Abstract
Background and importance
Although advanced airway management is beneficial for patients with out-of-hospital cardiac arrest (OHCA) in certain situations, the impact of advanced airway management success or failure by the emergency medical service (EMS) crew on the clinical time course and outcomes has not yet been thoroughly evaluated.
Objectives
To evaluate the impact of EMS crew members’ prehospital advanced airway management failure on patient outcomes in OHCA.
Design
Retrospective multicentre registry study.
Setting and Participants
Data from an OHCA survey in a Japanese retrospective multicentre study conducted between 2019 and 2021 were reviewed.
Outcome measures and analysis
Patients who underwent advanced airway management were divided into success and failure groups. The baseline characteristics and outcomes of the two groups were evaluated. Propensity score matching was performed by creating matched success and failure groups to analyse sensitivity. The primary outcome was 30-day survival, and secondary outcomes were favourable neurological outcomes at discharge, time from on-scene EMS arrival to hospital arrival, and return of spontaneous circulation (ROSC).
Main results
Overall, 4474 patients who underwent prehospital advanced airway management were analysed. Among them, 4074 and 400 patients were in the success and failure groups, respectively. The 30-day survival rates (success vs. failure, 4.4 vs. 2.3%; P = 0.043) and ROSC (29.9 vs. 16.8%; P < 0.001) in the failure group were lower than those in the success group. There were no significant differences in survival rate at hospital discharge (3.6 vs. 2.0%; P = 0.093) and favourable neurological outcomes (1.3 vs. 1.3%; P = 0.930) between the groups. The median time from on-scene EMS arrival to hospital arrival (min) [28.0 (22.0–34.0) vs. 29.0 (25.9–35.0); P < 0.001] in the failure group was longer than that in the success group. After propensity score matching, the results showed a similar trend.
Conclusion
Prehospital advanced airway management failure was associated with lower 30-day survival rates, ROSC, and a longer time between EMS arrival and hospital arrival. These findings suggest that failure of prehospital advanced airway management could potentially worsen the outcomes of patients with OHCA.
Keywords: airway management, neurological outcomes, out-of-hospital cardiac arrest, resuscitation, survival
Introduction
Out-of-hospital cardiac arrest (OHCA) remains a critical public health issue, with a high mortality rate despite updates to cardiopulmonary resuscitation (CPR) guidelines [1,2]. Improvements in early access to emergency medical care [3,4], rapid defibrillation [5], and integrated postresuscitation care [6] have increased the survival rates of patients with OHCA. Moreover, emergency medical service (EMS) providers play a critical role in prehospital care [7].
In the Japanese EMS system, respiratory management of patients with OHCA involves ventilation using either a bag-valve-mask or advanced airway management, which includes placement of supraglottic airway devices or endotracheal intubation [8]. The bag-valve-mask is simple and time-saving; however, it carries the risk of air entering the stomach, leading to reflux and aspiration [9]. Furthermore, in cases where the bag-valve-mask method is used, achieving an effective seal for adequate ventilation may be challenging during transportation to a hospital [10].
In contrast to the bag-valve-mask method, advanced airway management has the potential to ensure proper oxygenation and ventilation, as well as protect the airway [11]. However, multiple or unsuccessful advanced airway management attempts can interrupt the continuity of chest compressions during CPR [12]. Furthermore, certain complications, such as tube misplacement, aspiration, regurgitation, airway injury, and time consumption have been reported in cases of advanced airway management [11]. Although prehospital advanced airway management has proven beneficial for outcomes in a limited situation or populations, such as patients with nonshockable rhythms [13], a few studies have indicated that advanced airway management is harmful to the outcomes of patients with OHCA [12,14]. Therefore, the efficacy and appropriateness of prehospital advanced airway management in patients with OHCA are debatable and depend on the clinical situation. Each EMS crew member in Japan determines whether the device is suitable for the respective case based on the physician’s guidance [15]. In a few cases, prehospital advanced airway management facilitated by an EMS presents considerable challenges [16].
Although previous studies have reported the effectiveness of prehospital advanced airway management in patients with OHCA [12,13], there have been no reports evaluating the impact of intubation attempts, whether successful or failed, on clinical outcomes. We hypothesised that the failure of prehospital advanced airway management might have adverse effects on patient outcomes, potentially because of time wasted on unsuccessful attempts and subsequent complications. Thus, the present study aimed to compare the clinical outcomes in patients with OHCA between successful and failed prehospital advanced airway management by EMS, using real data from a Japanese registry.
Materials and methods
Study design and setting
Data from a survey of OHCA survivors in the Kanto Region (SOS-KANTO) 2017 study, a retrospective, multicentre registry study conducted between September 2019 and March 2021, were analysed. This study aimed to accumulate the pre- and in-hospital records of patients, supported by the Kanto Regional Group of the Japanese Association for Acute Medicine [17].
Ethics approval and informed consent
This study complied with the principles of the 1964 Declaration of Helsinki and its later amendments and was approved by the institutional review board of Tokyo Medical and Dental University (Approval No. M2019-142). The requirement for informed consent was waived owing to the retrospective design of the study and the use of anonymised data.
Study population
The inclusion criteria of participants in the study were as follows: (a) patients aged greater than or equal to 18 years, (b) patients with OHCA who were transported to the participating hospitals, and (c) patients who underwent prehospital advanced airway management attempts during the study period. Patients who met at least one of the following criteria were excluded: (a) treated by doctors in a prehospital setting; (b) had a ‘do not attempt resuscitation’ order; (c) prehospital advanced airway management was not attempted (i.e. those who received only bag-valve-mask ventilation); and (d) missing data, including the details of prehospital advanced airway management or clinical outcomes.
Data collection
Clinical data and pre- and subsequent hospitalisation medical records were obtained from the SOS-KANTO 2017 study. The following information was retrospectively collected from the medical records: age, sex, incidence of witnessed cardiac arrest (CA) and bystander CPR, location of CA, initial cardiac rhythm, prehospital procedures (advanced airway management or bag-valve-mask), success or failure of advanced airway management, and time course.
The following information was collected at the hospital: return of spontaneous circulation (ROSC), aetiology of CA, 30-day survival, survival rate, and cerebral performance category (CPC) score at hospital discharge.
Outcomes and definitions
The primary outcome measure was 30-day survival. Secondary outcomes were survival at hospital discharge, favourable neurological outcomes at discharge, time from on-scene EMS arrival to hospital arrival, and ROSC. In this study, ROSC was defined as any ROSC during resuscitation. Neurological status at discharge was assessed using CPC scores, which classify neurological outcomes into five stages: (a) good cerebral performance, (b) moderate cerebral disability, (c) severe cerebral disability, (d) coma or vegetative state, and (e) death. A favourable neurological outcome was defined as a CPC score of 1 or 2 [18]. In this study, advanced airway management included the placement of supraglottic airway devices or endotracheal intubation. Furthermore, data regarding whether advanced airway management was successful or failed were extracted from the physicians’ medical records. Advanced airway management success was defined as the confirmation of proper advanced airway management by physicians through physical examination or imaging upon hospital arrival. Advanced airway management failure was defined as impossible advanced airway management or oesophageal intubation.
Statistical analyses
Among the included patients, those who underwent advanced airway management at least once were divided into two groups: success and failure. Subsequently, we evaluated the differences in baseline characteristics and outcomes between the two groups. Furthermore, we categorised patients who underwent advanced airway management into shockable and nonshockable rhythm groups to analyse each outcome. In the univariate analysis, continuous variables were reported as medians (interquartile ranges), whereas categorical variables were reported as numbers (percentages). Continuous variables were compared using the Mann–Whitney U test, and categorical variables were compared using Fisher’s exact test.
In addition, to analyse sensitivity, propensity score matching was performed by creating matched groups of advanced airway management success and failure. Propensity scores were calculated using logistic regression analysis (age, sex, witnessed CA, bystander CPR, initial shockable rhythm, prehospital automated external defibrillator use, location, time from EMS call to EMS arrival at the scene, and cardiac aetiology) [12]. The nearest neighbour method was used with a caliper of 0.25, which was the largest allowable difference in the propensity scores of matched participants to match the logit-transformed propensity scores of 1 : 1 between both groups. The absolute standardised mean difference was used to assess the matching balance for the different variables between the two groups, and matching was considered acceptable at values less than 0.1. Intergroup comparisons of the outcomes among propensity score-matched participants were performed using the χ2 test.
Differences were considered significant at a two-sided P value less than 0.05. All statistical analyses were conducted using SPSS software version 26 (IBM Corp., Armonk, New York, USA) and R software (version 4.3.1; R Foundation for Statistical Computing, Vienna, Austria).
Results
Among 9909 patients with OHCA, 4474 were included in the analysis; among them, 4074 (91.1%) and 400 (8.9%) patients were in the success and failure groups, respectively (Fig. 1).
Fig. 1.
Flow diagram of patient selection. AAM, advanced airway management; DNAR, do not attempt resuscitation.
Table 1 provides a comparison of patients who met the inclusion criteria between the success and failure groups. There were no significant differences in age, sex, incidence of witnessed CA, bystander CPR, initial shockable rhythm, or time from EMS call to on-scene EMS arrival. The proportion of CA from cardiac aetiology and CA at home was higher in the failure group than in the success group. Furthermore, there were no significant differences in the proportion of patients who underwent supraglottic airway device or endotracheal intubation between groups.
Table 1.
Comparison of characteristics between the advanced airway management success group and the advanced airway management failure group.
| All (n = 4474) | Success (n = 4074) | Failure (n = 400) | |
|---|---|---|---|
| Patient characteristics | |||
| Age (years), median (IQR) | 77.0 (66.0–85.0) | 77.0 (66.0–85.0) | 77.0 (66.0–84.0) |
| Female sex, n (%) | 1704 (38.1) | 1551 (38.1) | 153 (38.3) |
| CA at home, n (%) | 3119 (70.4) | 2822 (69.9) | 297 (75.6) |
| Witnessed CA, n (%) | 1946 (44.1) | 1789 (44.5) | 157 (39.8) |
| Bystander CPR, n (%) | 1943 (44.4) | 1786 (44.8) | 157 (40.8) |
| Initial shockable rhythm, n (%) | 321 (7.4) | 296 (7.4) | 25 (6.5) |
| Prehospital AED, n (%) | 546 (12.3) | 497 (12.3) | 49 (12.4) |
| Time from EMS call to on-scene EMS arrival (min), med (IQR) | 8.0 (6.0–10.0) | 8.0 (6.0–10.0) | 8.0 (6.0–10.0) |
| Type of AAM, n (%) | |||
| Supraglottic airway device | 3875 (86.6) | 3536 (86.8) | 339 (84.8) |
| Endotracheal intubation | 599 (13.4) | 538 (13.2) | 61 (15.3) |
| Cause of death, n (%) | |||
| Cardiac aetiology | 2873 (64.2) | 2578 (63.3) | 295 (73.8) |
| Cerebrovascular | 143 (3.2) | 135 (3.3) | 8 (2.0) |
| Respiratory disease | 240 (5.4) | 229 (5.6) | 11 (2.8) |
| Malignancy | 92 (2.1) | 86 (2.1) | 6 (1.5) |
| External causes | 648 (14.5) | 593 (14.6) | 55 (13.8) |
| Others | 478 (10.7) | 453 (11.1) | 25 (6.3) |
Continuous variables are presented as medians (interquartile ranges), and categorical variables are presented as n (%).
AAM, advanced airway management; AED, automated external defibrillator; CA, cardiac arrest; CPR, cardiopulmonary resuscitation; EMS, emergency medical service; IQR, interquartile range.
Supplementary Table S1, Supplemental Digital Content 1, http://links.lww.com/EJEM/A487 presents a comparison of patient characteristics and outcomes between patients who received supraglottic airway devices and endotracheal intubation. Of the 4474 patients who underwent advanced airway management, 3875 (86.6%) received a supraglottic airway device, and 599 (13.4%) underwent endotracheal intubation. There were no significant differences in 30-day survival (supraglottic airway device vs. endotracheal intubation, 4.1 vs. 5.0%), survival at hospital discharge (3.4 vs. 3.4%), and favourable neurological outcomes at hospital discharge (1.3 vs. 1.2%). ROSC was higher in the endotracheal intubation group than in the supraglottic airway device group (28.1 vs. 33.3%). The time from on-scene EMS arrival to hospital arrival (min) was longer in the endotracheal intubation group than in the supraglottic airway device group [27.0 (22.0–34.0) vs. 30.0 (25.0–36.0)].
Table 2 summarises the comparison of outcomes between the success and failure groups in patients who underwent advanced airway management at least once. The 30-day survival (success vs. failure, 4.4 vs. 2.3%; P = 0.043) and ROSC (29.9 vs. 16.8%; P < 0.001) rates in the failure group were lower than those in the success group, although there were no significant differences in survival rate at hospital discharge (3.6 vs. 2.0%; P = 0.093) and favourable neurological outcomes (1.3 vs. 1.3%; P = 0.930). The time from on-scene EMS arrival to hospital arrival (min) in the failure group was longer than that in the success group [28.0 (22.0–34.0) vs. 29.0 (25.0–35.0); P < 0.001]. Patients who underwent advanced airway management at least once were further subdivided and analysed based on whether they had an initial shockable or nonshockable rhythm. In patients who underwent advanced airway management at least once and who had initial shockable rhythms, the rate of 30-day survival, survival at hospital discharge, favourable neurological outcomes, ROSC, and the median time from on-scene EMS arrival to hospital arrival showed no significant differences between the success and failure groups. In patients who underwent advanced airway management at least once and who had initial nonshockable rhythms, the 30-day survival rate (3.2 vs. 0.6%; P = 0.005), survival rate at hospital discharge (2.5 vs. 0.3%; P = 0.007), and ROSC (28.4 vs. 14.7%; P < 0.001) in the failure group were lower than those in the success group. The median time from on-scene EMS arrival to hospital arrival (min) in the failure group was longer than that in the success group [28.0 (22.0–34.0) vs. 30.0 (25.0–35.0); P < 0.001].
Table 2.
Comparison of outcomes between the advanced airway management success group and the advanced airway management failure group.
| All | Success | Failure | P value | |
|---|---|---|---|---|
| Outcomes | ||||
| All patients attempting AAM | n = 4474 | n = 4074 | n = 400 | |
| Primary outcome | ||||
| 30-day survival, n (%) | 187 (4.2) | 178 (4.4) | 9 (2.3) | 0.043 |
| Secondary outcome | ||||
| Survival at hospital discharge, n (%) | 155 (3.5) | 147 (3.6) | 8 (2.0) | 0.093 |
| Favourable neurological outcome at hospital discharge, n (%) | 58 (1.3) | 53 (1.3) | 5 (1.3) | 0.930 |
| ROSC, n (%) | 1285 (28.7) | 1218 (29.9) | 67 (16.8) | <0.001 |
| Time from EMS arrival to hospital arrival (min), median (IQR) | 28.0 (22.0–34.0) | 28.0 (22.0–34.0) | 29.0 (25.0–35.0) | <0.001 |
| Patients with an initial shockable rhythm | n = 321 | n = 296 | n = 25 | |
| Primary outcome | ||||
| 30-day survival, n (%) | 62 (19.3) | 55 (18.6) | 7 (28.0) | 0.252 |
| Secondary outcome | ||||
| Survival at hospital discharge, n (%) | 57 (17.8) | 50 (16.9) | 7 (28.0) | 0.163 |
| Favourable neurological outcome at hospital discharge, n (%) | 28 (8.8) | 24 (8.1) | 4 (16.0) | 0.182 |
| ROSC, n (%) | 158 (49.2) | 146 (49.3) | 12 (48.0) | 0.899 |
| Time from EMS arrival to hospital arrival (min), median (IQR) | 26.0 (21.0–32.0) | 26.0 (21.0–32.0) | 26.0 (21.0–30.5) | 0.861 |
| Patients with nonshockable rhythm | n = 4044 | n = 3684 | n = 360 | |
| Primary outcome | ||||
| 30-day survival, n (%) | 120 (3.0) | 118 (3.2) | 2 (0.6) | 0.005 |
| Secondary outcome | ||||
| Survival at hospital discharge, n (%) | 92 (2.5) | 92 (2.5) | 1 (0.3) | 0.007 |
| Favourable neurological outcome at hospital discharge, n (%) | 29 (0.7) | 28 (0.8) | 1 (0.3) | 0.300 |
| ROSC, n (%) | 1099 (27.2) | 1046 (28.4) | 53 (14.7) | <0.001 |
| Time from EMS arrival to hospital arrival (min), median (IQR) | 28.0 (22.0–34.0) | 28.0 (22.0–34.0) | 30.0 (25.0–35.0) | <0.001 |
Continuous variables are presented as the median (interquartile range), and categorical variables are presented as n (%).
AAM, advanced airway management; EMS, emergency medical service; IQR, interquartile range; ROSC, return of spontaneous circulation.
Propensity score matching was used to create 344 matched pairs, whose baseline characteristics are shown in Supplementary Table S2, Supplemental Digital Content 2, http://links.lww.com/EJEM/A488. The absolute standardised mean difference values for each variable were approximately 0.1, indicating that a well-matched balance was achieved. Table 3 presents the outcomes of propensity score matching between the two groups. In the multivariate analysis, the 30-day survival and ROSC rates in the failure group tended to be lower than those in the success group. Furthermore, the median time from on-scene EMS arrival to hospital arrival was longer in the failure group than in the success group. Supplementary Tables S3 and S4, Supplemental Digital Content 3, http://links.lww.com/EJEM/A489 present the outcomes of propensity score matching in patients with initial shockable rhythm and nonshockable rhythm between the two groups, respectively. No significant differences were observed in 30-day survival, survival at hospital discharge, favourable neurological outcome at hospital discharge, ROSC, and time from EMS arrival to hospital arrival between the two groups. The 30-day survival and ROSC rates in the failure group were lower than those in the success group, although there were no significant differences in survival rates at hospital discharge and favourable neurological outcomes.
Table 3.
Outcomes after the propensity score matching
| Success (n = 344) | Failure (n = 344) | P value | |
|---|---|---|---|
| Outcomes | |||
| Primary outcome | |||
| 30-day survival, n (%) | 24 (7.0) | 17 (4.2) | 0.04 |
| Secondary outcome | |||
| Favourable neurological outcome at hospital discharge, n (%) | 8 (2.3) | 6 (1.7) | 0.180 |
| ROSC, n (%) | 67 (19.5) | 51 (14.8) | 0.003 |
| Time from EMS arrival to hospital arrival, median (IQR) | 25.5 (20.2–31.5) | 29.1 (23.5–33.2) | <0.001 |
Continuous variables are presented as the median (interquartile range), and categorical variables are presented as n (%).
EMS, emergency medical service; IQR, interquartile range; ROSC, return of spontaneous circulation.
Discussion
In this multicentre observational study, we observed that among patients who underwent prehospital advanced airway management by EMS crews at least once, the failure rate of advanced airway management was 7.9%. Prehospital advanced airway management failure was significantly associated with a lower 30-day survival rate, ROSC, and longer time from on-scene EMS arrival to hospital arrival. Although previous studies have evaluated the effectiveness of prehospital advanced airway management in patients with OHCA, to the best of our knowledge, our study is the first to assess the impact of prehospital advanced airway management failure on clinical and time-course outcomes.
Prehospital advanced airway management ensures sufficient oxygen delivery and controlled ventilation, which are crucial for the recovery of cardiac and organ function. Furthermore, advanced airway management plays a crucial role in preventing aspiration, securing airways for effective oxygenation, and removing CO2 [11]. However, the effect of prehospital advanced airway management on the clinical outcomes of patients with OHCA remains controversial. A previous study reported that supraglottic airway devices were more effective for adequate ventilation than endotracheal intubation or bag-valve-mask, owing to difficulties in performing intubation and manual bag-valve-mask ventilation outside the hospital. When comparing intubation and bag-valve-mask, patients with prehospital endotracheal intubation were effectively ventilated and had a higher rate of ROSC than those with bag-valve-mask [19]. When comparing intubation and supraglottic airway devices, patients who underwent prehospital endotracheal intubation had higher ROSC rates on hospital admission and survival rates than patients with supraglottic airway devices in the presence of automated chest compressions [20]. In a previous randomised-controlled trial comparing the bag-valve-mask and prehospital intubation groups in patients with OHCA, there were no significant differences in clinical and neurological outcomes, although the ROSC rate was higher in the intubation group than in the bag-valve-mask group [21]. The results of previous studies could be affected by confounders, suggesting selection bias and methodological differences, such as intention-to-treat analyses based on the initial advanced airway management intervention. The results of previous studies did not provide clear support for prehospital advanced airway management. On the basis of the insights from our research and the potential for advanced airway management failure, prioritising transportation with bag-valve-mask ventilation may be considered a feasible option. Further large-scale studies are needed to identify patient groups for whom transportation should be prioritised over prehospital advanced airway management in EMS systems.
The advanced airway management procedure, as well as its failure, has been reported to have harmful clinical effects in patients with OHCA. First, advanced airway management requires experienced operators with advanced skills, particularly in tracheal intubation. Oesophageal intubation is a common complication in the prehospital setting [22]. Previous studies have indicated that prehospital advanced airway management attempts can result in interruptions to chest compressions [23] and an increase in the time spent at the scene, leading to a delay in the initiation of transport [11,24]. Moreover, a prolonged scene time interval in OHCA has been linked to poorer survival outcomes [25]. In certain cases with difficult airways, multiple advanced airway management attempts may also lead to the loss of oxygenation and consumption of transport time [11]. Repeated or failed intubation attempts can lead to significant interruptions in chest compression. Notably, cases necessitating multiple advanced airway management attempts frequently represent inherently complex situations, and patient-specific factors may directly influence unfavourable outcomes in addition to the challenges posed by the advanced airway management procedure itself. Second, patients with advanced airway management may undergo more hyperventilation than patients with bag-valve-mask, which can lead to hyperoxaemia, hypocapnia, or both [26]. In addition, hyperventilation during out-of-hospital CPR can result in poor clinical outcomes [27]. Further studies are crucial to identify patients who could benefit from prehospital advanced airway management, given its potentially harmful aspects.
In this study, for patients with an initial shockable rhythm, advanced airway management failure did not affect the clinical and time-course outcomes. A previous study that could not evaluate data on successful or unsuccessful intubation reported that advanced airway management did not improve survival rates in patients with shockable rhythms, presumably because of the higher importance of immediate defibrillation and continuous CPR than advanced airway management; however, advanced airway management was associated with better survival in patients with nonshockable rhythms [13]. Considering these differences between our study and the previous one, in patients with an initial shockable rhythm, the clinical effect of the method of airway management during transportation could be lower than other factors, such as transport time or time interval to defibrillation. Nevertheless, this retrospective study could not elucidate the specific factors and mechanisms by which they influenced clinical outcomes; consequently, further large-scale prospective research is warranted.
Research has indicated that prehospital advanced life support, encompassing advanced airway management and epinephrine administration, was associated with extended total prehospital times and poorer neurological outcomes in patients with OHCA undergoing extracorporeal cardiopulmonary resuscitation (ECPR) [25]. These prehospital procedures should be evaluated not only in terms of total prehospital activity duration, but also considering the interaction with other interventions and the timing of each procedure. For patients with an initial shockable rhythm who may be candidates for ECPR, careful consideration should be given to balancing prehospital procedures against minimising delays to hospital transport, as prolonged prehospital times may delay critical in-hospital intervention, including ECPR. Considering that only 7% of the patients who underwent advanced airway management in this study had an initial shockable rhythm, further prospective studies are warranted to elucidate the optimal timing and application of prehospital advanced airway management, particularly in patients with an initial shockable rhythm who may be candidates for ECPR.
Limitations
This study had certain limitations. First, because of its observational nature, it was prone to residual confounding factors. Second, patients who did not undergo prehospital advanced airway management attempts were excluded from the study. This exclusion may introduce selection bias for two reasons: (a) different regions may have different protocols for prehospital advanced airway management attempts, and (b) some patients may not receive advanced airway management attempts due to physical characteristics (such as difficult airways) or challenging scene conditions. Although patients were eligible for advanced airway management, a small number were excluded even though bag-valve-mask ventilation was selected based on field judgement. Further research, including both patients who received prehospital advanced airway management and those who did not receive prehospital advanced airway management, is warranted to better understand the impact of prehospital advanced airway management strategies. In addition, this study did not conduct analyses comparing patients with advanced airway management success and failure, considering the difference in the type of airway device utilised (supraglottic airway device vs. endotracheal intubation). This important aspect warrants further investigation through prospective studies. Third, patients who received prehospital treatment from physicians were excluded, leading to a potential selection bias. Fourth, as this was a retrospective analysis of registry data not specifically designed to evaluate advanced airway management failure, we were unable to collect data pertaining to the reasons for advanced airway management failure, the number of advanced airway management attempts, the timing of advanced airway management failure, and the timing of advanced airway management failure recognition (during advanced airway management attempt, during transport, or upon hospital arrival). Fifth, we could not obtain data, including the time when advanced airway management attempts were initiated and the duration of advanced airway management attempts. Future prospective studies are necessary to obtain detailed data on the time-course of advanced airway management. Finally, although Utstein has recommended defining ROSC as the return of spontaneous circulation for greater than or equal to 30 s [28], the present study defined ROSC as any return of spontaneous circulation (no matter the duration) based on the absence of clinical data for the duration of ROSC in this study. Despite these limitations, the effects of advanced airway management failure on patient outcomes were evaluated. Across various patient cohorts, advanced airway management failure was not associated with favourable neurological outcomes. Although advanced airway management success was associated with an improvement in the rate of ROSC in a few cases, advanced airway management failure was associated with a long time between on-scene EMS arrival and hospital arrival. These advantages and disadvantages associated with prehospital advanced airway management should be recognised. This warrants further research to identify patients who would benefit from advanced airway management from EMS crews, including consideration of the number of attempts. In addition, enhancing the airway management skills of EMS providers through workshops and training programmes in medical facilities should be the focus.
Conclusion
Prehospital advanced airway management failure by the EMS crew was associated with a low 30-day survival rate and a long time between on-scene EMS arrival and arrival at the hospital. These findings suggest that failure of prehospital advanced airway management may potentially worsen patient outcomes. Further studies are needed to identify patients who may benefit from prehospital advanced airway management or who would be better served by prioritising transport over advanced airway management.
Acknowledgements
We thank all patients, their families, physicians, nurses, paramedics, and staff members. We also thank the research staff of the SOS-KANTO 2017.
Conflicts of interest
There are no conflicts of interest.
Supplementary Material
Footnotes
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website (www.euro-emergencymed.com).
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