The technique of inverse ratio ventilation. Steps to improve oxygenation and decrease dead space ventilation.

Inverse ratio ventilation (IRV) differs from other ventilatory techniques in that it employs a prolonged inspiratory time. In theory, pressure-control IRV allows you to maintain ventilation and oxygenation with lower peak airway and end-expiratory pressures; this may reduce the potential for lung damage secondary to shearing forces. Consider pressure-control IRV for patients with acute lung disease characterized by low lung compliance, diffuse microatelectasis, and increased intrapulmonary shunting. Currently, the chief limitation of this technique is that the patient cannot breathe spontaneously during its use. The best inspiratory to expiratory ratio is the shortest inspiratory time that improves oxygenation with minimal hemodynamic compromise; depression of cardiac output will negate any potential improvement in arterial oxygenation.