St John New Zealand (Hato Hone Aotearoa), Auckland, New Zealand
Paramedicine Research Unit, Paramedicine Department, Auckland University of Technology, Auckland, New Zealand.
BMJ Open. 2022 Jul 14;12(7):e058462. doi: 10.1136/bmjopen-2021-058462.
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.
A retrospective cohort study.
Prehospital emergency medical service provided by St John New Zealand over a 2-year period (1 July 2016 through 30 June 2018).
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.
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.
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.
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.
新西兰早期预警评分（NZEWS）在预测由护理人员在现场出院的低危患者不良预后方面的作用尚未得到研究。本研究的目的是评估 NZEWS 风险评估工具与非经救护车转运的低危、院前患者在 48 小时内早期死亡或救护车再次出勤的不良结局之间的相关性。
回顾性队列研究。
St John New Zealand 在 2 年期间（2016 年 7 月 1 日至 2018 年 6 月 30 日）提供的院前急救医疗服务。
83171 名低危成人患者，由救护车接诊并在现场出院。其中，41406 人有足够的记录数据来计算 NZEWS。
采用二元逻辑回归模型来研究 NZEWS 与 48 小时内再次出勤、2 天内死亡率、7 天内死亡率和 30 天内死亡率等不良结局之间的关系。
与参考组（NZEWS=0）相比，NZEWS 大于 0 与所有研究的不良结局显著相关（p<0.01）。2 天、7 天和 30 天死亡率与较高的早期预警评分之间存在惊人的相关性；早期预警评分>10 的患者 2 天死亡率的可能性是评分 0 的患者的 70 倍（调整后的比值比 70.64，95%置信区间：30.73 至 162.36）。对不良结局的最佳预测是 2 天和 7 天死亡率，其受试者工作特征曲线下面积的评分分别为 0.78（95%置信区间：0.73 至 0.82）和 0.74（95%置信区间：0.71 至 0.77）。
低危非转运患者的不良结局与 NZEWS 的风险预测显著相关。在该患者组中，较大的早期预警评分与 2 天死亡率之间存在极高的关联。这些发现表明，NZEWS 在决定现场出院低危患者的适当性时，对决策支持和提高安全性具有重要意义。
