Therapeutic Hypothermia in Children (TTM)

Therapeutic hypothermia, also called targeted temperature management (TTM), is an emergency procedure. It is used to lower the body temperature in a patient whose heartbeat has suddenly stopped (cardiac arrest).

During cardiac arrest, the brain cannot get enough oxygen. The brain also starts to swell, and that causes further damage to the brain. This procedure helps the heart and brain to recover by:

• Reducing swelling in the brain.
• Slowing the speed of body processes that create or use energy (metabolism).
• Decreasing the body’s need for oxygen.
• Possibly reducing the amount of substances (inflammatory agents) that circulate in the blood after cardiac arrest. These are substances that the body produces during times of stress and injury. They can cause further damage to vital organs, including the brain, heart, kidneys, liver, and lungs.

The procedure is usually done soon after the heart is restarted and a health care provider can feel a pulse. Cooling (hypothermia) may last for 12–24 hours.

Therapeutic hypothermia is only suitable for a select group of patients. A health care provider will need to discuss this with the child’s caregiver.

Tell a health care provider about:

• Any allergies your child has.
• All medicines your child is taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.
• Any problems your child or family members have had with anesthetic medicines.
• Any surgeries your child has had.
• Any medical conditions your child has.
• Any blood disorders your child has.

What are the risks?

Patients who undergo therapeutic hypothermia are critically ill and require a high level of care and medical intervention. In addition to risks that are related to a child’s medical conditions, a child may face other problems, including:

• Infection.
• Increased bleeding tendency.
• Damage to other structures or organs.
• Irregular heartbeats (arrhythmias).

Problems usually occur when the body temperature is lowered too far below the recommended range.

What happens before the procedure?

• If your child is not breathing and his or her heart is not beating:
  • The heart will be restarted (resuscitated) until there is a pulse. This may be done with CPR or a device that delivers an electric shock to the heart (defibrillator).
  • A breathing tube will be placed in your child’s mouth and down his or her throat to help deliver oxygen to the lungs. A medicine to help your child relax (sedative) will be used before and after the tube is placed.
• Your child may:
  • Be checked for head trauma and other organ injuries.
  • Be connected to various devices that monitor blood oxygen, heart rate, and other vital signs.
  • Have an IV inserted into a vein so he or she can be given fluids and medicines.
  • Be given medicines to help him or her relax (sedatives).

What happens during the procedure?

• Your child’s breathing tube will be connected to a machine (ventilator). The ventilator will help your child to breathe during the procedure.
• Your child’s body temperature will be lowered. This may be done with:
  • Cooling packs.
  • Cooling blankets.
  • Cold IV fluids.
• Your child will be given a sedative to prevent shivering and keep him or her comfortable. Your child may also be given medicines to relax the muscles (muscle relaxants).
• Your child’s temperature, blood pressure, heart rate, breathing rate, and blood oxygen level will be monitored closely.
• Health care providers will work to treat other conditions or injuries if needed.

This procedure may vary among health care providers and hospitals.

What happens after the procedure?

• Your child will slowly be rewarmed to a normal body temperature. This may take 8–12 hours. Rewarming may be done with dry blankets, in a warm room, or by gradually removing cooling devices.
• Your child will be monitored in the hospital’s intensive care unit (ICU).
• Your child’s temperature, blood pressure, heart rate, breathing rate, and blood oxygen level will be monitored closely.
• Your child will use a breathing tube and ventilator until he or she can breathe without help.
• Your child will receive fluids and nutrients through an IV.
• Your child will have more testing.
• Some children wake up very quickly after the treatment, and some wake up more slowly.
• The recovery process varies from person to person. Some children may not recover completely.

Summary

• Therapeutic hypothermia is an emergency procedure that lowers body temperature. This is used to treat a patient whose heartbeat has suddenly stopped (cardiac arrest).
• This procedure may help to reduce swelling in the brain, which can lower the chance of brain damage.
• Therapeutic hypothermia is useful for a select group of patients. Talk with your child’s health care provider about the risks and benefits of the procedure.