Introduction of a standardised maternity early warning system: indicative data from a before‐and‐after study at a large pilot site before national rollout in Aotearoa New Zealand

Abstract

Summary Strong evidence now demonstrates that recognition and response systems using standardised early warning scores can help prevent harm associated with in‐hospital clinical deterioration in non‐pregnant adult patients. However, a standardised maternity‐specific early warning system has not yet been agreed in the UK. In Aotearoa New Zealand, following the nationwide implementation of the standardised New Zealand Early Warning Score (NZEWS) for adult inpatients, a modified maternity‐specific variation (NZMEWS) was piloted in a major tertiary hospital in Auckland, before national rollout. Following implementation in July 2018, we observed a significant and sustained reduction in severe maternal morbidity as measured by emergency response calls to women who were very unwell (emergency response team call), and a non‐significant reduction in cardiorespiratory arrest team calls. Emergency response team calls to maternity wards fell from a median of 0.8 per 100 births at baseline (January 2017–May 2018) to 0.6 per 100 births monthly (from March 2019 to December 2020) (p < 0.0001). Cardiorespiratory arrest team calls to maternity wards fell from 0.14 per 100 births per quarter (quarter 1 2017–quarter 2 2018) to 0.09 calls per 100 births per quarter after NZMEWS was introduced (quarter 3 2018–quarter 4 2020) (p = 0.2593). These early results provide evidence that NZMEWS can detect and prevent deterioration of pregnant women, although there are multiple factors that may have contributed to the reduction in emergency response calls noted.

Comparison of the Aotearoa New Zealand Early Warning Score and National Early Warning Score to predict adverse inpatient events in a vital sign dataset

“…Although we have demonstrated that NZEWS has a high predictive value for adverse events, there may be additional patient safety benefits from national standardisation. There Although age and pregnancy-related physiology changes meant paediatric and obstetric patients were excluded, the effectiveness of an EWS in reducing maternal harm in the latter has been previously reported in this journal [30]. The New Zealand Maternity Early Warning Score (NZMEWS) is a blended system derived from NZEWS and Drake et al showed its introduction has resulted in a sustained reduction in severe maternal morbidity, and a non-significant reduction in cardiorespiratory arrest calls per 100 births [30].…”

“…Although age and pregnancy‐related physiology changes meant paediatric and obstetric patients were excluded, the effectiveness of an EWS in reducing maternal harm in the latter has been previously reported in this journal [30]. The New Zealand Maternity Early Warning Score (NZMEWS) is a blended system derived from NZEWS and Drake et al.…”

“…The New Zealand Maternity Early Warning Score (NZMEWS) is a blended system derived from NZEWS and Drake et al. showed its introduction has resulted in a sustained reduction in severe maternal morbidity, and a non‐significant reduction in cardiorespiratory arrest calls per 100 births [30].…”

Early warning scores: the case for aggregate vs. single extreme parameter activation to detect patient deterioration

“…A blended activation system is in place for obstetric patients in New Zealand, the New Zealand Maternity Early Warning Score (NZMEWS), which was derived from NZEWS and accounts for the physiological changes of pregnancy; Drake et al. showed its introduction has reduced maternal morbidity [20]. A similar process is underway in the UK, where a national Maternity Early Warning Score (MEWS), derived from NEWS2, is due to be rolled out, though this also uses aggregate scoring rather than single extreme parameter activation.…”

“…Though several scoring systems have made use of single extreme parameter activation, including the VitalPAC Early Warning Score (VIEWS), from which NEWS was developed, these were not designed to indicate that a single extreme parameter score infers a greater risk of mortality than an aggregate score of the same total. A blended activation system is in place for obstetric patients in New Zealand, the New Zealand Maternity Early Warning Score (NZMEWS), which was derived from NZEWS and accounts for the physiological changes of pregnancy; Drake et al showed its introduction has reduced maternal morbidity [20]. A similar process is underway in the UK, where a national Maternity Early Warning Score (MEWS), derived from NEWS2, is due to be rolled out, though this also uses aggregate scoring rather than single extreme parameter activation.…”