Airway management complications in children with difficult tracheal intubation from the Pediatric Difficult Intubation (PeDI) registry: a prospective cohort analysis

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Airway management complications in children with difficult tracheal intubation from the Pediatric Difficult Intubation (PeDI) registry: a prospective cohort analysis John Edem Fiadjoe, Akira Nishisaki, Narasimhan Jagannathan, Agnes I Hunyady, Robert S Greenberg, Paul I Reynolds, Maria E Matuszczak, Mohamed A Rehman, David M Polaner, Peter Szmuk, Vinay M Nadkarni, Francis X McGowan Jr, Ronald S Litman, Pete G Kovatsis

Summary Background Despite the established vulnerability of children during airway management, remarkably little is known about complications in children with difficult tracheal intubation. To address this concern, we developed a multicentre registry (Pediatric Difficult Intubation [PeDI]) to characterise risk factors for difficult tracheal intubation, establish the success rates of various tracheal intubation techniques, catalogue the complications of children with difficult tracheal intubation, and establish the effect of more than two tracheal intubation attempts on complications.

Lancet Respir Med 2015

Methods The PeDI registry consists of prospectively collected tracheal intubation data from 13 children’s hospitals in the USA. We established standard data collection methods before implementing the secure web-based registry. After establishing standard definitions, we collected and analysed patient, clinician, and practice data and tracheal intubation outcomes. We categorised complications as severe or non-severe.

Children’s Hospital of Philadelphia, Philadelphia, PA, USA (A Nishisaki MD, J E Fiadjoe MD, Prof F X McGowan Jr MD, Prof V M Nadkarni MD, Prof R S Litman DO); Perelman School of Medicine, University of Pennsylvania, Pennsylvania, PA, USA (J E Fiadjoe, Prof F X McGowan Jr, Prof V M Nadkarni, Prof M A Rehman MD, Prof R S Litman); Children’s Hospital Boston, Boston, MA, USA (P G Kovatsis MD); Harvard Medical School, Boston, MA, USA (P G Kovatsis); Ann and Robert H Lurie Children’s Hospital of Chicago, Chicago, IL, USA (N Jagannathan MD); Feinberg School of Medicine, Northwestern University, Illinois, IL, USA (N Jagannathan); The Children’s Hospital Denver, Denver, CO, USA (Prof D M Polaner MD); University of Colorado School of Medicine, Denver, CO, USA (Prof D M Polaner); Seattle Children’s Hospital, Seattle, WA, USA (A I Hunyady MD); University of Washington Medical School, Seattle, WA, USA (A I Hunyady); University of Michigan Medical School, Michigan, MI, USA (P I Reynolds MD); University of Texas Southwestern Medical Center, Dallas, TX, USA (Prof P Szmuk MD); Dallas and Children’s Medical Center at Dallas and Outcome Research Consortium, Cleveland, OH, USA (Prof P Szmuk); University of Texas Health Science Center Houston, Texas, TX, USA (M E Matuszczak MD);

Findings Between August, 2012, and January, 2015, 1018 difficult paediatric tracheal intubation encounters were done. The most frequently attempted first tracheal intubation techniques were direct laryngoscopy (n=461, 46%), fibre-optic bronchoscopy (n=284 [28%]), and indirect video laryngoscopy (n=183 [18%]) with first attempt success rates of 16 (3%) of 461 with direct laryngoscopy, 153 (54%) of 284 with fibre-optic bronchoscopy, and 101 (55%) of 183 with indirect video laryngoscopy. Tracheal intubation failed in 19 (2%) of cases. 204 (20%) children had at least one complication; 30 (3%) of these were severe and 192 (19%) were non-severe. The most common severe complication was cardiac arrest, which occurred in 15 (2%) patients. The occurrence of complications was associated with more than two tracheal intubation attempts, a weight of less than 10 kg, short thyromental distance, and three direct laryngoscopy attempts before an indirect technique. Temporary hypoxaemia was the most frequent non-severe complication. Interpretation More than two direct laryngoscopy attempts in children with difficult tracheal intubation are associated with a high failure rate and an increased incidence of severe complications. These results suggest that limiting the number of direct laryngoscopy attempts and quickly transitioning to an indirect technique when direct laryngoscopy fails would enhance patient safety. Funding None.

Introduction Tracheal intubation is a potentially life-saving procedure done by many clinicians and is usually easily accomplished with conventional direct laryngoscopy. Difficult tracheal intubation requires unique expertise and methods such as extraglottic airway devices, fibre-optic bronchoscopy, and video laryngoscopy.1 Despite the widespread use of these indirect techniques by various clinicians (eg, emergency room physicians, neonatologists, intensivists, surgeons, and anaesthesiologists), little is known about related adverse events.2–4 Children under care of an anaesthetist have more airway-related adverse events than adults.5 Analysis of the American Society of Anesthesiologists (ASA) closed claims database showed that respiratory events were more common in children than in adults (43% vs 30% respectively; p≤ 0·01) with greater mortality in paediatric claims than in adult claims (50% vs 35%; p ≤0·01).5,6 The Fourth National Audit

Project (NAP4) of the UK Royal College of Anaesthetists and the Difficult Airway Society did a study7,8 of major complications of airway management in their National Health Service hospitals during 1 year. They reported only ten events in children younger than 10 years, four of which were related to difficult intubation. Complications included subglottic narrowing, aspiration, and death. A knowledge gap exists about the efficacy of various indirect tracheal intubation methods in children, related complications, and their risk factors. We successfully designed and implemented a collaborative, multicentre web-based registry (the Pediatric Difficult Intubation (PeDI) registry) under the auspices of the Society for Pediatric Anesthesia to address these concerns and improve airway management in children with difficult tracheal intubation. The goals of the present study were to define the type and incidence of complications that arise from airway

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Published Online December 16, 2015 http://dx.doi.org/10.1016/ S2213-2600(15)00508-1 See Online/Comment http://dx.doi.org/10.1016/ S2213-2600(15)00519-6

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Articles

Children’s Memorial Herman Hospital, Houston, TX, USA (M E Matuszczak); and The Johns Hopkins Medical Insitutions, Baltimore, MD, USA (R S Greenberg MD) Correspondence to: Dr John E Fiadjoe, Children’s Hospital of Philadelphia, Department of Anesthesiology and Critical Care, Philadelphia, PA 19104, USA [email protected]

Research in context Evidence before the study Findings of single centre studies in adults have shown that repeated conventional tracheal intubation attempts in critically ill patients contribute to patient morbidity. Multicentre studies from paediatric intensive care units suggest that critically ill children are at high risk of complications during airway management in the intensive care unit. Little is known about the complications and associated risk factors of airway management in children with difficult tracheal intubation cared for by anaesthesiologists. Before undertaking this study we searched the scientific literature published between October, 1975, and October, 2011, with the terms “pediatric difficult intubation”, “difficult airway”, “difficult direct laryngoscopy”, “difficult tracheal intubation”, “complications and pediatric intubation”, “anesthesiology and pediatric difficult intubation” in various combinations. We filtered our results to exclude adult studies, case reports, and case series. We found no relevant large multicentre trials directly relating to this topic. The aim of our study was to establish the complications and their associated risk factors in children included in a prospective multicentre difficult tracheal intubation registry.

management in children with difficult tracheal intubation; establish the success of various tracheal intubation techniques; identify associations between patient, clinician, and practice characteristics, and the occurrence of complications; and establish the effect of multiple tracheal intubation attempts (>2 attempts) on complications.

Methods Study design The PeDI Collaborative Group was created as a special interest group within the Society for Pediatric Anesthesia with the goal to make possible multicentre collaboration and quality improvement in patients with difficult tracheal intubation. In December, 2010, members of the Society for Pediatric Anesthesia were solicited via electronic mail to take part in the special interest group; known experts in the paediatric anaesthesia community were also invited to participate. 48 members of the society responded and were included in the group; however, ten active members were instrumental in formulating the definitions for the registry. The group held four consensus development meetings between Oct 14, 2011, and Oct 17, 2012, which were attended by all the core members in person or by telephone conference. In addition to meetings held at the Society for Pediatric Anesthesia and ASA annual meetings, task force discussions were continued using a dedicated group listserv and telephone conferences to define paediatric airway management related terminology and adopt standard definitions in order to create a multicentre registry. The group defined relevant outcomes, developed a standard data collection sheet, standardised data definitions, and established 2

Added value of this study This study is the first to assess the complications of children with difficult tracheal intubation as established by anaesthesiologists. This study establishes the complication rates in these patients, identifies the risk factors for complications, and estimates the incidence of difficult tracheal intubation in children under anaesthesia care. This study has identified a high complication rate. This finding should encourage further investigations and a change in clinical practice patterns to enhance patient safety. Implications of all the available evidence Children with difficult tracheal intubation are a high-risk group and multiple tracheal intubation attempts are a key risk factor for complications. Clinicians should treat every tracheal intubation attempt as a critical intervention and should limit the number of direct laryngoscopy and tracheal intubation attempts in this population. Future research should investigate interventions to reduce these complications such as checklists and care protocols. Additionally, the role and efficacy of passive oxygenation during tracheal intubation is unclear and should be investigated.

standard operating procedures by expert consensus. This consensus was reached iteratively by open discussions until all ten core members reached agreement.

Study population We collected tracheal intubations supervised or performed by anaesthesiologists in elective and nonelective tracheal intubation situations. These situations included tracheal intubations in various anaesthetic locations and non-elective tracheal intubations from other hospital locations such as the emergency department and intensive care unit whenever the anaesthesiology team assisted with airway management. We used the following inclusion criteria in children younger than 18 years in whom an anaesthesiologist supervised or performed tracheal intubation: children with difficult laryngeal exposure with conventional direct laryngoscopy as assessed by the attending anaesthesiologist (Cormack and Lehane classification ≥3);9 children in whom conventional direct laryngoscopy was physically impossible because of anatomical reasons (eg, severely limited mouth opening or other craniofacial anomalies); children who had failed conventional direct laryngoscopy within the preceding 6 months; children in whom the attending anaesthesiologist deferred conventional direct laryngoscopy because of an unfavourable (predictive of a difficult laryngoscopy) airway physical examination (eg, neonatal Robin sequence) or the clinical situation in which a nonattending clinician obtains an unfavourable view that is unconfirmed with a subsequent conventional direct laryngoscopy by the attending anaesthesiologist.

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The airway physical examination was not standardised but was based on the assessment of the attending anaesthesiologists. Several cases met more than one inclusion criteria and all tracheal intubation attempts were collected if one of the inclusion criteria was met. Separately we also queried each anaesthesiologist attending about whether he or she anticipated the difficulty with mask ventilation or tracheal intubation or both.

We defined an intubation attempt as the act of inserting an airway device into the pharynx or naris with the intent to perform tracheal intubation. Many attempts to pass the tracheal tube through the vocal cords were regarded as one attempt provided the intubating device Cases entered

Complication

Centre A

395

Site enrolment and data capture

Centre B

231

33 (14%)

After Institutional Review Board approval, we developed and piloted a secure, password-protected web-based data entry portal at the data coordinating centre (at the Children’s Hospital of Philadelphia, PA, USA). We expanded this portal to 13 academic children’s hospitals in the USA. The contributing sites are listed in the acknowledgments section. Each site identified a project coordinator (paediatric anaesthesiologist attending). The project coordinator educated their faculty about the registry, developed a site-specific compliance plan to ensure 100% data capture and did monthly audits for data capture and accuracy. Our compliance plan included monthly data audits at each site and a standardised electronic medical record or manual search for missed cases. The data coordinating centre did monthly audits of the aggregate data to ensure data entry completeness and sent monthly missing data reports to the project coordinators at each site. A steering committee reviewed and approved each centre’s compliance plan before their full participation. One site failed to meet compliance with audits and 100% data capture and was excluded from the analysis. The web-based data entry portal used the Research Electronic Data Capture (REDCap) method hosted at the data coordinating centre.10 We prospectively created a standard data collection sheet that was completed either by a member of the anaesthesia care team, the site principal investigator, or one of the principal investigator’s designees whenever a difficult intubation was encountered. We had three methods of data collection and entry: an electronic medical record hot key alerted a research assistant by pager whenever a difficult intubation was encountered and the data was attempted to be collected shortly after the intubation; the attending physician completed the data entry sheet immediately after encountering a difficult intubation; and the care team was interviewed and data entry sheet was completed after a discovered case via an electronic medical record search or quality assurance process. In most cases the data sheet was collected immediately after the difficult intubation occurred. The site principal investigator or a member of the research team was responsible for verifying the data on the collection forms and entering the data into the online registry.

Centre C

117

23 (20%)

Definitions We deemed any patient who met our inclusion criteria (category 1–4) as having difficult tracheal intubation.

92 (23%)

Centre D

76

22 (29%)

Centre E

37

9 (24%)

Centre F

33

7 (21%)

Centre G

31

4 (13%)

Centre H

26

4 (15%)

Centre I

24

2 (8%)

Centre J

24

3 (13%)

Centre K

14

2 (14%)

Centre L Total

10

3 (30%)

1018

204 (20%)

Median (IQR)

33 (24–97)

18% (14–24)

Data are n or n (%) unless stated otherwise. Centres sorted by the number of difficult cases of tracheal intubation.

Table 1: Case distribution across centres

Anticipated difficult airway (n=821)

Unanticipated difficult airway (n=197)

Total (n=1018)

810 (99%)

188 (95%)

998 (98%)

10 (1%)

9 (5%)

19 (2%)

157 (19%)

47 (24%)

204 (20%)

19 (2%)

11 (6%)

30 (3%)

10 (1%)

5 (3%)

15 (1%)

Severe airway trauma

8 (1%)

6 (3%)

14 (1%)

Death

3 (<1%)

2 (1%)

Aspiration

1 (<1%)

0

1 (<1%)

Pneumothorax

1 (<1%)

0

1 (<1%)

Success* Surgical or failed airway* Any complications Severe complications† Cardiac arrest

Non-severe complications†

5 (<1%)

148 (18%)

44 (22%)

192 (19%)

Hypoxaemia

65 (8%)

29 (15%)

94 (9%)

Minor airway trauma

36 (4%)

8 (4%)

44 (4%)

Oesophageal intubation with immediate recognition

21 (3%)

11 (6%)

32 (3%)

Laryngospasm

24 (3%)

8 (4%)

32 (3%)

Epistaxis

12 (1%)

2 (1%)

14 (1%)

7 (1%)

5 (3%)

12 (1%)

10 (1%)

2 (1%)

12 (1%)

Bronchospasm Pharyngeal bleeding Arrhythmia

3 (<1%)

1 (1%)

4 (<1%)

Emesis

4 (<1%)

0

4 (<1%)

Data are n (%). *Outcome is missing in one case in anticipated difficult airway group. †Note that each case can have more than one complication. The complication rates were not significantly different between the anticipated and the unanticipated groups; however, severe complications were more commonly observed in the unanticipated difficult airway group (p=0·015, χ² test).

Table 2: Airway management outcomes and complications

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Anticipated difficult airway (n=821)

Unanticipated difficult airway (n=197)

No complications Complications (n=664) (n=157)

p value

No complications (n=150)

Complications (n=47)

Total (n=1018)

p value

No complications (n=814)

Complications (n=204)

p value

General Age (months)

79 (10–156)

34 (8–147)

0·08

25 (4–149)

7 (2–34)

0·009

68 (8–154)

23 (5–131)

Weight (kg)

20 (8–35)

12 (6–30)

0·007

12 (5–41)

7 (4–20)

0·009

18 (7–35)

11 (5–28)

0·0002

Weight <10 kg

200 (30%)

71 (45%)

0·0003

66 (44%)

28 (60%)

0·06

266 (33%)

99 (49%)

<0·0001

Male

369 (56%)

96 (61%)

108 (72%)

32 (68%)

0·61

477 (59%)

128 (63%)

ASA status (mean, median, IQR)* ASA-Emergency*

2·9 (3:3–3)

3·1 (3:3–3)

0·21 0·02

2·6 (3:2–3)

1·8 (3:2–3)

0·08

2·9 (3:3–3)

3 (3:3–3)

0·003

0·28 0·01

30 (5%)

14 (9%)

0·03

8 (6%)

2 (4%)

0·73

38 (5%)

16 (8%)

0·07

Operating room

606 (91%)

144 (92%)

0·86†

128 (86%)

36 (77%)

0·16†

734 (90%)

180 (88%)

0·41†

Off-site location

33 (5%)

3 (2%)

..

14 (9%)

2 (4%)

..

47 (6%)

5 (3%)

Intensive care unit

14 (2%)

6 (4%)

..

2 (1%)

1 (2%)

..

16 (2%)

7 (3%)

..

Other

11 (2%)

4 (2%)

..

6 (4%)

8 (17%)

..

17 (2%)

12 (6%)

..

Syndrome diagnosis‡

498 (75%)

119 (76%)

0·97‡

62 (42%)

16 (34%)

0·80‡

560 (69%)

135 (66%)

No syndrome diagnosis

143 (22%)

34 (22%)

..

83 (55%)

27 (57%)

226 (28%)

61 (30%)

23 (3%)

4 (2%)

5 (3%)

4 (9%)

28 (3%)

8 (4%)

Pierre-Robin sequence

94 (14%)

22 (14%)

0·96

4 (3%)

2 (4%)

0·58

98 (12%)

24 (12%)

0·91

Goldenhar syndrome

74 (11%)

11 (7%)

0·13

2 (1%)

0 (0%)

0·43

76 (9%)

11 (5%)

0·07

32 (5%)

11 (7%)

0·27

70 (47%)

17 (36%)

0·21

102 (13%)

28 (14%)

0·65

631 (95%)

146 (93%)

..

80 (53%)

30 (64%)

..

711 (87%)

176 (86%)

Location ..

Syndrome

Undefined§

0·54‡

Specific syndrome

Difficult airway exam¶ Normal Abnormal

..

Specific exam finding Micrognathia

290 (44%)

71 (45%)

0·73

21 (14%)

12 (26%)

0·07

311 (38%)

83 (41%)

0·52

Limited mouth opening

269 (41%)

58 (37%)

0·41

11 (7%)

7 (15%)

0·12

280 (34%)

65 (32%)

0·49

Cervical spine immobility

137 (21%)

30 (19%)

0·67

3 (2%)

1 (2%)

0·96

140 (17%)

31 (15%)

0·49

77 (12%)

33 (21%)

0·002

9 (6%)

5 (11%)

0·28

86 (11%)

38 (19%)

0·002

94 (14%)

30 (19%)

NA

NA

NA

NA

94 (12%)

30 (15%)

··

565 (85%)

126 (80%)

NA

NA

NA

NA

565 (69%)

126 (62%)

··

5 (1%)

1 (1%)

NA

NA

NA

NA

5 (1%)

1 (0%)

0 (0%)

0 (0%)

NA

NA

NA

NA

150 (18%)

47 (23%)

0·13||

Cormack scale 3–4

215 (32%)

85 (54%)

<0·001

143 (95%)

43 (91%)

0·32

358 (44%)

128 (63%)

<0·0001

Direct laryngoscopy impossible

169 (25%)

37 (24%)

0·62

0 (0%)

1 (2%)

0·24

169 (21%)

38 (19%)

0·50

Direct laryngoscopy failure within 109 (16%) 6 months

25 (16%)

0·88

2 (1%)

0 (0%)

1·00

111 (14%)

25 (12%)

0·60

Direct laryngoscopy is possible but harmful

29 (18%)

<0·001

4 (3%)

2 (4%)

0·58

235 (29%)

31 (15%)

<0·0001

Short thyromental distance Anticipated difficulty with: Mask ventilation and laryngoscopy Laryngoscopy only Mask ventilation only Unanticipated

··

Difficult direct laryngoscopy (inclusion criteria)**

231 (35%)

Data are n (%) or median (IQR), unless otherwise stated. ASA=American Society of Anesthesiology. NA=not applicable. *Datapoints were missing in 17 cases. †p value based on operating room vs outside of operating room. ‡Syndrome diagnosis was marked as yes if any known syndrome was diagnosed or suspected at the time of airway management; p value based on no syndrome vs syndrome undefined or confirmed. §Undefined was marked when a syndrome was suspected but not confirmed. ¶Difficult airway exam was performed by attending anaesthesiologists, data missing in one case. ||p value based on anticipated vs unanticipated difficulty before the case. **Difficult direct laryngoscopy (inclusion criteria): each case may meet more than one criterion. Syndrome diagnosis: marked as yes if any known syndrome is diagnosed or suspected at the time of airway management.

Table 3: Patient demographics and outcomes

(eg, direct laryngoscope or video laryngoscope) remained in place. We categorised complications as severe and non-severe, modified from the National Emergency Airway Registry for 4

Children (NEAR4KIDS) operational definitions.11,12 The following were categorised as severe complications: severe airway trauma (glottic or subglottic injury), clinical evidence of aspiration (chest radiograph or bronchoscopy evidence),

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Anticipated difficult airway (n=821) No complications (n=664)

Complications (n=157)

p value

Unanticipated difficult airway (n=197)

Total (n=1018)

No complications Complications (n=150) (n=47)

p value

No complications (n=814)

Complications (n=204)

p value

0·18

First attempt provider* Trainee

389 (59%)

99 (63%)

80 (54%)

29 (62%)

0·39

469 (58%)

128 (63%)

CRNA

116 (17%)

15 (10%)

··

37 (25%)

7 (15%)

··

153 (19%)

22 (11%)

··

Attending anaesthesiologist

139 (21%)

33 (21%)

··

29 (19%)

9 (19%)

··

168 (21%)

42 (21%)

··

18 (3%)

8 (5%)

··

1 (1%)

0 (0%)

··

19 (2%)

8 (4%)

··

2 (0%)

1 (1%)

··

2 (1%)

2 (4%)

··

4 (0%)

3 (1%)

··

Trainee

312 (47%)

55 (37%)

··

31 (22%)

3 (6%)

··

343 (43%)

58 (30%)

··

CRNA

72 (11%)

7 (5%)

··

6 (4%)

0 (0%)

··

78 (10%)

7 (4%)

236 (36%)

71 (48%)

96 (68%)

38 (83%)

332 (41%)

109 (56%)

Otolaryngologist Other

0·053

Successful provider†

Attending anaesthesiologist Otolaryngologist Other Attending only

0·007

0·051

·· 0·001

39 (6%)

14 (9%)

··

6 (4%)

4 (9%)

··

45 (5%)

18 (9%)

2 (0%)

2 (1%)

··

3 (2%)

1 (2%)

··

5 (1%)

3 (1%)

·· ··

107 (16%)

22 (14%)

0·52

29 (19%)

8 (17%)

0·72

136 (17%)

30 (15%)

0·49

Attending experience Median (year, IQR) Fellowship training (%)‡

8 (3–20)

7 (3–14)

0·23

8 (4–18)

9 (3–18)

0·77

8 (3–20)

8 (3–17)

0·37

631 (97%)

151 (97%)

0·68

137 (94%)

44 (94%)

0·73

768 (96%)

195 (97%)

0·96

Data are n (%) unless otherwise stated. CRNA=certified registered nurse anaesthetist. *Data missing in two cases; p value was based on trainee vs non-trainee. †17 intubations were never successful; data were missing in three cases; p value was based on attending anaesthesiologist vs other. ‡Attending fellowship training status is missing in 17 cases.

Table 4: Provider characteristics

Statistical analysis We did our statistical analysis with Stata (version 11.2). Our sample included all available data during the study period. We report summary statistics using means and standard deviation for parametric variables and medians

Trainee CRNA Otolaryngologist Other anaesthesiologist Primary anaesthesiologist

1200

1000

800 Number of cases

cardiac arrest, emergent surgical airway, oesophageal intubation with delayed recognition, pneumothorax, and death. Non-severe complications included minor airway trauma (dental or lip), pharyngeal bleeding, arrhythmia without haemodynamic consequences, bronchospasm, epistaxis, oesophageal intubation with immediate recognition, hypoxaemia, laryngospasm, and emesis without aspiration. We defined hypoxaemia as a 10% decrease from the pre-intubation oxygen saturation for more than 45 s. We collected other patient, clinician, and practice data related to airway management. These included patient demographics, airway physical examination findings, mask ventilation efficacy (assessed with the Han scale13), anaesthesia induction method, airway interventions, and outcome (intubation success or failure). Patients were a-priori categorised by weight (<10 kg vs ≥10 kg).14–18 Clinician data included the clinician type (attending, trainee, or registered nurse anaesthetist), the attending’s fellowship training status and years of experience (time since completion of fellowship training). We also documented the patients’ ASA physical status classification (1–6), a system to describe the patients’ medical condition before their anaesthetic.19 The addition of E to the classification denotes an emergent procedure.

600

400

200

0

1st

2nd

3rd

4th

5th

Tracheal intubation attempt

Figure 1: Proportion of airway providers for each attempt CRNA=certified registered nurse anaesthetist.

with interquartile ranges for non-parametric variables. We used histograms of the variable distributions to determine normality. We used a contingency table method with χ² test for categorical variables with a dichotomous outcome. For non-parametric variables, we used the Wilcoxon rank sum test. For multivariable analysis, occurrence of any complications was a dichotomous dependent variable, multiple attempts (≤2 attempts vs >2 attempts) was an independent variable, and factors associated with multiple attempts in

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Anticipated difficult airway (n=821) No complications (n=664)

Complications (n=157)

Induction technique

Unanticipated difficult airway (n=197)

p value

No complications (n=150)

Complications (n=47)

0·36

p value

Total (n=1018) No complications (n=814)

Complications (n=204)

0·15

p value

0·083

Mask induction

430 (65%)

99 (63%)

··

93 (62%)

24 (51%)

··

523 (64%)

123 (60%)

··

Intravenous induction

180 (27%)

43 (27%)

··

53 (36%)

20 (43%)

··

233 (29%)

63 (31%)

··

Intravenous sedation

36 (6%)

8 (5%)

··

2 (1%)

0 (0%)

··

38 (5%)

8 (4%)

··

Tracheal induction

9 (1%)

1 (1%)

··

0 (0%)

0 (0%)

··

9 (1%)

1 (0%)

··

NA

9 (1%)

6 (4%)

··

2 (1%)

3 (6%)

··

11 (1%)

9 (4%)

Anaesthesia approach

0·11

0·04

·· 0·005

General

610 (92%)

145 (92%)

··

145 (97%)

44 (94%)

··

755 (93%)

189 (93%)

··

Sedation

47 (7%)

7 (4%)

··

3 (2%)

0 (0%)

··

50 (6%)

7 (3%)

··

Awake

6 (1%)

4 (3%)

··

2 (1%)

0 (0%)

··

8 (1%)

4 (2%)

··

None

1 (0%)

1 (1%)

··

0 (0%)

3 (6%)

··

1 (0%)

4 (2%)

··

Intubation route*

0·12

0·22

0·088

Oral

488 (74%)

109 (73%)

··

128 (90%)

40 (87%)

··

616 (77%)

149 (76%)

··

Nasal

166 (25%)

37 (25%)

··

10 (7%)

5 (11%)

··

176 (22%)

42 (21%)

··

Surgical

0 (0%)

1 (0%)

··

0 (0%)

1 (2%)

··

0 (0%)

2 (1%)

··

Other

5 (1%)

3 (2%)

··

4 (3%)

0 (0%)

··

9 (1%)

3 (2%)

First attempt device†

0·006

0·30

·· 0·001

Direct laryngoscope

220 (33%)

69 (45%)

··

128 (87%)

44 (94%)

··

348 (43%)

113 (56%)

··

Flexible fibreoptic bronchoscope

226 (34%)

51 (33%)

··

5 (3%)

2 (4%)

··

231 (29%)

53 (26%)

··

Glidescope

158 (24%)

19 (12%)

··

5 (3%)

1 (2%)

··

163 (20%)

20 (10%)

··

57 (9%)

15 (10%)

··

10 (7%)

0 (0%)

··

67 (8%)

15 (7%)

··

41 (6%)

17 (12%)

··

46 (34%)

17 (37%)

··

87 (11%)

34 (18%)

Flexible fibreoptic bronchoscope

281 (43%)

69 (47%)

··

22 (16%)

6 (13%)

··

303 (39%)

75 (39%)

··

Glidescope

241 (37%)

42 (29%)

··

48 (36%)

13 (28%)

··

289 (37%)

55 (29%)

··

Other or combined Successful device‡

0·06

Direct laryngoscope

Other or combined Neuromuscular blockade use

0·49

0·037 ··

89 (14%)

18 (12%)

··

18 (13%)

10 (22%)

··

107 (14%)

28 (15%)

··

268 (40%)

63 (40%)

0·96

72 (48%)

30 (64%)

0·06

340 (42%)

93 (46%)

0·32

Data are n (%), unless otherwise stated. NA=not applicable. *Data are missing in 19 cases. †Data are missing in eight cases. ‡Intubation was not successful in 17 intubations.

Table 5: Association between practice characteristics and complications

univariate analysis as covariates. We deemed a p value of less than 0·05 as statistically significant.

Role of the funding source There was no funding source for this study. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.

Results The study period included data collected from our centres between Aug 6, 2012, and Jan 31, 2015. The 13 centres reported 1061 cases of tracheal intubation during this period. The four largest centres contributed most of the cases in the registry; table 1 reports the distribution of cases across centres. One centre was excluded because of lack of full compliance with data capture rates and audits, leaving 1018 cases for analysis (table 1). Three centres reported 112, 164, and 20 cases of difficult tracheal intubation in 2014 with anaesthetic case volumes that year 6

of 38 813, 35 000, and 8000, respectively. This finding translates to 0·28%, 0·47%, and 0·25% of anaesthetics, respectively suggesting a range of 2–5 difficult tracheal intubations in 1000 anaesthetised children. 80% (821/1018) of the difficult tracheal intubation cases were anticipated. 20% (204/1018) of cases had at least one complication. Cardiac arrest (n=15; 2%) was the most common severe complication, and hypoxaemia (n=94; 9%) was the most common non-severe complication. All cardiac arrests were preceded by hypoxaemia. Table 2 shows tracheal intubation-related outcomes. Four of the cardiac arrests were non-elective urgent intubations; two cases in the intensive care unit and two in the emergency room. 11 of the cardiac arrest cases were elective non-urgent tracheal intubations. Five patients died shortly after tracheal intubation (within 7 days), four were unrelated to tracheal intubation (cardiac arrest and withdrawal of care), and one was related to difficult tracheal intubation (hypoxaemic arrest). The complication rates were not significantly different between the anticipated and unanticipated

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Anticipated difficult airway (n=821) No complications (n=664)

Complications (n=157)

Mask ventilation

p value

Unanticipated difficult airway (n=197) No complications (n=150)

Complications (n=47)

<0·0001

p value

Total (n=1018) No complications Complications (n=814) (n=204)

0·03

p value

<0·0001

Easy mask ventilation

430 (65%)

66 (42%)

··

118 (79%)

30 (64%)

··

548 (67%)

96 (47%)

··

Airway adjunct needed

119 (18%)

39 (25%)

··

24 (16%)

11 (23%)

··

143 (18%)

50 (25%)

··

39 (6%)

28 (18%)

··

4 (3%)

6 (13%)

··

43 (5%)

34 (17%)

··

0 (0%)

5 (3%)

··

1 (<1%)

0 (0%)

··

1 (<1%)

5 (2%)

··

76 (11%)

19 (12%)

3 (2%)

0 (0%)

79 (10%)

19 (9%)

Difficult mask ventilation Impossible for mask ventilation Not attempted Extraglottic airway* Not attempted

<0·0001

0·45

<0·0001

553 (84%)

100 (64%)

··

120 (80%)

37 (79%)

··

673 (83%)

137 (67%)

··

Easy placement and ventilation

96 (14%)

34 (22%)

··

23 (15%)

6 (13%)

··

119 (15%)

40 (20%)

··

Easy placement and poor ventilation (tidal volume <5 mL/kg)

10 (2%)

11 (7%)

··

5 (3%)

3 (6%)

··

15 (2%)

14 (7%)

··

Difficult placement and easy ventilation

2 (<1%)

4 (2%)

··

1 (1%)

0 (0%)

··

3 (<1%)

4 (2%)

··

Difficult placement and difficult ventilation

0 (0%)

6 (4%)

··

0 (0%)

1 (2%)

··

0 (0%)

7 (3%)

··

Impossible to place

1 (0%)

2 (1%)

··

1 (1%)

0 (0%)

··

2 (<1%)

2 (1%)

Number of attempts (median, IQR)†

2 (1–3)

3 (2–4)

<0·0001

3 (3–5)

4 (3–6)

0·009

2 (1–3)

3 (2–5)

·· <0·0001

1

271 (41%)

23 (15%)

··

10 (7%)

2 (4%)

··

281 (34%)

25 (13%)

··

2

181 (27%)

33 (21%)

··

20 (13%)

4 (9%)

··

201 (25%)

37 (18%)

··

3

107 (16%)

36 (23%)

··

46 (31%)

9 (19%)

··

153 (19%)

45 (22%)

··

4

60 (9%)

26 (16%)

··

32 (21%)

11 (23%)

··

92 (11%)

37 (18%)

··

5

22 (4%)

11 (7%)

··

23 (15%)

7 (15%)

··

45 (6%)

18 (9%)

··

6

8 (1%)

8 (5%)

··

7 (5%)

3 (6%)

··

15 (2%)

11 (5%)

··

15 (2%)

20 (13%)

··

12 (8%)

11 (24%)

··

27 (3%)

31 (15%)

··

7 or more

Data are n (%), unless otherwise stated. *Extraglottic airway: data are missing in two cases. †p value calculated by Wilcoxon rank-sum test.

Table 6: Process characteristics

groups; however, severe complications were more common in the unanticipated group (χ² test p=0·015; table 2). Patients who weighed less than 10 kg had more tracheal intubations with complications (49% [99/204]) than tracheal intubations without complications (33% [266/814]; table 3). This was true in both the anticipated and unanticipated groups. Patients entered in the registry because of a failed direct laryngoscopy by the attending anaesthesiologist. Patients in category 1 (cases with Cormack classification 3 and 4) had a greater proportion of complications (n=128; 63%; p<0·0001), and patients in category 4 (suspected difficulty without attending direct laryngoscopy confirmation) had fewer complications (n=31 [15%]; p<0·0001; table 3). The median number of years of experience of the supervising anaesthesiologist was 8 years (IQR 3–20; table 4). Although attending physicians made 21% of first intubation attempts, they were the eventual successful clinician in 44% of cases, which meant they often took over the intubation from the other clinicians

(trainee and certified registered nurse anaesthetist). Figure 1 shows the distribution of clinician types attempting the first five tracheal intubations in patients who had five or more attempts. Of note trainees made 20% of fifth tracheal intubation attempts. The first attempt provider type was similar between anticipated and unanticipated difficult airway cases. The attending anaesthesiologist was the more successful provider in unanticipated difficult airway cases than in anticipated difficult airway cases. Inhalational induction of anaesthesia via facemask was the most common induction method used (64% [646/1018]; table 5). 77 (8%) of 1018 cases were difficult to ventilate by facemask. Six patients were impossible to ventilate by facemask. This difficulty was anticipated in five of these patients. Two patients received neuromuscular blockade without improvement in the ability to ventilate. Two patients were ventilated successfully using an extraglottic airway device after facemask ventilation failed. Tracheal intubation was successful in all six patients (table 6). The median number of tracheal intubation

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Proportion of cases with complications

0·6 0·5 0·4 0·3 0·2 0·1 0 1

2

3

4

5

6

≥7

Number of tracheal intubation attempts

Figure 2: Proportion of cases with complications by the number of attempts for airway management The average proportion of cases with complications by the number of required intubation attempts. Each error bar represents mean (SD).

Other Glidescope Flexible fibre-optic bronchoscope Direct laryngoscope

1200

1000

Number of cases

800

600

400

200

0

1st

2nd

3rd

4th

5th

Tracheal intubation attempt

Figure 3: Type of device for each attempt Other includes Airtraq, Karl Storz C-MAC, optical stylet, Anterior Commissure scope, and others. See Online for appendix

attempts was 2·5 (IQR 2–6) in these six patients. Three patients were intubated by otolaryngologists—one with a rigid bronchoscope and two with standard direct laryngoscopy with a grade 4 view. Flexible fibre-optic intubation was done successfully through an extraglottic airway in two patients and the GlideScope Cobalt was used in one patient. Two of these patients had cardiac arrest during tracheal intubation attempts and were successfully resuscitated. 43% (433/1018) of patients in the registry were managed with neuromuscular blockade. Cases where direct laryngoscopy was attempted for the first three attempts (direct laryngoscopy persistence) had more complications (48/158 [30%] vs 62/297 [21%]; p=0·02). The occurrence of a complication was associated with the number of attempts (figure 2): odds ratio (OR) 1·5 per attempt 8

(95% CI 1·4–1·6; p<0·0001). The median number of attempts was 3 (IQR 2–5) for cases with complications while the median was two attempts (IQR 1–3) for cases without complications (p<0·0001; table 6). Oxygen was rarely given during tracheal intubation attempts. The approaches reported included nasal cannula in 17 tracheal intubations, modified nasopharyngeal airway in 76 tracheal intubations, and an endoscopy mask in four tracheal intubations. Tracheal intubation failed in 2% (19/1017) of cases (table 2). The success rate of the first tracheal intubation attempt in the registry cohort was only 30% (n=288); however, 98% of the patients were eventually successfully intubated. Figure 3 shows the distributions of devices used for each attempt. 46% (461/1010) of cases used direct laryngoscopy for the first tracheal intubation attempt, while it was the successful device in 12% (121/978) of cases. Flexible fibre-optic laryngoscope was the first attempt device in 28% (284/1010) of patients, whereas it was the successful device in 37% (378/978) of cases. The most frequently attempted first tracheal intubation techniques were direct laryngoscopy (direct laryngoscopy; n=461 [46%]), indirect video laryngoscopy (n=183 [18%]), and fibre-optic bronchoscopy (n=284 [28%]) with success rates of 16 (3%) of 461, 101 (55%) of 183, and 153 (54%) of 284, respectively. An extraglottic airway was attempted in 208 (20%) of 1016 cases. Ventilation with the extraglottic airway was poor in 17% (36/208) cases in which it was attempted, and extraglottic airway placement was impossible in 2% (4/208) of insertion attempts (table 6). Of the 36 failed extraglottic airways 17% (14/84) received neuromuscular blockade and 19% (22/118) received no neuromuscular blockade. There were 455 cases with direct laryngoscopy as the initial approach that required three or more tracheal intubation attempts. Of these cases, an early transition (after the first or second direct laryngoscopy attempt) to a non-direct laryngoscopy technique was associated with fewer complications (62/297 [21%]) than cases with late transition (>2 direct laryngoscopy attempts; 48/158 [30%]; p=0·024). The appendix shows associations between the first attempted device and patient and provider characteristics (appendix p 1). After adjusting for clustering by site, patient factors, weight less than 10 kg, thyromental distance, ASA physical status, inclusion criteria, and first attempt device, many attempts (>2) were independently associated with the occurrence of any complication (OR 3·1, 95% CI 2·1–4·6; p<0·0001; table 7)

Discussion This prospective multicentre study estimated that difficult tracheal intubation occurred in 2–5 per 1000 paediatric anaesthesia cases in large academic centres in the USA. Furthermore, this registry showed that 20% of children with difficult tracheal intubations had a complication. We identified the following

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Univariate analysis

Multivariate analysis

OR (95% CI)

p value

OR (95% CI)

p value

Multiple attempt (>2 attempts)

3·48 (2·48–4·89)

<0·0001

3·08 (2·08–4·57)

<0·0001

Weight <10 kg

2·09 (1·51–2·88)

<0·0001

1·61 (1·13–2·31)

0·009

Physical exam: short thyromental distance

1·96 (1·28–3·00)

0·002

2·72 (1·71–4·35)

<0·0001

ASA status ASA-1

Reference

ASA-2

1·60 (0·44–5·74)

0·47

1·97 (0·53–7·27)

0·31

ASA-3

1·36 (0·39–4·72)

0·63

1·92 (0·54–6·85)

0·32

3·22 (0·89–11·57)

0·07

4·04 (1·07–15·20)

0·038

2·31 (1·66–3·21)

<0·0001

2·01 (1·20–3·37)

0·008

ASA-4 Difficult direct laryngoscopy as inclusion criteria (Cormack-Lehane 3–4 or failed)

Reference

First attempt device Direct laryngoscope

Reference

Flexible fiberoptic bronchoscope

0·66 (0·45–0·97)

0·03

Reference 2·13 (1·19–3·81)

0·011

Glidescope

0·37 (0·22–0·63)

<0·0002

0·92 (0·48–1·76)

0·79

Other device

0·80 (0·43–1·49)

0·48

1·13 (0·57–2·25)

0·72

Univariate and multivariate analysis with multiple attempts (≤2 attempts vs >2 attempts), weight (<10 kg vs ≥10 kg), American Society of Anesthesia (ASA) physical status, Direct laryngoscopy failure or Cormack-Lehane 3–4 as inclusion criteria, and first attempt device, adjusted for site-level clustering with random-effect model. Univariate analysis is adjusted for clustering by site. 993 cases in the multivariate analysis (ASA status was missing in 17 cases, device data was missing in eight cases and one case with ASA-5 status completely predicted outcome, therefore dropped from analysis). Overall model was significant (p<0·0001). OR=odds ratio. ASA=American Society of Anesthesia.

Table 7: Multivariate analysis for patient, provider, and process characteristics

associations with any complication (severe or nonsevere): multiple tracheal intubation attempts (>2), weight less than 10 kg, short thyromental distance, abnormal airway physical examination, and persistent direct laryngoscopy attempts (for the first three tracheal intubation attempts). Multivariable analysis confirmed the independent association of multiple attempts with complications (severe or non-severe). Furthermore, we noted an incremental increase in the occurrence of complications with each additional tracheal intubation attempt. The high percentage of difficult tracheal intubations that were anticipated (80%) probably meant that the team was prepared with the appropriate equipment and personnel and had information about the previously successful tracheal intubation approach. In the unanticipated difficult tracheal intubation group, teams were probably unprepared and not ready with the optimum equipment. Despite these population differences, increasing attempts and lower weight were associated with more complications in both groups. Understandably unanticipated difficult tracheal intubations had more severe complications and more tracheal intubation attempts and the attending anaesthesiologist was more likely to be the successful provider. These findings suggest that preparation matters and might lower the likelihood of severe complications. Hypoxaemia was the most common non-severe complication related to tracheal intubation and occurred in 9% of tracheal intubation attempts. Strategies to prevent hypoxaemia during tracheal intubation include pre-oxygenation via facemask and passive oxygen

administration during the attempt. Facemask preoxygenation is routinely done before tracheal intubation and is consistent with the ASA guideline to “administer facemask pre-oxygenation before initiating management of a difficult airway”.20,21 The ASA further states that practitioners should “actively pursue opportunities to deliver supplemental oxygen throughout the process of difficult airway management”. Although pre-oxygenation is presumably practised, few practitioners in participating centres provided supplemental oxygen during the actual intubation (10%). Children have higher oxygen consumption rates than adults and their rate of arterial oxygen desaturation when apnoeic is consequently much faster. This rapid desaturation rate creates a time pressure to intubate these children. This pressure is heightened by the common practice of intubation by trainees with senior supervision. When hypoxaemia occurs during tracheal intubation, the team has to interrupt the intubation attempt to ventilate the patient. This results in more tracheal intubation attempts to secure the airway. We speculate that passive oxygen administration during tracheal intubation might reduce the number of tracheal intubation attempts and the incidence of hypoxaemia. Anaesthesiologists often leverage the benefits of passive oxygenation during routine anaesthetic cases such as rigid bronchoscopy for airway examinations. Passive oxygenation during rigid bronchoscopy increases the time available for the otolaryngologist to complete the airway examination without oxygen desaturation. Likewise, passive oxygenation (eg, via nasal cannula, modified nasal airway or extraglottic airway) during the intubation will delay

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the onset of hypoxaemia and provide more time for the team to secure the tracheal tube with fewer overall tracheal intubation attempts. Passive oxygenation is effective in adults and was anecdotally reported to be effective in children with pyloric stenosis requiring rapid sequence intubation; we plan to explore the effectiveness more systematically in the future.22,23 The 15 children with difficult tracheal intubation who required cardiopulmonary resuscitation for cardiac arrest translates to an incidence of one in 68 cases experiencing cardiac arrest. This cardiac arrest incidence is substantially higher than the 1·4 in 10 000 reported in the general paediatric anaesthesiology population.24 11 of these procedures were non-emergent tracheal intubations in the operating room. This unexpectedly high incidence is a potential target for quality improvement. Reduction of hypoxaemia and persistent direct laryngoscopy, and the introduction of a protocol in which the most experienced laryngoscopist intervenes quickly when a trainee fails might reduce the incidence of cardiac arrest. We studied cases with five tracheal intubation attempts to understand the role the device and personnel had in the airway management. Standard direct laryngoscopy had a poor overall success rate (12%), but it still accounted for 21% of fifth attempts (figure 3). Attending physicians made only 21% of first tracheal intubation attempts and yet were the successful laryngoscopist more than 44% of the time indicating that they rescued the other clinicians (trainee, certified registered nurse anaesthetist) frequently. If these additional attempts were for the educational benefit of the trainees, the experience gained by trainees has to be carefully weighed against the consequences of multiple tracheal intubation attempts. The transition to the most experienced clinician should happen quickly in these patients. These data could be relevant to paediatric practitioners in other acute care areas including emergency departments, intensive care units, and intubations in the field. The original ASA practice guidelines for the management of patients with a difficult airway defined a difficult tracheal intubation as three failed conventional attempts and recommended that subsequent attempts use alternate devices.20 Our data suggest that this guideline was often not followed because repeated attempts with conventional direct laryngoscopy happened in many patients (figure 3). Could the use of an alternative technique after the failed attempt expedite intubation with fewer complications? Our data showed the tracheal intubations with late transition from repeated direct laryngoscopy attempts were associated with higher occurrence of complications. Patients in category 1 had a greater proportion of overall complications than those in category 4. This finding might suggest that patients in category 4 might have been easier to intubate (their difficulty was suspected and not diagnosed by direct laryngoscopy) or the fact that they did not have direct laryngoscopy translated to fewer attempts and less complications. 10

Other investigators have shown that repeated intubation attempts are associated with adverse events. Mort and colleagues25 noted that adult emergency room patients with more than two attempts had more hypoxaemia, oesophageal intubation, and cardiac arrest. Our study examined a different population (children), under controlled conditions (mostly elective operating room intubations) done by more experienced clinicians (mainly paediatric anaesthesiology fellows and attendings), but the effect of more than two tracheal intubation attempts is similar. Graciano and colleagues11 also reported similar findings in the paediatric intensive care unit. Neonatal and paediatric intensive care data suggest that inexperienced clinicians, frequent attempts, and younger patients were associated with greater complication rates. Based on our results, using a specific airway checklist may reduce adverse events in these patients. Deriving and implementing a standardised airway bundle checklist has been described in previous studies and seems like a natural progression of our work.26 The airway checklist could incorporate the plan to use an extraglottic airway early, consider and prepare for passive oxygenation during tracheal intubation attempts, and restrict the number of direct laryngoscopy attempts. Our study has several limitations. First, although 13 paediatric centres contributed data into the registry, four large centres contributed most of the cases. The specialised nature of the participating institutions and the proportion of cases reported by a small number of centres might limit the ability to generalise the results and their implications. Second, although we established a standard operational plan including rigorous data collection and audit processes, cases could still have been missed if difficult tracheal intubations were not documented in patient’s charts or reported by the care team. Missed cases could lead to under-reporting of multiple attempts or occurrence of complications. Furthermore tracheal intubation attempts and complications data are probably an under-representation of the true numbers because they were not independently collected and were self reported by the team. A video-based assessment of tracheal intubations in a paediatric emergency department showed that clinicians reported fewer adverse events than were recorded on independent video review. This result is probably a major limitation of our study and implies that we might have under-reported our complications.27 Third, we classified training level as trainees versus attendings, and we did not capture the actual trainee’s postgraduate year or whether the trainee was a resident or fellow. Fourth, patients in category 4 of our inclusion criteria were deemed difficult tracheal intubations at the discretion of the attending based on physical examination. The anaesthesiologist did not perform direct laryngoscopy in these patients, and it is possible that they might have been intubated easily with conventional direct laryngoscopy. Next, our statistical analysis assumes that each of the 1018 tracheal intubations are independent; however, if

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there is any dependency between tracheal intubations (eg, repeat patients), there might be less information in our dataset than we think. Although there were probably repeat patients, we believe that treating each tracheal intubation as independent is reasonable in view of the fact that the airway in children is in transition and because of this constant change, conditions during one tracheal intubation can be different from a subsequent tracheal intubation. This idea is well known in paediatric anaesthesia practice—eg, children with Pierre Robin sequence can be extremely difficult to intubate at birth but often become easier to intubate as they grow. Finally, we estimated the rate of difficult tracheal intubation to be roughly 0·2–0·5% of anaesthetic cases. Our centres tracked the number of anaesthetics done every year not the number of tracheal intubations done in anaesthetised patients. Because many patients are not intubated when anaesthetised, our calculations are an approximation of the true rate. In conclusion, we have defined the incidence and types of complications in children with difficult tracheal intubation across 12 paediatric centres and reported the tracheal intubation success rates of commonly used tracheal intubation devices and techniques. 20% of the patients meeting difficult tracheal intubation criteria had at least one complication. Taken together, we have learned that attempting more than two tracheal intubations in children with difficult tracheal intubation is associated with a high failure rate and increased incidence of complications. This high complication rate is multifactorial in origin. The patient-level factors include abnormal airway physical examination and lower patient age and weight. Process factors included multiple tracheal intubation attempts and multiple direct laryngoscopy attempts. Additionally, delays in transition from trainee to attending tracheal intubation attempts could have contributed to complications. We are now poised to create and disseminate a quality improvement bundle to address these complications across our centres. Our findings should affect the clinical decisions of all clinicians who perform this potentially life-saving procedure in children with difficult tracheal intubation. Contributors JEF, NJ, DMP, MEM, PS, VMN, FXM, RSL, MAR, PGK, PIR, and AIH contributed to manuscript authorship, study design, data interpretation, and data contribution; AN contributed to statistical analysis, study design, data interpretation, and data contribution; and RSG contributed to manuscript authorship, study design, and data interpretation. PeDI collaborative group Paul Stricker, Brad Taicher, Vidya Raman, Ralph Beltran, Ian Lewis, Bishr Haydar, Prabhat Koppera, Shobha Malviya, Katherine Gentry, Adrian Bosenberg, Patrick Olomu, Edgar Kiss, Judit Szolnoki, Jennifer Zieg, Madhankumar Sathyamoorthy, Vikram Patel, Codruta Soneru, Ricardo Falcon, Jimmy Windsor, Tim Peterson, Raymond Park, James Peyton, Denise Chan, Chris Glover, Paul Hopkins, Somaletha T Bhattacharya, Ricardo Riveros, Nicholas Dalesio, Martina Richtsfeld, Kumar Belani, Bin Zhang, John McCloskey, Olutoyin A Olutoye, Christopher Estrada, and Tarun Bhalla.

Participating centres Department of Anesthesia and Critical Care Medicine, Children’s Hospital of Philadelphia, PA, USA; Department of Anesthesiology Perioperative and Pain Medicine, Boston Children’s Hospital, Boston, MA, USA; Department of Anesthesiology and Pain Management, UT Southwestern Medical Center, Dallas, TX, USA; Department of Anesthesiology, Seattle Children’s Hospital, WA, USA; Department of Anesthesiology, Texas Children’s Hospital, Houston, TX, USA; Department of Pediatric Anesthesiology, University of Michigan Health Center, MI, USA; Department of Anesthesiology, University of Texas Medical School at Houston, Houston, TX, USA; Department of Anesthesiology, Children’s Hospital of Colorado, CO, USA; Department of Pediatric Anesthesiology, Lurie Children’s Hospital Chicago, Chicago, IL, USA; Department of Anesthesiology and Pain Medicine, Nationwide Children’s Hospital, Columbus, OH, USA; Department of Anesthesiology, the University of Mississippi Medical Center, Jackson, MI, USA; Department of Anesthesiology, Duke University, Durham, NC, USA; and Department of Anesthesiology and Pain Management, Children’s Hospital of Cleveland Clinic, Cleveland, OH, USA Declaration of interests RG discloses patents in the public domain relevant to airway management, FXM discloses grant funding from the Agency for Healthcare Research Quality and the Laerdal Foundation Center for Excellence, and AN discloses grant funding from the Agency for Healthcare Research Quality and the Laerdal Foundation Center for Excellence. All other authors declare no competing interests. Acknowledgments We thank the following individuals for their contributions to this work: Bill Greeley, Mark Schreiner, Jeff Feldman, Bin Zhang, Bishr Haydar, Kenneth Peeples, Ariel Vincent, Thea Goebel, Allison Wright, Shana Emery, Terri Voepel-Lewis, Sinead Rivard, Roxana Ploski, Jennifer Spears, John Hajduk, Ranu Jain, Rachel Bernier, Mark Breibart, Stephanie Coulombre, Ian Lewis, and Jessica Burkhardt. References 1 Fiadjoe J, Stricker P. Pediatric difficult airway management: current devices and techniques. Anesthesiol Clin 2009; 27: 185–95. 2 Fiadjoe JE, Gurnaney H, Dalesio N, et al. A prospective randomized equivalence trial of the GlideScope Cobalt® video laryngoscope to traditional direct laryngoscopy in neonates and infants. Anesthesiology 2012; 116: 622–28. 3 Vanderhal AL, Berci G, Simmons CF Jr, Hagiike M. A videolaryngoscopy technique for the intubation of the newborn: preliminary report. Pediatrics 2009; 124: e339–46. 4 Long E, Sabato S, Babl FE. Endotracheal intubation in the pediatric emergency department. Paediatr Anaesth 2014; 24: 1204–11. 5 Morray JP, Geiduschek JM, Caplan RA, Posner KL, Gild WM, Cheney FW. A comparison of pediatric and adult anesthesia closed malpractice claims. Anesthesiology 1993; 78: 461–67. 6 Jimenez N, Posner KL, Cheney FW, Caplan RA, Lee LA, Domino KB. An update on pediatric anesthesia liability: a closed claims analysis. Anesth Analg 2007; 104: 147–53. 7 Cook TM, Woodall N, Harper J, Benger J, and the Fourth National Audit Project. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 2: intensive care and emergency departments. Br J Anaesth 2011; 106: 632–42. 8 Cook TM, Woodall N, Frerk C, and the Fourth National Audit Project. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. Br J Anaesth 2011; 106: 617–31. 9 Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39: 1105–11. 10 Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap)--a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform 2009; 42: 377–81. 11 Graciano AL, Tamburro R, Thompson AE, Fiadjoe J, Nadkarni VM, Nishisaki A. Incidence and associated factors of difficult tracheal intubations in pediatric ICUs: a report from National Emergency Airway Registry for Children: NEAR4KIDS. Intensive Care Med 2014; 40: 1659–69.

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Nishisaki A, Turner DA, Brown CA 3rd, Walls RM, Nadkarni VM, and the National Emergency Airway Registry for Children (NEAR4KIDS), and the Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) Network. A National Emergency Airway Registry for children: landscape of tracheal intubation in 15 PICUs. Crit Care Med 2013; 41: 874–85. Han R, Tremper KK, Kheterpal S, O’Reilly M. Grading scale for mask ventilation. Anesthesiology 2004; 101: 267. Benumof JL, Dagg R, Benumof R. Critical hemoglobin desaturation will occur before return to an unparalyzed state following 1 mg/kg intravenous succinylcholine. Anesthesiology 1997; 87: 979–82. Denman WT, Goudsouzian NG. Position of the laryngeal mask airway. Anesthesiology 1992; 77: 401–02. Dubreuil M, Laffon M, Plaud B, Penon C, Ecoffey C. Complications and fiberoptic assessment of size 1 laryngeal mask airway. Anesth Analg 1993; 76: 527–29. Park C, Bahk JH, Ahn WS, Do SH, Lee KH. The laryngeal mask airway in infants and children. Can J Anaesth 2001; 48: 413–17. Duggan LJN. Unique airway issues in the pediatric population: McGraw Hill, 2012. Sankar A, Johnson SR, Beattie WS, Tait G, Wijeysundera DN. Reliability of the American Society of Anesthesiologists physical status scale in clinical practice. Br J Anaesth 2014; 113: 424–32. Practice guidelines for management of the difficult airway. A report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 1993; 78: 597–602. Apfelbaum JL, Hagberg CA, Caplan RA, et al, and the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 2013; 118: 251–70.

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Bhagwan SD. Levitan’s no desat with nasal cannula for infants with pyloric stenosis requiring intubation. Paediatr Anaesth 2013; 23: 297–98. Wimalasena Y, Burns B, Reid C, Ware S, Habig K. Apneic oxygenation was associated with decreased desaturation rates during rapid sequence intubation by an Australian helicopter emergency medicine service. Ann Emerg Med 2015; 65: 371–76. Morray JP, Geiduschek JM, Ramamoorthy C, et al. Anesthesiarelated cardiac arrest in children: initial findings of the Pediatric Perioperative Cardiac Arrest (POCA) Registry. Anesthesiology 2000; 93: 6–14. Mort TC. Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesth Analg 2004; 99: 607–13. Li S, Rehder KJ, Giuliano JS Jr, et al, and the National Emergency Airway Registry for Children (NEAR4KIDS) Investigators and Pediatric Acute Lung Injury and Sepsis Investigator (PALISI) Network Investigators. Development of a quality improvement bundle to reduce tracheal intubation-associated events in pediatric ICUs. Am J Med Qual 2014; published online Aug 20. DOI:10.1177/1062860614547259. Kerrey BT, Rinderknecht AS, Geis GL, Nigrovic LE, Mittiga MR. Rapid sequence intubation for pediatric emergency patients: higher frequency of failed attempts and adverse effects found by video review. Ann Emerg Med 2012; 60: 251–59.

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