Non-linear model of the mechanics of breathing applied to the use and design of ventilators.
Respiratory treatment involves clinical problems which are often related to the pulmonary and circulatory condition of the patient. Choice of a proper respirator and its adequate use are very important for overcoming a good deal of the clinical problems which may arise. A good automatic ventilator should, under all circumstances, be capable of assuring a suitable gas exchange at the pulmonary level with as little alteration as possible to the physiological functions of the body. In this paper a non-linear model of the mechanics of breathing is used to examine: (1) the effects of four theoretical inspiratory flow patterns in intermittent positive pressure ventilation (IPPV); (2) the differences obtained with respect to IPPV when we use a positive end-expiratory pressure (PEEP) or a negative pressure in the expiratory phase (IPNPV); (3) the performances of four automatic ventilators at present on the market and commonly used in departments of anaesthesia and intensive care. The results obtained by simulation of the respiratory system indicate that, in practice, an ideal ventilator neither exists nor can be designed. The manner of using the ventilator leads to different results, more so than the theoretical inspiratory flow pattern or the type of ventilator used. The tables and graphs shown in the paper help to utilize the ventilator in such a way as to optimize the parameters which, each time, are considered the most important.
D001696:Biomechanical Phenomena; D003201:Computers; D004867:Equipment Design; D006801:Humans; D007385:Intermittent Positive-Pressure Ventilation; D008433:Mathematics; D008954:Models, Biological; D011175:Positive-Pressure Respiration; D012119:Respiration; D012122:Ventilators, Mechanical