The incidences of prehospital advanced airway management by emergency medical technicians in South Korea are increasing; however, whether this procedure improves the survival outcomes of patients experiencing out-of-hospital cardiac arrest remains unclear. The present study aimed to investigate the association between prehospital advanced airway management and neurologic outcomes according to a transport time interval (TTI) using the Korean Cardiac Arrest Research Consortium database.
We retrospectively analyzed the favorable database entries that were prospectively collected between October 2015 and December 2016. Patients aged 18 years or older who experienced cardiac arrest that was presumed to be of a medical etiology and that occurred prior to the arrival of emergency medical service personnel were included. The exposure variable was the type of prehospital airway management provided by emergency medical technicians. The primary endpoint was a favorable neurologic outcome.
Of 1,871 patients who experienced out-of-hospital cardiac arrest, 785 (42.0%), 121 (6.5%), and 965 (51.6%) were managed with bag-valve-mask ventilation, endotracheal intubation (ETI), and supraglottic airway (SGA) devices, respectively. SGAs and ETI provided no advantage in terms of favorable neurologic outcome in patients with TTIs ≥12 minutes (odds ratio [OR], 1.37; confidence interval [CI], 0.65–2.87 for SGAs; OR, 1.31; CI, 0.30–5.81 for ETI) or in patients with TTI <12 minutes (OR, 0.57; CI, 0.31–1.07 for SGAs; OR, 0.63; CI, 0.12–3.26 for ETI).
Neither the prehospital use of SGA nor administration of ETI was associated with superior neurologic outcomes compared with bag-valve-mask ventilation.
Advanced airway management, including endotracheal intubation and the use of supraglottic airway devices, can facilitate the performance of high-quality cardiopulmonary resuscitation without interrupting chest compressions compared with bag-valve-mask ventilation, and increase the rates of short-term survival, the return of spontaneous circulation, and survival to admission.
Neither the prehospital use of supraglottic airway devices nor the performance of endotracheal intubation was associated with improved neurologic outcome compared to bag-valve-mask ventilation among patients experiencing out-of-hospital cardiac arrest.
During cardiopulmonary resuscitation (CPR) on a patient experiencing out-of-hospital cardiac arrest (OHCA), it is recommended that healthcare providers maintain bag-valve-mask (BVM) ventilation before performing advanced airway management [
With the increase in the proportion of level 1 emergency medical technicians (EMTs) among the 119 emergency medical service (EMS) agencies in South Korea, there has been an increasing trend toward performing advanced airway management, including ETI and SGA use, during the prehospital phase. However, the effects of prehospital airway management on the neurologic outcomes of patients experiencing OHCA remain unclear despite previous investigations [
Considering that prehospital airway management can minimize chest compression interruptions, provide effective ventilation, and reduce airway complications in patients with OHCA [
We retrospectively analyzed data from the KoCARC database that was recorded between October 2015 and December 2016. Patients aged 18 years or older who experienced cardiac arrest that was presumed to be of a medical etiology and that occurred prior to the arrival of EMS personnel on the scene were included in this study. The KoCARC registry excluded OHCA patients with terminal illnesses documented in their medical records as well as those under hospice care, those who were pregnant, and those with “do not resuscitate” directives. Furthermore, we also excluded the following groups: patients with OHCA verifiably caused by nonmedical etiologies such as trauma, drowning, poisoning, burn, asphyxia, and hanging [
The KoCARC registry is a multicenter nationwide network of 64 participating institutions for data collection and collaborative research from across South Korea. Data are collected according to standardized Utstein-style templates for OHCA to facilitate uniform reporting using precisely defined variables and outcomes. Data are error-checked prior to consolidation with the master dataset. The quality management committee provides feedback regarding quality management processes to the research coordinators and investigators [
The exposure variable in this study was the type of prehospital airway management provided by EMTs. The subjects were divided into three groups according to the prehospital airway management method (BVM, ETI, or SGA); patient demographics, arrest characteristics, and survival outcomes were compared among the three groups.
Neurologic status was assessed using cerebral performance category scores, which are based on a five-point scale in which scores of 1 (good recovery) and 2 (moderate disability) indicated favorable neurologic outcome. The primary endpoint was a favorable neurologic outcome, whereas the secondary endpoint was survival to hospital discharge. We used the following a favorable registry core variables: (1) patient demographics (i.e., sex, age, medical history of hypertension, diabetes, and dyslipidemia); (2) community resuscitation (i.e., ‘witnessed’ status, bystander CPR, and location of cardiac arrest occurrence); (3) EMS resuscitation (i.e., initial electrocardiogram rhythm, prehospital defibrillation, prehospital epinephrine administration, prehospital ROSC, elapsed time from the initial call to ambulance arrival at the scene [response time interval], elapsed time from arrival at the scene to departure [scene time interval], and elapsed time from departure to arrival at the emergency department [TTI]); and (4) hospital resuscitation and postresuscitation care (i.e., performed extracorporeal membrane oxygenation, coronary angiography, and target temperature management) [
The significance of differences between groups was tested using analysis of variance with post-hoc analysis (with multiple comparisons using the Bonferroni method) for continuous variables and Pearson chi-square test for categorical variables. The association between prehospital advanced airway management and outcomes was assessed using logistic regression analysis according to the TTI after classifying the patients into two groups, TTI ≥12 vs. <12 minutes; this cutoff was the time point found to show the greatest difference in the direction of this association. To assess homogeneity across the two groups, the Breslow-Day test was performed to determine OHCA outcomes by 12 minutes of transport time. Our subgroup analysis revealed that a TTI of 12 minutes presented the least homogeneity on Breslow-Day testing (P=0.028 for neurologic outcome, P=0.040 for survival to discharge). Logistic regression analysis was performed by adjusting the confounding variables based on a TTI of ≥12 and of <12 minutes to examine the association between prehospital advanced airway management and outcomes. We included potential confounding variables such as sex, age, response time interval, scene time interval, location of cardiac arrest occurrence, shockable rhythm, ‘witnessed’ status, bystander CPR, prehospital defibrillation, and prehospital epinephrine administration. The results are expressed as odds ratios (ORs) and 95% confidence intervals (CIs). All statistical tests were performed using SAS software ver. 9.4 (SAS Institute Inc., Cary, NC, USA), and P-values <0.05 were considered statistically significant.
Among the 3,187 OHCA subjects registered in the KoCARC database between October 1, 2015 and December 31, 2016, 94 patients aged <18 years were excluded. Additionally, 231 patients who were transferred from a different hospital prior to admission to the participating hospital, 912 who had unclear or unknown time variables between prehospital EMS site arrival and hospital arrival, 9 whose prehospital airway management methods were unknown, and 70 who experienced cardiac arrest in the ambulance were excluded. Ultimately, 1,871 patients were included in the final analysis. The subjects were divided into the following three groups according to the prehospital airway management method: BVM (n=785), SGA (n=965), and ETI (n=121) (
Patients in the ETI group were the oldest among the three, with subjects older than 65 years of age (median, 74 years) accounting for 73.6% (89 subjects) of the entire group. The BVM group had the lowest median on-scene time at 9 minutes, the highest rate of cardiac arrest occurring in a public place at 27.8% (218 subjects), and the highest witnessed cardiac arrest rate at 64% (502 subjects). Moreover, 23.4% and 24% of subjects in the SGA and ETI groups, respectively, required prehospital epinephrine administration; these rates were higher than that for the BVM group. Among the three groups, the BVM group had the highest survival to discharge rate and the highest proportion of patients with good neurologic outcomes at 11.8% and 8.7%, respectively.
After adjustment for potential confounders, neither SGA nor ETI use was associated with better neurologic outcomes than BVM ventilation (OR, 0.59; CI, 0.33–1.06 for SGA; OR, 0.77; CI, 0.21– 2.83 for ETI). Similarly, the use of SGA or ETI was not associated with improved survival to discharge compared to BVM ventilation (OR, 0.88; CI, 0.57–1.38 for SGA; OR, 1.52; CI, 0.66–3.47 for ETI) (
Among patients in whom the TTI was <12 minutes, those in the SGA and ETI groups had good neurologic outcome rates of 4.4% and 2.9% (P=0.561), as well as survival to discharge rates of 7.0% and 7.3% (P=0.950), respectively (
Our study revealed that the prehospital use of SGA and the performance of ETI were not associated with improved neurologic outcomes or survival to discharge compared to BVM ventilation regardless of transport time.
Conversely, a previous study by Kang et al. [
A recent randomized controlled trial (RCT) on prehospital ventilation support methods based on advanced life support performed in Belgium and France found that BVM was neither inferior nor non-inferior to ETI in terms of survival with favorable 28-day neurological function [
In our study, subjects in the SGA and ETI groups for whom advanced airway management was performed had longer on-scene times and higher rates of prehospital epinephrine administration than did those in the BVM group. Kang et al.’s study [
We also compared TTIs to reflect differences according to region (urban vs. rural) and to medical care accessibility. We hypothesized that prehospital advanced airway management will have advantages over BVM ventilation with respect to neurologic outcomes, and that the benefits of advanced airway management for patients with OHCA will increase with the length of the TTI because it can provide effective ventilation and reduce airway complications without interrupting chest compressions. After adjusting for confounding variables, there were no differences in rates of favorable neurologic outcomes among the BVM, SGA, and ETI groups regardless of transport time. A previous study by Wang et al. found that ETI performance was associated with chest compression interruptions, and that the no-flow time was actually extended in situations where CPR was required [
A previous study showed that if the TTI is expected to be under 14 minutes, it is reasonable to redirect patients experiencing OHCA to percutaneous coronary intervention-capable hospitals [
According to a previous study conducted in Japan, a group of subjects in whom advanced airway management was performed within four minutes of CPR initiation showed better neurologic outcomes than did the group in whom advanced airway management was performed after four minutes [
Our study had a number of limitations that may restrict the generalizability of our results. First, the integrity and validity of the data may be subject to the constraints inherent in multi-institutional observational studies. However, data were collected based on Utstein-style guidelines, and efforts were made to reduce the possibility of potential biases through quality control. Second, the competence levels of prehospital EMTs, regional differences, in-hospital CPR performance levels, and differences in post-cardiac arrest treatments were not reflected in our data; such variables may have influenced our results. Third, although multivariate analyses were performed to adjust for potential confounding variables, the possibility of selection bias still exists. The ETI group comprised the oldest subjects, and differences in the locations of cardiac arrest occurrence were observed; hence, there may have been bias in determining the EMT’s attempt and success rates when delivering prehospital advanced airway management to patients with OHCA. Fourth, the actual use of BVM in the field is difficult to identify via hospital records; this may also have contributed to reporting bias. Fifth, the KoCARC registry had insufficient information on the EMTs’ level of expertise, patients’ initial mental status upon admission to the emergency department, number of advanced airway management attempts, time of intervention, and type of SGA. Therefore, we could not investigate these parameters even though they may influence survival outcomes.
In conclusion, our study revealed no differences in the rates of favorable neurological outcomes between patients with OHCA who were managed using BVI, ETI, or SGA, regardless of transport time.
No potential conflict of interest relevant to this article was reported.
We would like to acknowledge and thank to investigators from all participating hospitals of KoCARC: Do Kyun Kim (Seoul National University Hospital), Sang Kuk Han, Phil Cho Choi (Kangbuk Samsung Medical Center), Sang O Park, Jong Won Kim (Konkuk University Medical Center), Han Sung Choi, Jong Seok Lee (Kyung Hee University Hospital), Sung Hyuk Choi, Young Hoon Yoon (Korea University Guro Hospital), Soo Jin Kim (Korea University Anam Hospital), Min Seob Sim, Gun Tak Lee (Samsung Medical Center), Shin Ahn (Asan Medical Center), Jong Whan Shin (SMG-SNU Boramae Medical Center), Sang Hyun Park, Keun Hong Park (Seoul Medical Center), In Cheol Park, Yoo Seok Park (Yonsei University Severance Hospital), Tae Young Kong (Yonsei University Gangnam Severance Hospital), Kyoung Won Lee, Chu Hyun Kim (Inje University Seoul Paik Hospital), Youngsuk Cho (Hallym University Kangdong Sacred Heart Hospital), Gu Hyun Kang, Yong Soo Jang (Hallym University Kangnam Sacred Heart Hospital), Tai Ho Im, Jae Hoon Oh (Hanyang University Seoul Hospital), Seok Ran Yeom, Sang Kyoon Han (Pusan National University Hospital), Jae Hoon Lee (Dong-A University Hospital), Kyung Woo Lee, Tae Chang Jang (Daegu Catholic University Medical Center), Jae-hyug Woo (Gachon University Gil Medical Center), Woon Jeong Lee, Seon Hee Woo (The Catholic University of Korea Incheon St. Mary’s Hospital), Sung Hyun Yun, Tae Jin Cho (Catholic Kwandong University International St. Mary’s Hospital), Sun Pyo Kim, Yong Jin Park (Chosun University Hospital), Jin Woong Lee, Wonjoon Jeong (Chungnam National University Hospital), Sung Soo Park, Jae Kwang Lee (Konyang University Hospital), Ryeok Ahn, Wook Jin Choi (Ulsan University Hospital), Young Gi Min, Eun Jung Park (Ajou University Hospital), You Hwan Jo, Joong Hee Kim (Seoul National University Bundang Hospital), In Byung Kim, Ki Ok Ahn (Myongji Hospital), Han Jin Cho (Korea University Ansan Hospital), Seung Cheol Lee, Sang Hun Lee (Dongguk University Ilsan Hospital), Young Sik Kim, Young Rock Ha (Bundang Jesaeng Hospital), Jin Sik Park, Myoung Woo Lee (Sejong Hospital), Dai Han Wi (Wonkwang University Sanbon Hospital), Ok Jun Kim, Tae Nyoung Chung (Cha University Bundang Medical Center), Soon Joo Wang, Hang A Park (Hallym University Dongtan Sacred Heart Hospital), Jun Hwi Cho, Chan Woo Park (Kangwon National University Hospital), An Mu Eob, Tae Hun Lee (Hallym University Chuncheon Sacred Heart Hospital), Sang Chul Kim, Hoon Kim (Chungbuk National University Hospital), Han Joo Choi , Chan Young Koh (Dankook University Hospital), Jung Won Lee, Dong Wook Lee (Soonchunhyang University Cheonan Hospital), Tae Oh Jung, Jae Chol Yoon (Chonbuk National University Hospital), Dai Hai Choi, Jung Tae Choi (Dongguk University Gyeongju Hospital), Jin Hee Jeong, Soo Hoon Lee (Gyeongsang National University Hospital), Ji Ho Ryu, Maeng Real Park (Pusan National University Yangsan Hospital ), Won Kim (Cheju Halla General Hospital), Sung Wook Song, Woo Jung Kim (Jeju National University Hospital), Joon-myoung Kwon, Eui Hyuk Kang (Mediplex Sejong Hospital), Sang Chan Jin, Tae-kwon Kim (Keimyung University Dongsan Medical Center), Hyuk Joong Choi (Hanyang University Guri Hospital), Seong Chun Kim (Gyeongsang National Univerisy Changwon Hospital).
And to steering committee, comprised of following individuals: Sung Oh Hwang (Chair, Wonju Severance Christian Hospital), Sang Do Shin (Chair of Steering Committee, Seoul National University hospital), Hyuk Jun Yang (Advisory Committee, Gachon University Gil hospital), Sung Phil Chung (Data Safety and Management Board, Gangnam Severance Hospital), Sung Woo Lee (Security and Monitoring Board, Korea University Anam hospital), Kyung Jun Song (Secretariat, SMG-SNU Boramae Medical Center), Seung Sik Hwang (Epidemiology and Prevention Research Committee, Seoul National University), Gyu Chong Cho (Community Resuscitation Research Committee, Hallym University Kangdong Sacred Heart Hospital), Sung Woo Moon (Emergency Medical Service Resuscitation Research Committee, Korea University Ansan Hospital), Kyoung Chul Cha (Hospital Resuscitation Research Committee, Wonju Severance Christian Hospital), Won Young Kim (Hypothermia and Post-Resuscitation Care Research Committee, Asan Medical Center), Sang Hoon Na (Cardiac Care Resuscitation Research Committee, Seoul National University Hospital), Young Ho Kwack (Pediatric Resuscitation Research Committee, Seoul National University hospital).
And lastly to member of Secretariat: Joo Yeong Kim (Korea University Ansan hospital), Jeong Ho Park (Seoul National University hospital), Sun Young Lee (Seoul National University hospital), and Jung Eun Kim (Seoul National University hospital).
Patients with out-of-hospital cardiac arrest analyzed in the current study. KoCARC, Korean Cardiac Arrest Research Consortium; OHCA, out-ofhospital cardiac arrest; EMS, emergency medical service.
Rates of good neurologic outcome (A), and survival to discharge (B) according to the transport time interval and prehospital airway management method. BVM, bag-valve-mask; SGA, supraglottic airway; ETI, endotracheal intubation.
Baseline characteristics and outcomes of the study population based on the prehospital airway management method
Total (n = 1,871) | Prehospital airway management |
P-value | |||
---|---|---|---|---|---|
BVM (n = 785) | SGA (n = 965) | ETI (n = 121) | |||
Sex | < 0.001 | ||||
Male | 1,223 (65.4) | 479 (61.0) | 673 (69.7) | 71 (58.7) | |
Female | 648 (34.6) | 306 (39.0) | 292 (30.3) | 50 (41.3) | |
Age (yr) | 0.003 | ||||
< 65 | 758 (40.5) | 335 (42.7) | 391 (40.5) | 32 (26.4) | |
≥ 65 | 1,113 (59.5) | 450 (57.3) | 574 (59.5) | 89 (73.6) | |
Age (yr) | 70 (56–78) | 68 (55–78) | 70 (56–78) | 74 (63–81) | 0.026 |
RTI (min) | 7 (6–10) | 7 (5–10) | 8 (6–10) | 7 (5–10) | 0.655 |
STI (min) | 11 (8–17) | 9 (6–13) | 14 (10–20) | 14 (10–20) | < 0.001 |
TTI (min) | 10 (6–14) | 10 (7–14) | 9 (6–13) | 10 (8–15) | 0.007 |
Location | < 0.001 | ||||
Home | 1,261 (67.4) | 478 (60.9) | 689 (71.4) | 94 (77.7) | |
Public place | 419 (22.4) | 218 (27.8) | 186 (19.3) | 15 (12.4) | |
Other/unknown | 191 (10.2) | 89 (11.3) | 90 (9.3) | 12 (9.9) | |
Comorbidities | |||||
Hypertension | 768 (41.0) | 302 (38.5) | 406 (42.1) | 60 (49.6) | 0.045 |
Diabetes mellitus | 482 (25.8) | 178 (22.7) | 261 (27.0) | 43 (35.5) | 0.005 |
Hyperlipidemia | 96 (5.1) | 48 (6.1) | 39 (4.0) | 9 (7.4) | 0.073 |
Witnessed cardiac arrest | 1,112 (59.2) | 502 (64.0) | 536 (55.5) | 70 (57.9) | 0.002 |
Bystander CPR | 961 (51.4) | 375 (47.8) | 524 (54.3) | 62 (51.2) | 0.025 |
Initial shockable rhythm | 366 (19.6) | 138 (17.6) | 207 (21.5) | 21 (17.4) | 0.104 |
Prehospital defibrillation | 483 (25.8) | 185 (23.6) | 271 (28.1) | 27 (22.3) | 0.066 |
Prehospital epinephrine administration | 293 (15.7) | 38 (4.8) | 226 (23.4) | 29 (24.0) | < 0.001 |
Prehospital ROSC | 242 (12.9) | 91 (11.6) | 134 (13.9) | 17 (14.0) | 0.339 |
Hospital treatment\ | |||||
CAG | 204 (10.9) | 80 (10.2) | 108 (11.2) | 16 (13.2) | 0.559 |
TTM | 143 (7.6) | 56 (7.1) | 73 (7.6) | 14 (11.6) | 0.230 |
ECMO | 46 (2.5) | 19 (2.4) | 19 (2.0) | 8 (6.6) | 0.008 |
Survival to discharge | 0.130 | ||||
Yes | 192 (10.3) | 93 (11.8) | 87 (8.9) | 13 (10.7) | |
No | 1,679 (89.7) | 692 (88.2) | 888 (91.1) | 109 (89.3) | |
Good neurologic outcome | 0.044 | ||||
Yes | 130 (6.9) | 68 (8.7) | 56 (5.8) | 6 (5.0) | |
No | 1,741 (93.1) | 717 (91.3) | 909 (94.2) | 115 (95.0) |
Values are presented as number (%) or median (interquartile range).
BVM, bag-valve-mask; SGA, supraglottic airway; ETI, endotracheal intubation; RTI, response time interval; STI, scene time interval; TTI, transport time interval; CPR, cardiopulmonary resuscitation; ROSC, return of spontaneous circulation; CAG, coronary angiography; TTM, targeted temperature management; ECMO, extracorporeal membrane oxygenation.
Differences were significant in post-hoc analysis of a one-way ANOVA test including BMV vs. ETI, and SGA vs. ETI.
Differences were significant in post-hoc analysis of a one-way ANOVA test including BMV vs. SGA, and BMV vs. ETI.
Differences were significant in post-hoc analysis of a one-way ANOVA test including BMV vs. SGA.
Effect of prehospital advanced airway management on survival outcomes
Prehospital airway management | Good neurologic outcome |
Survival to discharge |
||
---|---|---|---|---|
Crude OR (95% CI) | Adjusted OR |
Crude OR (95% CI) | Adjusted OR |
|
BVM | Reference | Reference | Reference | Reference |
SGA | 0.65 (0.45–0.94) | 0.59 (0.33–1.06) | 0.73 (0.53–0.99) | 0.88 (0.57–1.38) |
ETI | 0.55 (0.23–1.30) | 0.77 (0.21–2.83) | 0.90 (0.48–1.66) | 1.52 (0.66–3.47) |
OR, odds ratio; CI, confidence interval; BVM, bag-valve-mask; SGA, supraglottic airway; ETI, endotracheal intubation.
Adjusted for sex, age, response time interval, scene time interval, transport time interval, location of cardiac arrest occurrence, shockable rhythm, witnessed status, bystander cardiopulmonary resuscitation, prehospital defibrillation, and prehospital epinephrine administration.
Effect of prehospital advanced airway management on survival outcomes according to transport time interval
Good neurologic outcome |
Survival to discharge |
|||
---|---|---|---|---|
Crude OR (95% CI) | Adjusted OR |
Crude OR (95% CI) | Adjusted OR |
|
TTI ≥ 12 min (n = 684) | ||||
BVM | Reference | Reference | Reference | Reference |
SGA | 1.16 (0.65–2.06) | 1.37 (0.65–2.87) | 1.15 (0.71–1.87) | 1.54 (0.85–2.81) |
ETI | 1.03 (0.34–3.10) | 1.31 (0.30–5.81) | 1.46 (0.63–3.35) | 2.48 (0.87–7.11) |
TTI < 12 min (n = 1,187) | ||||
BVM | Reference | Reference | Reference | Reference |
SGA | 0.44 (0.27–0.72) | 0.57 (0.31–1.07) | 0.54 (0.36–0.81) | 0.79 (0.48–1.31) |
ETI | 0.29 (0.07–1.22) | 0.63 (0.12–3.26) | 0.56 (0.22–1.44) | 1.11 (0.38–3.25) |
OR, odds ratio; CI, confidence interval; TTI, transport time interval; BVM, bag-valve-mask; SGA, supraglottic airway; ETI, endotracheal intubation.
Adjusted for sex, age, response time interval, scene time interval, location of cardiac arrest occurrence, shockable rhythm, witnessed status, bystander cardiopulmonary resuscitation, prehospital defibrillation, and prehospital epinephrine administration.