Body cooling in pediatrics, also known as therapeutic hypothermia, is a specialized intervention used primarily for newborns with hypoxic-ischemic encephalopathy (HIE)—a condition caused by reduced oxygen or blood flow to the brain during birth
Purposes
- To protect the neurons by reducing cerebral metabolic rate
- To attenuate the release of excitatory amino acids such as glutamate and dopamine and improve the uptake of glutamate
- To lower the production of toxic nitric oxide and free radicals.
Types
- Whole-body hypothermia
- Selective head cooling
Eligibility Criteria for Therapeutic Hypothermia
- Gestational age: The newborn should be ≥35 weeks of gestation.
- Time: <6 hours post-birth.
- Evidence of asphyxia as defined by the presence of at least two of the following criteria:
- Apgar score <6 at 10 minutes or continued need for resuscitation with positive pressure ventilation with or without chest compression
- Any acute perinatal event that may result in hypoxic-ischemic encephalopathy
(HIE) such as placental abruption, cord prolapse, and severe abnormal FHR. - Cord pH <7 or base deficit 12 or more
- Arterial pH <7
- Clinically defined moderate or severe HIE (stage II or III based on modified Sanart’s classification).
- Moderate to severe abnormal background activity on amplitude-integrated electroencephalogram (EEG) (i.e., discontinuous, burst suppression, or low voltage with or without seizure activity.
Phases of Cooling
Phase 1: Active cooling, it is for 72 hours from the initiation of cooling
Phase 2: Rewarming, 12 hours of active gradual rewarming after completion of 72 hours of cooling. In this phase, the temperature will be increased by 0.5°C every second hourly as per the order.
Side Effects
- Delayed intracardiac conduction with sinus bradycardia
- Prolonged QT interval
- Ventricular arrhythmias
- Reduced cardiac output
- Hypotension
- Reduction in surfactant production
- Increase pulmonary vascular resistance
- Increase oxygen consumption and oxygen requirement
- Affects coagulation cascade and viscosity— coagulopathy that may be complicated by thrombus or hemorrhage
- Anemia
- Thrombocytopenia
- Leukopenia-increased risk of sepsis
- Renal impairment
- Metabolic and lactic acidosis
- Hypokalemia
- Hypoglycemia
- Impaired liver function
Equipment Needed
- Medi-therm III hyper/hypothermia system
- Rectal temperature probe
Nurse’s Responsibilities
Maintaining oxygenation:
- Babies who are on body cooling will be put on ventilator support to maintain adequate oxygenation and ventilation. Because hypothermia shifts the oxyhaemoglobin curve and can result in a decreased oxygen delivery. If the baby is not ventilated the metabolic rate may increase without increase in oxygen supply.
Maintaining perfusion:
- Peripheral IV line should be started before the initiation of cooling procedure as there will be vasoconstriction of peripheral vessels and hence poor perfusion.
Constant monitoring:
- The baby’s cardiopulmonary status should be constantly monitored. The newborn may go for hypovolemia and hypotension. Monitor BP and heart rate; watch for arrhythmias.
Check the rectal temperature and CO2 level should be corrected based on temperature. - 43-56% of newborns with HIE on undergoing body cooling therapy get seizures. So, they must be assessed for pupil reaction, level of consciousness, and signs of increased intracranial pressure. EEG should be monitored constantly during cooling. Also, they have to undergo formal EEG and magnetic resonance imaging (MRI) after 3-7 days of rewarming. At times, there is a need for MRI earlier to make decision regarding palliative care.
- Note the doctor if any side effects arise.
Sedation:
- Sedation with low dose of morphine infusion may be needed to provide optimal comfort and enhance the efficacy of cooling procedure. Inadequate sedation may result in increased metabolic rate.
Fluid and electrolyte:
- Serum electrolytes need to be monitored on admission, prior to the initiation of cooling then at 4, 8, 12, 24, and 72 hours.
- May need to restrict the fluid to avoid fluid overload and cerebral edema.
- Sodium and magnesium levels should be maintained at upper limit of normal to prevent the risk of cerebral edema and has neuroprotective effect, respectively.
Skin care:
- Assess the skin at frequent interval for color, perfusion, any breakdown, and signs of subcutaneous necrosis.
Subcutaneous necrosis is characterized by indurations, erythematous nodules, and plaques over bony prominence such as back, arms, buttocks, thighs, and chest. It may be due to the sensitivity of brown fat to hypoxia and made worse by cooling. - Repositioning of baby should be done at frequent interval.
Family-centered care:
- Explain the family members about body cooling procedure, that is, its benefits, risks, complications, and expected duration of therapy.
- Reassure the parents that their newborn will be kept comfortable during the therapy.
- Promote parent-child bond through changing nappy, touch, etc.
REFERENCES
- Annamma Jacob, Rekha, Jhadav Sonali Tarachand: Clinical Nursing Procedures: The Art of Nursing Practice, 5th Edition, March 2023, Jaypee Publishers, ISBN-13: 978-9356961845 ISBN-10: 9356961840
- Omayalachi CON, Manual of Nursing Procedures and Practice, Vol 1, 3 Edition 2023, Published by Wolters Kluwer’s, ISBN: 978-9393553294
- Sandra Nettina, Lippincott Manual of Nursing Practice, 11th Edition, January 2019, Published by Wolters Kluwer’s, ISBN-13:978-9388313285
- Ernstmeyer K, Christman E, editors. Nursing Fundamentals [Internet]. 2nd edition. Eau Claire (WI): Chippewa Valley Technical College; 2024. PART IV, NURSING PROCESS. Available from: https://www.ncbi.nlm.nih.gov/books/NBK610818/
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