The end of the tubing is placed under the surface of the water, at the required distance, to generate the desired PEEP. PEEP is easily accomplished by venting the expiratory tubing through a column of water. During certain procedures, Peak End Expiratory Pressure (PEEP) is required to prevent the lungs from collapsing. The lungs are now at atmospheric pressure. In the expiratory portion of the respiratory cycle, gases in the lungs are released through the expiratory tubing. Care is required to avoid over pressurizing the lungs with an excessive volume of gas. The final airway pressure will be determined by the tidal volume of the subject and the connecting tubing. Volume-controlled mouse ventilators deliver inspiratory gases at a constant flow for the entire period of the inspiratory portion of the respiratory cycle. Volume-controlled ventilation maintains constant inspiratory volume and allows the inspiratory pressure to vary dynamically with the tidal volume of the subject. At this time, there is no gas flow (inspiratory pause). Pressure in the airways and lungs is now maintained until the end of the inspiratory cycle. Gas delivery continues until reaching the inspiratory pressure threshold. Pressure-controlled rat and mouse ventilators deliver a constant flow of inspiratory gas at the onset of the inspiration portion of the respiratory cycle. Basic settings on a mechanical ventilator include: Mode Tidal Volume Respiratory rate (RR) Inspired oxygen concentration (Fio2) Positive end expiratory. Each value can be independently adjusted to meet your research needs. In the respiratory cycle, the inspiratory portion is typically one third of the cycle and the expiratory portion is two-thirds of the cycle.

Auto vent tidal volume chart