During the 5.5 years studied, 31,888 emergency airway management procedures were registered in ICU patients admitted from the emergency department. The most prevalent type of emergency airway management procedures were invasive ones, reaching 4720 procedures in 2017. In relation to the number of emergency department visits in Sweden yearly (1.9 million adult visits in year 2017 [20]) the estimated incidence of invasive airway management procedures would be 2.4/1000 ED visits.
To make sense, the number of procedures also needs to be related to staffing levels in Swedish emergency departments. However, Swedish EDs are staffed in different ways; either by emergency physicians (and trainees), or by rotating physicians from other departments in the hospital (for example medicine, surgery, orthopedics, neurology, infection), or by a combination of emergency physicians and rotating physicians. Therefore, it is difficult to estimate staffing levels in a national perspective [21].
However, examples from EDs of different sizes can give some indication of the order of magnitude of invasive airway procedure in relation to staffing. In Östergötland county with 467,000 inhabitants there are two hospitals with ICUs (Linköping and Norrköping). The ED in Linköping (academic hospital) is only staffed with emergency physicians and trainees, a total of about 60 physicians. In 2017 the number of invasive emergency airway management procedures were 124, resulting in approximately 2 intubations/physician and year. In a rural hospital in Skåne county, Ystad hospital, mainly staffed by emergency physicians and trainees, the number of invasive emergency airway management procedures in 2017 was 28, resulting in approximately 1.75 intubations/physician and year. A system with rotating physicians from other departements would probably result in more individuals working in the ED, and as a consequence even less intubations/physician and year. With previous literature about number of intubations needed to gain profiency in emergency situations in mind, this is a very low number.
Another important aspect when discussing airway management and training opportunities in the ED is prehospital intubations. There is no recent study on the incidence of prehospital intubations in Sweden. However, in our county Östergötland, the incidence of prehospital intubations is low. In 2017 the ambulance service registered 30 endotracheal intubations (personal communication), compared to 204 invasive emergency airway management procedures in hospital (Linköping and Norrköping combined). The total number of ambulance missions in the county in 2017 was approximately 48,500, rendering an incidence of 0.62 intubtions/1000 amublance missions, the majority of which were performed in CPR situations [20]. As mentioned in the introduction, the problem with few endotracheal intubation procedures per year and individual is also well-described in other countries and for other professions [6,7,8], especially in the pre-hospital setting. Cobas et al. has showed 31% failed prehospital intubations in a prehospital setting in the U. S [22]. It has been discussed whether this high rate of failed intubations is related to a dilution of intubation skills, with too few procedures per paramedic each year [23]. On the contrary, a success rate of 100% of prehospital intubations has been described by Helm et al. in a setting of helicopter emergency medical service where experienced trauma anesthetists performed the intubations [24]. The circumstances prehospitally may differ significantly from an in-hospital emergency department, and it is unclear to which extent the results from pre-hospital studies may be generalizable to other settings. Not surprisingly, however, the general tendency in the literature is that the success rate of emergency airway management procedures seems to increase with experience.
The problem with few endotracheal intubation procedures per individual may in part be overcome by simulation training. However, a systematic review reports that simulation training is not superior to non-simulation training (lectures, videos, self studies, problem-based learning and clinical observation) [25]. The challenges associated with few endotracheal intubation procedures is frequently discussed also for other specialties, such as trainees in pulmonary and critical care medicine. For trainees in these specialties, simulation and training in operating theatres may serve as a bridge to emergency airway management in the ICU – but it cannot fully compensate training opportunities in real-life emergency airway management [2]. Another aspect of invasive airway management is the technical development with the wide introduction of video-laryngoscopes. Video-laryngoscopes seem promising especially for intubations in patients with limited view (Cormace-Lehane grade III and IV) where video-laryngoscope seems to be superior to Macintoch/Miller blades [26]. In another study, video-laryngoscopes tended to increase the rate of first attempt success when compared to direct laryngoscopy [27]. It has also been shown that video-laryngoscopy (versus Macintosh blade) is faster and associated with less adverse events when used by unexperienced users (in simulation situations) [28]. In summary, video-laryngoscope should be available and used in the ED but one should also remember that video-laryngoscope does not solve all problems and in these cases it is important to have knowledge and experience of other methods for airway management.
A major limitation in our study is the large group of excluded patients due to lack of medical procedure codes. The reasons for lack of medical procedure codes are most likely multiple. When comparing the excluded patients with the included ones, the excluded patients seem to be less ill as indicated by lower SAPS3 score, shorter length of stay in the ICU and lower mortality rate. There was also a higher rate of patients who were only admitted for observation in the excluded group. In summary, many parameters indicate that the excluded group was healthier – and perhaps did not require any medical procedures. However, another explanation of missing codes for medical procedures could be inadequate registration of codes. This is a common problem in register-based research. The data in the Swedish intensive care register is reported prospectively during the ICU stay, and the registry has an automatic check for logical errors. In addition, local validations of diagnoses and procedures are done, but the registry has not been generally/externally validated. Some variables in the Swedish intensive registry, such as age, hospital type and primary diagnosis, are compulsory but medical procedures are not, which may also contribute to a higher frequency of missing data for procedures.
Another limitation may be the definition of “emergency” airway management procedures. Surveying previous literature on this topic, it is obvious that there is no consensus on how to define an emergency airway management procedure vs a non-emergent one. We have chosen to define an emergency procedure as a procedure performed within 3 h from the time of ICU admission. We believe that a 3 h time limit could be an appropriate cut-off to indicate which patients could potentially be eligible for airway management procedures in the emergency department, and we are aware that a patient’s condition could change dramatically within a 3 h time frame – i.e. a patient who is intubated after 2.5 h in the ICU might not have been appropriate to intubate already in the emergency department. Therefore, a time-limit of 3 h after ICU admission may result in an overestimation of emergency airway management procedures. However, a majority of the procedures were performed before ICU admission or within the first hour in ICU (Fig. 1).
To overcome several of the limitations in this study and to facilitate in-depth studies of airway management procedures in an emergency setting, it would be valuable to institute a European version of the American National Emergency Airway Registry (NEAR). In the light of the current debate on emergency airway management, and before making any changes in the organization of emergency airway management procedures, we suggest the establishment of a quality register focusing on airway management procedures. This register should also include information about, for example, first-pass success, surgical airway procedures, the provider’s experience of intubation, as well as data on complications, none of which can be evaluated with the existing Swedish intensive care register. Another question we cannot answer with the existing data is the number of emergency endotracheal intubations per individual physician, nor the success rate of intubation attempts. There may also be regional differences resulting in more frequent emergency endotracheal intubations in specific emergency departments, even if the mean number of invasive airway management procedures per physician is low on a national level.
In summary, our study shows that the number of invasive airway management procedures in Swedish EDs is low. This needs to be considered when implementing strategies for emergency airway management, since gaining and maintaining competence is a key factor for successful intubation in emergency situations. However, local conditions may vary, and it is important to take these into consideration when discussing the generalizability of our results to other countries and health care systems.
