What factors can be adjusted in volume-controlled ventilation to modify I:E ratio?

In volume-controlled ventilation, the I:E (inspiratory to expiratory) ratio can be modified primarily by adjusting the flow rate and the mandatory rate. The flow rate determines how quickly the tidal volume is delivered during the inspiratory phase. A higher flow rate typically leads to a shorter inspiratory time, which can effectively decrease the inspiratory time relative to the expiratory time, thereby modifying the I:E ratio.

The mandatory rate, or the set respiratory rate, can also influence the duration of inspiration and expiration. By altering the mandatory rate, healthcare providers can adjust the time available for expiration. For instance, increasing the respiratory rate means that there is less time for each expiration, which can modify the I:E ratio as well.

Other factors like tidal volume, PEEP, and end-tidal CO2 levels play important roles in ventilation management but do not directly adjust the I:E ratio in the same way. Tidal volume primarily affects the amount of air delivered with each breath but does not change the timing of the breaths. PEEP, while crucial for maintaining lung volume and preventing atelectasis, has its own role in influencing expiratory time but does not directly dictate the I:E ratio. End-tidal CO2 levels reflect the effectiveness of