Oregon Health and Sciences University

Observational study assessing efficacy of neonatal ammonia sepsis screening (NASS) in Oregon

Project Lead: Amy C. Yang, MD

Project AIM(s):  To reduce cases of neonatal hyperammonemia requiring hemodialysis management and prevent death by 100% in 1 year for the Oregon.  An electronic alert will remind hospital providers to order an ammonia level at the time of a sepsis work-up for an ill-appearing neonates. This will reduce the morbidity and mortality of neonatal hyperammonemia through earlier diagnosis and treatment. 

Narrative Description

At OHSU, between 6/2020-12/2022, there were ~5712 live births, and the Alert triggered for 374 neonates (~12 alerts/month). At OHSU we have detected 11 cases with NH3 >100µM; of these, 3 cases had NH3 >150µM, meeting definition of hyperammonemia. 1 was transient hyperammonemia that self-resolved (false positive), while 2 cases were subsequently diagnosed with inborn error of metabolism, one of which required IV ammonia scavenger. OHSU providers obtained a plasma ammonia level for 121/374 neonates (32%). Providers deferred plasma ammonia measurement for 253/374 neonates (68%). Our partial retrospective chart review found that 26/253 deferments involved a neonate with symptoms possibly related to neonatal hyperammonemia (i.e., tachypnea, hypothermia, poor feeding, vomiting, or lethargy). Of those 26 deferred measurements, on feedback, clinicians felt that the neonate did not appear ill or had clinically improved (5 cases), felt it was too difficult to draw the blood for the measurement (6 cases), provided no justification (15 cases), but likely due to prioritizing other blood testing. However, despite deferring plasma ammonia measurement, the blood culture (requiring 1 mL of blood) was completed in 240/253 deferral cases; this suggests that if the ease of obtaining a plasma ammonia level were improved, providers might order NH3 more when the Alert prompts, lowering the “failure to screen” rate. We are hoping with a bedside testing device, we can improve this screen rate at OHSU. 

  • We have demonstrated that the Neonatal Ammonia Sepsis Screen (NASS) Alert is accepted within our institution as well as at other institutions. Within OHSU, the Alert triggers in 12 patients per month, about half of which occurs in the ER, suggesting this is not a very burdensome electronic Alert that would result in Alert fatigue and reflects the smart design of the Alert parameters. 
  • However, despite a reasonable number of Alerts per month, the resulting ammonia screen rate at OHSU remains at around 30%, lower compared to outside collaborating partner sites. Various factors may contribute to the low screen rate: 
  • OHSU and similar tertiary hospitals like CHOP may have a clearer clinical picture from transferring providers/hospitals, lowering clinical suspicion for IEMs 
  • Difficulty in drawing additional blood sample for ammonia measurement in a neonate 
  • Lack of global awareness of the NASS clinical guidelines and Alert amongst rotating ordering providers, including residents, nurses, physician assistants. 
  • We have demonstrated NASS Clinical Guidelines and Alert can help detect neonatal hyperammonia earlier with better clinical outcomes, despite some challenges. 

We have demonstrated that a hospital-based screening program for neonatal hyperammonemia at the time of a sepsis work-up, with a well-designed electronic record Alert, can be readily accepted and implemented across various medical centers throughout our region. We have demonstrated NASS can lead to earlier detection of neonatal hyperammonemia resulting from inborn error of metabolism, leading to good outcomes. 

Diagnostic quality problem type, failure, or category (symptoms, observed problems, gaps in performance) addressed by the intervention

  • Information gathering
  • Information integration
  • Information interpretation
  • Establishing an explanation (diagnosis)
  • Communicating explanation to patient

Root causes/causative factors addressed by the intervention

  • Workflow (includes testing, follow-up, and referrals)
  • Health information sharing and accessibility via health IT
  • Knowledge gaps/inexperience

Setting of the diagnostic quality improvement intervention

  • Ambulatory medical care setting (e.g., clinic, office, urgent care)