This condition has been recognized in preterm neonates, in which it is associated with severe lung pathology, after vigorous resuscitation, or in the presence of assisted ventilation.

[3] The symptomatic patient may present with dyspnea, cyanosis, chest pain, pulsus paradoxus, bradycardia or tachycardia.

[citation needed] The mechanism responsible for pneumopericardium is the ‘Macklin effect’ – There is initially an increased pressure gradient between the alveoli and the interstitial space.

[citation needed] On physical examination, the patient may have the classic “Beck’s triad” – hypotension, raised JVP and distant heart sounds, when complicated by cardiac tamponade.

When air and fluid mix together in the pericardial sac, a tinkling sound superimposed over a succussion splash is heard.