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Background and Objectives: Direct transport to a cardiac arrest centre following out-of-hospital cardiac arrest may be associated with higher survival. However, there is limited evidence available to support this within the New Zealand context. This study used a propensity score-matched cohort to investigate whether direct transport to a cardiac arrest centre improved survival in New Zealand. Methods: A retrospective cohort study was conducted using the Aotearoa New Zealand Paramedic Care Collection (ANZPaCC) database for adults treated for out-of-hospital cardiac arrest of presumed cardiac aetiology between 1 July 2018 to 30 June 2023. Propensity score-matched analysis was used to investigate survival at 30-days post-event according to the receiving hospital being a cardiac arrest centre versus a non-cardiac arrest centre. Results: There were 2,297 OHCA patients included. Propensity matching resulted in 554 matched pairs (n = 1108). Thirty-day survival in propensity score-matched patients transported directly to a cardiac arrest centre (56%) versus a non-cardiac arrest centre (45%) was not significantly different (adjusted Odds Ratio 0.78 95%CI 0.54, 1.13, p = 0.19). Shockable presenting rhythm, bystander CPR, and presence of STEMI were associated with a higher odds of 30 day survival (p < 0.05). Maori or Pacific Peoples ethnicity and older age were associated with lower survival (p < 0.05). Conclusions: This study found no statistically significant difference in outcomes for OHCA patients transferred to a cardiac arrest compared to a non-cardiac arrest centre. However, the odds ratio of 0.78, equivalent to a 22% decrease in 30-day mortality, is consistent with benefit associated with management by a cardiac arrest centre. Further research in larger cohorts with detailed information on known outcome predictors, or large randomised clinical trials are needed.
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Objective: To describe the First Responder Shock Trial (FIRST), which aims to determine whether equipping frequently responding, smartphone-activated (GoodSAM) first responders with an ultraportable AED can increase 30-day survival rates in OHCA. Methods: The FIRST trial is an investigator-initiated, bi-national (Victoria, Australia and New Zealand), registry-nested cluster-randomised controlled trial where the unit of randomisation is the smartphone-activated (GoodSAM) first responder. High-frequency GoodSAM responders are randomised 1:1 to receive an ultraportable, single-use AED or standard alert procedures using the GoodSAM app.The primary outcome is survival to 30 days. The secondary outcome measures (shockable rhythm, return of spontaneous circulation, event survival, and time to first shock delivery) are routinely collected by OHCA registries in both regions. The trial was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR) (Registration: ACTRN12622000448741) on 22 March 2022. Results: The trial started in November 2022 and the last patient is expected to be enrolled in November 2024. We aim to detect a 7% increase in the proportion of 30-day survivors, from 9% in patients attended by control responders to 16% in patients attended by responders randomised to the ultraportable AED intervention arm. With 80% power, an alpha of 0.05, a cluster size of 1.5 and a coefficient of variation for cluster sizes of 1, the sample size required to detect this difference is 714 (357 per arm). Conclusion: The FIRST study will increase our understanding of the potential role of portable AED use by smartphone-activated community responders and their impact on survival outcomes.
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OBJECTIVES: The utility of New Zealand Early Warning Score (NZEWS) for prediction of adversity in low-acuity patients discharged at scene by paramedics has not been investigated. The objective of this study was to evaluate the association between the NZEWS risk-assessment tool and adverse outcomes of early mortality or ambulance reattendance within 48 hours in low-acuity, prehospital patients not transported by ambulance. DESIGN: A retrospective cohort study. SETTING: Prehospital emergency medical service provided by St John New Zealand over a 2-year period (1 July 2016 through 30 June 2018). PARTICIPANTS: 83 171 low-acuity, adult patients who were attended by an ambulance and discharged at scene. Of these, 41 406 had sufficient recorded data to calculate an NZEWS. PRIMARY AND SECONDARY OUTCOMES AND MEASURES: Binary logistic regression modelling was used to investigate the association between the NZEWS and adverse outcomes of reattendance within 48 hours, mortality within 2 days, mortality within 7 days and mortality within 30 days. RESULTS: An NZEWS greater than 0 was significantly associated with all adverse outcomes studied (p<0.01), compared with the reference group (NZEWS=0). There was a startling correlation between 2-day, 7-day and 30-day mortality and higher early warning scores; the odds of 2-day mortality in patients with an early warning score>10 was 70 times that of those scoring 0 (adjusted OR 70.64, 95% CI: 30.73 to 162.36). The best predictability for adverse outcome was observed for 2-day and 7-day mortality, with moderate area under the receiver operating characteristic curve scores of 0.78 (95% CI: 0.73 to 0.82) and 0.74 (95% CI: 0.71 to 0.77), respectively. CONCLUSIONS: Adverse outcomes in low-acuity non-transported patients show a significant association with risk prediction by the NZEWS. There was a very high association between large early warning scores and 2-day mortality in this patient group. These findings suggest that NZEWS has significant utility for decision support and improving safety when determining the appropriateness of discharging low-acuity patients at the scene.
