The induction will be similar in both groups; Pre-oxygenation for 5 minutes will be done in all patients and then they will receive 0.02 mg/Kg midazolam, 1μg/Kg fentanyl, 2mg/kg Propofol slowly until loss of verbal contact and rocurronium 0.6 mg/kg intravenously.Till the establishment of adequate neuromuscular block, the patients' ventilation will be assisted manually using a face mask. During this period the patients' lungs will be ventilated with 100% oxygen.