A ventilator controls or assists gas movement through a patient circuit while monitoring pressure, flow, volume, timing, oxygen concentration, and alarm conditions. Designs vary widely—from turbine-driven portable units to systems supplied by compressed medical gases—but every ventilator depends on a precisely controlled gas path and validated sensing.
Key takeaways
- The gas source, blending, inspiratory control, patient circuit, expiratory path, sensors, and software form one system.
- Pressure and flow measurements are used for control, monitoring, triggering, and alarm decisions.
- Circuits, filters, humidifiers, valves, oxygen sensors, batteries, and accessories must match the intended configuration.
01
Gas source and inspiratory path
A ventilator may receive air and oxygen from facility pipelines, cylinders, an internal compressor, or a turbine that draws room air. Regulators, filters, proportional valves, flow-control devices, and blending components create the requested inspiratory gas. An oxygen sensor or analyzer provides concentration feedback, while flow and pressure sensing inform closed-loop control.
02
Patient circuit and expiratory path
The circuit can include inspiratory and expiratory limbs, filters, humidification, water traps, nebulizer interfaces, exhalation valves, and proximal sensors. Some devices place the expiratory valve inside the ventilator; others use a disposable valve or single-limb leak configuration. Circuit type and compensation must match the mode and manufacturer instructions.
03
Control, triggering, and monitoring
Control software coordinates breath timing, target pressure or volume, flow pattern, trigger sensitivity, cycling, PEEP, and safety limits. Sensors may be zeroed or checked against reference conditions. A leak, obstruction, condensation, damaged diaphragm, sensor drift, valve fault, or incorrect circuit configuration can affect both delivery and displayed measurements.
04
Alarms, batteries, and return to service
High and low pressure, minute volume, apnea, disconnect, oxygen, power, battery, and technical alarms help identify unsafe or failed conditions. Battery capacity and gas availability matter during transport. Service verification can require calibrated pressure, flow, volume, oxygen, leakage, alarm, battery, and electrical-safety testing across specified modes.
Ventilators are life-support devices. Interrupted or incorrect support can cause serious harm. This overview is not an operating or repair procedure; only qualified personnel should configure, test, service, or return ventilators to clinical use.
Related terminology
Terms with a published definition link directly to the glossary.