These may be provided via a hospital’s central manifold supply with a blender mixing them to achieve the desired oxygen concentration (FiO 2). Source of pressurised gas: Clearly, both oxygen and air are required. (c) Combined: Most intensive care unit ventilators are combined with pneumatic power used to deliver the breath whilst an electronically controlled microprocessor controls the valves that regulate the characteristics of the breath.Ģ. (b) Electrical: AC or DC current is used to drive the pistons and compressors that generate pressure.
(a) Pneumatic: Compressed medical gases are used as the energy source. The basic build of a mechanical ventilator can be described according to (1) input power, (2) source of pressurised gas, (3) drive mechanism, or (4) control circuit. Physics of Mechanical VentilatorsĪ mechanical ventilator either fully or partially supports a patient’s work of breathing. It does this bygenerating a flow of gas into the breathing circuit and this flow is determined by settings as discussed below.
Phases of a ventilatory breath are determined by trigger, limit, and cycling.Ī ventilator delivers a set volume of gas to a patient based on volume, pressure, or flow as set by the operator.This pressure gradient isknown as the transairway pressure. Gas flows into the lungs down a pressure gradient between the airway and the alveoli.Mechanical ventilators can be classified according to their input power, pressurised gas source, and drive mechanism.A ventilator delivers a set volume of gas to a patient based on volume, pressure, or flow..
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