Venous air embolism and active lung inflation at high and low CVP: a study in "upright" anesthetized sheep

To assess the safety and efficacy of the maneuver of active lung inflation (ALI) after venous air embolism, measurements were made of pulmonary artery occlusion pressure (PAOP), central venous pressure (CVP), and superior jugular bulb pressure (JbP) as an index of cerebral venous sinus pressure in eight sheep before and after a 2-ml/kg air embolus and before and in the release phase of an ALI to a pressure of 4 kPa (30 mm Hg). (PAOP-CVP) difference decreased significantly after the air embolus with a further decrease after ALI (P less than 0.01). An increase in JbP occurred with ALI only when the CVP was elevated before the injection of air. After air embolism in neurosurgery, ALI may increase the likelihood of paradoxical embolism in patients at risk and may also fail to help in identifying the site of air entry.