Purpose:
1. To provide patient assessment and management guidance to UTSW/BioTel EMS Providers about Accidental Hypothermia
Background and Definition:
Diagnosis and Clinical Features:
Table 1 – Clinical Staging of Accidental Hypothermia† | ||
Stage | Torso + These Signs and Symptoms | Typical Core Temperature |
I | Conscious, shivering | 35 to 32°C (95 to 90°F) |
II | Impaired consciousness, not shivering | Less than 32 to 28°C (Less than 90 to 82°F) |
III | Unconscious, not shivering, vital signs present | Less than 28 to 24°C (Less than 82 to 75°F) |
IV | No vital signs, fixed and dilated pupils | Less than 24°C (Less than 75°F) |
†Adapted from Brown DJA, et al. 2012. NEJM 367:20; 1930-1938.
*Refer to the Table of Secondary Conditions (Table 3) below
Pre-Hospital Patient Care and Transport:
Table 2 – Rewarming Methods for Accidental Hypothermia Pre-Hospital Hospital Passive Active – External Dry Patient Heating Pad, Warm Water Bottles Shelter from wind and wet conditions, insulate from ground Immersion in Warm Bath Move patient to warm environment External Convection Heaters (e.g. Lamps) Blanket or Clothing Insulation Forced Air Warming Blankets (Bair Hugger®) Head Cover Active – Internal (See Appendix) Heat Packs, Warm Water Bottles, if available Catheter, Body Cavity Lavage, Peritoneal Dialysis Shivering: increases heat production, but requires caloric replacement (if possible) Extracorporeal Rewarming (See Appendix) Provide warm, sweet drinks or 40% oral glucose gel to alert patients with normal airway ECMO, Cardiopulmonary Bypass, Hemodialysis
Destination Decision-Making – Consult BioTel or Hospital Capabilities Matrix:
Critical Documentation Items:
Table 3 – Examples of Conditions Associated with Secondary Hypothermia† Impaired Thermoregulation Increased Heat Loss Central Nervous System Disease, e.g. Stroke Multi-System Trauma Central Nervous System Trauma Shock Spinal Cord Transection Burns Extremes of age: Newly Born and Elderly Cardiopulmonary Disease Alcoholic or Diabetic Ketoacidosis Major Infection (bacterial or viral or parasitic) Lactic Acidosis Emergency Childbirth Hypoglycemia Cold IV or IO Infusions Extreme Physical Exertion Heat-Stroke Treatment Malnutrition Disseminated Cancer Hypothyroidism and Other Endocrine Diseases Medication- and Toxin-Induced Skin Diseases Impaired Shivering †Adapted from Brown DJA et al. 2012. NEJM 367:20; 1930-1938.
Summary:
- EMS Providers must screen for accidental hypothermia, even in a relatively warm environment, especially in patients with a wide range of conditions and diseases (Table 3)
- Patient care goals: maintain hemodynamic stability, prevent further heat loss, aggressively resuscitate cardiac arrest and prevent limb loss
- Patients with Stage I hypothermia should be transported to the nearest appropriate facility, unless the Online Medical Control Physician advises otherwise
- Most patients with Stage II and III hypothermia should be transported to a Level I or Level II Trauma Center, or to a hospital capable of internal/invasive rewarming procedures (Consult the Hospital Capabilities Matrix or BioTel for destination assistance)
- For patients with Stage IV hypothermia and cardiac arrest/CPR due to ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT), a single defibrillation attempt should be performed on-scene, followed by rapid transport and rewarming:
- CPR and further defibrillation attempts and epinephrine administration should be performed en route:
- This differs from standard treatment for normothermic VF/pVT cardiac arrest
- There is no proven benefit for the administration of amiodarone, lidocaine or other anti-arrhythmics in hypothermic arrest due to VF/pVT
- Patients with Stage IV hypothermia should NOT be considered dead until rewarming has been performed at the appropriate receiving hospital:
- Pre-hospital CPR should be withheld or termination of resuscitation efforts should be considered ONLY if there are obvious signs of irreversible death, there is a valid OOH-DNR order, or conditions are unsafe for EMS Providers
- Refer to the relevant UTSW/BioTel EMS Treatment Guidelines and Policies, especially the ALTERED LEVEL OF CONSCIOUSNESS, ASYSTOLE/PEA, CARDIAC ARREST, POST-CARDIAC ARREST, TRAUMA and VFIB/pulselessVTACH Treatment Guidelines, and the DESTINATION and DETERMINATION of DEATH Policies
- Consult BioTel at any time with questions or concerns
References and Resources:
- Brown DJA, et al. NEJM 2012; 367(20):1930-1938
- Soar J, et al. Resuscitation 2010; 81:1400-1433
- Vanden Hoek TL, et al. Circulation 2010; 122:Suppl 3:S829-S861
- National Model – EMS Clinical Guidelines (October 2014) (accessed 12/28/2014)
Appendix – Active Internal and Invasive Rewarming Methods (Refer to Table 2):
- Intravascular Temperature Management
- A special central venous catheter warms the patient by heat exchange, as blood passes over special saline-filled balloons on the catheter in a large vein
- Other methods that can be used in special circumstances, if available:
- Hemodialysis
- Venovenous or Venoarterial ECMO (a form of cardiopulmonary bypass)
- Cardiopulmonary Bypass
- Other methods:
- Infusing warm fluids into the peritoneal or thoracic cavity, stomach or bladder