Therapeutic temperature modulation involves cooling the body temperature to a set goal (mostly 32-34C) to improve the outcome of patients who have suffered cardiopulmonary arrest. One of the common adverse effects of this therapy is shivering. This blog summarizes the anti-shivering protocol that is used at the Neurological Institute of New York, Columbia University College of Physicians and Surgeons, as published in 2011.
Table. The Columbia Anti-Shivering Protocol.*Mnemonic: AMBS-DO-DO-Pro-Vec
- Use Bedside Shivering Assessment Scale (BSAS Score) with a goal to achieve no to minimal shivering (BSAS </=1)
- (Step 0) start AMBS, continued throughout entire cooling period
- (Step 1) add opiate or dexmedetomidine if goal not reached
- consider opiates if poorly controlled pain or bradycardic
- consider dexmedetomidine if uncontrolled agitation
- (Step 2) combine dexmedetomidine and opiate
- (Step 3) add deep sedation with propofol (50–75 mcg/kg/min) [*only increases in the initial dose of propofol or high levels of propofol considered as shivering interventions]
- (Step 4) Neuromuscular blockade with boluses of a paralytic – prefer vecuronium (0.15 mg/kg IV bolus)
NSUH Shivering Algorithm
Prior to TTM:
- apply BAIR hugger surface warmer at max temperature of 42C
- Buspirone 30mg PO /NGT q8h
- Acetaminophen 650mg PR/PO/NGT q4h standing
Start TTM – hourly BSAS
Step 1 (if BSAS >1):
- Dexmedetomidine 0.3 ug/Kg/hr, titrate by 1.5 ug/Kg/hr
- Magnesium sulfate 4g IV bolus then 1g/hr to reach serum Mg 3.0-4.0
- Serum Mg levels q8h
Step 2 (if BSAS >1):
- Add propofol at 20 ug/Kg/min, titrate to max 50 ug/Kg/min
Step 3 (if BSAS >1):
- Fentanyl 50-150 ug bolus, then 75 ug/hr
Step 4 (if BSAS >1):
- d/c TTM or add cisatracurium drip or intermittent vecuronium boluses
Table. The Bedside Shivering Assessment Scale:
- 0 = no shivering (neither visually nor with palpation of thorax)
- 1 = MILD (localized to neck and/or thorax only)
- 2= MODERATE (intermittent involvement of UE/LE or continuous involvement of UE)
- 3 = SEVERE (intermittent or continous total body involvement including UE and/or LE and thorax)
A study showed:
- 18% of patients required only step 0 interventions
- 29% received 1 agent
- 35% received 2 agents
- 15% received 3 agents
- 2.4 received 4 agents
Factors in predicting number of anti-shivering interventions used:
Young men with lower BSA scores were more likely to require more interventions for shivering (due to greater muscle mass.)
Also, lower GCS = decreased ability to modulate core body temperature, so shivering response is dampened.
Mechanisms of Action:
- Counterwarming. Mean skin temperature ~20% input to hypothalamus about body temperature
- Acetaminophen – inhibits cyclooxygenase-mediated prostaglandin synthesis to lower the hypothalamic set point
- Buspirone – acts on 5-HT1A receptor to lower the shivering threshold
- Magnesium sulfate infusion (shown to increase comfort and decrease time to goal temperature) – cause peripheral vasodilation
- Dexmeditomidine – central alpha-2 receptor agonist with anti-shivering properties on vasoconstriction and shivering thresholds
- side effect: bradycardia, hypotension
- advantage: lack of respiratory depression
- Opiates – μ- and κ-opioid receptor agonists impair thermoregulatory control
- Meperidine – affect alpha 2B adrenoceptor subtype, lowers seizure threshold
- Fentanyl – less selective anti-shivering properties, primary mechanism of shiver due to sedative impact on brain-injured patients
- Propofol – mildly reduces vasoconstriction and shivering thresholds
- Side effects: hypotension, negative cardiac ionotropy, sedation, and propofol infusion syndrome
- Side effects: loss of neurologic exam, weakness associated with critical illness
- needs adequate sedation
- advantage: quickest method of ceasing the shivering response
Other Interventions to Decrease Shivering
- Dantrolene – decrease shivering by peripheral actions on muscle by reducing gain
- Ketamine and Ondansetron – lowers shivering threshold
Meperidine: Postoperative shivering (off-label use): IV: 25 to 50 mg once (limit to ≤48 hours, doses should not exceed 600 mg/24 hours)
Vecuronium: Control of refractory shivering in adequately sedated patients during therapeutic hypothermia after cardiac arrest (off-label use): IV: 8-12 mg; redose as needed to control shivering. Note: Duration of action prolonged in hypothermic patients. May mask seizure activity.
Another Anti-Shiver algorithm:
*PT = per NG tube.
 Choi, H. Alex et al. ‘Prevention Of Shivering During Therapeutic Temperature Modulation: The Columbia Anti-Shivering Protocol’. Neurocritical Care 14.3 (2011): 389-394.
 Presciutti, M., M. K. Bader, and M. Hepburn. ‘Shivering Management During Therapeutic Temperature Modulation: Nurses’ Perspective’. Critical Care Nurse 32.1 (2012): 33-42. Web.
 Uptodate.com, ‘Vecuronium’ and ‘Meperidine,’ accessed 12/06/2015.
 NSUH Shivering Protocol.
 Kuroda, Yasuhiro. “Neurocritical Care Update”. Journal of Intensive Care 4.1 (2016): n. pag.