Mask ventilation during induction of anesthesia can be improved by administration of neuromuscular blocking agents (NMBAs). NMBAs are usually administered after testing mask ventilation; however, muscle relaxants may improve mask ventilation and they do not alter mask ventilation. Thus, growing evidence suggests to administer muscle relaxants before testing mask ventilation.We will administer rocuronium 0.3 mg/kg, 0.6 mg/kg, 0.9 mg/kg and saline (placebo group) before starting with mask ventilation. We will grade mask ventilation based on various scores before and after rocuronium application. Afterwards patient`s tracheas will be intubated. We assess risk factors for difficult mask ventilation.