Inclusion Criteria:  age 2-18 years ASA I-II qualification to surgival procedures requiring muscle relaxation for more than 30 minutes parental consent of children below 16 yrs and parental and child's consent if child was older than 16 yrs of age Bioethical Commission approvement No 161/17  Exclusion Criteria:  ASA III and more age below 2 yrs lack of consent allergy to studied drugs less than 30 minutes of relaxation required