Search Strategy (No. of Records Retrieved)

Search Strategy (no. Of records retrieved)

Medline via pubmed

#1 Intubation[MH] OR Intubation, intratracheal[MH] OR Intubation, Gastrointestinal[MH] (43831)

#2 Endotracheal Intubation[ALL] OR Tracheal Intubation[ALL] OR Intratracheal Intubation[ALL] (38373)

#3 Esophageal Intubation[ALL] or Oesophageal Intubation [ALL] (517)

#4 Endotracheal Tube[ALL] OR Tracheal Tube [ALL] OR ET Tube[ALL] OR ETT[ALL] OR TT[ALL] (24980)

#5 "Ultrasonography"[MH] OR "ultrasonography" [SH] OR "Ultrasonics"[MH] (349638)

#6 Ultraso*[ALL] OR Sonograph*[ALL] (420621)

#7 #1 OR #2 OR #3 OR #4 (69980)

#8 #5 OR #6 (475227)

#9 #7 AND #8 (1235)

Embase via Ovid

#1 tracheal intubation.mp. (7730)

#2 exp endotracheal intubation/ or exp intubation/ or exp endotracheal tube/ or exp trachea/ or endotracheal tube.mp. or exp instrumentation/ (156602)

#3 esophageal intubation.mp. or exp esophagus intubation/ (1151)

#4 exp ultrasound/ or exp ultrasound scanner/ or ultrasound.mp. (291100)

#5 ultraso$.mp. (393878)

#6 Sonography.mp. or exp echography/ (531015)

#7 #1 or #2 or #3 (158000)

#8 #4 or #5 or #6 (715970)

#9 #7 or #8 ( 6938)

Cochrane library search

#1 MeSH descriptor: [Intubation] explode all trees (4115)

#2 MeSH descriptor: [Intubation, Intratracheal] explode all trees (3405)

#3 MeSH descriptor: [Intubation, Gastrointestinal] explode all trees 576

#4 Endotracheal Intubation or Tracheal Intubation or Intratracheal Intubation 5208

#5 Esophageal Intubation or Oesophageal Intubation 311

#6 Endotracheal Tube or Tracheal Tube or ET Tube or ETT or TT 4663

#7 MeSH descriptor: [Ultrasonography] explode all trees 7806

#8 MeSH descriptor: [Ultrasonics] explode all trees 256

#9 Ultraso* or Sonograph* 20122

#10 #1 or #2 or #3 or #4 or #5 or #6 9790

#11 #7 or #8 or #9 21951

#12 #10 and #11 356

Following key words are used to search databases:

(Endotracheal OR Intratracheal OR Esophageal intubation) and (ultrasonography OR Ultrasound OR Sonography)

Tripdatabase (http://www.tripdatabase.com) (372)

Korea Med(http://www.koreamed.org) (10)

Lilcas (http://lilacs.bvsalud.org) (0)

Open grey (http://www.opengrey.eu) (0)

Following keywords are used to search trial registry:

1.  endotracheal intubation and ultrasonography

2.  endotracheal intubation and ultrasound

3.  endotracheal intubation and sonography

4.  intratracheal intubation and sonography

5.  intratracheal intubation and ultrasonography

6.  intratracheal intubation and ultrasound.

Clinical Trial Registry (http://apps.who.int/trialsearch) (42)