Highlights
- •Macklin is a radiological sign consisting in air dissecting peribronchial sheaths.
- •Macklin sign is often detected on chest CT scan in patients with barotrauma.
- •Link between Macklin and barotrauma is described in various ways in literature.
- •Recent studies proposed Macklin as an accurate predictor of barotrauma.
- •Macklin could identify patient at risk for barotrauma, to try to prevent it.
Abstract
Introduction
Recent studies suggested that Macklin sign is a predictor of barotrauma in patients
with acute respiratory distress syndrome (ARDS). We performed a systematic review
to further characterize the clinical role of Macklin.
Methods
PubMed, Scopus, Cochrane Central Register and Embase were searched for studies reporting
data on Macklin. Studies without data on chest CT, pediatric studies, non-human and
cadaver studies, case reports and series including <5 patients were excluded. The
primary objective was to assess the number of patients with Macklin sign and barotrauma.
Secondary objectives were: occurrence of Macklin in different populations, clinical
use of Macklin, prognostic impact of Macklin.
Results
Seven studies enrolling 979 patients were included. Macklin was present in 4–22% of
COVID-19 patients. It was associated with barotrauma in 124/138 (89.8%) of cases.
Macklin sign preceded barotrauma in 65/69 cases (94.2%) 3–8 days in advance. Four
studies used Macklin as pathophysiological explanation for barotrauma, two studies
as a predictor of barotrauma and one as a decision-making tool. Two studies suggested
that Macklin is a strong predictor of barotrauma in ARDS patients and one study used
Macklin sign to candidate high-risk ARDS patients to awake extracorporeal membrane
oxygenation (ECMO). A possible correlation between Macklin and worse prognosis was
suggested in two studies on COVID-19 and blunt chest trauma.
Conclusions
Increasing evidence suggests that Macklin sign anticipate barotrauma in patients with
ARDS and there are initial reports on use of Macklin as a decision-making tool. Further
studies investigating the role of Macklin sign in ARDS are justified.
Graphical abstract

Graphical Abstract
Keywords
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Article info
Publication history
Published online: February 27, 2023
Accepted:
February 27,
2023
Received in revised form:
February 26,
2023
Received:
November 23,
2022
Identification
Copyright
© 2023 Elsevier Ltd. All rights reserved.