This Germany-wide, multi-center, epidemiologic study is designed to evaluate the incidence of post-operative/anesthesia effects of muscle relaxants (i.e. post-operative residual curarization: PORC) and their effect on patient outcome. Aside from biometric data, type of operation, use of muscle relaxants and neuromuscular monitoring, all patients will be clinically evaluated after their operation in the post-anesthesia care unit. To look at long-term effects, patients will be followed-up 28 days after their operation/anesthesia regarding post-operative/anesthesia morbidity and mortality.