OBSTETRICS Use of Maternal Early Warning Trigger tool reduces maternal morbidity Laurence E. Shields, MD; Suzanne Wiesner, RN, MBA; Catherine Klein, RN, CNM; Barbara Pelletreau, RN, MPH; Herman L. Hedriana, MD BACKGROUND: Maternal mortality in the United States has increased unabated for the past 20 years. Maternal morbidity is also affecting an increasingly large number of women in the United States. A number of national and state organizations have recommend the use of maternal early warning tools as a method to combat this problem. There are limited data suggesting that the use of these types of clinical assessment tools can reduce maternal morbidity. OBJECTIVE: We sought to determine if maternal morbidity could be reduced with the implementation of a clinical pathway-specific Maternal Early Warning Trigger (MEWT) tool. STUDY DESIGN: The tool was developed internally and prospectively implemented as a pilot project in 6 of 29 hospitals within a large hospital system. The primary goal was early assessment and treatment of patients suspected of clinical deterioration. The tool addressed the 4 most common areas of maternal morbidity: sepsis, cardiopulmonary dysfunction, preeclampsia-hypertension, and hemorrhage. To be considered positive, triggers needed to be sustained for >20 minutes and were defined as severe (single abnormal value): maternal heart rate (HR) >130 beats/min (bpm), respiratory rate >30/min, mean arterial pressure <55 mm Hg, oxygen saturation <90%, or nurse concern; or nonsevere (required 2 abnormal values): temperature >38 or <36  C, blood pressure >160/110 or <85/45 mm Hg, HR >110 or <50 bpm, respiratory rate >24 or <10/min, oxygen saturation <93%, fetal HR >160 bpm, altered mental status, or disproportionate pain. Within each group, recommended management or assessment was also provided. Outcome measures were Centers for Disease Control and Prevention (CDC)-defined severe maternal morbidity, composite maternal morbidity, and intensive care unit (ICU) admissions. Two time intervals were used to analyze the effect of the MEWT tool: a 24-month baseline control period and a 13-month MEWT study period. To determine that the findings noted were not simply changes that would have occurred without the utilization of the early warning tool, we also compared a control population from nonpilot sites during the same baseline and 13-month time periods. RESULTS: There were 36,832 deliveries at the pilot sites (24,221 pre- and 12,611 post-MEWT testing) and 146,359 at the nonpilot sites (95,718 pre- and 50,641 post-MEWT testing) during the 2 study time periods. Use of the MEWT tool resulted in significant reductions in CDC severe maternal morbidity (P < 0.01) and composite morbidity (P < 0.01). ICU admissions were unchanged. At nonpilot sites CDC severe maternal morbidity, composite morbidity, and ICU admissions were unchanged between baseline and the post-MEWT testing time period. CONCLUSION: The use of the MEWT tool in this study, designed to address 4 of the most common causes of maternal morbidity, as well as provide assessment and management recommendations, resulted in significant improvement in maternal morbidity. The variation in hospital delivery services at the pilot sites suggests that this maternal early warning tool would be suitable for use in the majority of maternity centers in the United States. Key words: critical vital signs, maternal decompensation, maternal mortality Introduction Maternal mortality in the United States has increased unabated for the past 20 years. Correspondingly, there has also been a simultaneous increase in se- vere maternal morbidity. 1 A number of reasons have been cited for the increase in poor maternal outcome, including the rise in the prevalence of comorbid conditions (obesity, hypertension, and diabetes) and the growing cesarean delivery rate. 1,2 State and national review of maternal deaths have suggested that significant improvement could have been made in the care provided to many of the women who died, and many of these cases were potentially preventable events. 3-5 The increasing rate of maternal mortality and morbidity has gained widespread recognition and a variety of local, state, and national projects have been designed to address the issue. 6,7 One of the proposed methods to reduce both maternal mortality and morbidity has been through the use of clinical tools that would allow early recognition of patients who would likely benefit from more aggressive interventions or transfer to a higher level of care. 8,9 A number of proposed identification tools have been designed. 9-12 Key elements of any proposed tool must include ease of use, the ability to identify relevant clinical markers of patient deterioration, 13 and ideally, guidance for management that ultimately can be shown to reduce maternal morbidity. In Great Britain the modified early obstetric warning system (MEOWS) has been proposed and in the United States the National Council for Patient Safety recently proposed the use of the maternal early warning criteria (MERC). 9,10 Although the use of these tools is widely supported, there are no uniform criteria for inclusion or what degree of abnormality should be used to trigger more aggressive intervention, Cite this article as: Shields LE, Wiesner S, Klein C, et al. Use of Maternal Early Warning Trigger tool reduces maternal morbidity. Am J Obstet Gynecol 2016; volume:x.ex-x.ex. 0002-9378/$36.00 ª 2016 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog.2016.01.154 MONTH 2016 American Journal of Obstetrics & Gynecology 1.e1 Original Research ajog.org