Hypothermia

Hypothermia is a medical emergency characterized by a core body temperature below the normal range of 95°F (35°C).

Causes of Hypothermia:

1. Increased heat loss

   • Homeless population

   • Elderly patients

   • Submersion injuries

   • Drugs, EtOH, CO poisoning can all cause increased vasodilation, leading to increased heat loss

2. Decreased heat production

   • Endocrine (hypothyroidism, hypoadrenalism, hypoglycemia)

   • Erythrodermas (psoriasis, exfoliative dermatitis, eczema, burns)

   • Impaired shivering

   • Impaired thermoregulation

   • Sepsis

Swiss Hypothermia Staging System:

Stage 1: Mild (32-35°C) - Shivering, mild confusion, awake

Stage 2: Moderate (28-32°C) - Severe shivering, altered mental status

Stage 3: Severe (20-28°C) - Loss of consciousness, bradycardia, shivering may cease

Stage 4: Profound (<20°C) – Unobtainable vital signs

Associated Complications:

1. Cardiac dysfunction

   1. Dysrhythmias can occur when body temperature drops below 30°C

   2. There is typically a drop in temperature and MAP after rewarming is started due to vasoconstriction

2. Cold injuries (frostbite, etc. Maybe there will be more on this at a later date)

3. Coagulopathy (patient may be coagulopathic despite normal labs because the lab rewarms the sample)

   1. Impaired clotting function

   2. Thromboembolism (due to hemoconcentration and poor circulation)

   3. DIC

4. Impaired pharmacology

   1. Protein binding increases when temperature drops, rendering drugs ineffective

   2. Oral meds are not absorbed well due to decreased GI motility

   3. IM route is impaired due to vasoconstriction

5. Rhabdomyolysis

General Management:

1. Airway, Breathing, Circulation (ABCs)

   • Hypothermia causes a leftward shift in oxygen curve so support with oxygen, and prepare for intubation depending on how profound the hypothermia is

2. ECG Findings

   • Patients usually have sinus bradycardia, can progress to a fib with slow ventricular response

   • Severe cases can develop v fib

   • Osborn or "J" waves (associated with moderate to severe hypothermia)
     

3. Remove Wet Clothing - Prevent further heat loss

4. Passive External Rewarming - Insulate the patient, provide warm blankets

5. Active External Rewarming (should be done for moderate hypothermia)

   • Use forced warm air blankets or radiant heaters – our ED uses the Bair Hugger

6. Active Internal Rewarming (for severe hypothermia)

   • Warmed intravenous fluids (warmed to 38-42°C)

• Heated humidified oxygen

• Various lavages (Thoracic, peritoneal, bladder, GI)

Management during Cardiac Arrest:

1. CPR – initiate if patient does not have a pulse (should also assess if patient is still breathing)

   • It is challenging to assess vital signs in hypothermic patients - use end tidal or POCUS to help assist to see if patient is breathing and has cardiac function

   • Starting CPR if the patient does have a pulse may precipitate ventricular rhythms

   • Hypothermic patients have higher chances of improved neurological outcome and survival than normothermic patients that arrest

2. Defibrillation

   • Use defibrillation if indicated, but note that hypothermic patients may not respond to defibrillation until adequately warmed

3. ECMO

   • Patients with refractory hypothermia should be considered for ECMO

   • Patients with out-of-hospital-cardiac-arrest that are hypothermic should ideally be transported to an ECMO center

   • If patient is unstable (dysrhythmia, severe hypothermia, etc) ECMO teams should be contacted early in the ED visit

Stay warm out there this weekend!

Paal P, Pasquier M, Darocha T, Lechner R, Kosinski S, Wallner B, Zafren K, Brugger H. Accidental Hypothermia: 2021 Update. Int J Environ Res Public Health. 2022 Jan 3;19(1):501. doi: 10.3390/ijerph19010501. PMID: 35010760; PMCID: PMC8744717.

Baumgartner EA, Belson M, Rubin C, Patel M. Hypothermia and other cold-related morbidity emergency department visits: United States, 1995-2004. Wilderness Environ Med 2008;19:233-237

Brown et al., Accidental Hypothermia. N Engl J Med 2012; 367:1930-1938

Soft Tissue Foreign Body

General

·      Transient inflammation is an integral part of normal wound healing.

·      Foreign debris in a wound provokes an inflammatory response in an effort to eliminate or contain the invader.

·      Large quantities of devitalized tissue, foreign debris, bacteria, or other irritants present within a wound intensify this protective response.

·      Prolonged or intense inflammatory responses delay wound healing and destroys surrounding tissue and bone.

·      If the body can’t dissolve or dispose of foreign material, it gets encapsulated within a fibrous capsule.

·      Type of foreign body can make a difference in the inflammatory reaction

o   Inert Material (glass, metal, plastic) may have no abnormal tissue response. Some metals may have oxidizing properties that can cause minor inflammation.

o   Vegetative Material (wood, thorns, spines) trigger SEVERE inflammatory reactions.

o   Marine material (sea urchin spines) can cause chronic inflammation with granuloma formation.

·      Infections are the most common complication of retained objects.

o   Typically, they can be resistant to therapies such as antibiotics, anti-inflammatory drugs, and steroids.

o   Some infections will resolve spontaneously once the foreign body is removed.

o   Vegetative foreign bodies may also cause fungal infections, particularly in immunosuppressed patients.

o   Chronic, delayed, and recurrent infections are associated with retained foreign bodies

Physical Exam

·      Make effort to visually inspect all recesses of a wound.

·      Wounds deeper than 5 mm and wounds whose depth cannot be visualized have a higher association with foreign bodies.

·      If punctures and other narrow wounds make direct visualization difficult and there is concern about a foreign body below the surface, the wound margins should be extended with a scalpel.

·      Blind probing with a hemostat is a less effective but sometimes is an acceptable alternative to wound exploration when the wound is narrow and deep and extending the wound is not desirable.

·      A closed hemostat should be introduced into the wound and either used as a probe or spread open and then withdrawn.

·      If an instrument strikes a metallic or glass foreign body, it will produce a grating sensation.

Imaging

·      Beneficial to obtain post removal imaging of multiple foreign bodies to ensure all pieces were found

Localizing Techniques

·      It’s easier to detect the presence of a foreign body than to locate its exact position.

·      If radiopaque, can estimate location and depth by taping radiopaque skin markers such as paper clips on skin at wound entrance or directly above the object.

·      Another method is using hypodermic needles, two or three needles inserted into skin near the object after anesthetizing the area at 90 degrees to each other to create a frame of reference.

·      Almost all glass is visible on radiographs if it is 2 mm or larger, and glass does not have to contain lead to be visible on plain films

·      Ultrasound can identify a wide variety of soft tissue foreign bodies such as wood, fish bones, sea urchin spines, other organic material, fiber, and plastic, with >90% sensitivity for foreign bodies >4 to 5 mm

o   Foreign bodies appear as hyperechoic foci, usually with acoustic shadowing extending distally.

o   A hyperechoic rim, or halo sign, indicates an abscess or granuloma around the object.

o    Sonography can estimate the depth of a foreign body below the skin surface and guide object removal in real time.

Treatment

·      Not all foreign bodies must be removed, and not all that require removal must be extracted in the ED 

·      Thorns, spines, wood splinters, and other vegetative materials should be promptly removed because they cause intense and excessive inflammation.

·      Heavily contaminated objects such as teeth and soil covered objects should be removed ASAP.

·      Antibiotics treatment CANNOT replace foreign body removal.

·      Glass, metal, and plastic are relatively inert, and removal can be postponed, if necessary.

o   Glass foreign bodies in hands or feet can cause persistent pain with gripping or walking, and they can sever nerves or tendons years after the initial injury.

o   Deep, sharp foreign bodies in these locations should be referred to appropriate specialists for eventual removal.

·      Use adequate anesthetics to achieve pain control, good lighting, and tourniquets if needed.

·      Although most foreign bodies in hands should be removed because the hand is mobile and sensitive, deep exploration of the hand by the emergency physician is not recommended because knowledge and experience are needed to avoid injury to numerous closely spaced vital structures.

Post Removal Treatment

·      After removal irrigate wound thoroughly

·      In general, if concern for contaminated puncture wound, then enlarge entrance wound to allow for more effective cleaning.

·      Post procedure x-ray if multiple objects removed

·      Update tetanus

·      Wounds in which all foreign contaminants can be removed and those in locations with good blood supply can be closed primarily. Otherwise, delayed primary closure is preferred.

·      NO PROVEN BENEFIT FOR PROPHYLACTIC ANTIBIOTICS FOR UNINFECTED WOUNDS CONTAINING FOREIGN BODIES

·      Antibiotics are justified for infected wounds, particularly when removal must be postponed

·      Delayed removal – refer to surgeon or interventional radiologist for delayed removal of foreign bodies.

o   If a foreign body is near a joint or highly mobile region, the affected area should be splinted before removal to prevent further injury or migration of the object.

References

Tintinallis Emergency Medicine A Comprehensive Study Guide 

https://www.aafp.org/afp/2007/0901/p683.html

http://www.emdocs.net/soft-tissue-foreign-bodies-ed-presentation-evaluation-and-management/