Fig. 1.  (A ) This graph describing the correlation between severity and rate of occurrence was used to determine the main failure modes of the postoperative process. (B ) This graph describing the correlation between severity and capacity to detect the occurrence of a given sign was used to determine the main failure modes of the postoperative process. ↘BP = hypotension; β- =β-adrenergic receptor blocker withdrawal; ↗HR = tachycardia; Insul = blood glucose disorder; ↘RBC = postoperative anemia.