Paediatric Intensive Care Unit ( PICU ) Cooling Guideline - LGI

Publication: 31/03/2016  --
Last review: 04/04/2019  
Next review: 04/04/2022  
Clinical Guideline
ID: 4569 
Approved By: Trust Clinical Guidelines Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2019  


This Clinical Guideline is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

LGI PICU Cooling Guideline

  1. Why do we cool patients?
  2. What does the current literature say about cooling? - THAPCA trail results
  3. Which patients SHOULD be considered for cooling?
  4. Which patients SHOULD NOT be cooled (exclusion criteria)?
  5. What temperature should the patient be cooled to and for how long?
  6. When should the patient be cooled?
  7. How should the patient be cooled?
  8. What parameters should be monitored during cooling?
  9. What are the adverse effects of cooling?
  10. What about Re- warming?
  11. Flow chart
  12. References

Why do we cool patients?

  • Two neonatal and one paediatric trial as well as some adult clinical trials have shown improved outcomes in patients who have been cooled following hypoxic-ischaemic or cardiac (ventricular fibrillation) arrest events2,3,5,6
  • There is also historic evidence from cold water drowning and deep hypothermic circulatory arrest used in cardiac surgery, demonstrating neurologically intact survival in spite of prolonged periods of cardiac arrest
  • Current resuscitation guidelines recommend cooling following cardiac arrest in children
  • Cooling reduces metabolic demand and oxygen consumption and preserves organ function
  • Cooling also has other uses, for example: treating Low Cardiac Output State (LCOS) and Junctional Ectopic Tachycardia(JET) and Hyper-pyrexia

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What does the current literature say about cooling?

  • There is equipoise in the literature regarding the benefits of cooling post cardiac arrest as the more recent clinical trials in adults have demonstrated longer hospital stays without improvement in outcome2
  • The evidence from neonatal hypoxic ischaemic encephalopathy trials demonstrate improved survival and neurological outcome with cooling3
  • The THAPCA (Therapeutic Hypothermia after Out-of-Hospital Cardiac Arrest in Children) trial which was published in May 2015 showed no significant difference in the outcomes of children treated with therapeutic hypothermia following cardiac arrest compared to normothermia1.
  • (
  • THAPCA Results:
    A total of 295 patients underwent randomization. Among the 260 patients with data that could be evaluated and who had a Vineland Adaptive Behavior Scales, second edition (VABS-II) score of at least 70 before cardiac arrest, there was no significant difference in the primary outcome between the hypothermia group and the normothermia group (20% vs. 12%; relative likelihood, 1.54; 95% confidence interval [CI], 0.86 to 2.76; P=0.14). Among all the patients with data that could be evaluated, the change in the VABS-II score from baseline to 12 months was not significantly different (P=0.13) and 1-year survival was similar (38% in the hypothermia group vs. 29% in the normothermia group; relative likelihood, 1.29; 95% CI, 0.93 to 1.79; P=0.13). The groups had similar incidences of infection and serious arrhythmias, as well as similar use of blood products and 28-day mortality.
  • There are however a number of considerations regarding the trial:
    • The trial population was a small sample size
    • Both groups were cooled ie. the study group was cooled to hypothermia and the control group was cooled to normothermia.
    • The confidence intervals are wide
    • The raw data shows a trend towards improved survival and neurological outcome in the hypothermia group
    • There are on-going clinical trials which will inform future practice

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Which patients SHOULD be considered for cooling?

  • Paediatric patients up to the age of 16 Years who have suffered a cardiac arrest of longer than 5 minutes duration and remain unconscious post resuscitation 
  • Patients who are being resuscitated on to extracorporeal support (ECMO) 
  • Post-arrest patients who do not meet the exclusion criteria
  • Cardiac patients at risk of or with Low Cardiac Output State (LCOS) and Junctional ectopic tachycardia (JET)
  • Patients in Low Cardiac Output State and needing more than one inotrope
  • Patients with refractory tachyarrythmias
  • Patients who have persistent pyrexia of 39 degrees or more with associated haemodynamic or metabolic instability - cool to 38 degrees
  • Head injury patients with persistent temperature of over 38 degrees (these patients should be cooled to a minimum of 37.0 degrees)

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Which patients SHOULD NOT be considered for cooling?

  • Post-arrest patients who are deemed by the on-duty Intensivist to be irrecoverable (cooling does not stop the patient from dying but may delay death)
  • Patients who have active major haemorrhage
  • Head injury patients who are NOT pyrexial unless they are being cooled for refractory high Intracranial Pressure (ICP) when other measures have failed
  • Septic patients, unless there is hyperpyrexia associated with haemodynamic instability

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What temperature should the patient be cooled to and for how long?

  • Post arrest patients should be cooled to 35 degrees for 48 hours (Range: 34.5-35.5 degrees)
  • Cardiac patients should be cooled to 35 degrees for 12 hours unless otherwise specified by the on duty Consultant Intensivist (Range 34.5-35.5 degrees)
  • Head injury patients should only be cooled at Consultant request only and should be cooled to 37 degrees for 24 hours (Range 36.5-37.5 degrees)
  • Septic patients should only be cooled at Consultant request only and they should be cooled to 38 degrees for 24 hours (Range 37.5-38.5 degrees)

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When should the patient be cooled?

  • Post-arrest patients should be cooled as soon as possible after the event, if there are no cooling facilities available, the patient should not be actively re-warmed
  • Cardiac (e.g post cardiac surgery), Septic and Neuro (e.g head injury / refractory status epilepticus) patients should be cooled at the discretion of the on duty Intensivist
  • Patients who are being resuscitated onto ECMO (Extra Corporeal Membrane Oxygenation) should be rapidly cooled during cannulation (use ice packs on and around the head and intravenous cold sodium chloride 0.9% to achieve this)

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How should the patient be cooled?

  • There are 3 phases of cooling: Induction, Maintenance and Re-warming
  • The Re-warming phase is the MOST RISKY time for the patient
  • Once a decision to cool a patient has been made, the patient should be cooled as rapidly as possible to the desired temperature (35 degrees post arrest and for cardiac patients - see flow diagram)
  • Ensure the patient is adequately sedated before cooling commences
  • Commence paralysis once the temperature drops below 36 degrees to prevent shivering
  • Patients should be cooled with a cooling blanket or appropriate cooling system
  • If a cooling blanket is not available, the patient can be cooled in the first instance with cool packs and the polar air blanket
  • If cooling is not adequate, then 5-10ml/kg of cold (refrigerated) intravenous sodium chloride 0.9% can be given over 15-30 minutes to achieve the desired temperature
  • Gastric and bladder washouts with cold sodium chloride 0.9% infusion fluid can only be used under the supervision of the on-duty Intensivist (this is unlicensed use of sodium chloride 0.9% infusion fluid)
  • In rare instances Continuous Veno-Venous Hemofilatration Dialysis (CVVHD) can be used to cool patients when other strategies have failed but the benefits must outweigh the risks

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What parameters should be monitored during cooling?

  • Core temperature must be monitored using an appropriately placed oesophageal probe (mid-oesophageal)
  • Peripheral temperature should be continuously monitored
  • Usual monitoring of vital signs - blood pressure should be monitored via an arterial line
  • 4-6 hourly blood gases + 12 hourly central venous gas to assess the central venous oxygen saturations  (can be done instead of an arterial gas)


  • Usual PICU blood tests according to clinical status (see blood testing on PICU Guide)
  • Daily blood cultures for patients cooled longer than 48 hours
  • Peripheral perfusion ie. 6 hourly skin colour and integrity check
  • 12-lead ECG if the pulse rate drops below 100 beats per minute in a neonate; 80 beats per minute in an older child or 60 beats per minute in a teenager

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What are the potential adverse effects of Cooling?

  • Shivering which results in an increase in metabolic demand
  • Bradycardia/ arrhythmias
  • Immunosuppression with increased infection risk
  • Mild coagulopathy (mild platelet dysfunction and delay in thrombus formation - only relevant in bleeding patients and those cooled below 35 degrees)7
  • Electrolyte disturbances
  • Insulin resistance
  • Impaired drug clearance
  • Cold diuresis and hypovolaemia

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What about Re-warming?

  • Re-warming is the MOST RISKY TIME for the patient and should be strictly controlled
  • Rapid re-warming is associated with haemodynamic instability and adverse neurological outcomes
  • Patients should not be actively re-warmed in the first instance, the cooling strategies should be reduced to allow for a gradual rise in core temperature
  • Patients should be re-warmed at a rate of NO MORE THAN 0.5 degrees every 2 hours to a temperature between 36 and 37 degrees (normothermia)
  • Once normothermia is achieved, it should be maintained.
  • The patient should not be allowed to overshoot and become pyrexial for atleast 12 hours after achieving normothermia
  • If the temperature rises above 37 degrees or is rising faster than 0.5 degrees every 2 hours, cooling strategies should be re-implemented to bring the temperature back in to the target range

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Flow Diagram


Record: 4569
Clinical condition:

Cooling following cardiac arrest

Target patient group: Paediatric patients less than 16 years of age
Target professional group(s): Secondary Care Doctors
Secondary Care Nurses
Adapted from:

Evidence base


  1. Moler FW, Silverstein FS, Holubkov R, et al Therapeutic Hypothermia after Out-of-Hospital Cardiac Arrest in Children. N Engl J Med. 2015 May 14;372(20):1898-908. doi: 10.1056/NEJMoa1411480. Epub 2015 Apr 25.
  2.  Nielsen N, Wetterslev J, Cronberg T, et al Targeted temperature management at 33 degrees Celsius versus 36 degrees Celsius after cardiac arrest N Engl J Med. 2013 Dec 5;369(23):2197-206. doi: 10.1056/NEJMoa1310519. Epub 2013 Nov 17.
  3. Azzopardi DV, Strohm B, Edwards AD, et al  Moderate Hypothermia to Treat Perinatal Asphyxial Encephalopathy . N Engl J Med. 2009 Oct 1;361(14):1349-58. doi: 10.1056/NEJMoa0900854.
  4. Adelson PD Hypothermia following Pediatric Traumatic Brain Injury J Neurotrauma. 2009 Mar;26(3):429-36. doi: 10.1089/neu.2008.0571.
  5. Bernard SA1, Gray TW, Buist MD, Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia N Engl J Med. 2002 Feb 21;346(8):557-63.
  6. Hypothermia after Cardiac Arrest Study Group. Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest. N Engl J Med. 2002 Feb 21;346(8):549-56.
  7. Polderman KH, Hypothermia and coagulation. Crit Care 2012;16(Suppl 2):A20

Approved By

Trust Clinical Guidelines Group

Document history

LHP version 1.0

Related information

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