A blood clot that forms in an airway can act as a ball valve during respiration, letting air in during inspiration but preventing air outflow during expiration. Prompt recognition and clot removal are essential to prevent respiratory complications.


The presence of a tracheostomy or endotracheal tube may favor this ball valve motion. A clot formed about a tube could act as a one way valve. The normal airway shows an inverse taper and an obstructing clot would normally prevent air inflow and allow outflow.


Clinical features:

(1) recent history of bleeding in the airways due to trauma or coagulopathy

(2) decrease in oxygen saturation

(3) decrease in minute ventilation

(4) decrease in breath sounds

(5) If the patient is on a respirator, then the pressure-volume curve will show airway obstruction.

(6) presence of a blood clot on bronchoscopy.



(1) hyperinflation of the lungs, progressing to emphysematous change

(2) pneumothorax

(3) hemodynamic compromise

(4) hypoxemia


Possible techniques for clot removal:

(1) Replacement of an endotracheal or tracheostomy tube if the clot is intraluminal.

(2) Suction.

(3) Use of a thrombolytic agent.

(4) Forceps extraction


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