Reverse Macklin effect

Abstract

The Macklin effect is associated with alveolar rupture causing a centripetal spread of air along the peribronchovascular interstitial sheath leading to pneumomediastinum, usually seen in ventilator-related barotrauma or blunt chest trauma. We are presenting a peculiar case of iatrogenic (post-intubational) tracheal injury with massive subcutaneous emphysema and pneumomediastinum, in whom, we suspect that the primary tracheal injury and pneumomediastinum led to dissection of air along the peribronchovascular interstitium, culminating in atelectasis of lung due to compression of the distal-most airways, with no primary parenchymal abnormality. This supposed "reversal" of pathophysiological sequence of the Macklin effect makes it a unique finding.

Keywords: Peribronchial interstitial emphysema; Pneumomediastinum; Tracheal injury.

Fig. 1

Axial section of chest computerized tomography showing the pneumomediastinum (green arrow), subcutaneous emphysema (yellow arrow), peribronchial interstitial emphysema (red arrow), and collapsed segmental bronchi (blue arrow)

Fig. 2

Coronal section of computerized tomography showing the peribronchial interstitial emphysema (red arrow), causing a collapse of segmental bronchi (blue arrow) and atelectasis of the right lower lobe

Fig. 3

Virtual bronchoscopic image (top-down view) depicting a tear (white arrow) in the right posterolateral wall of the lower trachea

Fig. 4

Intraoperative image (right thoracotomy approach) revealing the tracheal tear (white arrow), extending from the lower trachea just into the proximal right main bronchus, with the endotracheal tube exposed. The trachea was exposed after dividing and retracting the azygous vein stumps (black sutures)