[Methods in mixed ventilation: advantages, disadvantages and consequences for work of breathing]

During partial ventilatory support modes both the ventilator and the patient are performing mechanical work. These modes are currently used as mechanical ventilatory support to provide a better synchronism between the patient and the machine and to avoid a complete rest of the respiratory muscles, or as modes of weaning from mechanical ventilation. Assist control ventilation allows the patient to regulate his own respiratory rate by triggering preset ventilatory cycles. Synchronized intermittent mandatory ventilation includes both controlled cycles and spontaneous breathing cycles. Lastly, during inspiratory pressure support, each spontaneous cycle is assisted by pressurization of the circuit. This latter modality alone seems efficiently to decrease the patients' breathing work while allowing complete synchronism between patient and ventilator.