A randomised trial comparing 80% and 100% inspired oxygen concentrations for time to adequate preoxygenation using end-tidal oxygen concentration targets
G Venkata Poornima, A Chaitanya Pratyusha, CH Rama Krishna Prasad, Ramachandran Gopinath, Rama Krishna Ravula, R SharanyaABSTRACT
Background and Aims:
Preoxygenation with 100% oxygen is associated with absorption atelectasis. This study compared 80% and 100% fractional inspired oxygen concentration (FiO 2 ) for the time to achieve adequate preoxygenation, defined by end-tidal oxygen (EtO 2 ). Secondary outcomes included the incidence of postoperative atelectasis, proportion of patients requiring more than 3 minutes for preoxygenation, haemodynamic changes, and desaturation.
Methods:
Two-hundred patients for general anaesthesia were randomly divided into either Group I or Group S, the intervention and the standard practice groups, and were preoxygenated with 80% and 100% FiO
2
, respectively. The time taken to reach an EtO
2
of 10% below the administered FiO
2
was considered the time to adequate preoxygenation. A lung ultrasonography was performed at baseline and again immediately after extubation. Independent
Results:
The median preoxygenation time was comparable between groups: 95 s [interquartile range (IQR) 70–133] and 99.5 s (IQR 80.3–140) in Group I and S, respectively (
Conclusion:
Non-inferiority of FiO 2 80% with 100% could not be established within the prespecified margin, though the median time to achieve adequate preoxygenation was comparable.