Final answer:
The patient's sudden cardiopulmonary arrest following the administration of the last unit of blood is most likely caused by an air embolus, rather than his high cholesterol, cardiac bypass surgery itself, or lack of familiarity with equipment.
The correct answer is option c) Air embolus.
Step-by-step explanation:
The suspected cause of the patient's condition, immediately following the administration of the last unit of blood and experiencing cardiopulmonary arrest, is most likely an air embolus. An air embolus can occur during medical procedures, such as a cardiac bypass surgery, when an air bubble enters the vascular system and obstructs the flow of blood. This is a critical situation because it can imped your blood flow, leading to severe consequences including cardiac arrest.
While the patient's history of high cholesterol and the fact that he was undergoing cardiac bypass surgery are relevant to his overall health, they are not directly associated with his immediate reaction after receiving blood. The lack of familiarity with equipment is an unlikely cause in this scenario because it does not typically result in sudden cardiopulmonary arrest in the absence of a specific error or malfunction.
The correct answer is option c) Air embolus.