Predictive value of the New Zealand Early Warning Score for early mortality in low-acuity patients discharged at scene by paramedics: an observational study.

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.

Changes in demand for emergency ambulances during a nationwide lockdown that resulted in elimination of COVID-19: an observational study from New Zealand.

OBJECTIVE: To examine the impact of a 5-week national lockdown on ambulance service demand during the COVID-19 pandemic in New Zealand. DESIGN: A descriptive cross-sectional, observational study. SETTING: High-quality data from ambulance electronic clinical records, New Zealand. PARTICIPANTS: Ambulance records were obtained from 588 690 attendances during pre-lockdown (prior to 17 February 2020) and from 36 238 records during the lockdown period (23 March to 26 April 2020). MAIN OUTCOME MEASURES: Ambulance service utilisation during lockdown was compared with pre-lockdown: (a) descriptive analyses of ambulance events and proportions of event types for each period, (b) absolute rates of ambulance attendance (event types/week) for each period. RESULTS: During lockdown, ambulance patients were more likely to be attended at home and less likely to be aged between 16 and 25 years. There was a significant increase in the proportion of lower acuity patients (Status 3 and Status 4) attended (p<0.001) and a corresponding increase in patients not transported from scene (p<0.001). Road traffic crashes (p<0.001) and alcohol-related incidents (p<0.001) significantly decreased. There was a decrease in the absolute number of weekly ambulance attendances (ratio (95% CI), 0.89 (0.87 to 0.91), p<0.001), attendances to respiratory conditions (0.74 (0.61 to 0.86), p=0.01), and trauma (0.81 (0.77 to 0.85), p<0.001). However, there was a significant increase in ambulance attendances for mental health conditions (1.37 (1.22 to 1.51), p=0.005). CONCLUSIONS: Despite the relative absence of COVID-19 in the community during the 5-week nationwide lockdown, there were significant differences in ambulance utilisation during this period. The lockdown was associated with an increase in ambulance attendances for mental health conditions and is of concern. In considering future lockdowns, the potential implications on a population's mental well-being will need to be seriously considered against the benefits of elimination of virus transmission.