Hypothermia Flashcards
Criteria for cooling?
>= 36 weeks who are =< 6 hours old and meet A or B and C
Consider in >= 35 weeks
A. cord pH =< 7.0 or BE >= -16 OR
B. pH 7.01-7.15 or base deficit -10 to -15.9 on cord gas or blood gas within 1 H AND
- Hx of acute perinatal event (such as but not limited to cord prolapse, placental abruption or uterine rupture) AND
- Apgar score =< 5 at 10 min or at least 10 min of PPV
C. Evidence of moderate-to-severe encephalopathy, demonstrated by presence of seizures OR at least one sign in 3 or more of the 6 categories below:
Cooling may be deferred if an infant’s neurological status has fully returned to normal within 30-45 minutes after birth
Exclusion criteria for cooling in neonates
- moribund infants/infants with congenital or genetic abnormalities
- severe IUGR
- significant coagulopathy
- severe head trauma or intracranial bleeding
Side effects of hypothermia
- sinus brady (HR 80-100)
- hypotension (possibly need inotropes)
- PPHN with impaired oxygenation
- mild thrombocytopenia
- prolong bleeding time
- subcutaneous fat necrosis with or without hypercalcemia
Stop hypothermia and rewarm if:
(happens in <10% of cases)
- hypotension despite inotropic support
- PPHN with hypoxemia despite adquate treatment
- clinically significant coagulopathy despite treatment
Infants with HIE at risk for:
- arrhythmia
- anemia
- leukopenia
- hypoglycemia
- hypokalemia
- urinary retention
- coagulopathy
How do you provide hypothermia for neonates?
(start from community hospital)
COMMUNITY HOSPITAL
-
Passive cooling while awaiting transport (remove hat, blanket, and turn off overhead warmer)
- do not use ice packs
- monitor temp q15 min to ensure temp doesn’t decrease below 33
COOLING
- Two setups:
- whole body cooling to rectal temp 33.5 +/- 0.5
- recommended preferentially
- Head cooling to 34.5 +/- 0.5
- whole body cooling to rectal temp 33.5 +/- 0.5
- Cool for 72 hours
- Rewarm over 6-12 hours; by 0.5 q1-2 hours
- if seizures and worsening of clinical encephalopathy —> recool for 24 hours
- Brain imaging
- once rewarming has finished, on day of life 4 or 5
- Consider repeat on DOL 10-14 when imaging and clinical features discordant or when diagnostic ambiguity persists
- Follow up at 18-24 months with multi-D team
What percent of babies with HIE post cooling have CP or severe disability
- CP or severe disability > 30% of HIE affected newborns
- cognitive deficits, vison, sensorineural hearing loss, epilepsy
How do you rewarm a baby post cooling?
- Rewarm over 6-12 hours; by 0.5 q1-2 hours
- if seizures and worsening of clinical encephalopathy —> recool for 24 hours
What are adjunctive therapies to cooling in neonates with HIE?
- Analgesic
- Longer serum clearance of morphine, fentanyl, and midaz
- low infusion of morphine =< 10 mcg/kg/h or equivalent opioid is recommended as initial approach
- Antiepileptic
- use cautiously but treat neonatal seizures
- serum levels in first 72 hours
- Minimal enteral feeding (10-20 ml/kg/d) during hypothermia
- more than minimal feeds not safe because decreased gut perfusion
- Aim for normal everything
- Minimize fluctuations in CO2, avoid hyperoxia, ensure adequate tissue perfusion with appropriate pressors/inotropes, normal BG, treat hyperbili, minimize handling