Indication of mechanical ventilation and selection of ventilatory mode in acute respiratory failure

Abstract

There is little arguments about indications of mechanical ventilation (MV) for acute respiratory acidosis which does not respond to conservative therapy. MV for severe hypoxemea without hypercapnia, on the contrary, is a matter of controversy. The author believes that beneficial effects of MV are expected in critically ill patients even without hypercapnia, since MV not only increases alveolar ventilation but also reduces burden of respiratory work and energy expenditure.
We now have several modes of MV available such as differential lung ventilation (DLV), high frequency ventilation (HFV) and so on. Marked hypoxemia due to severe unilateral or uneven pulmonary lesion which is resistant to conventional MV can be treated successfully by DLV. The author speculates that HFV is effective to mobilize sputa in the peripheral bronchi resulting in improved oxygenation.
Precise evaluation of pathophysiology of the patient's lungs and delicate application of selected modes of MV can improve survival of critically ill patients with acute respiratory failure.