The arterial cannula is being deaired. This ensures that no air bubbles are pushed into the circulation (possibly causing a stroke) when extracorporeal circulation is instituted. The cannula is connected to the arterial line of the bypass circuit (which is seen to the left with a clamp on it).
The surgeon is placing a purse-string suture in the right atrial appendage through which the venous cannula will be passed. The assistant is using forceps to retract and expose the appendage. The arterial cannula is seen in the background exiting the aorta.
Link to this frame from your Personal Thumbnails page?
Click the "Update" button to save your Notes and Personal Thumbnails.