Final answer:
Misdirection of the aortic cannula during cardiac surgery can lead to air embolism, a serious and potentially fatal complication causing obstructive shock due to blockage in the vascular system.
Step-by-step explanation:
A potential complication related to the misdirection of the aortic cannula during cardiac surgery is air embolism. When the cannula is improperly placed, there is a risk that air may enter the circulation and travel to various parts of the body, leading to blockages in blood vessels, which can have serious consequences, including stroke, myocardial infarction, or even death. Obstructive shock may occur if the embolism lodges within the pulmonary vessels, which is a significant blocker in the vascular system, leading to interrupted blood flow and life-threatening complications.