An accident, in common language, is an unpredictable event. In the medical profession, it's called an unforeseeable medical complication: this term describes the whole of the damages done to a patient as a result of a medical procedure and in absence of fault or error. It's an event whose occurrence can be anticipated, but can't be foreseen in advance. It must be differentiated from a medical error which points to the medical act or the intervention of the doctor and can relieve the responsibility of the latter. Medical complications only concern surgery.