1. Among the pool of eligible candidates, after taking written informed consent from study participants ,105 subjects will be selected randomly and will be allotted into 3 groups, group I, group II and group III.( A simple randomisation technique will be followed. A total of 105 random numbers will generated at the beginning of the study and kept centrally with the study guide. While participants will be kept blind to the procedure and group allocation, the same is not feasible for the investigators due to the inherent nature of the interventions. Although the statistician who performs the data analysis will be blind to the intervention, the master chart and statistical review were also conducted by the study guide, who will not blind to the intervention. ) 2. Once the subject is allocated to either of the three group, the subject will continue to participate in the study.In the operating room, patients will be positioned supine with their neck flexed and head extended. The American Society of Anaesthesiologists (ASA) standard monitoring will be applied , and pulse-oximetry of the same make will be used in all patients. Group allocation will be disclosed to the intraoperative anesthesia team at this point. 3. GA induction will be standardised. Fresh gas flow will be set at 10L/ min.Patient will be pre oxygenated for 3 minutes from this point by any of the following methods in which they are allocated. 4. Group I - The group with Facemask (with fresh gas flow of 10L/min and FiO2 100), patients will be breathing spontaneously with tidal volume breathing, without bagging or pressure support . 5. Group II - In the PSV group, the PSV will be given using BPL E-FLO 6C Anesthesia Machine and circle absorbent system with face mask. Pressure support of 10CmH2O and FIO2 100.6. Group III- In the PSV +PEEP group settings of PSV 10CMH2O, PEEP of 8 CmH2O, FIO2 100. 7. After three minutes of pre oxygenation patient will be induced with propofol (1.5-2.5 mg/Kg) bolus dose followed by propofol infusion of 200mcg/kg/min). 8. Two check ventilation breath will be performed to ensure that the patient is able to be ventilated - Vecuronium 0.1 mg/Kg will be administered and facemark will be removed from patient. 9. From this point ,time taken for desaturation till 92% of SpO2 (IN SECONDS) will be recorded . Heamodynamic parameters (HR, NIBP) will be recorded. After SpO2 reaches 92% , patients will be mask ventilated for 2 minutes, followed by endotracheal intubation or supraglottic airway insertion will be performed and anesthesia will be continued as per plan. . 10. The correct placement of the ET tube will be confirmed by capnography and five-point auscultation (five breaths). After this, standard management will be followed for both ventilation and peri-operative management as per protocol for all three groups. 11.Heamodynamic parameters will be recorded at the beginning of preoxygeantion, at the end of pre oxygenation, at the end of safe apnea period and 2 minutes after ventilation later. 12.The statistical analysis will be done by appropriate statistical methods like mean,percentages, standard deviation, Chi-square test and other relevant type of statistical tests depending upon the type of data collected. |