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CC BY-NC-ND 4.0 · Indian J Radiol Imaging 2021; 31(04): 805-808
DOI: 10.1055/s-0041-1741093
Original Article

Venous Air Microembolism in Chest CT Angiography: Evidence of Normalization of Deviance Phenomenon

Claudio Silva
1   Department of Radiology, Clinica Alemana de Santiago, School of Medicine, Clinica Alemana - Universidad del Desarrollo, Santiago, Chile
,
Ema Leal
1   Department of Radiology, Clinica Alemana de Santiago, School of Medicine, Clinica Alemana - Universidad del Desarrollo, Santiago, Chile
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Abstract

Purpose This article provides evidence that detection of venous air microbubbles (VAMB) in chest computed tomography angiography (CTA) can be an indicator for “normalization of deviance” phenomenon in CT.

Method and Materials Institutional review board-approved retrospective study, with waiver for informed consent. Contrast-enhanced chest CT performed during 6 months were reviewed for presence of VAMB in venous segments visible in chest CT (subclavian, brachiocephalic vein, superior vena cava) and cardiac chambers. VAMB volumes were quantified through a semiautomatic method (MIAlite plugin for OsiriX), using a region of interest (ROI) covering the bubble. With basal results, protocols for correct injection technique were reinforced, and VAMB were estimated again at 1 and 3 months. Six months later, questionnaires were sent to the CT technologists to inquire about their perception of VAMB. Descriptive measures with central distribution and dispersion were performed; statistical significance was considered at p < 0.05.

Results A total of 602 chest CTA were analyzed, 332 were women (55.14%), with a median age of 58 (interquartile range [IQR] 44–72) years. Among those, 16.11% (100 cases) presented VAMB. Most were emergency department patients (51.6%), male (50.3%), with a median age of 54 (IQR 26) years. There was no difference on detection of VAMB regarding sex (p = 0.19), age (p = 0.46), or referral diagnosis (p = 0.35). Mean air bubbles volume was 0.2 mL (range 0.01–3.4 mL). After intervention, the number of exams with VAMB dropped to 3.29 % (3/91) (p < 0.001). On the 6-month query, 50% of the technicians still considered that VMAB is inevitable, and 60% thought that the occurrence is not associated to risk, and therefore, not actionable.

Conclusion VAMB are a frequent finding in chest CTA, and being independent from patient-related variables, it is likely due to technical issues such as intravenous access manipulation during the exam. Reduction after reinforcement of proper performance, and certification of a low concern from CT technicians for any risk associated, provides evidence that there is normalization of deviance in this everyday procedure.

Keywords

air bubbles - air embolism - computed tomography angiography - normalization of deviance

Declaration of Patient Consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.


Authors' Contributions

C.S. conceived and designed the study. C.S. and E.L. performed extensive research on the topic. C.S. and E.L. acquired the data, performed data extraction, and interpreted the data. C.S. performed the statistical analysis. C.S. and E.L. drafted, reviewed, and edited the manuscript.


Financial Support and Sponsorship

None.




Publication History

Article published online:
10 January 2022

© 2022. Indian Radiological Association. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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