What is the most common cause of breathlessness and fever after surgery?

The most common cause of breathlessness and fever after surgery is pneumonia. This condition can occur due to various factors related to the surgical process, including the effects of anesthesia, prolonged immobility, and the presence of secretions in the lungs. After surgery, patients often have compromised respiratory function, which can make it easier for bacteria to colonize the lungs, leading to an infection. Symptoms such as fever and difficulty breathing are classic manifestations of pneumonia, particularly in the postoperative setting.

While heart failure, blood clots, and infections at the surgery site can also contribute to breathlessness and fever, they are less frequently encountered than pneumonia in the immediate postoperative period. Heart failure typically presents with more chronic symptoms and is less likely to arise acutely after surgery in patients without a prior history. Blood clots, while serious and possible, often present with more specific signs such as swelling in the legs or sudden chest pain. Infections at the surgical site usually cause localized symptoms rather than systemic manifestations like fever and breathlessness, making pneumonia the most likely culprit in this scenario.