The Small Animal Ventilator, suitable for a mouse or guinea pig, operates as either a volume or pressure-cycled ventilator, meaning that it dispenses a designated volume of air with each breath or it ventilates until a designated lung pressure is reached. Pressure-cycled ventilation prevents hyper-inflation of small animal lungs. When the ventilator operates in Volume mode, it dispenses a known airflow into the lungs for a set inspiratory time to generate the desired tidal volumes. The three controls – respiratory rate, inspiratory time and flow rate – allow for accuracy and extraordinary flexibility over a wide range of volumes, breaths-per-minute and I/E ratios. When the ventilator operates in Pressure mode, a built-in solid-state transducer monitors airway pressure. Simply set the desired end-inspiratory pressure. During inspiration, airflow is introduced into the lungs until this pressure is reached, at which point inspiration is terminated.