Process and devices for automatically specifying the frequency set point of a ventilator

Abstract

A process, a signal processing unit and to a ventilator automatically calculate a set point for a frequency, with which the ventilator performs ventilation strokes and thereby mechanically ventilates the patient. An alveolar or proximal minute volume is predefined. A lung time constant for the lungs of the patient is determined. The volume of a dead space in a fluid connection between the lungs and the ventilator is determined. A mandatory frequency set point (f) for the mandatory ventilation of the patient is calculated. An ideal frequency (f), with which the patient can achieve the minute volume by means of spontaneous breathing, is calculated. The ventilation frequency set point is calculated as a weighted average of the mandatory frequency set point (f) and of the ideal frequency (f). The averaging depends on a determined actual intensity of the spontaneous breathing of the patient.