Rare. Complication of childbirth: pneumomediastinum accompanied by subcutaneous emphysema of the neck and the face. It starts during the second phase of the labour but usually appears only in the  post-partum period. Seems more frequent in the primiparous and following the delivery of a large newborn.

Pathophysiology: repeated Valsalva maneuvers can cause rupture of marginal alveoli with inlet air in the mediastinum. Air then passively diffuses into the areas of least resistance, which explains the emphysema. In case of breach of the pleura, a pneumothorax can be associated. Typical sign: crackling synchronous with the pulse ("Hammam sign").

Symptoms: retro - or latero-sternal pain, dyspnea, palpitations; sometimes loss of heart sounds.

Differential diagnosis: pulmonary or amniotic embolism, spontaneous pneumothorax, dissecting aortic aneurysm. Conservative treatment is usually sufficient.

Anesthetic implications: 

increased risk of spontaneous pneumothorax ? If anesthesia is necessary in the postpartum period, it is better to opt for regional anesthesia or a general anesthetic under spontaneous ventilation.

References : 

-        Houari N, Labib S, Berdai M-A, Harandou M. 
Pneumomédiastin et emphysème sous-cutané du post-partum : une nouvelle observation. 
Ann Fr Anesth Réanim 2012 ; 31 : 728-30.

Updated: April 2019