Inspiratory

Pressure-controlled rat and mouse ventilators deliver a constant flow of inspiratory gas at the onset of the inspiration portion of the respiratory cycle. Gas delivery continues until reaching the inspiratory pressure threshold. Pressure in the airways and lungs is now maintained until the end of the inspiratory cycle. At this time, there is no gas flow (inspiratory pause).

Volume-controlled ventilation maintains constant inspiratory volume and allows the inspiratory pressure to vary dynamically with the tidal volume of the subject. Volume-controlled mouse ventilators deliver inspiratory gases at a constant flow for the entire period of the inspiratory portion of the respiratory cycle. The final airway pressure will be determined by the tidal volume of the subject and the connecting tubing. Care is required to avoid over pressurizing the lungs with an excessive volume of gas.

Expiratory

In the expiratory portion of the respiratory cycle, gases in the lungs are released through the expiratory tubing. The lungs are now at atmospheric pressure. During certain procedures, peak end expiratory pressure (PEEP) is required to prevent the lungs from collapsing. PEEP is easily accomplished by venting the expiratory tubing through a column of water. The end of the tubing is placed under the surface of the water, at the required distance, to generate the desired PEEP.

Your specific application will determine which type of rat and mouse ventilator is best suited for your research.