Notes – Hypothermia/Cold Exposure

Hypothermia/Cold Exposure

Patient Safety Considerations

  1. Given the additive effects of additional cold stress, the patient should be removed from the cold environment as soon as operationally feasible
  2. In patients suffering from moderate to severe hypothermia, it is critical to not allow these patients to stand or exercise as this may cause circulatory collapse
  3. Devices that self-generate heat (e.g. heat packs) that are being utilized during the rewarming process should be wrapped in a barrier to avoid direct contact with the skin and to prevent burns. Available evidence suggests that heat packs with peak temperatures above 45°C (113°F) are most likely to cause burns. In patients who are unresponsive, or unable to recognize a developing injury, please check the area in which the heating pad is placed regularly to ensure no tissue damage occurs.

Notes/Educational Pearls

Key Considerations

Considerations in cardiac arrest

  1. The following are contraindications for initiation of resuscitation in the hypothermic patient:
    1. Obvious fatal injuries (such as decapitation)
    2. The patient exhibits signs of being frozen (such as ice formation in the airway)
    3. Chest wall rigidity such that compressions are impossible
    4. Danger to rescuers or rescuer exhaustion
    5. Avalanche victims buried for 35 minutes or longer with airway obstruction by ice or snow
  2. Fixed and dilated pupils, apparent rigor mortis, and dependent lividity may not be contraindication for resuscitation in the severely hypothermic patient
  3. The mainstay of therapy in severe hypothermia and cardiac arrest should be effective chest compressions and attempts at rewarming
    1. Chest compressions should be provided at the same rate as in normothermic patients
  4. The temperature at which defibrillation should first be attempted in the severely hypothermic cardiac arrest victim and the number of defibrillation attempts is unclear. There are different approaches regarding resuscitation of the hypothermic arrest patient.
    1. Per the American Heart Association (AHA), if the patient has a shockable rhythm (VF/VT), defibrillation should be attempted – It is reasonable to continue defibrillation attempts per AHA protocols concurrently with rewarming strategies
    2. If defibrillation is unsuccessful and the patient’s core temperature is greater than 30°C (86°F), follow guidelines for normothermic patients
    3. If available monitors reveal asystole, CPR alone is the mainstay of therapy
    4. If monitoring reveals an organized rhythm (other than VF or VT) and no pulses are detected, do not start CPR, but continue to monitor
      1. While this may represent pulseless electrical activity (PEA), this may also represent situations in which the patient’s pulses are not detectable but remain effective due to decreased metabolic needs
      2. In the case of PEA, the rhythm will deteriorate rapidly to asystole, in which case, CPR should be initiated
      3. Given the potential to cause VF with chest compressions, the Alaska guidance offers that it is better to maintain effective cardiac activity than to start CPR and cause VF
  5. Manage the airway per standard care in cardiac arrest victims [see Cardiac Arrest guideline]
    1. In the absence of advanced airways, ventilate the patient at the same rate as a normothermic patient
    2. If the patient has an advanced airway, ventilate at half the rate recommended for a normothermic patient to prevent hyperventilation. If ETCO2 is available, ventilate to maintain normal ETCO2 levels
  6. Upon ROSC, treat per Adult Post-ROSC guideline
  7. Patients with severe hypothermia and arrest may benefit from resuscitation even after prolonged downtime, and survival with intact neurologic function has been observed even after prolonged resuscitation
    1. Patients should not be considered deceased until rewarming has been attempted
  8. If a hypothermic patient clearly suffered cardiac arrest and subsequently became hypothermic afterward with prolonged down time between arrest and rescue, there is no rationale for initiating resuscitation and warming the patient

Pertinent Assessment Findings

  1. Identification of associated traumatic injuries (when present)
  2. Identification of localized freezing injuries
  3. Patient core temperature (when available)

Quality Improvement

Associated NEMSIS Protocol(s) (eProtocol.01)

  • 9914023 – Environmental-Cold Exposure
  • 9914031 – Environmental-Hypothermia
  • 9914025 – Environmental-Frostbite/Cold Injury

Key Documentation Elements

  • Duration of cold exposure
  • Ambient temperature and recent range of temperatures
  • Rewarming attempts or other therapies performed prior to EMS arrival
  • Patient use of alcohol/drugs

Performance Measures

  • Patient core temperature and means of measurement (when available)
  • Presence of cardiac dysrhythmias
  • Documentation of associated trauma (when present)
  • Blood glucose level obtained
  • EMS Compass® Measures (for additional information, see http://www.emscompass.org)
    • Hypoglycemia-01: Treatment administered for hypoglycemia. Measure of patients who received treatment to correct their hypoglycemia
    • Trauma-01: Pain assessment of injured patients. Recognizing that pain is undertreated in injured patients, it is important to assess whether a patient is experiencing pain
    • Trauma-02: Pain re-assessment of injured patients. Recognizing that pain is undertreated in injured patients, it is important to assess whether a patient is experiencing pain

References

  1. Alaska Emergency Medical Services. State of Alaska Cold Injury Guidelines – 2014. Anchorage, AK: Department of Health and Social Services, Division of Public Health; July 15, 2014 (early release version, provided by Dr. Ken Zafren).
  2. Brown DJ, Brugger H, Boyd J, Paal P. Accidental Hypothermia. NEJM. 2012;367(2):1930-8.
  3. Bureau of Emergency Medical Services. State of New Hampshire Patient Care Protocols: Hypothermia adult & pediatric. Concord, NH: New Hampshire Department of Safety. http://www.nh.gov/safety/divisions/fstems/ems/advlifesup/documents/ptprotocols.pdf. Effective 2013. Accessed June 11, 2013.
  4. Danzl DF. Accidental Hypothermia. In Auerbach PS, ed. Wilderness Medicine, 6th Edition. Philadelphia, PA: Elsevier; 2012:116-142.
  5. Freer L, Imray CHE. Frostbite. In Auerbach PS, ed. Wilderness Medicine, 6th Edition. Philadelphia, PA: Elsevier; 2012:181-201.
  6. Jackson Hole Fire/EMS. Operations Manual: Hypothermia/frostbite. Jackson Hole, WY: Teton County. http://www.tetonwyo.org/fire/docs/Policies/Div17-EMSOperations/Article4-TreatmentProtocols/174.25HypothermiaFrostbite.pdf. Effective September 2011. Accessed March 15, 2014.
  7. Massachusetts Office of EMS. EMS Statewide Treatment Protocols: Hypothermia/cold emergencies. Boston, MA: Massachusetts Department of Public Health. http://www.mass.gov/eohhs/provider/guidelines-resources/clinical-treatment/public-health-oems-treatment-protocols.html. Effective March 1, 2012. Accessed June 11, 2013.
  8. Maine EMS. Maine EMS Prehospital Treatment Protocols: Hypothermia. Augusta, ME: Maine Department of Public Safety. http://www.maine.gov/ems/documents/2013_Maine_EMS_Protocols.pdf. Effective December 1, 2011. Accessed June 11, 2013.
  9. McIntosh SE, Hamonko M, Freer L, et al. Wilderness Medical Society guidelines for the prevention and treatment of frostbite. Wilderness Environ Med. 2011;22(2):156-66.
  10. McIntosh SE, Opacic M, Freer L, et al. Wilderness Medical Society practice guidelines for the prevention and treatment of frostbite: 2014 update. Wilderness Environ Med. 2014;25(4):S43-54.
  11. Pennsylvania Bureau of Emergency Medical Services. Pennsylvania Statewide Advanced Life Support Protocols: Hypothermia/cold injury/frostbite. Harrisburg, PA: Pennsylvania Department of Health. http://www.portal.state.pa.us/portal/server.pt/community/emergency_medical_services/14138/ems_statewide_protocols/625966. Effective July 1, 2001. Accessed June 11, 2013.
  12. Rhode Island Center for Emergency Medical Services. Rhode Island Statewide Emergency Medical Services Protocols: Cold exposure – frostbite. Providence, RI: Rhode Island Department of Health. http://www.health.ri.gov/publications/protocols/EMSProtocols_Aug2011_RevisedOnly.pdf. Effective October 1, 2010. Accessed June 11, 2013.
  13. Venden Hoek et al. Part 12: cardiac arrest in special situations. 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2010;122;(18 Suppl 3):S829-61.
  14. Zafren K, Giesbrecht GG, Danzl DF, et al. Wilderness Medical Society practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia: 2014 update. Wilderness Environ Med. 2014;25(4 Suppl):S66-85.