Negative Pressure Ventilation is still an effective method of non-invasive external ventilation and represents a valid alternative to traditional ventilation methods.
It works in the same manner as natural breathing as it consists of both Inspiratory and Expiratory phases. Both phases are performed through a Negative Pressure Ventilator and specific accessories to be connected to the latter, such as a Cuirass or a Poncho amongh others.
The ventilator firstly applies a negative pressure forcing the diaphragm moves downwards while the rib muscles pull the ribs out expanding the chest: this process expands the lungs and generates a lower pressure inside the chest cavity (Inspiratory Phase); negative, in fact, means that the pressure decreases below normal atmospheric level, causing air to be sucked into the airways and the lungs. The ventilator then switches to positive pressure and forces air in the chamber so that the chest will be compressed and the lungs will exhale, although the exhalation can also be passive through the ambient, which is often sufficient to deflate the lungs.
This technique can often replace invasive ventilation: this increases the patient’s comfort and, moreover, reduces the risk of side-effects normally associated to other ventilation methods.