[Modern forms of artificial respiration]

Mechanical ventilation has become a widely used technique in anaesthesiology and intensive care medicine. Difficulties arise with patients who suffer from acute or chronic pulmonary disease. Lung models are used to simulate the behaviour of healthy and diseased lungs and to optimize breathing patterns. Flow-controlled ventilation is suitable for healthy lungs. Diseased lungs need more finely differentiated ventilatory modes that adapt to the different time constants within the lung. PCV seems to have some advantages in ventilation of such lungs. It has been demonstrated that prolongation of inspiratory time and inversion of the I:E ratio can open nonventilated compartments of the lung and thus reduce intrapulmonary shunt. BiPAP ventilation and APRV serve the same purpose. Additionally, they support spontaneous breathing of the patient. Weaning from the respirator can be achieved by either reducing the number of mandatory breaths (IMV, SIMV, MMV) or reducing the work of breathing by applying inspiratory pressure support (PSV). Both techniques can be applied simultaneously. BiPAP ventilation and APRV are also suitable for weaning patients from a ventilator. Respirators able to adapt breathing patterns to the lung mechanics of a patient automatically on the basis of a breath-to-breath lung function analysis (ALV) are currently in clinical development.