 Patients undergoing major surgery are exposed to extensive damage of tissues, which induces widespread activation of the inflammatory system, called systemic inflammatory response syndrome SIRS.This activation of the inflammatory system may induce instability of the heart and respiration in the postoperative period. The degree of physiologic response to postoperative SIRS as well as the degree of postoperative pain differ between patients. Therefore, patients undergoing anesthesia and major surgery are treated in a post anesthesia care unit PACU after end of surgery.Admittance to a PACU is expensive. The time patients need to stay in a PACU after major surgery has not been extensively studied, and more appropriate tools for prediction of length of stay are needed. 