Central Maine Medical Center
CRITICAL CARE
Critical Care Guideline No. 4
SUBJECT: Therapeutic Hypothermia after Cardiac Arrest Guideline
Guideline Statement:
In studies of out-of-hospital cardiac arrest, induced therapeutic hypothermia protocols have contributed to
improved neurological outcomes. Studies have shown that lowering brain temperature, even by a few
degrees, decreases ischemic damage.
Goals: To improve outcomes in patients with coma following resuscitation from out-ofhospital or in-hospital cardiac arrest. Patient is cooled for 24 hours at a temperature of 33
degrees Celsius. The target time to reach the goal is as soon as possible or within 6 hours from
the cardiac arrest which resulted in coma. The 24 hour time period is from the time of initiation
of cooling, not from the time the target temperature is reached.
Location: ICU/SSU/ED
Indications:
No more than 8 hours have elapsed since the return of spontaneous circulation (ROSC).
Encephalopathy is present, (typically defined as the patient being unable to follow
verbal commands).
There is no life threatening infection or bleeding.
Aggressive care is warranted and desired by the patient or family/next of kin.
Equipment:
1. Temperature Sensing Foley catheter
2. Artic Sun Cooling System
3. Appropriate size Artic Sun cooling pads
4. Arterial line (recommended)
5. Central Line
6. BIS monitoring set up
Procedure:
PreInduction Phase
Protocol: (goal temperature 33°C to be achieved as soon as possible or a target time to reach
the goal is as soon as possible or within 6 hours from the cardiac arrest which resulted in coma)
1. Notify Critical Care Provider as soon as possible
2. If cooling efforts started pre-hospital – continue until Critical Care Provider arrives.
3. Temperature sensing Foley catheter should be placed.
4. Patient should already be intubated, have 2 peripheral IV’s, and consider a central
line and an arterial line.
5. Vital signs including temperatures: every 15 minutes X 4 during initiation of
hypothermia and at the start of rewarming, then every hour and prn when patient
condition warrants.
6. Skin integrity checks every 1-2 hours.
7. Apply BIS (BiSpectral Index) monitor. Once cooling procedure initiated, titrate
sedation medications to maintain a BIS below 50.
8. Perform bedside shivering assessment every hour from the initiation of hypothermia
until return to normothermia (temp greater or equal to 36-37° C) is achieved (See
scale as attachment A ).
9. Lacrilube ointment to both eyes every 4 hours and PRN eye dryness/lack of blink
while on NMB
10. Labs on admission: Blood Culture x2, Sputum Culture and Urine Culture
NOTE: If patients baseline temperature is less than 33°C at initiation of ARCTIC
SUN, allow for passive re-warming up to 33°C before starting the ARCTIC SUN
device.
Medications:
11. Bedside Shivering Assessment Scale (BSAS)- see Attachment A (every hour until
the return of normothermia achieved).
a. BSAS
i. If BSAS remains greater than 1 initiate Propofol per orders
ii. If BSAS remains greater than 1 on Propofol add Fentanyl per orders
iii. If BSAS remains greater than 1 on Propofol and Fentanyl add
Vecuronium per orders
iv. Increase sedative and/or analgesia dose prior to increasing Vecuronium
per orders.
b. Obtain baseline Train of four (TOF) prior to any NMB and every hour if patient
is on a NMB infusion. TOF monitoring during hypothermia is challenging due
to peripheral vasoconstriction and slowing of peripheral nerve conduction
c. Avoid use of continuous infusion NMB if possible
d. Shivering Interventions as ordered as ordered
12. Sedation: Initiate prior to starting hypothermia and neuromuscular blocking agent.
Propofol (Diprivan) infusion (1000mg in 100ml ) as ordered
Start infusion at 5mcg/kg/minute. Titrate to a RASS -1 to -2 and BIS Goal
below 50
Continuous Infusion: max rate of 50 mcg/kg/min - automatic stop after 48 hours
Titrate Method: Frequency of rate change by 5mcg/kg/minute every 20 minutes
OR
Versed(Midazolam) infusion(100mg/100 ml) as ordered
Start infusion at 2mg/hr. Titrate to a RASS -1 to -2
Continuous Infusion: max rate of 6mg/min
Titration Method: Frequency of rate change by 1mg/hr every 20 minutes.
13.
Analgesia: Initiate prior to starting hypothermia & neuromuscular blocking agent.
Fentanyl infusion 2.5 mg (2500 mcg) in 125 ml Normal Saline
Bolus dose: 25 mcg IV over 1-2 minutes (suggested 1-2 mcg/kg prior to each
increase in rate)
Continuous Infusion: 20-200 mcg/hr. Titrate to a pain score of 1-2 or RASS 0 to
-1.
Titration method: Frequency of rate change by 25 mcg/hr every 20 minutes
14. Neuromuscular Blockade: as ordered -avoid use of continuous infusion NMB if possible –
Based on Bedside Shivering Scale – see Attachment A.
Vecuronium bolus dose: 0.08 to 0.1 mg/kg intermittent bolus every 30 minutes to 1 hour
or
Vecuronium drip 100 mg per 100 ml D5W - 0.8-1.7 mcg/kg/min
Initial bolus: 0.08-0.1 mg/kg IV over 1-2 minutes.
Continuous Infusion: max rate 1.7 mcg/kg.min. Titrate to a BSAS(shivering
score) as noted above and Train of Four (TOF) 2/4 (level of paralysis)
Titration Method: Frequency of rate change 0.3 mcg/kg/min every 4 hours.
Cooling Phase
15. Goal is to cool the patient to 33°C ASAP or within 6 hours.
16. Measure and record BSAS score q1 hour during induction, cooling and
rewarming phases.
Cooling Methods:
17. Artic Sun Cooling System- see Attachment C
Choose correct pad size based on chart, evaluate and document skin integrity and
condition before pad placement and every one to two hours after placement for
changes in skin integrity and condition. Set up:
a. Turn machine on, connect pads and temperature probe.
b. While in “Stop” Press the down arrow once to reach “Set Target
Temperature
c. Auto Mode”. Check to see if target is set to desired temp. (If not follow
instructions on the machine).
d. Press Automatic Mode and begin cooling.
May use Artic Sun simultaneously with Rapid Infusion cooling method listed below to
cool faster or use as a single method:
18. Rapid infusion of ice cold 4°C Lactated Ringers or Normal Saline. Give 30 ml/kg
IV x 1 dose over 30 minutes via a peripheral line or femoral venous catheter (safety
of jugular or subclavian route not established). If already given prehospital and
patients temp still ≥ 35°C, may repeat.
Or
19. Apply ice packs to patient’s neck, axilla, and femoral groins after patient is sedated
and place patient on 2 cooling blankets. (blankets should be placed above and
below the patient with sheet between patient & blanket) and set to 33°C .
a. When patient reaches 32-34°C, set blanket to 33°C and remove ice packs.
b. Remove cooling blanket if patient temp drops below 32°C until temperature
returns to 33°C.
c. Notify provider if target temperature not achieved within 4 hours.
d. After 24 hr. of hypothermia at 32-34°C, remove blankets & allow passive
rewarming to 36-37°C.
Re-warmingPhase
The re-warming phase may be the most critical, as peripheral beds, which were once constricted, start
to dilate. This shift sometimes causes hypotension. The literature recommends that the body be re-
warmed at a temperature of 0.25-.33°C every hour. It will take the patient about 12 hours to passively
re-warm. The goal of re-warming is normothermia, avoid hyperthermia. If using Artic Sun
system – see Attachment C do not take pads off to rewarm, the system is designed to rewarm with
pads in place.
Rewarming:
20. Begin re-warming 24 hours after the beginning of cooling (not 24 hours after target
temperature is reached): Paralysis, then sedation, to be discontinued during or after
re-warming, based on shivering and other critical patient issues.
21. Discontinue neuromuscular blocking agent when temp is 36°C.
22. Wean Propofol rapidly when temp is 36°C and observe for seizure activity and report
any to provider.
23. Artic Sun System:
a. Place device in Stop Mode and press the down arrow once.
b. Press Enter to change value and hold the UP arrow until the re warming
target temp is displayed.
c. Press Enter to save value.
d. Maintain Normothermia with pads in place for 24 hours.
24. Alternatives rewarming methods:
a. Turn room thermostat up to normal
b. Turn on heater on ventilator
c. Turn off cooling blanket
d. May use regular blankets
e. Do not use warm air blanket unless temp not 36°C after twelve hours of
passive re-warming.
25. Tests:
a. 12 lead ECG – STEMI to Cath Lab
b. Blood glucose q2 hours while patient is hypothermic. Notify the provider if
blood sugar is less than 60 or greater than 300. Insulin protocol as ordered
c. BMP, magnesium, ionized calcium q 6 hours while hypothermic.
d. CBC/Hemogram, PTT/INR, ABG daily while hypothermic
26. DVT/VTE prophylaxis per protocol
27. IV Adult Electrolyte Protocol:
28. Stop all potassium administration 8 hours prior to re-warming.
29. GI prophylaxis Protocol
NOTE: Provider should consider empiric antibiotics on a case by case basis (see order set).
References
1. Executive Summary: 2010 American Heart Association Guidelines for Cardiopulmonary
Resuscitation and Emergency Cardiovascular Care.
2. Seder, D and Jarrah, S, Therapeutic Hypothermia for Cardiac Arrest: A Practical Approach.
Critical Care Neurology. 2008 Pages 509-517
3. Chamorro C, et.al. Anesthesia & Analgesia Protocol during therapeutic hypothermia
after cardiac arrest: A systematic Review. Anesth Analg 2010; 110:1328-35.
4. CMMC Clinical Policy: Titration Medication Orders. 2011
New:
12/07
Revised 6/2011- MP
Attachment A:
Bedside Shivering Scale
0: None: no shivering noted on palpation of the masseter, neck or chest wall
1: Mild: shivering localized to the neck and/or thorax only
2: Moderate: shivering involves gross movement of the upper extremities (in
addition to neck & thorax)
3: Severe: shivering involves gross movements of the trunk and upper extremities
Badjatia N, et.al. Metabolic Impact of Shivering During Therapeutic Temperature Modulation: The Bedside
Shivering Assessment Scale. Stroke2008. 39:3242-3247.
Attachment B: Therapeutic
Hypothermia Algorithm
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Determine
Eligibility
If cooling efforts started pre-hospital continuing till Critical Care
Provider arrives
Notify Critical Care Provider ASAP
Initiation of hypothermia within 8 hours of arrest
Goal: Temperature 33 degrees C - ASAP and within 6 hours
Induction Phase/Patient needs:
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Place a Temp sensing Foley placed –connected to monitor
2 peripheral IV’s and an A-line
Central Line placed
Sedation & analgesia per orders
Neuromuscular Blockade per orders
Dose adjustments for shivering or ventilator asynchrony per orders
Cooling Methods

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Artic Sun System and/or
Cold Fluids given rapidly per protocol –
or
Ice packs and cooling blankets per protocol
Maintenance Phase & Documentation
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Perform Bedside Shivering Assessment every
hour until the return of normothermia achieved.
VS & Temperature documentation: every 15
minutes X4 during initial cooling and then every1
hour.
Discontinue neuromuscular blocking agent when
cooling blankets are removed.
Wean Propofol rapidly when temp is 36°C and
observe for seizures
Alternative Cooling Method parameters: When patient reaches 3234°C, set blanket to 33°C and remove ice
packs.
 Remove cooling blanket if patient temp
drops below 32° C until temperature
returns to 33°C.
 Strict monitoring for no shivering
 DO NOT let patients temp fall below 32
degrees
 Notify Provider if target temp not achieved
within 4 hours
Other: see protocol
Rewarming Phase: GOAL IS NORMOTHERMIA –
avoid hyperthermia
 At a temperature of 0.25-.33°C every hour. It will take the
patient about twelve hours to re-warm.
 The goal of re-warming is normothermia, avoid
hyperthermia.
 Begin re-warming 24 hours after the beginning of cooling
(not 24 hours after target temperature is reached):
 VS and Temp every 15 minutes until temperature reaches
36°C, then every 1 hour
 Maintain Normothermia with pads in place for 24 hours
 If temperature of 36 is not reached within 12 hours, notify
provider and initiate active rewarming process as ordered.
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Glucose every 2 hours
Every 6 hour labs & Daily Labs
DVT/VTE prophylaxis
GI prophylaxis
Electrolyte protocol
Stop all potassium
administration 8 hours prior to
rewarming
Shivering & Seizure
management as needed
Attachment C: Artic Sun instructions: