Fig. 1From: Effects of small-dose S-ketamine on anesthesia-induced atelectasis in patients undergoing general anesthesia accessed by lung ultrasound: study protocol for a randomized, double-blinded controlled trialFlow diagram of the Consolidated Standards of Reporting Trials [36]. Group 1, S-ketamine group; group 2, normal saline group; T1, after radial artery puncture; T2, 15 min after tracheal intubation; T3, before extubationBack to article page