Systemic air embolism is traditionally considered as an extremely rare complication of percutaneous lung biopsy. Current literature includes mainly case reports or small case series of SAE. Majority of cases resulted in cardiac and/or neurological symptoms, often causing death. In most reported cases, the diagnosis of systemic air embolism referred to clinical manifestations without radiological diagnosis at the time of the procedure. Hence, its incidence might be underestimated in case of asymptomatic patients. Immediate recognition of air embolism during the procedure has been reported as the main factor to minimize severe complications since specific management of patient can be initiated earlier.

The purpose of this study is to retrospectively assess the incidence of systemic air embolism depicted at the time of the procedure on a whole thoracic CT, systematically performed after transthoracic lung biopsy in a large cohort of consecutive patients. Secondary objectives are to determine possible influencing factors and to evaluate clinical outcomes.

In this retrospective cohort study, all consecutive lung biopsies performed between April 2014 to May 2016 at our department of cardiothoracic interventional radiology were included using the local thoracic biopsy database. Biopsies were scheduled after the weekly multidisciplinary lung cancer meeting approval. Pleural, parietal and mediastinal lesions were excluded due to the absence of intra-parenchymal pathway. Radiofrequency ablation and peripheral nodule marking procedure were also excluded.

A complete retrospective imaging review of the procedures was performed on a PACS workstation by an experienced chest radiologist. Clinical data was also collected from the electronic medical record system.

Variables analyzed were age, sex, spirometry data, emphysema on CT, therapeutics previously done, target lesion characteristics (location, depth, and nodule size and feature), patient position, length of intrapulmonary biopsy path, number of pleural needle passes, biopsy length and number of biopsy passes. Procedural air embolism and other associated complications (hemoptysis and pneumothorax) and their management and consequences (length of hospitalization and additional action) were recorded.

Patient's characteristics with and without air embolism were compared using Student or Wilcoxon rank test for continuous variables and Chi-square or Fisher test for categorical ones. To determine the relative importance of air embolism occurrence influencing factors, multivariate logistic regression analysis was performed on variables according to significance level or clinical coherence. A backward selection was used; the α-to-enter and the α-to-exit were set, respectively, at 0.20 and 0.10. Statistical bilateral significance threshold was set at 5%. Statistical analyses were performed using SAS version 9.1 (SAS Institute, Cary, North Carolina).

Inclusion Criteria:

- percutaneous CT guided lung biopsies

Exclusion criteria:

• absence of intra-parenchymal pathway (pleural, parietal or mediastinal lesions)
• radiofrequency ablation
• peripheral nodule marking procedure

All consecutive lung biopsies performed between April 2014 to May 2016 at our department of cardiothoracic interventional radiology were included using the local thoracic biopsy database.