An interventional study, on adults, comparing two types of face masks for giving oxygen and helping patients breathe during general anaesthesia in people with sunken cheeks

INTERVENTION: Intervention1: AMBU RESUSCITATOR MASK: preoxygenation and mask ventilation using ambu resuscitator face mask after induction of general anesthesia Control Intervention1: Conventional anesthetic face mask: Preoxygenation and mask ventilation using conventional face mask after induction of general anaesthesia. CONDITION: Health Condition 1: O‐ Medical and Surgical PRIMARY OUTCOME: time taken to attain 90 percentage end tidal oxygenTimepoint: randomized, cross over study SECONDARY OUTCOME: to evaluate the adequacy of tidal volume delivery during bag mask ventilation, the need to use two‐person bag mask ventilation, airway adjuncts and increase in fresh gas flow.Timepoint: randomized, cross over study INCLUSION CRITERIA: Adult patients of both sexes, ASA 1 to 3, who are anticipated to have difficult mask seal, due to edentulous status or having sunken cheeks, who are scheduled for elective surgery and require general anaesthesia will be enrolled.