A Retrospective Study on the Practice and Safety of Airway Management in Dutch Emergency Departments
Conditions: Endotracheal Intubation
Sponsor: Frisius Medisch Centrum

 
 
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A retrospective study on the practice and safety of airway 
management in Dutch emergency departments 
  
  
  
RESEARCH PROTOCOL 
  
December 2023 
  
  
  
 
Protocol ID 
…. 
Short title 
Airway management in Dutch emergency departme
Version 
1 

 
 
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Date 
15-12-2023 
Principal investigator(s) 
 
Other investigators 
P. Veldhuis 
M. Labberton 
H. Lameijer 
Sponsor 
Medisch Centrum Leeuwarden 
Subsidizing party 
None 
 
  
PROTOCOL SIGNATURE SHEET 
  
Name 
Signature 
Date 
Head of the Department: 
R. Seinstra 
 
 
Principal Investigator: 
Dr. Heleen Lameijer 
 
 
 
 
 

 
 
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SUMMARY ................................................................................................................................. 4 
1.  INTRODUCTION AND RATIONALE .................................................................................... 4 
3.STUDY DESIGN ..................................................................................................................... 6 
4.STUDY POPULATION ........................................................................................................... 6 
4.1 Population (base) ............................................................................................................. 6 
4.2 Inclusion criteria ............................................................................................................... 6 
4.3 Exclusion criteria .............................................................................................................. 6 
4.4 Sample size calculation ................................................................................................... 6 
5.METHODS .............................................................................................................................. 6 
5.1 Study parameters ............................................................................................................. 6 
5.2 Data acquisition ................................................................................................................ 9 
5.2.1Identification of subjects ............................................................................................. 9 
5.2.2Abstraction forms........................................................................................................ 9 
5.2.3Quality of data acquisition .......................................................................................... 9 
5.2.4Missing data ............................................................................................................. 10 
6.STATISTICAL ANALYSIS .................................................................................................... 10 
7.ETHICAL CONSIDERATIONS ............................................................................................. 10 
7.1 Regulation statement ..................................................................................................... 10 
8.ADMINISTRATIVE ASPECTS, MONITORING AND PUBLICATION.................................. 11 
8.1 Handling and storage of data and documents............................................................... 11 
9.REFERENCES ..................................................................................................................... 11 
 
 
                                                                                                                 
 
 
 

 
 
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SUMMARY 
Rationale: 
Objective: To describe and evaluate the practice and safety of endotracheal intubation of patients 
in Dutch emergency departments (ED). 
Study design: Retrospective cohort study. 
Study population: Patients who underwent endotracheal intubation in the ED of one of the 
participating hospitals in the Netherlands 
Intervention (if applicable): Not applicable. 
Main study parameters: The practice of, indications for and incidence of complications of 
endotracheal intubation in the ED.  
Nature and extent of the burden and risks associated with participation, benefit and group 
relatedness: Due to the retrospective design, there is no active involvement of patients or 
randomisation, and only data relevant to the study will be collected. Data collection will be 
completely anonymized. 
 
1.   INTRODUCTION AND RATIONALE 
Endotracheal intubation can be a lifesaving intervention for critically ill patients in the emergency 
department (ED).  Endotracheal intubation is, however, a high-risk procedure with many potential 
complications, which seem to be even more prevalent when carried out in the ED compared to for 
example the operating theater(5). This is possibly due to multiple reasons such as a sicker 
population, non-elective setting, a higher variability among indications for intubation or competence 
of providers. 
Internationally, large registries were established and multiple observational studies have been 
performed to gain more information about the methods, safety and complications of intubations in 
the ED. For example, a multicenter study in Australia and New Zealand set up the ANZEDAR 
(The Australian and New Zealand Emergency Department Airway Registry) and reported on the 
practice, indications, success rate and safety of 3710 intubations performed in emergency 
departments (1). The same was done with the NEAR (National Emergency Airway Registry) 
including ED’s from the United States, Canada and Australia; in a prospective, multicenter 
international registry of intubations in emergency departments a total number of 17,583 

 
 
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intubations were registered and analyzed (3). These studies gave more insight into patient 
demographics, staff characteristics, pharmacologic agents used and complication rates. In the 
UK, a national audit project (NAP4) showed that there were relatively far more complications of 
airway management in the ED compared to the operating theater and that complications in the 
ED were more likely to result in harm or death than complications in the operating theater. 
Individual case review identified avoidable deaths and areas of care that need improvement (5,6). 
While in recent years these studies have added to our knowledge of ED airway management, there 
is still a lack of high-quality studies and there is a strong argument for increased research. To date, 
no studies have been published of airway management in Dutch EDs. We therefore have no 
knowledge about any factors possibly influencing intubation outcomes and complications nor 
comparability with international data. Among these are factors that have been associated with 
preventable harm and death and insight into these factors could be used for improvement of the 
safety of airway management in Dutch EDs (6). 
This study is therefore intended to provide a comprehensive review of the clinical practice and 
characteristics of endotracheal intubations within Dutch EDs. The results could potentially be used 
for comparative analysis against global datasets. Additionally, the insights gained from this study 
will shed light on existing gaps prevalent in the current registration processes of intubations in the 
Netherlands. Furthermore, these insights could act as a stepping stone for future investigations 
that can lead to a deeper understanding of the methodologies, safety protocols, and associated 
complications of endotracheal intubations within Dutch EDs.   
 
 
 
 
2. 
OBJECTIVES 
Primary outcome:       
Describing characteristics of the practice of  endotracheal intubation in Dutch EDs, including 
information about patient demographics, indications for  endotracheal intubation,  intubation 
performer characteristics, equipment and medication used and complications due to intubation.  

 
 
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3. 
STUDY DESIGN 
This is a retrospective cohort study using electronic patient charts of patients who underwent 
endotracheal intubation in the emergency departments of the participating hospitals. 
  
4. 
STUDY POPULATION 
4.1 Population (base) 
Patients undergoing endotracheal intubation in the emergency department of one of the 
participating hospitals. 
4.2 Inclusion criteria 
Patients who underwent endotracheal intubation between 01-01-2019 and 31-12-2023 in the 
participating ED’s.  
4.3 Exclusion criteria 
Patients for which no information about the intubation can be found in the electronic patient 
chart will be excluded from the study.  
4.4 Sample size calculation 
Not applicable. Data of all patients eligible for the study will be included. 
  
5. 
METHODS 
5.1 Study parameters 
 
• 
Intubator characteristics: 
 Specialty 
▪ 
Emergency medicine 
▪ 
Anesthesia 
▪ 
Intensive care medicine 
▪ 
Other  
 Seniority 
▪ 
Consultant 
▪ 
Resident 

 
 
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▪ 
Junior 
doctor 
 
• 
Indication for intubation: 
 Trauma 
 Burns 
 Drowning 
 Overdose/ingestion 
 Respiratory failure 
 Cardiac arrest (active cardiac arrest) 
 Post-cardiac arrest 
 Stroke 
 Seizure 
 Altered mental status due to other cause (if altered mental status due to stroke, 
intoxication, seizure or post-cardiac arrest then score as the primary cause)  
 Sepsis 
 Cardiac failure 
 Airway obstruction 
 GI bleed 
 Anaphylaxis 
 Other 
 
• 
Sedation 
agent 
used 
(Ketamine, 
etomidate, 
propofol, 
midazolam) 
 
• 
Paralytic 
agent 
used 
(Rocuronium 
/ 
Succinylcholine) 
 
• 
Method of intubation 
 Direct laryngoscopy 
 
 Video (hyperangulated or direct) 
 
 Fiberoptic 
 Surgical airway 
 
 Use of airway adjuncts? If yes, which … 
 
• 
Patient characteristics: age (years), gender (male/female), weight/obesity (BMI). 
 

 
 
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• 
Vital parameters before intubation (respiratory rate, saturation, systolic blood pressure 
(SBP), heart rate). 
 
• 
Was a pre-intubation airway assessment performed? Yes / no / missing 
 
• 
If yes, were there any signs of a difficult intubation?  
 
• 
Performance and mode of pre-oxgenation; no pre-oxygenation / nasal canula / NRM /  mask 
ventilation / NIV / missing 
 
• 
Was capnography used during intubation? Yes / no / missing 
 
• 
The occurrence of complications of endotracheal inubation. Complications will be identified 
in two ways. The first option is that a complication is explicitly stated in the electronic 
medical record. The second option is that there are significant changes in vital signs as 
described in more detail below.  The following complications will be registered:   
● significant decrease of peripheral oxygen saturation (SpO2). Defined as a 
desaturation of >10% from baseline or as defined by the treating physician 
● significant decrease of blood pressure. Defined as a systolic pressure <90mmHg 
with a drop of >20% from baseline or as defined by the treating physician.  
● significant increase of blood pressure. Defined as a systolic pressure > 160mmHg 
with a rise of >20% from baseline, or as defined by the treating physician. 
● significant bradycardia. Defined as a heart rate < 40/min and a drop of > 20% from 
baseline, or as defined by the treating physician.   
● significant tachycardia. Defined as a heart rate > 160/min and a rise of > 20% from 
baseline, or as defined by the treating physician. 
● 
 dental or airway trauma due to intubation attempt 
● oesophageal or mainstem bronchial intubation 
● vomiting or aspiration 
● laryngospasm 
● equipment failure 
● medication error 
● cardiac arrest 
● failed attempt / need for an emergency surgical airway  
● other, …. 
For inclusion, complications should have occurred within 10 min of intubation, even if 
recognised after this time. 

 
 
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• 
As it is expected that complications of intubations are recorded in the electronic chart, the 
absence of notions of complications could be interpreted as an uncomplicated intubation. 
However, other physicians always explicitly mention that no complication occurred. 
Therefore, in this study the occurrence of complications can be coded as: 
● Complications occurred (complication specified) 
● No statement about complications 
● Explicitly stated that no complications occurred  
 
5.2 Data acquisition 
To guarantee accurate and consistent data acquisition, a data acquisition system will be used as 
proposed in emergency medicine literature. (5,6) Data abstraction forms will be used, abstracters 
will be trained and interrater reliability will be measured using Cohen’s kappa. Data abstraction will 
be blinded, which means that during data abstraction they will not be aware of the aim of the study. 
 
5.2.1 
Identification of subjects 
We will collect data by searching the database via one or multiple ways, depending on the local 
registration infrastructure of the hospital. Options are searching for procedural code for 
endotracheal intubation, screening ICU admissions, screening resuscitation room logbooks, 
screening medication logbooks for intubation medication, searching ICD-10 code for cardiac arrest 
and 
other 
pathologies 
that 
could 
lead 
to 
intubation.  
 
5.2.2 
Abstraction forms 
The abstraction form is attached as an appendix. All data will be abstracted via an electronic 
abstraction form. The data is completely anonymized and cannot be linked to individual patients. 
The abstraction forms will be pilot tested in the participating hospitals. 
 
5.2.3 
Quality of data acquisition 
All abstractors are medical students, emergency medicine trainees or emergency medicine 
physicians. They will receive an abstractor manual and a standardized training program. During 
this training, abstractors will be instructed about definitions used in the abstraction form and how 
to interpret the medical charts. During the abstraction phase, abstractor meetings will be scheduled 

 
 
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to discuss coding rules and to resolve disputes. To assess interrater reliability, interrater variability 
will be measured using Cohen’s Kappa. 10% of the charts will be reviewed by two abstractors, 
after which interrater agreement will be calculated. Interrater agreement will be assessed for the 
incidence of complications, method of intubations and sedation agent. 
 
5.2.4 
Missing data 
All missing data will be reported in the results section.  
  
  
6. 
STATISTICAL ANALYSIS 
Continuous data are presented as mean and standard deviation or median with interquartile range 
(IQR), depending on normality of data (graphically and numerically assessed), whereas nominal 
data are presented as absolute numbers and percentages. The Chi-square test or Fisher exact 
test will be used for comparison of nominal variables and the independent t-test and Mann Whitney 
test will be used when appropriate for comparison of continuous variables across treatment 
groups.. For all tests a p < .05 will be used to indicate statistical significance. All tests are two-
tailed. Statistical analysis will be performed using IBM SPSS Statistics Premium' V 22 for Windows 
(IBM Corp. Released 2011. IBM SPSS Statistics for Windows, version 22.0. Armonk, NY: IBM 
Corp.). 
  
7. 
ETHICAL CONSIDERATIONS 
7.1 Regulation statement 
The patients will not be asked for signed informed consent. The data collection will be retrospective 
and completely anonymized. Patients are not randomized. In addition, this research focuses on 
standardized care and no new or additional actions were carried out. We suspect to screen at least 
500-1000 patients for inclusion and find it not feasible to ask every patient for consent 
retrospectively. This would cost a disproportionate amount of effort and possibly excludes a large 
number of patients due to not being able to reach the patient, especially since it is expected that a 
high proportion of the patients died due to the seriousness of the underlying disease. Also, to a 
lesser amount it may cause a selection bias because it could be more difficult to get consent in the 
case of complicated intubations. Data will be derived from electronic patient files, from 2019up to 

 
 
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now. Asking for informed consent from patients who had an intubation 3 years ago would not 
outweigh disadvantages for the patient.  
  
8. 
ADMINISTRATIVE ASPECTS, MONITORING AND PUBLICATION 
8.1 Handling and storage of data and documents 
Study data files (SPSS, REDCap) will be stored electronically on a secured data source within the 
Medical Centre Leeuwarden, only accessible for the research team, during the study period. After 
this only the primary investigator will have excess. All files will be stored for 15 years. 
 
 
9. 
REFERENCES 
 
1. Alkhouri H, Vassiliadis J, Murray M, Mackenzie J, Tzannes A, McCarthy S, et al. 
Emergency airway management in Australian and New Zealand emergency 
departments: A multicentre descriptive study of 3710 emergency intubations. EMA - 
Emergency Medicine Australasia. 2017 Oct 1;29(5):499–508. 
2. Brown CA, Bair AE, Pallin DJ, Walls RM. Techniques, success, and adverse events of 
emergency department adult intubations. Ann Emerg Med. 2015 Apr 1;65(4):363-370.e1. 
3. Carlson JN, Zocchi M, Marsh K, McCoy C, Pines JM, Christensen A, Kornas R, Venkat 
A. Procedural Experience With Intubation: Results From a National Emergency Medicine 
Group. Ann Emerg Med. 2019 Dec;74(6):786-794. 
4. Cook T, Behringer EC, Benger J. Airway management outside the operating room: 
Hazardous and incompletely studied. Vol. 25, Current Opinion in Anaesthesiology. 2012. 
p. 461–9. 
5. Cook TM, Woodall N, Harper J, Benger J. 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(5):632–42. 
6. Gilbert EH, Lowenstein SR, Kozioi-Mclain J, Barta DC, Steiner J. Chart Reviews In 
Emergency Medicine Research: Where Are The Methods?Worster A, Bledsoe RD, Cleve 
P, Fernandes CM, Upadhye S, Eva K. Reassessing the methods of medical record 
review studies in emergency medicine research. Ann Emerg Med. 2005;45(4):448–51.