The Registry for Neonatal Encephalopathy

Background

Neonatal encephalopathy has been defined as a "syndrome of disturbed neurological function in the earliest days of life in the term infant, manifested by difficulty with initiating and maintaining respiration, depression of tone and reflexes, subnormal level of consciousness, and often by seizures. "¹ The prevalence of neonatal encephalopathy has been estimated to be 3.8 per 1000 live term births.^2,3 In the past it was accepted that fetal asphyxia during labor and delivery was the predominant cause of neonatal encephalopathy and cerebral palsy, leading to the diagnosis of hypoxic-ischemic encephalopathy, HIE, for most infants presenting with encephalopathy soon after birth. More recently, it has been recognized that there may be multiple etiologies for neonatal encephalopathy, that the proportion of cases attributable to perinatal hypoxic-ischemic injury is unclear, and that the significant predisposing factors and those contributing to unfavorable long-term outcome are for the most part unknown.⁴ Data from a large multicenter registry will be needed to address these critical questions.

Two additional arguments support the need for a registry of neonatal encephalopathy. First, given the paucity of scientific data, variation in routine practice for the diagnosis and management of neonatal encephalopathy is likely to be great leading to deficiencies in the quality and safety of medical care for these high risk infants.⁵ Second, if new therapies such as hypothermia and neuroprotective agents are to be tested appropriately and used effectively, selection criteria for treatment must be developed and assessed, and prospective studies planned and designed.6 The Vermont Oxford Network Registry for Neonatal Encephalopathy will provide the necessary information.

The Vermont Oxford Network is a collaborative network of neonatologists and other health care professionals, representing nearly 600 institutions from North America and around the world (www.vtoxford.org). Membership is voluntary and open to all who are interested. The nonprofit network is supported by membership fees, research grants, and contracts. The primary philosophy of the Vermont Oxford Network is to improve the quality, safety and efficiency of medical care for newborn infants and their families through a coordinated program of research, education, and quality improvement projects. In support of all three aspects of this program, the Network maintains a database for infants with birth weights of 401 to 1500 grams who were born at participating centers or admitted to them within 28 days of birth. Members also have the option of submitting data for all NICU infants regardless of birth weight. Members of the Vermont Oxford Network complete brief data forms using standardized definitions. The database provides core data for network clinical trials, is used for observational studies and outcomes research, and generates reports for members that compare their performance with that of other NICUs in the Network. These reports are produced quarterly and are intended for use in local quality management efforts. The Vermont Oxford Network also conducts formal quality improvement collaboratives for its members and hosts an Annual Quality Congress for Neonatology. These will provide forums for practical exploration of issues related to the quality and safety of care for infants with neonatal encephalopathy.

In 2003, the Vermont Oxford Network database enrolled approximately 35,000 infants weighing 401 to 1500 gm from 441 NICUs. In 2003, 73 NICUs reported data for 33,592 infants of all birth weights cared for in their units. Of the 15,304 infants with gestational ages of 36 weeks or more at these NICUs, 222 were identified with hypoxic ischemic encephalopathy, HIE, and 552 with seizures. There were 627 infants with either HIE or seizures; approximately 9 infants per NICU on average. Since the eligibility criteria for the Registry are not as stringent as the current definition of HIE in the expanded database, we expect that the number of eligible infants at each center will be somewhat larger. Although for any individual NICU the number of infants will be relatively small, we have the potential to capture a significant proportion of infants in the US with moderate to severe encephalopathy.