Ventilation and the critically ill parturient

Positive-pressure ventilation is the keystone in the management of pulmonar y dysfunction in the critically ill. An increased understanding of both the benefits and hazards has led to a general consensus regarding the optimal techniques to ensure adequate gas exchange. Unfortunately, the same cannot be said for ventilation terminology which, due to a lack of standardization , lends itself to confusion. Pulmonary dysfunction in the parturient may ar ise from thoracic or extra-thoracic pathologies but both may be defined as acute lung injury. In its most severe form this constitutes acute respirato ry distress syndrome. Acute lung injury results in reduced lung compliance and a marked decrease in the volume of functional lung. Ventilation strateg ies are now designed to recruit as much available lung tissue as possible w hile simultaneously minimizing the injurious effects of alveolar over-diste nsion. Upon resolution of the underlying pathology mechanical ventilation m ay be withdrawn. Recent evidence suggests that this final stage need not be protracted, and if certain criteria are fulfilled, rapid weaning is feasib le.