Microvasculature in ventilator-induced lung injury: target or cause?

Clinicians managing acute lung injury must reconcile the competing objectives of ensuring adequate oxygen delivery and minimizing the adverse effects of ventilatory support. Judging from our experimental work, microvascular stresses appear to be a potent cofactor in the development of pulmonary edema as well as in the expression of lung damage resulting from an injurious pattern of ventilation. When the lung is ventilated with high pressure, raising pre-capillary pressure or reducing post capillary pressure are both undesirable. Raising ventilation frequency may also have cost. Such observations imply that reducing the demands for blood flow and ventilation are important considerations in formulating a lung protective approach to mechanical ventilation of ARDS.