Abstract
Aim
To examine the success rates of emergency department airway management by resident physicians in Japan.
Methods
We conducted an analysis of a multicentre prospective registry (Japanese Emergency Airway Network Registry) of 13 academic and community emergency departments in Japan. We included all patients who underwent emergency intubation performed by postgraduate year 1 to 5 transitional or emergency medicine residents (resident physicians) between April 2010 and August 2012. Outcome measures were success rates by the first intubator, and by rescue intubator, according to the level of training.
Results
We recorded 4,094 intubations (capture rate, 96%); 2,800 attempts (2,800/4,094; 68%; 95% confidence interval (CI), 67%–70%) were initially performed by resident physicians. Overall success rate on the first attempt was 63% (1,767/2,789; 95%CI, 61%–64%); the rate improved over the first 3 years of training before reaching a plateau (P trend < 0.001). Success rate by the first intubator was 78% (2,185/2,800; 95%CI, 76%–79%); the rate steadily improved as level of training increased (P trend < 0.001). Of 597 failed intubation attempts by the first intubator, 41% (247/597; 95%CI, 37%–45%) of rescue attempts were performed by resident physicians. Success rate on the first rescue attempt was 76% (187/247; 95%CI, 70%–81%), and success rate by first rescue intubator was 89% (220/247; 95%CI, 85%–93%). These rates on rescue attempts steadily improved as level of training increased (both P trend < 0.001). Intubations were ultimately successful in 2,778 encounters (99.6%).
Conclusion
In this multicentre study characterizing emergency airway management across Japan, we observed that emergency department intubations were primarily managed by resident physicians with acceptably high success rates overall.
Keywords: Education, emergency airway management, intubation, resident physician, success rates
Background
Emergency airway management is a critical intervention performed in the emergency department (ED); therefore, training in airway management is one of the most essential components of emergency medicine residency training.1, 2, 3 In Japan, airway management by emergency physicians is becoming more common as the specialty continues to grow.4
Surveillance of critical emergency procedures is essential for reasons of training, policy, and clinical practice development. In North America, surveillance studies demonstrated that ED intubations by emergency medicine residents, largely using a rapid sequence intubation technique, can be performed safely and with high levels of success.1, 5 Additionally, several smaller studies outside North America have reported intubation methods and success rates by resident physicians within single institutions;6, 7, 8, 9, 10, 11 however, comprehensive large multicentre studies are lacking in other industrialized nations.
To address the knowledge gap in the literature, we analyzed a large, prospective, multicentre database to examine the success rates of ED airway management by resident physicians in Japan. Replication of success in ED airway management performed by resident physicians in differing healthcare settings and professional training systems would illustrate the advent of emergency medicine as a specialty internationally.
Methods
Study design and setting
Data used in this analysis were obtained via the Japanese Emergency Airway Network (JEAN).4, 12, 13, 14 JEAN was initiated in April 2010 as a consortium of 13 academic and community medical centres from different geographic regions across Japan. All 13 EDs were staffed by emergency attending physicians, and 12 had affiliations with emergency medicine residency training programs. The participating institutions included 11 Critical Medical Care Centres and had an average ED census of 29,000 patient visits per year (range 10,000 to 67,000). Complete description of study methodology has been described previously.4, 12, 13, 14 The institutional review board of each participating centre approved the protocol with waiver of informed consent before data collection.
Selection of participants
Data were gathered prospectively from April 2010 through August 2012 on patients who presented to these 13 institutions' EDs and underwent emergency intubation. We included all adults and children undergoing emergency intubation during a 29‐month period by transitional year residents (postgraduate year [PGY] 1 and 2) and emergency medicine residents (PGY 3, 4, and 5). Resident physicians were defined as transitional year residents and emergency medicine residents. Transitional year residents rotated through all of the departments including emergency medicine and also performed intubation in EDs. To focus on airway management by transitional year residents and emergency medicine residents, we excluded patients who had first intubation attempt by residents of other specialty such as surgery and anaesthesia.
Data collection
The physician performing each intubation was referred to as the intubator. After each intubation, the intubator completed a data form that included patient's age, sex, primary indication for intubation, method of airway management, all medications used to facilitate intubation, level of training and specialty of the intubator, number of attempts, success or failure, and adverse events.4 An “oral attempt” was defined as a single insertion of the laryngoscope (or other device) past the teeth.1 An attempt was successful if it resulted in an endotracheal tube being placed through the vocal cords. Intubation‐related adverse events included cardiac arrest, dysrhythmia, hypotension, hypoxemia, unrecognized esophageal intubation, regurgitation, airway trauma, dental or lip trauma, and mainstem bronchus intubation.12
We monitored compliance with data form completion. Where the data collection form was missing, we interviewed the involved physicians and reviewed medical records to ascertain airway management details. These post hoc interviews occurred within 2 weeks of the patient encounter.
Outcome measures
Outcome measures of interest were intubation success rates according to the primary indication for intubation, the level of training, and the intubation method; and adverse event rates by the level of training.
Statistical analysis
We analyzed each outcome with simple descriptive statistics with 95% confidence intervals (CIs). Based on the general approach of Sagarin et al.,1 we described success rates on the first attempt and by the first intubator, stratified by the level of training; analyses excluded 11 patients who had immediate cricothyrotomy on the first intubation attempt.1 Success rate on the first attempt was defined by the total number of successful intubation on the first attempt divided by the total number of first intubation attempt. Intubation attempt by the first intubator was defined as an attempt or series of attempts at intubation of a patient for whom no other physicians had attempted intubation. Accordingly, success rate by the first intubator was defined by the total number of successful intubation by the first intubator divided by the total number of patients attempted by the first intubator. Then, we further examined success rates on the first rescue attempt and by the first rescue intubator. Rescue intubation attempt was defined as an attempt at intubation in a patient for whom another physician had previously tried and failed to intubate.1 We also examined the performance in emergency attending physicians to provide a comparison with resident physicians; this analysis excluded 10 patients who had immediate cricothyrotomy on the first attempt. Furthermore, we used Cochran–Armitage testing to assess whether the success rates improved as the level of training increased. Data analyses were conducted with JMP statistical software version 9.0.2 (SAS Institute, Cary, North Carolina).
Results
During the 29‐month study period, there were 4,268 patients requiring emergency airway management; the database recorded 4,094 intubations (capture rate, 96%; Fig. 1). We excluded 6 patients because of missing information on the level of intubator training. Additionally, 492 first attempts were performed by non‐emergency medicine specialties or residents of other specialty. Among 3,596 first attempts performed by emergency physicians, 2,800 first attempts (2,800/4,094; 68%; 95%CI, 67%–70%) were performed by resident physicians, and therefore eligible for our analysis.
Figure 1.
Derivation of the study groups for initial and rescue intubation attempts.
Intubation attempts by first intubator
The primary indication for intubation was medical in 84% (2,342/2,789; 95%CI, 83%–85%) and traumatic in 16% (447/2,789; 95%CI, 15%–17%). Among the first attempts by resident physicians, the success rate on the first attempt was 64% (1,520/2,342; 95%CI, 63%–69%) for medical and 55% (247/447; 95%CI, 51%–60%) for trauma patients. The success rate by the first intubator was 79% (1,857/2,342; 95%CI, 78%–81%) for medical and 73% (328/447; 95%CI, 69%–77%) for trauma patients.
Figure 2 breaks down the outcomes of intubation attempts by the first intubator. After a failed intubation, the resident either would be rescued by another physician or would try again, resulting in either a success or failure. Figure 3 demonstrates the success rate on intubation attempts by the first intubator, according to the level of training. For overall resident physicians, success rate on the first attempt was 63% (1,767/2,789; 95%CI, 61%–64%). In particularly, the success rate was 48% in PGY‐1 (216/448; 95%CI, 44%–53%) and 59% (685/1,169; 95%CI, 56%–61%) in PGY‐2; the rate improved over the first 3 years of training before reaching a plateau (Ptrend < 0.001). Success rate by the first intubator was 78% (2,185/2,789; 95%CI, 76%–79%); the rate steadily improved as level of training increased (Ptrend < 0.001).
Figure 2.
Outcomes of initial ED intubation attempts by resident physicians.
Abbreviations: PGY, postgraduate year.
*Percentage of total initial attempts by this PGY level of resident physicians.
†Cricothyrotomy or tracheostomy was used as the first method of intubation.
Figure 3.
Intubation success rates on first attempts and by first intubator, according to level of training.
Abbreviations: PGY, postgraduate year.
Table 1 outlines the resident intubation success rates by intubation method. One‐sixth of intubation attempts by the first intubator used a rapid sequence intubation; the majority was intubated with no medications. The success rates on the first attempt with rapid sequence intubation, no medication, and sedation ranged from 60% to 65%. Likewise, the success rates by the first intubator for each oral intubation method ranged from 78% to 79%.
Table 1.
Intubation success rates by first and rescue intubator, according to intubation methods
| Intubation attempts by first intubator | No. (%) | Success on first attempt, % (95% CI) | Success by First Intubator, % (95% CI) |
|---|---|---|---|
| Rapid sequence intubation | 464 (17) | 65 (61–69) | 79 (75–82) |
| Oral no medication | 1,565 (56) | 65 (62–67) | 79 (77–81) |
| Oral sedation only | 647 (23) | 60 (56–64) | 78 (75–81) |
| Nasotracheal | 14 (0.5) | 43 (13–73) | 64 (35–87) |
| Cricothyrotomy | 11 (0.4) | 73 (39–94) | 73 (39–94) |
| Othera | 99 (4) | 58 (48–67) | 75 (65–83) |
| Total | 2,800 (100) | 63 (61–64) | 78 (76–79) |
| Intubation attempts by rescue intubator | No. (%) | Success on first rescue attempt, % (95% CI) | Success by first rescue intubator, % (95% CI) |
|---|---|---|---|
| Rapid sequence intubation | 42 (18) | 71 (57–86) | 88 (72–98) |
| Oral no medication | 139 (56) | 81 (74–87) | 90 (85–95) |
| Oral sedation only | 59 (24) | 64 (52–77) | 88 (80–97) |
| Nasotracheal | 1 (<1) | 100 (3–100) | 100 (3–100) |
| Cricothyrotomy | 2 (<1) | 100 (16–100) | 100 (16–100) |
| Othera | 4 (2) | 75 (19–99) | 100 (40–100) |
| Total | 247 (100) | 75 (70–81) | 89 (86–93) |
Defined as oral intubation using topical anaesthesia, lidocaine, atropine, or paralytics without sedatives.
CI, confidence intervals.
Intubation attempts by rescue intubator
In the entire database, there were 597 encounters, in which an initial attempt by a resident physician failed, and thus the patient underwent rescue intubation attempts (Fig. 1). Of these, 41% (247/597; 95%CI, 37%–45%) of rescue intubation attempts were performed by resident physicians, and 49% (292/597; 95%CI, 45%–53%) were by emergency medicine attending physicians. Figure 4 demonstrates the success rates by rescue intubators according to the level of training. For overall resident physicians, success rate on the first rescue attempt was 76% (187/247; 95%CI, 70%–81%); success rate by the first rescue intubator was 89% (220/247; 95%CI, 85%–93%). Success rates on the first rescue attempts improved as level of training increased (Ptrend = 0.011). Likewise, success rates by the first rescue intubator improved as level of training increased (Ptrend < 0.001). The methods used for rescue attempts were similar to those for the first intubation attempts (Table 1). Including intubations subsequently rescued by attending physicians, intubation attempts initially performed by resident physicians were ultimately successful in 2,778 encounters (99.6%).
Figure 4.
Intubation success rates on first rescue attempts and by first rescue intubator, according to level of training.
Abbreviations: PGY, postgraduate year.
Adverse Events
Table 2 demonstrates the adverse event rates by level of training. Overall, the adverse event rate was 13% (350/2,789; 95%CI, 11%–14%). The adverse event rate varied across the levels of training; PGY‐1 (75/448; 17%; 95%CI, 13%–20%) and PGY‐5 residents (32/184; 17%; 95%CI, 12%–23%) had the highest adverse event rates.
Table 2.
Intubation‐related adverse event rates, according to the level of training at the first intubation attempts
| Level of training | No. of intubation attempt | Adverse event rate, % (95% CI) |
|---|---|---|
| PGY 1 | 448 | 17 (13–20) |
| PGY 2 | 1,169 | 13 (11–15) |
| PGY 3 | 695 | 10 (7–12) |
| PGY 4 | 293 | 9 (6–12) |
| PGY 5 | 184 | 17 (12–23) |
| Attending physician | 786 | 7 (5–9) |
PGY, postgraduate year; CI, confidence interval.
Discussion
In this multicentre study, we demonstrated that ED intubations were primarily managed by resident physicians in Japan. Our study also demonstrated a steady improvement in success rates both on the initial and rescue attempts over the residency training. This study established that resident physicians and emergency physicians have acceptably high overall success rates in performing ED airway management in Japan.
In contrast, the success rate of 63% on the first attempt by resident physicians was not satisfactory and lower than that of previous studies, in which the success rate ranged from 80% to 85%.1, 2, 3, 5, 6 Reasons for this disparity are likely multifactorial; possible explanation includes differences in airway difficulty, ED staffing, and procedural experience, and the much lower use of paralytics in this registry.1 The literature has reported the higher success rates with rapid sequence intubation compared to those with other methods; indeed, the success rates on the first attempt with rapid sequence intubation ranged from 77% to 85%.1, 3, 5, 15 However, even with rapid sequence intubation, the observed success rate of 65% on the first attempt by resident physicians was also lower compared to that in the previous studies.1, 5 Therefore, the discrepancy in the success rates may be attributable to a lack in intubation skill set in the resident physicians rather than the lower use of rapid sequence intubation. Our findings may reflect inadequate residency training due to the lack of robust evidence‐based airway management education and review process of emergency medicine residency training programs.4
Success rates on the first attempt by resident physicians improved from the PGY 1 through PGY 3, and stabilized thereafter. These findings were similar to a previous North American study1 and to be expected, given the increase in experience gained during the first few years of residency training. It is possible that the improvement over time would have been even greater than the observed rates because junior residents were more likely to be allowed attempts on patients with anticipated “easy” airways, whereas more difficult cases may be reserved for senior residents.
Rescue intubations performed by the PGY 1 resident physicians were rare. There was only one rescue intubation attempt performed by PGY 1 residents. In this case, the intubation attempt was subsequently rescued by an emergency medicine attending physician after six failed attempts. The PGY 2 residents performed rescue intubations with lower success rates compared to their initial attempts. By contrast, the PGY 3, 4, and 5 residents performed first rescue intubations with rather higher success rates compared to their initial attempts. These findings also suggested that higher‐level residents more commonly played a supervisory role and gained skills for rescue airway techniques in difficult cases.
Now, multiple studies arrived at similar conclusions that resident physicians play a major role on emergency airway management with acceptably high success rates overall despite differing populations and healthcare systems; our study illustrates the advent of emergency medicine as a specialty internationally. However, we also identified room for improvement. The low success rates on the first attempts by PGY 1 and 2 resident physicians, in conjunction of the literature demonstrating the higher incidence of airway‐related complications with repeated intubation attempts,12, 16 suggested that the training of these residents may not be sufficient before “live” intubations in the ED setting. This result can better inform a system of care for critically ill patients who require emergency airway management. At individual provider and researcher level, evidence to guide the provision of optimal airway management in EDs remains limited.17 High‐quality research into the difficult airway predictions, intubation methods, and rescue techniques, coupled with dissemination of these findings could substantially improve airway management for critically ill patients. At the population and health system level, as intubation is vital to the emergency physician's skill set, an organized and structured setting demonstrating competence in intubation skills is warranted.18 Potential approach includes development and implementation of intubation mastering programs by using learning and deliberate practice approach, simulation‐based curricula, and utilization of video‐laryngoscopes.19, 20, 21, 22 Improvement of the quality of emergency care is the responsibility of multiple entities; however, there may be a stronger chance of improvement of the quality of airway management if the leadership and direction of governmental and professional agencies were strengthened.
Limitations
Our study has several potential limitations. First, passive surveillance introduces the potential of reporting bias; therefore, underestimation of the rate of failed intubations and adverse events is possible. Although we performed interviews of the involved physicians and analyses of patient medical records to complete missing data, validation of existing data is not logistically feasible. Nevertheless, we used a previously applied self‐reporting system with structured data forms, uniform definitions,1, 5 and achieved a high capture rate. We believe that these data represent the best available data.
Second, this study was purely descriptive and did not adjust for potential confounders. Therefore, we can make no assumptions about the reasons for the observed differences success rates across the levels of training. It is therefore possible that residents at more advanced levels of training selectively attempted to intubate the more difficult patients. Consequently, it is possible that the true learning curve is different than that demonstrated in this study.
Finally, this descriptive study was not designed to measure patient outcomes after ED disposition such as mortality or to evaluate relationships between ED airway management and outcomes. A more accurate analysis of outcomes and complications requires follow‐up with patients during the remainder of their hospitalization or on autopsy.
Conclusions
In this multi‐centre study characterizing ED airway management across Japan, we observed that ED intubations were primarily managed by resident physicians with acceptably high success rates overall. Indeed, approximately 70% of ED intubations were initially performed by resident physicians; intubations were ultimately successful in 99.6%. However, the lower success rates on the first attempts calls for specific educational and quality improvement efforts to advance excellence in emergency airway management, which, in turn, may improve patient outcomes.
Conflict of Interest
None.
Acknowledgements
This study was supported by a grant for emergency medicine research from Harvard Affiliated Emergency Medicine Residency, and a grant from St. Luke's Life Science Institute. The study sponsors have no involvement in the study design, in the collection, analysis and interpretation of data, in the writing of the manuscript, and in the decision to submit the manuscript for publication.
The authors acknowledge the following research personnel at the study hospitals for their assistance with this project: Fukui University Hospital (Hiroshi Morita MD), Fukui Prefectural Hospital (Hideya Nagai, MD), Japanese Red Cross Medical Center of Wakayama (Hiroshi Okamoto, MD), Kameda Medical Center (Kenzo Tanaka, MD), Kurashiki Central Hospital (Hiroshi Okamoto, MD), National Center for Global Health and Medicine (Shunichiro Nakao, MD), Nigata City General Hospital (Nobuhiro Sato, MD), Obama Municipal Hospital (Yukinori Kato, MD), Okinawa Chubu Prefectural Hospital (Masashi Okubo, MD), Saiseikai Senri Hospital (Kazuaki Shigemitsu, MD), Shonan Kamakura General Hospital (Taichi Imamura, MD), and St. Marianna University School of Medicine Hospital (Yasuaki Koyama, MD). Finally, we are grateful to our many emergency physicians and residents for their perseverance in pursuing new knowledge about this vital resuscitative procedure.
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