Are doctors whose patients die during surgical operations required to pay expiation?

If a patient's death is caused by the negligence or incompetence of doctors, they are liable for expiation (kaffarah), and blood money (diyah) is obligatory upon their 'aqilah (male relatives on the father's side, who are responsible for paying blood money in certain cases), because it is considered an accidental killing. However, if the doctor is an expert and there was no negligence, then there is no blame upon them, and no guarantee (of recompense) is required.