Grundlagen der lungenmechanik unter beatmung

Abstract

The study of lung mechanics deals with the pressures acting on the respiratory system (lungs and chest wall) and the changes in volume that they produce. In mechanical ventilation, the technical gas delivery system (ventilator, respiratory tubing system, gas humidifier) and the respiratory system of the patient form a connected pneumatic system of high complexity. The respiratory system produces a mechanical impedance to ventilator output. Impedance is composed of an elastic and a non-elastic, i.e., resistive part. The corresponding indices describing respiratory mechanics are compliance and flow resistance. Based on the equation of motion of the respiratory system, the methods of analyzing semistatic compliance and resistance during mechanical ventilation are described. Quantitative analysis of respiratory system mechanics (a) is a prerequisite for the understanding of the complex patient-ventilator interaction, (b) provides important clinical information on pulmonary function and the course of disease, and (c) allows the physician at the bedside to adjust the ventilatory settings to the needs of the individual patient.