Comparison of two Methods of Preoxygenation in Elderly Patients Undergoing Surgery under General Anaesthesia

Background and Aims: Preoxygenation is performed routinely as an integral part of induction for general anaesthesia to reduce the risk of hypoxia for planned or unplanned periods of apnoea during the induction of anaesthesia. 3-5 minutes of tidal volume preoxygenation is the most preferred technique of choice for preoxygenation. This technique may not be feasible in emergency situations. Faster method of preoxygenation may be more useful and a better alternative in certain clinical conditions like rapid sequence induction, life saving emergencies etc. This study aims to compare the effectiveness between two methods of preoxygenation i.e. 8 vital capacity breath (VCB) in 1 minute and Tidal volume breathing (TVB) for 3 minutes and in elderly patients, by assessing changes in arterial oxygen tension (PaO 2 )and apneoa induced desaturation time. Material and Methods: This prospective randomised controlled double blind study was conducted with 60 elderly patients (age 60-70 yrs) and were divided into 2 groups-Group VCB and Group TVB. After preoxygenation with either method, anaesthesia was induced in all patients. Mask ventilation was not done and following intubation endotracheal tube was kept open to atmosphere. The time taken for the patients to desaturate to 90% was noted and immediately ventilation was resumed. Arterial blood gas samples were taken while patients were breathing room air, immediately after preoxygenation and at 90% desaturation. Results: After preoxygenation group VCB had significant higher PaO 2 values than group TVB( 451.50 68.57 vs 400.19 63.69). The apnoea induced desaturation time for group VCB was 494.77 18.92 secs and group TVB was 506.67 22.70 secs, which was statistical insignificant.