Question 4

4.1       Outline the potential  effects of an intercostal catheter inserted into the left chest and attached to an underwater seal drain following a left pneumonectomy. The drain is unclamped and attached to an underwater seal drain.

4.2       Explain how you would manage this situation.

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College Answer

Using an underwater seal drain is inappropriate following a pneumonectomy.
A drain attached to an underwater seal will cause air to be removed from the left chest. There is no lung to expand to fill the space so the mediastinum will move to the left. This results in rapid distortion of major veins and reduced venous return. This causes reduced cardiac output and hypotension.

The situation can be prevented by immediate clamping or when mediastinal shift has occurred letting air back into the chest (by disconnecting the UWSD) resolves the situation or consider active injection of air / intermittent unclamping. It would also be necessary to contact the surgeon to ascertain how the UWSD had come to be attached.


This is a question about a complication which is uncommon precisely because everybody is so familiar with it.

If you keep sucking air out of a pneumonectomised chest, you will cause mediastinal shift, kinking of the greater vessels, and hemodynamic collapse. Its the physiological equivalent of a tension pneumothorax.

The simple act of letting air back into the chest cavity tends to be enough to resolve this issue.

The suggestion that we then call the surgeons and interrogate them about why they mismanaged their patient is a deliciously ICU-typical response. That's why everyone hates us.

So.. why would you put a dangerous death-tube into a person's chest when you know it will cause some sort of complication, particularly a complication exciting enough to appear in the SAQs?

Well, it turns out there are good reasons for it.

The whole post-pneumonectomy chest tube issue is discussed in slightly greater detail in the brief scribble summary about the care for the post-pneumonectomy patient,  in the "Required Reading" section for the Cardiothoracic ICU topic area.



Weissberg, Dov. "Post-Pneumonectomy Chest Tubes." Texas Heart Institute Journal 29.2 (2002): 155.