Therapeutic Hypothermia Management

Introduction to Therapeutic Hypothermia

The American Heart Association recommends achieving therapeutic hypothermia through a three-phase process (induction, maintenance, and rewarming) using multiple cooling modalities combined with sedation and neuromuscular blockade to prevent shivering, with continuous core temperature monitoring to maintain target temperatures of 32°C to 34°C 1

Servo-controlled cooling blankets positioned under or above the patient provide the primary method for surface cooling 1
Ice packs applied to the groin, axillae, and neck offer simple but slower cooling 2, 3
Cold-water baths or wet towels combined with fanning can reduce core temperature 2
Lowering room temperature serves as an adjunctive measure 1
Cooling helmets represent another external option, though less commonly used 2
Cold crystalloid infusion at 4°C administered as 30 mL/kg over 30 minutes significantly reduces core temperature without causing pulmonary edema 2, 3
Continuous infusions are relatively safe for lowering temperature 1
Avoid intravenous push administration of cold saline due to risk of profound bradycardia 1
Intravascular heat exchange devices enable rapid cooling and precise temperature control but are too invasive for prehospital or emergency department use 2, 3
Endovascular cooling catheters are not used in pediatrics due to large diameter and thrombosis risk, though may be considered for older children 1

Continuous core temperature monitoring is mandatory during therapeutic hypothermia 1, 2
Bladder temperature probe is reliable for continuous monitoring 2, 4
Esophageal temperature probe is accurate core measurement 1
Rectal temperature probe is reliable core measurement 1
Pulmonary artery catheter can be used if already in situ 2, 4
Tympanic temperature measurements are less reliable, especially when intermittent 2

Target temperature should be achieved as quickly as possible, though optimal interval remains unknown 1
Cooling should be initiated as soon as possible after ROSC but appears successful even if delayed 4-6 hours 2, 3, 4
Maintain target temperature of 32°C-34°C for 12-24 hours in adults 2, 6
In pediatrics, maintain for 120 hours (5 days) based on THAPCA trials 1, 7
For normothermia/fever prevention, maintain temperature ≤37.5°C using pharmacological measures, uncovering the patient, lowering ambient temperature, and cooling devices if temperature exceeds 37.7°C 5

Shivering must be prevented as it leads to warming and increases oxygen consumption 2, 3, 4
Neuromuscular blockers combined with sedation represent the standard approach used in definitive trials 2, 4

Hypokalemia, hypophosphatemia, hypomagnesemia, and hypocalcemia develop during hypothermia and may precipitate arrhythmias 1
Close monitoring and treatment of electrolyte imbalances are required, especially during induction 1
Hypothermia decreases insulin sensitivity, placing patients at risk for hyperglycemia 1
Bradycardia and hypotension have been observed during hypothermia 1

Do not allow core temperature to fall considerably below 32°C as complications (arrhythmias, infection, coagulopathy) increase significantly 2, 4
Do not use rapid IV push of cold saline due to bradycardia risk 1
Do not use endovascular catheters in young children due to thrombosis risk 1
Do not allow rapid rewarming as rebound hyperthermia worsens outcomes 2, 3, 4
Thrombocytopenia occurs but has not been associated with increased bleeding or blood product requirements 1
Infection rates were not different in recent THAPCA trials despite theoretical immune system alterations 1
Coagulopathy risk increases with deeper hypothermia below 32°C 2, 4