Table 1 Search strategies

#1

ultrasonography[MeSH Terms]

#2

((((((((((((((((((((((((Diagnostic Ultrasound[Title/Abstract]) OR (Diagnostic Ultrasounds[Title/Abstract])) OR (Ultrasound, Diagnostic[Title/Abstract])) OR (Ultrasounds, Diagnostic[Title/Abstract])) OR (Ultrasound Imaging[Title/Abstract])) OR (Imaging, Ultrasound[Title/Abstract])) OR (Imagings, Ultrasound[Title/Abstract])) OR (Echotomography[Title/Abstract])) OR (Ultrasonic Imaging[Title/Abstract])) OR (Imaging, Ultrasonic[Title/Abstract])) OR (Sonography, Medical[Title/Abstract])) OR (Medical Sonography[Title/Abstract])) OR (Ultrasonographic Imaging[Title/Abstract])) OR (Imaging, Ultrasonographic[Title/Abstract])) OR (Imagings, Ultrasonographic[Title/Abstract])) OR (Ultrasonographic Imagings[Title/Abstract])) OR (Echography[Title/Abstract])) OR (Diagnosis, Ultrasonic[Title/Abstract])) OR (Diagnoses, Ultrasonic[Title/Abstract])) OR (Ultrasonic Diagnoses[Title/Abstract])) OR (Ultrasonic Diagnosis[Title/Abstract])) OR (Echotomography, Computer[Title/Abstract])) OR (Computer Echotomography[Title/Abstract])) OR (Tomography, Ultrasonic[Title/Abstract])) OR (Ultrasonic Tomography[Title/Abstract])

#3

((ultrasound-guided[Title/Abstract]) OR (lung ultrasound[Title/Abstract])) OR (lung ultrasonography[Title/Abstract])

#4

#1 OR #2 OR #3

#5

(((((recruitment maneuver[Title/Abstract]) OR (recruitment maneuvers[Title/Abstract])) OR (RM[Title/Abstract])) OR (open lung[Title/Abstract])) OR (protected ventilation[Title/Abstract])) OR (protective ventilation[Title/Abstract])

#6

pulmonary atelectasis[MeSH Terms]

#7

(((((((((((((((((((((((((((((((((((((((((((((((Atelectases, Pulmonary[Title/Abstract]) OR (Atelectasis, Pulmonary[Title/Abstract])) OR (Pulmonary Atelectases[Title/Abstract])) OR (Lung Collapse[Title/Abstract])) OR (Collapse, Lung[Title/Abstract])) OR (Atelectasis[Title/Abstract])) OR (Atelectases[Title/Abstract])) OR (Congestive Pulmonary Atelectasis[Title/Abstract])) OR (Atelectases, Congestive Pulmonary[Title/Abstract])) OR (Atelectasis, Congestive Pulmonary[Title/Abstract])) OR (Congestive Pulmonary Atelectases[Title/Abstract])) OR (Pulmonary Atelectases, Congestive[Title/Abstract])) OR (Pulmonary Atelectasis, Congestive[Title/Abstract])) OR (Congestive Atelectasis[Title/Abstract])) OR (Atelectases, Congestive[Title/Abstract])) OR (Congestive Atelectases[Title/Abstract])) OR (Atelectasis, Congestive[Title/Abstract])) OR (Resorption Pulmonary Atelectasis[Title/Abstract])) OR (Atelectases, Resorption Pulmonary[Title/Abstract])) OR (Atelectasis, Resorption Pulmonary[Title/Abstract])) OR (Pulmonary Atelectases, Resorption[Title/Abstract])) OR (Pulmonary Atelectasis, Resorption[Title/Abstract])) OR (Resorption Pulmonary Atelectases[Title/Abstract])) OR (Resorption Atelectasis[Title/Abstract])) OR (Atelectases, Resorption[Title/Abstract])) OR (Atelectasis, Resorption[Title/Abstract])) OR (Resorption Atelectases[Title/Abstract])) OR (Contraction Pulmonary Atelectasis[Title/Abstract])) OR (Atelectases, Contraction Pulmonary[Title/Abstract])) OR (Atelectasis, Contraction Pulmonary[Title/Abstract])) OR (Contraction Pulmonary Atelectases[Title/Abstract])) OR (Pulmonary Atelectases, Contraction[Title/Abstract])) OR (Pulmonary Atelectasis, Contraction[Title/Abstract])) OR (Postoperative Pulmonary Atelectasis[Title/Abstract])) OR (Atelectases, Postoperative Pulmonary[Title/Abstract])) OR (Atelectasis, Postoperative Pulmonary[Title/Abstract])) OR (Postoperative Pulmonary Atelectases[Title/Abstract])) OR (Pulmonary Atelectasis, Postoperative[Title/Abstract])) OR (Compression Pulmonary Atelectasis[Title/Abstract])) OR (Atelectases, Compression Pulmonary[Title/Abstract])) OR (Atelectasis, Compression Pulmonary[Title/Abstract])) OR (Compression Pulmonary Atelectases[Title/Abstract])) OR (Pulmonary Atelectases, Compression[Title/Abstract])) OR (Pulmonary Atelectasis, Compression[Title/Abstract])) OR (Compression Atelectasis[Title/Abstract])) OR (Atelectases, Compression[Title/Abstract])) OR (Atelectasis, Compression[Title/Abstract])) OR (Compression Atelectases[Title/Abstract])

#8

#6 OR #7

#9

((randomized controlled trial[Publication Type] OR randomized[Title/Abstract] OR

placebo[Title/Abstract]) OR (RCT[Title/Abstract]))

#10

#4 AND #5 AND #8 AND #9