Techniques for automated feedback control of mechanical ventilation

Mechanical ventilators have become more sophisticated with the advent of mi croprocessor control. Advances in monitoring have also improved our ability to harmonize patient-ventilator interaction. The next obvious step in this technologic progression is to turn over some decision making to the ventil ator, In the jargon of today, we are "closing the loop." Ventilators have u sed closed-loop control for simple tasks for the last decade. Newer closed- loop processes include modes that increase or decrease support based on a s ingle-monitored variable. An example is the automated control of pressure s upport to maintain a deired tidal volume. More sophisticated closed-loop te chniques, such as proportional assist ventilation and adaptive support vent ilation, not only monitor multiple input variables but also use closed-loop control of several variables, This article reviews the closed-loop ventila tion modes currently available to clinicians.