Our study on 89 women, in a single health board in Scotland, which compared three different SSSs – namely mSIRS, qSOFA and MEWS, with positive culture, revealed comparable performance by mSIRS and MEWS with similar values for sensitivity, specificity, PPV, NPV and AUROC. Most importantly the values for AUROC for both mSIRS and MEWS were around 50% indicating that their ability to predict sepsis was close to chance compared to positive culture. Estimates for qSOFA were unreliable in our study due to low number of women with positive qSOFA.
On evaluating compliance with the use of SSCB, only 33 (37.1%) of these women were found to have sepsis six sticker on their medical notes denoting low levels of compliance with providing timely recommended sepsis care. Among those who received SSCB, only 2 women received it within the recommended 1 h following diagnosis. While most received 4/6 elements of SSCB, only around 79% received catheterization and the minority (27.3%) were administered oxygen.
Our findings regarding comparison of SSSs with positive culture threw up meaningful results only for mSIRS and MEWS. mSIRS is a modification of the SIRS criteria and has been in use in the hospitals of the health board since 2015 [7]. mSIRS performance was similar to that of MEWS which indicated that mSIRS was probably one of the better performing SSS in obstetric settings. This can be inferred in the light of findings where MEWS was compared to six different published MOEWS and was found to perform better than all of them [9]. The different MOEWS were reported to have low PPV, ranging between 1.4 and 5.1%, while AUROC ranged from 0.52 to 0.72 [9].
The use of SIRS criteria in the original definition of sepsis were not specific and its values can be elevated in cases of other non-infectious disease such as burns or injury and in cases unrelated to infection [12, 13]. In addition, women undergo changes in their physiological and laboratory measurements during pregnancy and post-partum periods. These changes overlapped with the SIRS criteria and made the diagnosis critical, particularly when respiratory rate, heart rate, white cell count and blood pressure values, expected to be outside the adult normal reference range [12, 13].
An important thing to note here is the continued use of mSIRS (though SIRS was found highly inadequate after decades of use [1]) in the health board that was studied and the presence of numerous MOEWS in various obstetric setting across the world; this points towards the lack of consensus [13] about a single validated SSS which is needed for use in obstetric settings and is currently missing.
It has been proposed that the qSOFA definition should be able to identify women at an early stage of severe maternal infection to allow healthcare practitioners to initiate treatment [14]. The definition of severe maternal sepsis excludes the early stage of sepsis and delays the initiation of treatment for these women. The new definition of maternal sepsis is “a life-threatening condition defined as organ dysfunction resulting from infection during pregnancy, childbirth, post-abortion, or the postpartum period” [15]. When applied to our sample, this criterion was able to determine sepsis in only two women. It seems that it can be used in very sick women to determine their need for ICU admission, but has limited applicability to sepsis cases in maternity wards.
Finally, we considered comparing the various SSSs to positive culture. Our results with different SSSs show uncertainty about systems to be used in diagnosis and culture-proven sepsis is still the diagnostic gold standard. There were only 29 positive culture results among 75 women (38.6%), which is in line with the evidence [16]. Despite being the gold standard there are severe deficiencies in using culture tests in clinical settings due to poor specificity and precious time lost in waiting for culture results [16]. These shortcomings with culture tests further underline the need for creating an effective SSS with high sensitivity and specificity for early use in clinical settings.
The early identification and management of sepsis in maternity is recommended [17], as delay in diagnosis or treatment can lead to maternal mortality and morbidity, which are associated with a delay in administering the appropriate therapy and management to these women [18]. Culture-proven sepsis results were obtained 48 h after therapy had been initiated for these women, and an early identification tool is necessary so that treatment can be delivered early. The limited applicability of various biomarkers due to the non-specific or non-sensitive nature of these criteria, arising from the altered physiological functions of pregnant women, could lead to under- or over-treatment. The unnecessary use of antibiotic therapy to treat maternal sepsis could drive antibiotic resistance and further medical complications [4, 19], while delay in managing sepsis can result in many complications including organ failure, hysterectomy and death [18,19,20].
The use of clinical judgement is currently recommended to facilitate the diagnosis of sepsis, which should not rely solely on SSSs or laboratory tests [20]. Chorioamnionitis cases, for example, may have a clinical diagnosis and a histological diagnosis but women might not have a positive microbiological culture while being treated with antibiotic for clinical chorioamnionitis [20]. Overall, the current system of diagnosing sepsis hardly relies on the effectiveness of the early warning scores and this might be a hindrance for validating these tools in identifying ill patients.
In order to make SSSs more effective, addition of biomarkers has been suggested. Procalcitonin (PCT) shows better prediction of sepsis compared to CRP; nevertheless, there is a reported lack of accuracy [21]. Serum PCT rises and peaks in a short time compared to CRP and it has been found to be useful in modern clinical practice. However, there is limited information about PCT in pregnancy, and determining the most appropriate reference range of this biomarker in pregnant women [22]. Its high level of negative predicted values leads to a misleading identification of sepsis [23]. Martín and colleagues recommend the design of a scoring system based on combined biomarker values including CRP, PCT and lactate to aid physicians in their treatment decisions, which has the potential to reduce the use of antibiotics and of culture tests [24].
With respect to compliance with SSCB, recent studies have indicated that very few patients received all the six interventions of the bundle within the recommended 1 h and the elements were not consistently applied [11]. This is in line with our findings. There are possibly a number of barriers that might hinder the timely and effective delivery of SSCB – a few have been described such as insufficient audit and feedback, poor teamwork and communication, inadequate training, lack of resources and concerns about using SSCB in certain patients [25]. However, health personnel also displayed positive factors in favour of SSCB such as confidence in knowledge and skills, and belief in the benefits of SSCB among others [25]. Since compliance with SSCB can vary among facilities, regular audits, continued use, further research into non-compliance at facility level and improving the strengths of the staff at facility level can lead to better implementation of SSCB.
