Massive air embolism after lung biopsy.

A 69-year-old man presented with pneumogenic sepsis. A chest radiograph showed bilateral extensive infiltrates that did not respond to broad-spectrum antibiotic treatment. Progressive respiratory failure necessitated invasive mechanical ventilation (bilevel positive airway pressure, 0.5 inspiratory oxygen saturation; peak inspiratory pressure, 24 cm H 2 O; positive end-expiratory pressure, 8 cm H 2 O). Chest computed tomography (CT) revealed inflammatory infiltrates with caverns and bilateral pleural effusions. Blood and bronchoalveolar cultures remained sterile. Therefore, computed tomography-guided lung biopsy was performed with an 18-gauge core needle with the patient in prone position (Figure, A). A control computed tomography scan (Figure, B) revealed massive systemic air embolism. Shortly thereafter, the patient developed cardiorespiratory failure. Cardiopulmonary resuscitation remained unsuccessful. Percutaneous computed tomography-guided lung biopsy is a frequently performed procedure for histological and microbiological analyses of pulmonary lesions and infiltrates. Moderate complication rates have been described, including pneumothorax (27%), intraparenchymal hemorrhage (11%), or hemoptysis (7%). 1 Systemic air embolism is an extremely rare and feared complication that is potentially fatal, reported previously to have an incidence of ≈0.02% to 0.7%. 2 However, it can be assumed that there is a much higher incidence of systemic air embolism because of clinically unapparent cases (0.4% to 3.8%). Systemic arterial air embolism is caused by the entry of gas into the pulmonary veins or directly into the arteries of the systemic circulation. A common mechanism is that a biopsy needle opens a pulmonary vein to the atmosphere. Direct formation of fistulae between pulmonary veins and alveoli or bronchi is another possible mechanism. Any factor that increases pressure gradient between airway and pulmonary vein may promote the entrance of air into the pulmonary vein and cause air embolism 2 : positive end-expiratory pressure ventilation, coughing during lung biopsy (Valsalva), or obstructive pulmonary disease (chronic obstructive pulmonary disease) with air trapping may increase airway pressure and thus the risk of air embolism. Prone position, which implies a puncture site at a level above the heart, is also considered to increase pressure gradient between airway and pulmonary vein and therefore is a risk factor. Lung diseases with cavitary or cystic lesions or larger needle size with the needle tip placed not properly in the lesion may be associated with an increased risk for air embolism. The coaxial technique is often discussed as a risk factor for systemic air embolisms, but there are a number of cases described without the use of …