Implementation of the Sepsis Risk Calculator at an Academic Birth Hospital

Discussion

We demonstrate that the SRC can be adopted as the primary means of EOS risk assessment in s large, academic, perinatal center, with a significant impact on antibiotic and laboratory test use and with short-term safety. We were able to leverage existing resources to make the transition from the use of a categorical risk-based algorithm to the use of the SRC as the primary means of assessing risk of EOS among term and late-preterm infants. Our approach was different from that validated in the birth centers of the KPNC system.¹² We adopted the SRC approach published by Escobar et al,¹³ who used recursive partitioning and split validation to provide estimates of the impact of care algorithms based on estimated risk at birth <0.65, 0.65 to 1.54, and >1.54 per 1000 LBs. For practical purposes, we based our local algorithm on risk estimate cutoffs of 0.7 per 1000 LBs and 1.5 per 1000 LBs. Despite this difference in approach, the 41% decrease in empirical antibiotic use is similar in magnitude to that observed in the KPNC study (48%), although an overall lower rate of empirical antibiotic use was achieved in the KPNC hospitals.

Once we developed the local SRC algorithm described in Table 1, we needed to determine how it would be integrated into the daily workflow of a center with >5000 annual deliveries. The multivariate models that are in the SRC were based on objective data for calculation within an EMR and were meant to be applied to all infants in the targeted birth population. Because our local EMR could not accommodate the model equations, we partnered with our information technology personnel to provide a link from our existing EMR to the public SRC Web site. We also modified existing documentation tools to record the SRC variables and the risk estimate obtained at birth. To ensure that a risk estimate at birth would be calculated for every newborn of ≥36 weeks’ gestation, the SRC was placed in the workflow of the labor and delivery nursing staff. Labor and delivery nurses at our center are the only type of perinatal caregivers who are universally in attendance at all births, and they are the same caregivers who were charged with ensuring compliance with the pre-SRC policies. Nurse educators provided SRC education to each labor and delivery and postpartum nurse in small-group sessions. Finally, we ensured that the protocol was straightforward; after calculating the risk estimate at birth, the labor and delivery nurse simply had to call the NICU team to assess any infant with a value of ≥0.7 per 1000 LBs if the team was not already in attendance. All subsequent assessments of clinical status and antibiotic decisions were made by the NICU team. The robustness of these processes is illustrated by the fact that the sepsis risk estimate at birth was calculated and communicated for ∼99% of the >6000 infants born at ≥36 weeks’ gestation during the post-SRC period.

After implementation, we received feedback from the nursing staff about 2 concerns. First, the staff sought clarification about how to categorize administered intrapartum antibiotic therapy. Second, staff observed that it was not uncommon for elevated maternal temperature to be documented shortly after delivery but not recognized during delivery, often because of delays in obtaining routine vital signs toward the end of delivery. In response, we developed detailed instructions that helped address these and other issues frequently encountered by staff as they familiarized themselves with the SRC (Supplemental Table 6).

One unique aspect of our local approach to SRC implementation should be emphasized. We eliminated the routine use of CBC counts and CRP levels and based empirical antibiotic decisions solely on the risk estimate at birth and the newborn clinical condition. We made this decision on the basis of data demonstrating the poor sensitivity of these laboratory tests in predicting EOS among term and late-preterm infants.^20–22 Clinicians could choose to obtain these tests on the basis of their clinical judgment in specific situations and often did so; nonetheless, laboratory testing for EOS declined by ∼80% among WBN infants and by ∼50% among infants admitted to the NICU.

The decrease in antibiotic use in our center primarily resulted from changes in the care of 2 specific types of infants. The first type included infants with risk estimates at birth in the range of 0.7 to 1.49 per 1000 LBs. These infants were often born in the setting of risk factors that were considered in our pre-SRC policy, such as maternal fever >100.5°F or ROM >18 hours. We required close surveillance of these infants in the WBN, aware that these infants may have been administered antibiotics or subjected to laboratory testing in the pre-SRC period. Such infants comprised <3% of the infants admitted to WBN, which may have contributed to the observed compliance with enhanced surveillance requirements. Neonatal medical providers had a low threshold of concern for these moderate-risk infants when they did exhibit signs of clinical instability; nearly one-quarter of the infants in the range of 0.7 to 1.49 per 1000 LBs were admitted to the NICU for observation, and half of those admitted received empirical antibiotic treatment in concert with SRC recommendations. The second type that contributed to the observed decrease in empirical antibiotic administration included infants with risk estimates at birth of <0.7 per 1000 LBs who were admitted to the NICU with initial equivocal clinical status. This was reflected in the decrease in empirical antibiotic use and laboratory testing among infants admitted to the NICU for any reason (Table 4). Even among infants admitted to the NICU for whom blood cultures were obtained, 19% were never administered antibiotics because symptoms improved or were attributed to noninfectious causes (data not shown).

The goal in all approaches to neonatal sepsis risk assessment is to ensure safety by assessing the likelihood of infection and administering empirical antibiotics to prevent the development or progression of clinical illness. The performance of CDC- and American Academy of Pediatrics–recommended algorithms in achieving such goals has never been quantified, nor was such performance the basis of those recommendations. The safety of using the SRC to assess newborn risk of EOS was addressed in the prospective validation study done at KPNC birth centers. As assessed by late presentation of EOS during the birth hospitalization; by outcomes among those with culture-confirmed EOS; and by the incidence of re-hospitalization with culture-confirmed EOS after birth hospital discharge, the SRC approach was found to be as safe as previous CDC-recommended algorithms.¹² In our center, we found no evidence of later presentation of illness as assessed by the use of laboratory testing and antibiotics beyond 72 hours of age. However, a limitation of our study is that as a perinatal birth center located in a hospital that provides adult medical care, we do not readmit newborns after discharge for any indication other than hyperbilirubinemia, and we cannot assess neonatal outcomes postdischarge. Infants born at our birth center come from a large urban and suburban metropolitan area and seek pediatric care at a variety of public and private practices. Furthermore, the rate of rehospitalization for EOS in the KPNC study in both the pre- and post-SRC periods (∼5 per 100 000 LBs) reveals that it is a rare outcome that is unlikely to be observed by any individual perinatal center.

A review of the EOS cases that occurred during our study period revealed a final, important aspect of neonatal risk assessment. Recent attention has been given in the media and in state legislatures to the need for pediatric sepsis policies and protocols.²³ We believe that specific policies addressing neonatal EOS risk assessment, ongoing attention to compliance with such policies, and periodic review of the outcomes of such policies are also critical to neonatal care. However, case 2 in our study reveals the limits of neonatal risk assessment. This case of GBS sepsis occurred in an infant who was born without any specific risk factors that would have flagged the infant in our pre-SRC period, with a risk estimate of 0.3 per 1000 and reassuring clinical condition at birth. The infant was found to have new-onset tachypnea, lethargy, and poor feeding at ∼36 hours of age, prompting transfer to the NICU. This infant was born to a mother who was GBS-negative. GBS-specific EOS among term infants born to mothers who are GBS-negative is well documented.^1,24 This case illustrates the importance of combining universal risk-assessment protocols with ongoing clinical assessment. No protocol can function without excellent clinical care.