Therapeutic Hypothermia for Treatment of Neonatal Encephalopathy

Current Research and Nursing Care

Carmen K. Cederholm, BSN, RN, CCRN; C. Michael Cotten, MD, MHS


NAINR. 2014;14(2):77-81. 

In This Article

Who Should Be Cooled?

A gestational age of 36 weeks is usually the minimum age required for TH.[11,12] Cooling of younger infants has not been studied on a large scale; however, some institutions have expanded the eligibility down to 34 weeks gestational age.[32,33] Additionally, the therapeutic window for hypothermia ends at 6 hours of age and it is believed that implementation after that time does not yield the same level of protection.[4] Therefore, the infant must be less than 6 hours old. General exclusions include presence of major congenital anomalies or weight less than 1800 grams.[34] Then, a combination of clinical findings, lab results, and neurological examination is used to diagnose NE. Some institutions may also use amplitude-integrated electroencephalography (aEEG) to identify cooling candidates.[35]

Clinical findings that indicate NE include history of an acute perinatal event such as cord prolapse or placental abruption, Apgar ≤ 5 at 5 or 10 minutes, and continued need for resuscitation or ventilator support after delivery.[34] Lab results indicative of increased risk for NE include cord blood or postnatal blood gas pH of ≤ 7.0 at ≤ 1 hour of life or base deficit ≥ 16 mEq/L at ≤ 1 hour of life.[34] Neurological status is assessed using the modified Sarnat score and infants are categorized as mild, moderate, or severe if they present with 3 of the 6 indicators for a stage.[34] Generally, only infants with moderate to severe NE will be cooled.[34] A decision tree adapted from the NICHD NRN Whole Body Hypothermia trial combining all eligibility criteria for cooling is provided in Table 2 .[36]