Patients, general public and health insurance funds focus more and more on the quality of medical performance. Anaesthesia related severe morbidity and mortality are unsuitable to judge the quality of an anaesthesia procedure. Other aspects like rapid and comfortable postoperative recovery or satisfaction of the patients with the anaesthesia procedure experience therefore rising attention. With this critical review we aim to give support for appraisal of already published studies and for design and realization of future trials.