PPV in pneumothorax

[whiteorgo]

Hello,

What's the exact mechanism behind the reason why positive pressure ventilation will worsen pneumothorax into tension pneumothorax? Is it the barotrauma and the increase intra-thoracic pressure that increases it? I couldn't find the exact answer so thought I would ask. Thanks!

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[mikey014]

Positive pressure through damaged lung, air on the pleura, increased thoracic pressure, shift of mediastinum, decreased preload, decreased cardiac output

 

[vector2]

Hello,

What's the exact mechanism behind the reason why positive pressure ventilation will worsen pneumothorax into tension pneumothorax? Is it the barotrauma and the increase intra-thoracic pressure that increases it? I couldn't find the exact answer so thought I would ask. Thanks!

There are general two mechanisms by which unwanted air can accumulate in the pleural space. One is internal, I.e. a rupture of the airway/alveoli/interstitium allows inspired air to come in but not easily exit. The second is external- trauma or iatrogenesis to chest wall allows atmospheric air to accumulate in the pleura. The first mechanism is by the far the most common in critically ill pts, and this is the one where positive pressure can be the most dangerous. Ppv in internal ptx can frequently allow air to bypass the damaged lung, accumulate in the pleura, and then become trapped by a one way valve effect during expiration. Therefore the ptx just keeps growing with each subsequent breath leading to tension physiology. The same physiology can occur with external ptx although in those cases the air becomes trapped when it enters pleura during a spontaneous breath.

 

[fakin' the funk]

Hello,

What's the exact mechanism behind the reason why positive pressure ventilation will worsen pneumothorax into tension pneumothorax? Is it the barotrauma and the increase intra-thoracic pressure that increases it? I couldn't find the exact answer so thought I would ask. Thanks!

Ptx and Bpf are not the same thing.