Fig. 2
![Fig. 2](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12871-022-01798-z/MediaObjects/12871_2022_1798_Fig2_HTML.png)
Schematic diagram of the study protocol. LUS: lung ultrasound score; RMs: recruitment manoeuvres; PACU: postanaesthesia care unit; UD: ultrasound-guided; SI: sustained inflation; T0: immediately before induction; T1:immediately after induction; T2: immediately after the end of surgery; T3: 30Â min after tracheal extubation