Table 1 Characteristics of the included studies. Oesophageal intubation refers specifically to unrecognised oesophageal intubation. All physician teams utilised muscle relaxants

Aijian 1989 [17]

USA

< 19 years, arrested patients only

28

Non-physician, no relaxants

Road

Overall intubation success, overall airway complication, oesophageal intubation, endobronchial intubation

Moderate

Andrew 2015 [18]

Australia

< 16 years

16

Non-physician, with relaxants

Helicopter

Overall and first look success rate, multiple attempts

Low

Babl 2001 [19]

USA

< 19 years

15

Non-physician, no relaxants

Road

Overall intubation success rate

Low

Baker 2009 [20]

USA

< 18 years

148

Non-physician, no relaxants

Road

Overall and first look success rate, overall complication rate

Moderate

Bankole 2011 [6]

USA

< 13 years, traumatic head injury only

31

Non-physician, no relaxants

Helicopter and road

Overall success and airway complication rate, oesophageal intubation, multiple attempts

Low

Boswell 1995 [21]

USA

< 14 years, unconscious trauma patients transported by helicopter only

58

Non-physician, no relaxants

Helicopter

Overall intubation success rate

Moderate

Brownstein 1996 [22]

USA

< 16 years, successful field intubations only

355

Non-physician, with relaxants

Road

Overall complication, oesophageal and endobronchial intubation rate, aspiration rate

Moderate

Burns 2017 [10]

Australia

< 16 years

82

Physician

Helicopter and road

Overall intubation and first look success, overall airway complication, oesophageal and endobronchial intubation, hypoxia, aspiration, multiple attempts

Low

Burton 2003 [23]

USA

< 13 years

137

Non-physician, no relaxants

Road

Overall intubation success rate

Low

Carlson 2015 [3]

USA

< 18 years

3049

Non-physician, no relaxants

Helicopter and road

Overall intubation success rate

Moderate

Demaret 2016 [24]

Belgium

< 16 years

353

Physician

Road

Overall intubation and first look success

Low

Dyson 2017 [25]

Australia

< 15 years

434

Non-physician, with relaxants

Road

Overall intubation and first look success

Low

Ehrlich 2004 [26]

USA

< 19 years, trauma only

59

Non-physician, with relaxants

Helicopter and road

First look success, overall airway complication, oesophageal and endobronchial intubation, aspiration rate

Moderate

Eich 2009 [1]

Germany

< 14 years

82, 58 reported in detail

Physician

Helicopter and road

Overall intubation and first look success, overall airway complication, oesophageal and endobronchial intubation, multiple attempts

Moderate

Garner 2019 [7]

Australia

< 16 years

(a) 7, (b) 61

(a) Non-physician, no relaxants; (b) physician

(a) Road, (b) helicopter

Overall intubation and first look success, overall airway complication, oesophageal and endobronchial intubation, hypoxia, aspiration rate, multiple attempts

Low

Garza 2005 [5]

USA

< 16 years, arrested patients only

86

Non-physician, no relaxants

Road

Overall intubation success rate

Moderate

Gausche 2000 [27]

USA

< 12 years

324

Non-physician, no relaxants

Road

Overall intubation success rate, overall airway complication, oesophageal and endobronchial intubation rate

Low

Gerritse 2010 [8]

Netherlands

< 16 years

(a) 86, (b) 214

(a) Non-physician, no relaxants; (b) physician

(a) Helicopter, (b) road

Overall intubation success, overall airway complication, oesophageal intubation rate

Low

Hansen 2015 [28]

USA

< 18 years

(a) 2444, (b) 408

(a) Non-physician, no relaxants; (b) non-physician, with relaxants

Helicopter and road

Overall intubation success, oesophageal intubation rate

Moderate

Hansen 2018 [29]

USA

< 18 years, transported cardiac arrests only

35

Non-physician, no relaxants

Road

Overall intubation success, multiple attempt rate

Low

Harrison 2004 [30]

USA

< 13 years

143

Non-physician, with relaxants

Helicopter and road

Overall intubation and first look success, oesophageal intubation, hypoxia, multiple attempts

Moderate

Heschl 2018 [31]

Australia

< 15 years

87

Non-physician, with relaxants

Helicopter

Overall intubation and first look success, oesophageal intubation, multiple attempts

Moderate

Jarvis 2019 [32]

USA

< 15 years

(a) 406, (b) 49

(a) Non-physician, no relaxants; (b) non-physician, with relaxants

Helicopter and road

First look success

Moderate

Kumar 1997 [33]

USA

< 16 years, arrested patients only

39

Non-physician, no relaxants

Road

Overall intubation success rate

Moderate

Lavery 1992 [34]

USA

< 19 years, trauma only

14

Non-physician, no relaxants

Road

Overall intubation success rate

Moderate

Losek 1989 [35]

USA

< 19 years

63

Non-physician, no relaxants

Road

Overall intubation and first look success, multiple attempts

Low

Losek 1994 [36]

USA

< 19 years

193

Non-physician, no relaxants

Road

Overall intubation success rate

Low

Martinon 2011 [37]

France

2–15 years, unintentional traumatic brain injury only

(a) 188, (b) 108

(a) Physician before guideline; (b) physician after guidelines

Road

Overall success rate, overall airway complication rates, hypoxia

Moderate

Moors 2018 [38]

Netherlands

< 17 years

(a) 79, (b) 103

(a) Non-physician, no relaxants; (b) physician

(a) Road, (b) helicopter

Overall intubation success, oesophageal and endobronchial intubation

Low

Nakayama 1990 [39]

USA

Trauma admissions to a paediatric trauma centre

14

Non-physician, no relaxants

Road

Overall intubation success, overall airway complication rate, oesophageal and endobronchial intubation rates

Moderate

Nevin 2014 [40]

UK

< 16 years, trauma only

315

Physician

Helicopter and road

Overall intubation success, oesophageal intubation rate, multiple attempts

Low

Paul 1999 [41]

USA

< 13 years, trauma only

6

Paramedic

Road

Overall intubation success rate

Moderate

Pointer 1989 [42]

USA

< 15 years

36

Non-physician, no relaxants

Road

Overall intubation and first look success, overall airway complication, oesophageal and endobronchial intubation, multiple attempts

Low

Prekker 2016 [43]

USA

< 13 years

299

Non-physician, with relaxants

Road

Overall intubation and first look success, overall airway complication, oesophageal and endobronchial intubation, aspiration rate, multiple attempts

Low

Schmidt 2016 [9]

Switzerland

< 17 years

215

Physician

Helicopter

Overall intubation and first look success, oesophageal intubation

Low

Simons 2017 [44]

Finland

< 16 years

34

Physician

Helicopter and road

Oesophageal and endobronchial intubation rate, aspiration rate

Moderate

Sing 1996 [45]

USA

< 18 years, relaxant assisted cases only

40

Non-physician, with relaxants

Helicopter

Overall intubation and first look success, overall airway complication, oesophageal and endobronchial intubation, hypoxia, aspiration rate

Low

Tarpgaard 2015 [46]

Denmark

< 16 years

25

Physician

Helicopter and road

Overall intubation and first look success, overall airway complication, oesophageal intubation, hypoxia, aspiration rate

Low

Tollefsen 2013 [47]

USA

< 15 years

260

Non-physician, with relaxants

Helicopter

Overall intubation and first look success, oesophageal intubation, multiple attempts

Low

Vilke 2002 [48]

USA

< 15 years

324

Non-physician, no relaxants

Helicopter and road

Overall intubation success, and oesophageal intubation

Low