Clinical studies of tracheal gas insufflation

Tracheal gas insufflation (TGI) is an adjunct to mechanical ventilation that allows ventilation with small tidal volumes while carbon dioxide (CO2) is satisfactorily cleared. Pioneering studies in healthy animals and in humans suffering respiratory failure showed that the expiratory flushing of proximal dead space decreased minute ventilation with no change in arterial partial pressure of carbon dioxide (PaCO2). Recent work indicates that conventional mechanical ventilation aided by TGI may represent a novel ventilatory strategy that succeeds in limiting both the distending forces acting on the lungs and the PaCO2 elevation of permissive hypercapnia. Furthermore, some studies suggest that weaning aided by TGI may allow a reduction in minute ventilation, PaCO2, physiologic dead space, and the patient's respiratory demands. Clinical use of TGI requires careful monitoring of delivered volumes and pressures to ensure safe clinical application and to evaluate the effect on lung function. Finally, routine use of TGI in intensive care warrants further investigation to solve some technical problems and randomized clinical trials to confirm the beneficial effects in the absence of complications.