1. Intubation required immidiately in case of cardiac arrest or asphyxia, 2. Pregnancy, severe chronic respiratory, uncontrolled gastric reflux disease and any nasopharyngeal anatomical obstacle, 3. Those patients has intubated in ICU.

1. Intubation required immidiately in case of cardiac arrest or asphyxia, 2. Pregnancy, severe chronic respiratory, uncontrolled gastric reflux disease and any nasopharyngeal anatomical obstacle, 3. Those patients has intubated in ICU.