Ventilation interface comprising at least: - a main gas supply line comprising a first gas inlet port for receiving gas delivered by a medical ventilator; - an additional gas supply line comprising a second gas inlet port for receiving gas delivered by an additional gas source; and - an expiratory line; - the additional gas supply line comprising a first inspiratory chamber and a second inspiratory chamber arranged in parallel with each other; - the first inspiratory chamber containing a first inspiratory reservoir of variable internal volume arranged within a first inspiratory enclosure, the variable internal volume of the first inspiratory reservoir being in fluidic communication with the additional gas supply line, and - the second inspiratory chamber containing a second inspiratory reservoir of variable internal volume arranged within a second inspiratory enclosure, the variable internal volume of the second inspiratory reservoir being in fluidic communication with the additional gas supply line, - the expiratory line comprising a first expiratory chamber and a second expiratory chamber arranged in parallel with each other; - the first expiratory chamber containing a first expiratory reservoir of variable internal volume arranged within a first expiratory enclosure, the variable internal volume of the first expiratory reservoir being in fluidic communication with the expiratory line; and - the second expiratory chamber comprising a second expiratory reservoir of variable internal volume arranged within a second expiratory enclosure, the variable internal volume of the second expiratory reservoir being in fluidic communication with the expiratory line; and - the main gas supply line being in fluidic communication with the internal volumes of the first and second inspiratory and expiratory enclosures. - a main gas supply line comprising a first gas inlet port for receiving gas delivered by a medical ventilator; - an additional gas supply line comprising a second gas inlet port for receiving gas delivered by an additional gas source; and - an expiratory line; - the additional gas supply line comprising a first inspiratory chamber and a second inspiratory chamber arranged in parallel with each other; - the first inspiratory chamber containing a first inspiratory reservoir of variable internal volume arranged within a first inspiratory enclosure, the variable internal volume of the first inspiratory reservoir being in fluidic communication with the additional gas supply line, and - the second inspiratory chamber containing a second inspiratory reservoir of variable internal volume arranged within a second inspiratory enclosure, the variable internal volume of the second inspiratory reservoir being in fluidic communication with the additional gas supply line, - the expiratory line comprising a first expiratory chamber and a second expiratory chamber arranged in parallel with each other; - the first expiratory chamber containing a first expiratory reservoir of variable internal volume arranged within a first expiratory enclosure, the variable internal volume of the first expiratory reservoir being in fluidic communication with the expiratory line; and - the second expiratory chamber comprising a second expiratory reservoir of variable internal volume arranged within a second expiratory enclosure, the variable internal volume of the second expiratory reservoir being in fluidic communication with the expiratory line; and - the main gas supply line being in fluidic communication with the internal volumes of the first and second inspiratory and expiratory enclosures.