This article summarizes the current actual knowledge in possibilities of examination of patients´ condition before surgery with respect to its risks in various biological and functional patients´ condition and possibility of development some complications during operation and during postoperative period. The term of operating trauma is defined. A list of important operation risks is presented (anaesthetic, respiratory, cardial, nutritive, thromboembolic, infection, allergic reaction, and functional reserve).
The procedures in preparation of patient to surgery and ones in postoperative period are recommended.