Whole-body hypothermia for hypoxic-ischemic encephalopathy (HIE)
Screening criteria
Screen term infants for eligibility if they had poor respiratory effort at birth and needed resuscitation or appear encephalopathic.
Inclusion criteria
Infants > 36 weeks and > 1800 grams with Perinatal Depression (Part A) and HIE (Part B).
Part A: Physiologic criteria for acute perinatal depression:
1) Cord gas or first postnatal blood gas at < 1 hour of age with either pH <7.0 or base deficit > 16 mmol/L.
OR
2) If cord gas or first postnatal blood gas at < 1 hour of age has either a pH of 7.01 - 7.15 or a base deficit of 10 - 15.9 mmol/L or if a blood gas is not available then the following additional criteria are required.
- An acute perinatal event (e.g., late or variable decelerations, cord prolapse, cord rupture, uterine rupture, maternal trauma, hemorrhage, abruptio placenta, etc.) and either:
- Apgar score of < 5 at 10 minutes or
- ii. Need for ventilation initiated at birth and continued for at least 10 minutes
Exclusion criteria
- Inability to initiate cooling by 6 hours after birth.
- Known chromosomal anomaly (excluding Trisomy 21, Turners, etc).
- Presence of major congenital anomalies.
- Infants in extremis for whom no additional intensive therapy will be offered.
If an infant meets either criteria A1 or A2, proceed to Part B (neurological criteria and exam).
Part B - Neurological criteria: Infants meet criteria if either seizures or HIE is present.
Evidence for HIE:
Moderate/severe hypoxic-ischemic encephalopathy (HIE) will be defined as either seizures or in the absence of seizures, the presence of signs in 3 of 6 categories from the neurological exam.
Category | Moderate Encephalopathy | Severe Encephalopathy |
---|---|---|
1. Spontaneous activity | Decreased activity | No activity |
2. Posture |
Distal flexion or complete extension or frog-legged |
Decerebrate |
3. Autonomic system Pupils |
Constricted |
Skew deviation/dilated/non-reactive |
4. Tone |
Hypotonia (focal or general) |
Flaccid |
5. Primitive reflexes Suck |
Weak |
Absent |
6. Level of consciousness |
Lethargic (decreased activity, arousable, responsive to stimuli) |
Lethargic (decreased activity, arousable, responsive to stimuli) |
Timing of the examination:
The exam should be done in the first 1 - 3 hours of life once the patient’s cardiopulmonary status has been stabilized.
Performance of the neurological examination for Whole Body Cooling:
The neurological examination should take 10 - 15 minutes to complete and be performed by the attending and/or fellow. The exam is to be recorded in the admit note and performed in the following order: Spontaneous activity, posture, autonomic system, tone (via ROM), primitive reflexes and level of consciousness (response to stimuli).
Patients who have HIE as defined by seizures will still need to have a neurological exam for cooling performed and documented.
If the infant meets physiologic criteria A1or A2 and neurologic criteria B without exclusion criteria, then whole body cooling can be initiated by ordering “Cooling per protocol”.
Reference: N Engl J Med 2005; 353:1574-84.