Chapter 7 - Ventilators and anesthesia systems

Abstract

Ventilators and anesthesia systems are integral parts of modern hospitals. Early ventilator systems comprised many knobs and keys, but modern automatic ventilators are simple with few ventilation modes. Sophisticated instrumentation has provided new approaches to modern medication, diagnosis, and treatment. Various parameters define the market classifications of anesthesia systems and ventilator support. Anesthetic ventilators are of two types—namely, double-circuit designs and single-circuit piston configurations. The ascending bellows of the double-circuit design are considered safer than descending bellows. Single-circuit piston ventilators have the advantage of delivering accurate tidal volume. Both ventilators work with electricity as the source of energy. Patient safety is improved with several modifications in the circle system with different types of ventilators and anesthesia systems. Gas decoupling and modifications in piston ventilators and descending bellows reduce the incidence of ventilator-induced volutrauma. Additionally, conventional volume controls with modern anesthesia ventilators provide newer, user-friendly modes of ventilator support, such as pressure-control ventilation, pressure-support ventilation (PSV), and synchronized intermittent mandatory ventilation. The PSV mode is useful specifically for patients on spontaneous respiration support with a laryngeal mask airway, for whom these support systems provide multiple benefits. However, ventilator use is also associated with patient risk factors. To use this support system safely, all hospitals and anesthesiologists must have a basic operational understanding of the mechanics of breathing circuits.