New conclusions drawn from the results of the dissertation Postoperative analgesia for abdominal surgery by intravenous PCA using morphine combined with ketamine (1: 1 ratio) and fentanyl alone were similar at rest in first 48 hour but better during movement at timepoints in second day compared to using morphine alone (with mean VAS score in groups of morphine-ketamine and fentanyl lower than in morphine group at the 24 th, 36 th and 48 th hour, p<0.05).