Improved functional survival after OHCA is associated with increased advanced airway management at the prefecture level: The All-Japan Utstein Registry

doi:10.21203/rs.3.rs-1737741/v1

Download PDF

Article

Improved functional survival after OHCA is associated with increased advanced airway management at the prefecture level: The All-Japan Utstein Registry

https://doi.org/10.21203/rs.3.rs-1737741/v1

This work is licensed under a CC BY 4.0 License

You are reading this latest preprint version

Background

Out-of-hospital cardiac arrest (OHCA) has high incidence and mortality. The survival benefit of advanced airway management (AAM) for OHCA remains controversial. In Japan, AAM are performed for OHCA by EMS, however the relationship between resuscitation outcomes and AAM at the prefecture level has not been evaluated. The purpose of this study was to describe the association between AAM and neurologically favorable survival (CPC ≦ 2) at prefecture level.

Methods

This was a retrospective, population-based study of adult OHCA patients ( ≧ 18) from 2014 to 2017 in Japan. We categorized OHCA into four quartiles based on AAM by prefecture and assessed the CPC ≦ 2 for each quartile. Multivariable logistic regression was used to assess impact of AAM on survival.

Results

Among 493,577 OHCA cases, 403,707 matched our inclusion criteria. They were classified into quartiles based on AAM by prefecture (G1: Lowest AAM group, G4: Highest AAM group). The number of CPC ≦ 2 survivors increased from G1 to G4. In the adjusted multivariable regression, higher AAM use was associated with CPC ≦ 2.

Conclusions

High prefecture AAM use was associated with neurologically favorable survival (CPC ≦ 2) in OHCA. Further studies are needed to better understand these finding.

Out-of-hospital cardiac arrest

Advanced airway management

Outcome

Cerebral performance category

Out-of-hospital cardiac arrest (OHCA) is a major public health concern due to its high incidence and mortality. ¹⁻³ Early activation of emergency medical services (EMS) is one of the key components in the OHCA chain of survival.

Basic life support (BLS), which consists of early cardiopulmonary resuscitation (CPR) and timely defibrillation, improves outcomes in patient with out-of-hospital cardiac arrest.⁴⁻⁶ The provision of oxygenation and ventilation of the lungs via bag-valve-mask (BVM) devices, supraglottic airway placement (SGA), or endotracheal intubation (ETI) are important additional resuscitation skills delivered by EMS personnel.⁷ Recent studies have raised questions about the survival benefits of advanced airway management (AAM) with the use of SGA or ETI compared to BVM ventilation in this clinical setting.⁸-¹⁵ However, there have not been any definitive studies evaluating the association between advanced airway management strategies and patient centered outcomes such as survival with good neurological status.

A better understanding of the relationship between factors influencing prehospital ROSC and neurologically favorable survival following OHCA is important for countries with a growing aging population such as Japan. In Japan, there are differences in the use of AAM techniques by EMS personal for OHCA across prefectures (regions), and resuscitation outcome differences based on AAM use has not been well studied.

The purpose of this study was to assess the use of AAM during OHCA in each Japanese prefecture and to evaluate the association between AAM use at a prefecture level (by quartiles) and good functional survival.

Study design, setting, population

This was a retrospective cohort study examining data from January 1, 2014 to December 31, 2017 reported to the All-Japan Utstein Registry database. We included OHCA patients who were 18 years of age or older. The All-Japan Utstein Registry of the Fire and Disaster Management Agency is a prospective, population based, nationwide registry of out-of-hospital cardiac arrest launched in January 2005, which records resuscitation related data according to the international Utstein-style reporting system.¹⁶ Details of the registry have been described previously.¹⁷ Cardiac arrest was defined as the cessation of cardiac mechanical activity, as confirmed by the absence of signs of circulation.¹⁶ Each EMS authority submitted anonymized data to the registry.

The EMS system in Japan

Japan has a total land area of 377,976㎢ and is divided into 47 prefectures as a large area which has its own local government like states.(Fig.1) The population is about 126 million, and the population density is 338.22 persons per square meter. Prehospital life support is provided 24 hours a day through a Fire-based EMS system. Among EMS personnel, specially trained emergency care providers known as emergency life-saving technicians (ELSTs) are authorized to use automated external defibrillators. Since the 1991 enactment of the ELST Law, most ambulances in Japan are manned by at least one ELST. They resuscitate OHCA patients according to protocols developed by local medical control councils based on recommended guidelines from the Japan Resuscitation Council and International Liaison Committee on Resuscitation. As for prehospital medical control (MC), each prefecture has its own prefectural MC council, and 251 regional MC councils have been established from the regional characteristics throughout Japan.

In 1991, ELST were also permitted to use supraglottic airway devices (laryngeal mask airway, laryngeal tube, and esophageal-tracheal twin lumen airway device) for patients with OHCA under medical control direction.¹⁸ Since 2004, endotracheal intubation can be performed by specially trained ELSTs who have completed an additional 62 hours of training sessions and have performed 30 supervised successful intubations in operating rooms.¹⁹ Each prefectural and regional MC council examines and implements emergency operation protocols independently.²⁰⁻²¹ With support and direction from online medical control, specially trained ELSTs are also permitted to perform other advanced life care including administering adrenaline and performing ETI in patients with OHCA. In Japan, EMS providers are generally not permitted to terminate resuscitation in the field, and all patients who have resuscitation attempted must be transported to the hospital. Resuscitation is not attempted under particular circumstances (e.g. decapitation, incineration, decomposition, rigor mortis, or dependent cyanosis). Although all ELSTs can use SGA devices such as laryngeal tubes or laryngeal masks, only specially trained, certified ELSTs are permitted to perform endotracheal intubation under direction from online medical control. These ELSTs are allowed to perform endotracheal intubation during cardiac arrest and are not permitted to intubate following ROSC. Treatment for cardiac arrest during the study time period were based on the Japanese cardiopulmonary resuscitation guidelines,²² which are based on the consensus statements of the International Liaison Committee on Resuscitation (ILCOR).²³

In Japan, specially trained ELSTs are authorized to perform ETI under medical direction for cardiac arrest patients (lack of pulse and apnea) as follows: 1. The patient meets indications for endotracheal intubation. 2. It is impossible to maintain the patient’s airway with SGA, because of (a) asphyxia due to foreign-body airway obstruction or, (b) in cases in which the medical control doctor judges ETI to be required. 3. Patients are ineligible for endotracheal intubation, if there is: (i) suspected cervical spine injury, (ii) head-tilt difficulty, (iii) trismus, (iv) difficulty with laryngoscope insertion, (v) difficulty with larynx expansion after laryngoscope insertion, (vi) difficulty in visualizing the vocal chords, (vii) prolonged unsuccessful attempts, (viii) the ELST on the scene is not certified to perform endotracheal intubation, and (ix) rapid sequence intubation (paralysis and sedation) is permitted at any time.

Selection of participants

We included patients with complete data who were 18 years of age and above, and excluded EMS witnessed and cases where the witness status was unknown. We also only included patients that had care provided by an ELST with the ability to provided AAM and excluded cases that involved prehospital care delivered by a physician at any time. In this study, cases of failed attempts at AAM were classified as cases without AAM. The study protocol have been performed in accordance with the Declaration of Helsinki, and was approved by the Ethics Committee of Kansai Medical University. The requirement for individual informed consent was waived per the Personal Information Protection Law and National Research Ethics Guideline in Japan.

Data collection and quality control

Data was collected with the use of a form based on the Utstein guidelines for reporting OHCA, and included details on age, gender, witness status, initial cardiac rhythm, time course of resuscitation, bystander-initiated CPR, advanced airway management, adrenaline administration, as well as pre-hospital return of spontaneous circulation (ROSC), one-month survival, and neurological status one month after the event. The time course of EMS activity included both response time (from 119 call to EMS arrival on scene) and total prehospital time (from 119 call to EMS hospital arrival). All survivors were evaluated at one month after the event for their neurological function by the EMS personnel in charge. The data form was filled out by the EMS personnel in cooperation with the physicians in charge of the patients, and the data were integrated into the registry All data was logic-checked by the computer system and were confirmed by the implementation working group. If a data form was incomplete, the FDMA would return it to the respective fire station for completion and follow up on any missing data.²⁴

Outcomes

Neurological outcome was clinically determined by the physician caring for survivors one month after successful resuscitation, using the cerebral performance category (CPC) scale: category 1, good cerebral performance; category 2, moderate cerebral disability; category 3, severe cerebral disability; category 4, coma or vegetative state; and category 5, death. The primary outcome measure was neurologically favorable one-month survival, defined as CPC category 1 or 2. Secondary outcome was survival at one month and ROSC.

Statistical analysis

AAM proportional use for OHCA cases was calculated for the included cases by prefecture and the prefectures were classified into four groups based on quartiles.

Patient and EMS characteristics as well as outcomes were evaluated for each quartile group. As a secondary analysis, we evaluated cases where AAM was performed within each group. Patient characteristics were compared using chi-square test for categorical variables and one-way analysis of variance for ordinal variables. EMS characteristics such as procedures and care time intervals were tested with univariable regression models for categorical variables and linear tests for numerical variables. Logistic regression for CPC 1 or 2 was used to adjust for confounding factors. Odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated, controlling for age, gender, witnessed status, bystander CPR, presenting initial rhythm (shockable or non-shockable), prehospital defibrillation at any time, response time and total prehospital time. All statistical analyses were performed using SPSS statistical package ver. 23.0J (SPSS, Inc., Chicago, IL). All tests were 2-tailed, and P values of < 0.05 were considered statistically significant.

During the study period from January 1, 2014 to December 31, 2017, 493,577 OHCA cases, ≥ 18 years of age were reported in the All-Japan Utstein Registry. The number of cases that met the study inclusion criteria was 403,707 cases. The AAM implementation of each prefecture was calculated, and the mean proportion was 47.4%, the minimum was 6.1%, and the maximum was 99.6%. (Fig. 2) The quartile of the AAM implementation proportion was 31.5% for the 25th percentile, 47.4% for the 50th percentile, and 59% for the 75th percentile. The 403,707 cases were then classified as follows according to the quartiles according to AAM use; the first quartile (G1, < 31.5%): 99,534 cases, 2nd quartile (G2, 31.5–47.4%): 80,612 cases, 3rd quartile (G3, 47.4–59%): 89,166 cases, 4th quartile (G4, ≧59%): 134,395 cases. (Fig. 3)

The characteristics of each group (G1-G4) were as follows. The mean age was G1: 75 ± 16 years, G2: 77 ± 15 years, G3: 76 ± 15 years, G4: 76 ± 16 years. AAM use for G1 was: 18,090 cases 18.2%, G2: 28,167 cases 34.9%, G3: 41,878 cases 47.0%, G4: 75,439 cases 56.1%. The number of ETI and SGA performed in groups G1 to G4 were as follows; (G1: ETI 3,327 cases, SGA 14,763 cases, G2: ETI 6,340 cases, SGA 21,827 cases, G3: ETI 5,727 cases, SGA 36,151 cases, G4: ETI 15,075 cases, SGA 60,364 cases). Epinephrine administration tended to be lower in G1 and higher in G4; (G1: 11,479 cases 11.5%, G2: 10,955 cases 13.6%, G3: 17,840 cases 20.0%, G4: 36,503 cases 27.2%). (Table 1) As AAM implementation increased from G1 to G4, the p for trend showed a significant improvement in all outcomes including prehospital ROSC, 1-month survival, and 1-month of patients with a CPC1 or 2 group. (Table 1) In multivariate analysis for CPC 1or 2 after adjusting for confounders, the key predictor variables were: Witnessed by bystander (OR 6.050, 95% CI: 5.716–6.404, p < 0.001), bystander CPR (OR: 2.537, 95% CI: 2.411–2.670, p < 0.001), and initial shockable rhythm (OR : 6.078, 95%CI : 5.748–6.427, p < 0.001). Factors associated with poor prognosis included: one year increase in age (OR : 0.969, 95%CI : 0.968–0.970, p < 0.001), AAM implementation (OR : 0.225, 95%CI : 0.211–0.239, p < 0.001), and epinephrine administration (OR : 0.302, 95%CI : 0.280–0.326, p < 0.001). (Table 2) High AAM implementation was associated with better neurological outcome (CPC 1 or 2) (G1 Reference; G2 OR: 1.203, 95%CI : 1.121–1.285, p < 0.001; G3 OR : 1.675, 95%CI : 1.566–1.792, p < 0.001; G4 OR : 1.859, 95%CI : 1.743–1.982, p < 0.001). (Table 2)

Table 1

Background of OHCA cases and OHCA survival outcomes grouped by Implementation Proportion of Advanced Airway Management (Quartile G1 to G4).
Background of OHCA
	G1	G2	G3	G4	P for trend
Number of case	99,534	80,612	89,166	134,395
Age (y.o), mean (S.D.)	75.6 ± 15.9	76.6 ± 15.2	76.3 ± 15.3	75.6 ± 15.7	0.88
Male, n (%)	56283 (56.5)	45,461 (56.4)	50,534 (56.7)	75,732 (56.4)	< 0.001
Presumed cardiac causes, n(%)	59,009 (59.3)	47,814 (59.3)	53,290 (59.8)	87,644 (65.2)	< 0.001
Witnessed by bystander, n(%)	37,029 (37.2)	28,405 (35.2)	32,020 (35.9)	48,488 (36.1)	< 0.001
Bystander CPR, n(%)	47,815(48.0)	42,356 (52.5)	50,341 (56.5)	69,456 (51.7)	< 0.001
Initial rhythm VF, n(%)	6,144 (6.2)	4,821 (6.0)	5,553 (6.2)	8,546 (6.4)	< 0.001
AAM, n(%)	18,090 (18.2)	28,167 (34.9)	41,878 (47.0)	75,439 (56.1)	< 0.001
ETI, n(%)	3,327 (3.3)	6,340 (7.9)	5,727 (6.4)	15,075 (11.2)
SGA, n(%)	14,763 (14.9)	21,827 (27.0)	36,151 (40.6)	60,364 (44.9)
Epinephrine, n(%)	11,479 (11.5)	10,955 (13.6)	17,840 (20.0)	36,503 (27.2)	< 0.001
EMS care interval (min), mean (S.D.)
Call to ambulance arrives on the scene	7.7 ± 3.7	8.6 ± 4.1	8.3 ± 3.6	7.4 ± 3.2	< 0.001
Call to AAM implementation	19.9 ± 7.7	20.6 ± 8.3	18.4 ± 7.3	17.3 ± 6.1	< 0.001
Call to Epinephrine	24.6 ± 7.6	26.9 ± 8.5	24.2 ± 8.4	23.7 ± 7.8	< 0.001
Call to hospital arrival	35.3 ± 12.7	34.2 ± 12.7	32.2 ± 11.9	33.7 ± 12.9	< 0.001
Survival outcomes of OHCA
ROSC in the field	8,446 (8.5)	5,915 (7.3)	8,043 (9.0)	13,361 (9.9)	< 0.001
Survival at one month	5,061 (5.1)	3,935 (4.9)	4,466 (5.0)	8,043 (6.0)	< 0.001
CPC 1 or 2	2,870 (2.9)	2,113 (2.6)	2,567 (2.9)	4,275 (3.2)	< 0.001
OHCA, Out-of-hospital cardiac arrest; CPR, cardiopulmonary resuscitation; AAM, advanced airway management; ETI, endotracheal intubation; SGA, supraglottic airway placement; EMS, emergency medical service; ROSC, return of spontaneous circulation; CPC, the cerebral performance category

Table 2

Multivariate analysis for Survival with CPC1 or 2
	OR	95% CI		P
Age	0.969	0.968	0.970	P < 0.001
Male	1.218	1.156	1.284	P < 0.001
Presumed cardiac causes	1.626	1.537	1.721	P < 0.001
Witnessed by bystander	6.050	5.716	6.404	P < 0.001
Bystander CPR	2.537	2.411	2.670	P < 0.001
initial shockable rhythm	6.078	5.748	6.427	P < 0.001
AAM implementation	0.225	0.211	0.239	P < 0.001
Epinephrine administration	0.302	0.280	0.326	P < 0.001
Call to ambulance arrives on the scene	0.918	0.910	0.926	P < 0.001
Call to hospital arrival	1.012	1.011	1.014	P < 0.001
AAM implementation proportion by prefecture
G1(< 31.5%)	Reference	Reference	Reference	Reference
G2(31.5%-47.4%)	1.203	1.121	1.285	P < 0.001
G3(47.4%-59%)	1.675	1.566	1.792	P < 0.001
G4( ≧ 59%)	1.859	1.743	1.982	P < 0.001
CPC, the cerebral performance category, OR, odds ratio; CI, confidence interval; CPR, cardiopulmonary resuscitation; AAM, advanced airway management

In a secondary analysis, we also analyzed only the OHCA cases with AAM performed separately. The characteristics of the AAM cases in each quartile (G1 to G4) were as follows. The mean age was G1: 76 ± 14 years, G2: 77 ± 14 years, G3: 77 ± 14 years, G4: 76 ± 15 years. The percentages of ETI and SGA in groups G1 to G4 were as follows; (G1: ETI 18.3%, SGA 81.7%, G2: ETI 22.5%, SGA 77.5%, G3: ETI 13.7%, SGA 86.3%, G4: ETI 20.0%, SGA 80.0%). Epinephrine administration tended to be lower in G1 and higher in G4; (G1: 4,530 cases 25.0%, G2: 5,968 cases 21.2%, G3: 11,753 cases 28.0%, G4: 29,779 cases 39.5%). (Table 3) As AAM use increased from G1 to G4, the p for trend showed a significant difference, and improvement in survival was observed in all outcomes including prehospital ROSC, 1-month survival, and 1-month of patients with a CPC1 or 2 group. (Table 3) In multivariate analysis for CPC 1or 2 after adjusting for confounders, the key predictor variables were: Witnessed by bystander (OR 3.480, 95% CI: 3.068–3.948, p < 0.001), and initial shockable rhythm (OR : 12.54, 95%CI : 11.10-14.16, p < 0.001). Factors associated with poor prognosis included: one year increase in age (OR : 0.968, 95%CI : 0.968–0.974, p < 0.001), and epinephrine administration (OR : 0.641, 95%CI : 0.575–0.716, p < 0.001). (Table 4) High AAM implementation was associated with a better neurological outcome (CPC 1 or 2) (G1 reference; G2 OR : 1.158, 95%CI : 0.924–1.453, p = 0.203; G3 OR : 1.717, 95%CI : 1.408–2.093, p < 0.001; G4 OR : 1.723, 95%CI : 1.432–2.074, p < 0.001). (Table 4)

Table 3

Background and survival outcomes of the cardiac arrest cases (AAM performed cases)
Background of AAM performed cases
	G1	G2	G3	G4	P for trend
Number of case	18,090	28,167	41,878	75,439
Age (y.o), mean (S.D.)	75.5 ± 14.4	76.8 ± 14.2	76.7 ± 14.3	76.1 ± 14.5	0.486
Male, n (%)	10,824 (59.8)	16,325 (58.0)	24,396 (58.3)	43,190 (57.3)	< 0.001
Presumed cardiac causes, n(%)	11,003 (60.8)	17,266 (61.3)	25,880 (61.8)	50,890 (67.5)	< 0.001
Witnessed by bystander, n(%)	7,939 (43.9)	10,333 (36.7)	15,560 (37.2)	27,676 (37.2)	< 0.001
Bystander CPR, n(%)	9,423(52.1)	15,143 (53.8)	24,487 (58.5)	39,319 (52.1)	< 0.001
Initial rhythm VF, n(%)	1,299 (7.2)	1,578 (5.6)	2,621 (6.3)	4,864 (6.4)	0.886
ETI, n(%)	3,327 (18.3)	6,340 (22.5)	5,727 (13.7)	1,5075 (20.0)
SGA, n(%)	14,763 (81.7)	21,827 (77.5)	36,151 (86.3)	60,364 (80.0)
Epinephrine, n(%)	4,530 (25.0)	5,968 (21.2)	11,753 (28.0)	29,779 (39.5)	< 0.001
EMS care interval (min), mean (S.D.)
Call to ambulance arrives on the scene	8.3 ± 4.1	8.9 ± 4.3	8.4 ± 3.7	7.6 ± 3.3	< 0.001
Call to AAM implementation	20.2 ± 7.5	20.9 ± 8.1	18.5 ± 7.3	17.4 ± 6.1	< 0.001
Call to Epinephrine	25.2 ± 8.3	27.8 ± 8.9	24.4 ± 8.7	23.9 ± 7.9	< 0.001
Call to hospital arrival	39.1 ± 12.7	37.6 ± 12.9	34.8 ± 11.9	35.8 ± 13.1	< 0.001
Survival outcomes of AAM performed cases
ROSC in the field	1,627 (9.3)	1,714 (6.1)	3,482 (8.3)	7,372 (9.8)	< 0.001
Survival at one month	576 (3.2)	716 (2.5)	1,380 (3.3)	3,104 (4.1)	< 0.001
CPC 1 or 2	148 (0.8)	193 (0.7)	461 (1.1)	961 (1.3)	< 0.001
CPR, cardiopulmonary resuscitation; AAM, advanced airway management; ETI, endotracheal intubation; SGA, supraglottic airway placement; EMS, emergency medical service; ROSC, return of spontaneous circulation; CPC, the cerebral performance category

Table 4

Multivariate analysis for Survival with CPC1 or 2 (AAM performed cases)
	OR	95% CI		P
Age	0.968	0.968	0.974	P < 0.001
Male	1.132	1.001	1.281	0.048
Presumed cardiac causes	1.264	1.099	1.454	0.001
Witnessed by bystander	3.480	3.068	3.948	P < 0.001
Bystander CPR	1.199	1.079	1.332	0.001
initial shockable rhythm	12.54	11.10	14.16	P < 0.001
Epinephrine administration	0.641	0.575	0.716	P < 0.001
Call to ambulance arrives on the scene	0.870	0.851	0.889	P < 0.001
Call to hospital arrival	1.001	0.997	1.006	0.482
AAM implementation proportion by prefecture
G1(< 31.5%)	Reference	Reference	Reference	Reference
G2(31.5%-47.4%)	1.158	0.924	1.453	0.203
G3(47.4%-59%)	1.717	1.408	2.093	P < 0.001
G4( ≧ 59%)	1.723	1.432	2.074	P < 0.001
CPC, the cerebral performance category, OR, odds ratio; CI, confidence interval; CPR, cardiopulmonary resuscitation; AAM, advanced airway management

This study is the first to evaluate the relationship between AAM use at the prefecture level and neurological outcomes for OHCA in Japan. The study examined prefectural AAM implementation for 403,707 OHCA patients and its impact on good neurological survival at one month based on the All Japan Utstein Registry. In previous observational studies, prehospital AAM implementation by EMS personnel has been associated with worse outcomes. ⁸⁻¹⁴ In Japan, EMS are allowed to perform AAM only for cardiac arrests that do not achieve ROSC after CPR and defibrillation. However, some of the findings from these prior observational studies may have had biased results favoring no AAM because patients who received AAM were likely to be more severe, since ROSC could not be achieved prior to or during transportation, a state that is potentially associated with less favorable outcomes. In all observational studies assessing cardiac arrest interventions, “resuscitation time bias” (that is, the fact that patients undergoing longer resuscitation tend to receive more interventions) remains a crucial limitation. ²⁵ This resuscitation bias in part may explain the findings of prior studies suggesting that AAM does not improve prognosis. In fact, our study also showed similar findings with negative correlation between AAM and CPC 1 or 2 outcomes at one month. (Table 2) However, comparisons between the G1 to G4 groups based on the quartile of the AAM implementation across prefectures allowed us to examine the association without considering the resuscitation time bias. As the AAM implementation proportion increased, the number of survivors with CPC1 or 2 also increased. (P for trend < 0.001) (Table 1,3) In the multivariate analysis for CPC1 or 2 after adjusted confounders, high AAM implementation was associated with a better neurological outcome (CPC 1 or 2) (p < 0.001) (Table 2,4)

Unless closely monitored, CPR quality may be interrupted when AAM is introduced into EMS systems. In this study however, at a prefecture level, the increased use of AAM did not adversely affect the prognosis of OHCA and on the contrary improved it. In the group with a high AAM implementation, AAM tended to being implemented sooner than low implementation group, but our analysis is limited without information of time required to perform AAM. Wang et al. reported that the proportion of successful first endotracheal intubation was as low as 51%. ²⁶ Indeed, up to 20% of out-of-hospital tracheal intubation efforts are unsuccessful. ²⁷ The low ETI success proportion may not reflect typical paramedic ETI practice, and suggests that OHCA outcomes may have been different with better paramedic ETI skills in these studies. Jabre et al, showed that physicians performed tracheal intubation for OHCA patients outside the hospital with a high success proportion, the favorable functional survival (CPC 1–2) at day 28 was 4.2% and not different than that achieved with BVM ventilation. These authors also noted that there was no significant difference between the 2 groups (BVM vs. ETI) with regards to chest compression fraction CCF (87% in ETI group vs 86% in the BMV group; difference, − 1% [95% CI − 4–2%]; P = .70). ²⁸ Without AAM, ventilation can be performed at 30: 2, and following AAM ventilation can be performed asynchronously. Chest compressions are interrupted during AAM, but there is no need to interrupt chest compressions after AAM, which may enhance the effectiveness of CPR. Further improvement in outcomes may be expected by improving the quality of CPR, the success rate of AAM and shortening the insertion time for AAM.

Limitations

With regards to limitations, we note that since this was a retrospective, observational study, missing data may affect our conclusions and therefore our results need to be interpreted with caution. Second, as mentioned previously there is a possibility of resuscitation time bias. Third, there are factors that cannot be investigated, such as the quality of resuscitation including CPR, the time course of the resuscitation interval, the precise location of cardiac arrest, and the ECG waveforms that require shock, but where shock was not administered. Forth, there is the issue of ‘ecological bias’. We grouped prefectures based on their use of AAM. However, there may be other unmeasured/unobserved confounders that may be driving differences between groups, such geographic factors like hospital distances, system factors like ELST numbers, training, quality, organizational culture and financial issues. Also regional MC committees had variations in medical protocols. Sixth, our data lack information about the in-hospital care following successful prehospital resuscitation (hemodynamic support, targeted temperature management, and coronary intervention therapy). Seventh, It was not possible to investigate the number and reasons for AAM failures and the time it took for the AAM to take place. Eighth, there is a selection bias in the AAM implementation content between regions, whether it is due to a supraglottic airway device or endotracheal intubation. Ninth, the large sample size might be leading to statistically significant differences which are not clinically meaningful. Finally, other AAM papers have used survival to hospital discharge as an outcome, but our study used CPC1/2 at one month in survivors as the primary outcome. While this makes direct comparisons with other studies difficult, neurologically favorable survival is a more valuable patient-oriented outcome.

Future Research

There is a need for further research on pre-hospital AAM. This also applies to the cases where pre-hospital AAM may be appropriate but is not performed. Research is needed to clarify whether there are situations in which certain airway approaches are superior. And research should incorporate objective measures of success in oxygenation and ventilation.

We found that high AAM use at the prefecture level was associated with better neurological outcomes (CPC 1 or 2) for OHCA cases in Japan. Further studies are needed to understand the impact of prehospital AAM implementation.

OHCA: Out-of-hospital cardiac arrest; EMS: emergency medical services; BLS: Basic life support; CPR: cardiopulmonary resuscitation; BVM: bag-valve-mask; SGA: supraglottic airway placement; ETI: endotracheal intubation; AAM: advanced airway management; ELSTs: emergency life-saving technicians; MC: medical control; ILCOR: International Liaison Committee on Resuscitation; ROSC: return of spontaneous circulation; CPC: cerebral performance category

Acknowledgments

We thank all the EMS personnel and participating physicians in Japan and the FDMA for their generous cooperation in establishing and maintaining the database.

Authors’ contributions

AO: Collection of data, analyses and interpretation of data, writing the manuscript. KK: Study conception and design, collection of data, analyses and interpretation of data, revision manuscript. MRD: Interpretation of data, revision manuscript. FN: Interpretation of data, revision manuscript. MN: Interpretation of data, revision manuscript. MK: Interpretation of data, revision manuscript. KS: Interpretation of data, revision manuscript. TM: Interpretation of data, revision manuscript. HI: Interpretation of data, revision manuscript. MEHO: Interpretation of data, revision manuscript. YK: Interpretation of data, revision manuscript.

Funding source

Not applicable.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Ethics approval and consent to participate

All participating physicians consented to participate.

Consent for publication

All participating physicians agreed to publication of the results.

Competing interests

The authors declare that they have no competing interests

Mozaffarian D, et al. Heart disease and stroke statistics—2015 update: a report from the American Heart Association. Circulation. 131(4), e29-322 (2015).
Ro YS, et al. A trend in epidemiology and outcomes of out-of-hospital cardiac arrest by urbanization level: a nationwide observational study from 2006 to 2010 in South Korea. Resuscitation. 84, 547–57 (2013).
Yang HJ, et al. Epidemiology and outcomes in out-of-hospital cardiac arrest: a report fromthe NEDIS-based cardiac arrest registry in Korea. J Korean Med Sci. 30, 95–103 (2015).
Myat A, Song KJ & Rea T. Out-of-hospital cardiac arrest: current concepts. Lancet. 391, 970–9 (2018).
Iwami T, Kitamura T, Kiyohara K & Kawamura T. Dissemination of Chest Compression-Only Cardiopulmonary Resuscitation and Survival After Out-of-Hospital Cardiac Arrest. Circulation. 132, 415–22 (2015).
Kitamura T, et al. Public-Access Defibrillation and Out-of-Hospital Cardiac Arrest in Japan. N Engl J Med. 375, 1649–59 (2016).
Ong MEH, Perkins GD & Cariou A. Out-of-hospital cardiac arrest: prehospital management. Lancet. 391, 980–8 (2018).
Gausche M, et al. Effect of out-of-hospital pediatric endotracheal intubation on survival and neurological outcome: a controlled clinical trial. JAMA. 283(6), 783 – 90 (2000).
Hanif MA, Kaji AH & Niemann JT. Advanced airway management does not improve outcome of outof- hospital cardiac arrest. Acad Emerg Med. 17(9), 926–931 (2010).
Studnek JR, et al. The association between prehospital endotracheal intubation attempts and survival to hospital discharge among out-of-hospital cardiac arrest patients. Acad Emerg Med. 17(9), 918 – 25 (2010).
Nagao T, et al. Effects of bag-mask vs advanced airway ventilation for patients undergoing prolonged cardiopulmonary resuscitation in pre-hospital setting. J Emerg Med. 42(2), 162 – 70 (2012).
Shin SD, Ahn KO, Song KJ, Park CB & Lee EJ. Outof-hospital airway management and cardiac arrest outcomes: a propensity score matched analysis. Resuscitation. 83(3), 313-9 (2012).
Egly J, et al. Assessing the impact of prehospital intubation on survival in outof-hospital cardiac arrest. Prehosp Emerg Care. 15(1), 44 – 9 (2011).
Wang HE, et al. Endotracheal intubation versus supraglottic airway insertion in out of-hospital cardiac arrest. Resuscitation. 83(9), 1061-6 (2012).
Carney N, et al. Prehospital Airway Management: A Systematic Review. Prehosp Emerg Care. 20, 1–12 (2021).
Jacobs I, et al. International Liason Committee on Resusitation. Cardiac arrest and cardiopulmonary resuscitation outcome reports: update and simplification of the Utstein templates for resuscitation registries. A statement for healthcare professionals from a task force of the international liaison committee on resuscitation (American Heart Association, European Resuscitation Council, Australian Resuscitation Council, New Zealand Resuscitation Council, Heart and Stroke Foundation of Canada, InterAmerican Heart Foundation, Resuscitation Council of Southern Africa). Resuscitation. 63, 233–49 (2004).
Kitamura T, et al, Implementation Working Group for the All-Japan Utstein Registry of the Fire and Disaster Management Agency. Nationwide public-access defibrillation in Japan. N Engl J Med. 362, 994–1004 (2010).
Hagihara A, et al. Prehospital epinephrine use and survival among patients with out-of-hospital cardiac arrest. JAMA 307(11), 1161–8 (2012).
Ambulance Service Planning Office of Fire and Disaster Management Agency of Japan. Airway Management With Endotracheal Intubation by Emergency Life Saving Technicians. 2004. http://www.mhlw.go.jp/shingi/2009/03/dl/s0325-12g_0001.pdf. Accessed July 10, 2012.
Ministry of Health, Labour and Welfare of Japan: National Medical Control Council Liaison Committee. Available online at: https://www.mhlw.go.jp/stf/shingi/other-isei_202743.html
Ambulance Service Planning Office of Fire and Disaster Management Agency of Japan: Effect of first aid for cardiopulmonary arrest [in Japanese]. Available online at: http://www.fdma.go.jp/neuter/topics/houdou/2101/2101221houdou.pdf [accessed 10.05.10]
Japan Resuscitation Council. 2010 Japanese guidelines for emergency care and cardiopulmonary resuscitation. Japan: Health Shuppansha (2011).
Nolan JP, et al. Part 1: Executive summary: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Resuscitation. 81(Suppl 1), e1-25 (2010).
Onoe A, et al. Outcomes of patients with OHCA of presumed cardiac etiology that did not achieve prehospital restoration of spontaneous circulation: The All-Japan Utstein Registry experience. Resuscitation. 162, 245–50 (2021).
Andersen LW, Grossestreuer AV & Donnino MW. “Resuscitation time bias”-A unique challenge for observational cardiac arrest research. Resuscitation. 125, 79–82 (2018).
Wang HE, et al. Effect of a Strategy of Initial Laryngeal Tube Insertion vs Endotracheal Intubation on 72-Hour Survival in Adults With Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial. JAMA. 320, 769–78 (2018).
Wang HE & Yealy DM. How many attempts are required to accomplish out-of-hospital endotracheal intubation? Acad Emerg Med. 13(4), 372-7 (2006).
Jabre P, et al. Effect of Bag-Mask Ventilation vs Endotracheal Intubation During Cardiopulmonary Resuscitation on Neurological Outcome After Out-of-Hospital Cardiorespiratory Arrest: A Randomized Clinical Trial. JAMA. 319(8), 779–87 (2018).

No competing interests reported.

Download PDF

Editorial decision: Major revision
15 Sep, 2022
Reviews received at journal
04 Sep, 2022
Reviewers agreed at journal
24 Aug, 2022
Reviewers invited by journal
15 Aug, 2022
Editor assigned by journal
09 Aug, 2022
Editor invited by journal
13 Jun, 2022
Submission checks completed at journal
13 Jun, 2022
First submitted to journal
08 Jun, 2022

You are reading this latest preprint version

Improved functional survival after OHCA is associated with increased advanced airway management at the prefecture level: The All-Japan Utstein Registry

Status:

Version 1

Abstract

Background

Methods

Results

Conclusions

Figures

Introduction

Methods

Results

Discussion

Conclusions

Abbreviations

Declarations

References

Additional Declarations

Status:

Version 1