot independently meet respiratory demands. Accordingly, the ventilator operates in a pressure support mode to provide sufficient pressure to overcome any deficit in the patient's ability to breathe. Volume-controlled modes of ventilator operation are also known, where flow or volume is the controlled parameter, rather than controlling pressure (although pressure limiting settings may also be applied to prevent pulmonary barotrauma), and are primarily used for passive patient therapy. ...

AI Technical Summary

Problems solved by technology

In conclusion, it is difficult to achieve a clinical use period of sufficient duration during which P is reliably achieved in active patients mus (t) ~ 0, in order to estimate R and C

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