Association between case volume of ambulance stations and clinical outcomes of out-of-hospital cardiac arrest: A nationwide multilevel analysis

Association Between Ambulance Station Case Volume and Clinical Outcomes in Moderate to Severe Trauma

OBJECTIVES

The effect of the case volume of emergency medical services (EMS) on the clinical outcomes of trauma is uncertain. The purpose of this study was to evaluate the association between the case volume of an ambulance station and clinical outcomes in moderate to severe trauma patients.

METHODS

Adult trauma patients with injury severity scores greater than 8 who were transported by the EMS between 2018 and 2019 were analyzed. The main exposure was the annual case volume of moderate to severe trauma at the ambulance station where the patient-transporting ambulance was based: low-volume (less than 60 cases), intermediate-volume (between 60 and 89 cases), and high-volume (equal or greater than 90 cases). The primary outcome was in-hospital mortality. Multilevel multivariable logistic regression analysis was conducted to calculate adjusted odds ratios (AORs) and 95% confidence intervals (CIs), with the high-volume group used as the reference.

RESULTS

In total, 21,498 trauma patients were analyzed. The high-volume group exhibited lower in-hospital mortality, 447 (9.0%), compared to 867 (14.1%) in the intermediate-volume group and 1,458 (14.1%) in the low-volume group. There were a significantly higher odds of in-hospital mortality: the low-volume group (AOR 95% CI: 1.20 (0.95-1.51)) and intermediate-volume group (AOR 95% CI: 1.29 (1.02-1.64)) when compared to the high-volume group.

CONCLUSIONS

The case volume at an ambulance station is associated with in-hospital mortality in patients with moderate to severe trauma. These results should be considered when constructing an EMS system and education program for prehospital trauma care.

Impact of COVID-19 on Out-of-Hospital Cardiac Arrest in Korea

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a global public health crisis that has had a significant impact on emergency medical services (EMS). Several studies have reported an increase in the incidence of out-of-hospital cardiac arrest (OHCA) and a decreased survival due to COVID-19, which has been limited to a short period or has been reported in some regions. This study aimed to investigate the effect of COVID-19 on OHCA patients using a nationwide database.

METHODS

We included adult OHCA patients treated by EMS providers from January 19, 2019 to January 20, 2021. The years before and after the first confirmed case in Korea were set as the non-COVID-19 and COVID-19 periods, respectively. The main exposure of interest was the COVID-19 period, and the primary outcome was prehospital return of spontaneous circulation (ROSC). Other OHCA variables were compared before and after the COVID-19 pandemic and analyzed. We performed a multivariable logistic regression analysis to understand the independent effect of the COVID-19 period on prehospital ROSC.

RESULTS

The final analysis included 51,921 eligible patients, including 25,355 (48.8%) during the non-COVID-19 period and 26,566 (51.2%) during the COVID-19 period. Prehospital ROSC deteriorated during the COVID-19 period (10.2% vs. 11.1%, P = 0.001). In the main analysis, the adjusted odds ratios (AORs) for prehospital ROSC showed no significant differences between the COVID-19 and non-COVID-19 periods (AOR [95% confidence interval], 1.02 [0.96-1.09]).

CONCLUSION

This study found that the proportion of prehospital ROSC was lower during the COVID-19 period than during the non-COVID-19 period; however, there was no statistical significance when adjusting for potential confounders. Continuous efforts are needed to restore the broken chain of survival in the prehospital phase and increase the survival rate of OHCA patients.

Effect of a Targeted Ambulance Treatment Quality Improvement Programme on Outcomes from Out-of-Hospital Cardiac Arrest: A Metropolitan Citywide Intervention Study

The performance of ambulance crew affects the quality of pre-hospital treatment, which is vital to the survival for out-of-hospital cardiac arrest (OHCA) patients, yet remains suboptimal in China. In this retrospective analysis study, we aimed to examine the effect of a citywide quality improvement programme on provision of prehospital advanced life support (ALS) by emergency medical service (EMS) system. EMS-treated adult OHCA patients after the implementation of the programme (1 January 2021 to 30 June 2022) were compared with historical controls (1 June 2019 to 31 August 2020) in Suzhou. Multivariable logistic regression analysis and propensity score matching procedures were applied to compare the outcomes between two periods for total OHCA cases and subgroup of cases treated by fixed or non-fixed ambulance crews. A total of 1465 patients (pre-period/post-period: 610/855) were included. In the 1:1 matched analysis of 591 cases for each period, significant improvement (p < 0.05) was observed for the proportion of intravenous (IV) access (23.4% vs. 68.2%), advanced airway management (49.2% vs. 57.0%), and return of spontaneous circulation (ROSC) at handover (5.4% vs. 9.0%). The fixed ambulance crews performed better than non-fixed group in IV access and advanced airway management for both periods. There were significant increases in IV access (AOR 12.66, 95%CI 9.02−18.10, p < 0.001), advanced airway management (AOR 1.67, 95% CI 1.30−2.16, p < 0.001) and ROSC at handover (AOR 2.37, 95%CI 1.38−4.23, p = 0.002) after intervention in unfixed group, while no significant improvement was observed in fixed group except for IV access (AOR 7.65, 95%CI 9.02−18.10, p < 0.001). In conclusion, the quality improvement program was positively associated with the provision of prehospital ALS interventions and prehospital ROSC following OHCA. The fixed ambulance crews performed better in critical care provision and prehospital outcome, yet increased protocol adherence and targeted training could fill the underperformance of non-fixed crews efficaciously.

Effects of a designated ambulance team response on prehospital return of spontaneous circulation and advanced cardiac life support of out-of-hospital cardiac arrest: A nationwide natural experimental study

OBJECTIVES

This study aimed to investigate the effects of adding advanced cardiac life support (ACLS) training to an existing basic life support program and the operation of a designated team response for patients with out-of-hospital cardiac arrest (OHCA) on prehospital return of spontaneous circulation (ROSC) and ACLS management.

METHODS

A natural experimental study was conducted for emergency medical service (EMS)-treated adult patients with OHCA in 2020. In 2019, a quarter of the EMS clinicians were trained in a 3-day ACLS courses, and they were designated to be dispatched first in suspected OHCA. Some were dispatched only to major emergencies, such as OHCA and myocardial infarction (dedicated team), while others were dispatched to all emergencies with priority to major ones (non-dedicated team). The exposure was the ambulance response type: dedicated, no-dedicated, and basic teams (others). The primary outcome was prehospital ROSC. The secondary outcomes were prehospital ACLS (advanced airway management and intravenous access). A multivariable logistic regression analysis was conducted to investigate the effect of ambulance response type on study outcomes.

RESULTS

Among 23,512 eligible patients with OHCA, 54.8% (12,874) were treated by the basic team, 36.5% (8,580) by the non-dedicated ACLS team, and 8.8% (2,058) were treated by the dedicated ACLS team. Prehospital ROSC was greater for the designated team than for the basic team (dedicated ACLS team 13.8%, non-dedicated ACLS team 11.3%, and basic team 6.7%) (p <0.01). In the final logistic regression analysis, compared with the basic team, the designated ACLS team was associated with a higher probability of prehospital ROSC (AOR (95% CIs), 1.88 (1.68-2.09) compared to the non-dedicated ACLS team, and 2.46 (2.09-2.90) compared to the dedicated ACLS team), prehospital advanced airway management (1.72 (1.57-1.87) and 1.73 (1.48-2.03), respectively), and intravenous access (2.29 (2.16-2.43) and 2.76 (2.50-3.04), respectively).

CONCLUSION

Additional ACLS training and operation of a designated OHCA team response were associated with higher rates of prehospital ROSC and prehospital ACLS provision. However, further research is needed to find the optimal operation for EMS to improve survival outcomes.

The ED-PLANN Score: A Simple Risk Stratification Tool for Out-of-Hospital Cardiac Arrests Derived from Emergency Departments in Korea

Early risk stratification of out-of-hospital cardiac arrest (OHCA) patients with insufficient information in emergency departments (ED) is difficult but critical in improving intensive care resource allocation. This study aimed to develop a simple risk stratification score using initial information in the ED. Adult patients who had OHCA with medical etiology from 2016 to 2020 were enrolled from the Korean Cardiac Arrest Research Consortium (KoCARC) database. To develop a scoring system, a backward logistic regression analysis was conducted. The developed scoring system was validated in both external dataset and internal bootstrap resampling. A total of 8240 patients were analyzed, including 4712 in the development cohort and 3528 in the external validation cohort. An ED-PLANN score (range 0–5) was developed incorporating 1 point for each: P for serum pH ≤ 7.1, L for serum lactate ≥ 10 mmol/L, A for age ≥ 70 years old, N for non-shockable rhythm, and N for no-prehospital return of spontaneous circulation. The area under the receiver operating characteristics curve (AUROC) for favorable neurological outcome was 0.93 (95% CI, 0.92–0.94) in the development cohort, 0.94 (95% CI, 0.92–0.95) in the validation cohort. Hosmer–Lemeshow goodness-of-fit tests also indicated good agreement. The ED-PLANN score is a practical and easily applicable clinical scoring system for predicting favorable neurological outcomes of OHCA patients.