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Program Information. Critical Temperature-Related Illnesses. Dorothy W. Bird, MD Suresh Agarwal, MD Department of Surgery Boston University Medical Center. Temperature-Related Illness. Hypothermia Systemic Hypothermia Non-freezing Injuries Freezing Injuries Hyperthermia

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  1. Program Information

  2. Critical Temperature-Related Illnesses Dorothy W. Bird, MD Suresh Agarwal, MD Department of Surgery Boston University Medical Center

  3. Temperature-Related Illness Hypothermia Systemic Hypothermia Non-freezing Injuries Freezing Injuries Hyperthermia Heat Exhaustion Heat Stroke Drug-Induced Hyperthermia

  4. Heat Exchange Mechanisms Radiation: loss of heat by infrared rays Conduction: transfer of heat from object to object Convection: current of air carrying heat away from skin Evaporation: warming of water to transform it from liquid to gas

  5. Normal Temperature Regulation Human body generates 1oC/hour Transfers heat to the environment to maintain body temperature +/- 0.6oC Normal body temperatures: 32oC skin 37oC sublingual 38oC rectum 38.5oC deep liver

  6. Hypothermia <35oC (95oF) Primary (accidental): decrease in core body temperature from environmental cold stress Secondary: due to metabolic disorder resulting in abnormal heat production or heat-conserving mechanism

  7. Hypothermia - Systemic Effects A. Cardiovascular Delayed bradycardia (32oC) ↓MAP, ↓contractility, ↓CO EKG: J-wave, PR, QRS, QT prolongation 30oC atrial or ventricular fibrillation 25oC asystole B. Respiratory ↓RR, hypoxia, respiratory acidosis ↑mucus (cold bronchorrhea) ↓ciliary action, ↓cough reflex; pneumonia

  8. J-Wave http://www.rcsed.ac.uk/fellows/bcpaterson/new_page_3.htm

  9. Hypothermia – Systemic Effects C. CNS Abnormal EEG <34oC; Flat EEG 19-29oC Hyper-reflexia >32oC; Hypo-reflexia <32oC ↓Mentation, ↓Motor function D. Coagulation Platelet sequestration (portal), thrombocytopenia Impaired platelet function Coagulation factors: ↓40% activity, ↑PT, PTT DIC-like syndrome, risk of thromboembolic event

  10. Hypothermia – Systemic Effects E. Renal ↓Na+ reabsorption F. GI Ileus, bowel wall edema, impaired hepatic drug detoxification, pancreatitis, hyperamylasemia, gastric erosions

  11. Hypothermia – Systemic Effects G. Endocrine Hyperglycemia H. Immune ↓endothelial cell adhesion results in ↑infection

  12. Hypothermia - Management ABCs first! May be hard to palpate pulse/BP in cold, stiff victim EKG: look for any organized rhythm as evidence of life CPR ONLY in absence of cardiac rhythm NO cardiac drugs or defibrillation <28oC

  13. Hypothermia - Rewarming Mild Hypothermia (32-35oC) Warm environment – blanket, head cover Moderate Hypothermia (30-32oC) Heating pad, warm water immersion Severe Hypothermia (<30oC) Warm IV fluids (65oC) / blood products (49oC) Cardiopulmonary bypass Lavage

  14. Re-warming Rates Spontaneous: 1.2oC/h Spontaneous + Shivering: 3.6oC/h Passive External Rewarming: 0.5-2.0oC/h Active External Rewarming: 1.0-2.5oC/h Body Cavity Lavage: 1.0-3.0oC/hour Cardiopulmnary Bypass: 1.0-2.0oC/3-5min CAVR: 1oC/15.4 min

  15. CAVR Continuous arteriovenous re-warming Level I warming system Percutaneous femoral arterial and venous lines Creates AV fistula where blood is pumped via patient’s own BP through external warming system More rapid re-warming than other methods Less invasive, no heparinization needed Improved survival, multisystem organ failure, SICU stay vs other methods

  16. Hypothermia in Trauma Very common after injury A form of secondary, unintentional hypothemia Ominous sign!! Worsened outcome / mortality if due to trauma ↑ mortality if patient controlled for ISS, shock, resuscitation volume

  17. Hypothermia in Trauma Stricter Severity Classification: Mild: 36-34oC Moderate: 34-32oC Severe: <32oC Rapid re-warming with CAVR proven more effective Failure to re-warm is detrimental to survival!

  18. Non-freezing Injury Chilblain (Pernio) Cause: Repeated exposure to cold above freezing Pathophysiology: chronic dermal vasculitis Appearance: pruritic, red-purple papules, maculares, plaques, nodules, edema, blisters Treatment: shelter, elevation on sheepskin, gradual rewarming at room temperature Sequelae: dermopathy; treat with antiadrenergic (prazosin) or calcium-channel blocker (nifedipine)

  19. www.answers.com/topic/chilblain www.ohiohealth.com/bodymayo.cfm?xyzpdqabc=0... Chilblain

  20. Non-freezing Injury Trench foot (hand) Cause: chronic exposure to wet conditions just above freezing Pathophysiology: alternating arterial vasospasm and vasodilation Appearance: edema, blisters, redness, ecchymosis, ulceration Treatment: removal from cold, wet environment; gentle warm, dry air; elevation; wound care Sequelae: cellulitis, lymphangitis, gangrene, demyelation, atrophy, osteoporosis, fallen arches

  21. Trench Foot • www.visualstatistics.net • www.pbase.com

  22. Frostbite Freezing injury: Ice crystal formation, cellular dehydration, microvascular occlusion Pathophysiology: 1. cellular death from freezing cold 2. alternating vasoconstriction/vasodilation (Hunting reaction)→ repeat freeze/thaw cycle→ ↑blood viscocity→ progressive thrombosis→ ischemia/necrosis 3. re-warming→ secondary ischemia/reperfusion

  23. Frostbite Classification: 1st Degree: tissue freezing, central white anesthetic patch, surrounding erythema 2nd Degree: tissue freezing, blisters of clear or milky fluid, surrounding edema/erythema 3rd Degree: tissue freezing and subcutaneous/skin death, hemorrhagic blisters, black eschar (2 weeks) 4th Degree: tissue necrosis, gangrene, full-thickness tissue loss; hard, cold white, anesthetic

  24. Frostbite • www.geradts.com • www.alpineinstitute.blogspot.com

  25. Frostbite Treatment 1. Pre-thaw/Pre-hospital Phase Protect injured limb from trauma No thawing until definitive re-warming is ensured NO rubbing!

  26. Frostbite 2. Re-warming/Hospital Phase Rapid re-warming: immersion in large water bath (40-42oC) x30-45 minutes Narcotic pain relief as needed 3. Post-thaw Phase Wound care: clean and dry skin, elevate, sterile cotton applied between affected toes/fingers, protect from unintentional trauma with tent/cradle

  27. Frostbite Wound Care Uninfected blebs: keep intact (self-dressing) Daily or BID dressing change/cleansing in warm whirlpool bath Aloe vera cream (thromboxane inhibitor) Physical therapy with edema resolves No tobacco, nicotine, vasoconstrictors

  28. Frostbite Sequelae Cold insensitivity Hyperhidrosis Neuropathy ↓ nail/hair growth Persistent Raynaud’s phenomenon ↑ risk for re-injury

  29. Hyperthemia Hyperthemia vs. Fever: elevated body temperature Hyperthermia: abnormal temperature regulation Fever: normal temperature regulation with elevated set-point Hyperpyrexia: extreme temperature elevation (>40oC)

  30. Heat Exhaustion Heat exposure resulting in volume depletion Flu-like symptoms: Hyperthermia(>36oC), muscle cramps, nausea, malaise, tachycardia Hypernatremia (sweating)/Hyponatremia ( excessive water consumption) No neurologic impairment Treatment: volume/electrolyte repletion

  31. Heat Stroke Extremely elevated body temp (>41oC) Neurologic dysfunction Severe volume depletion, hypotensive, multiorgan failure, rhabodmyolysis, acute renal failure, DIC, transaminitits Anhidrosis Classic Type Exertional Type

  32. Heat Stroke Treatment Volume and electrolyte repletion Immediate cooling External cooling: ice pack to groin, axilla, ice to neck, chest; cooling blankets Evaporative cooling: spray skin with cool water and fan; will decrease temp by 0.3oC/min Internal cooling: cold water lavage to stomach, bladder, rectum

  33. Drug-Induced Hyperthermia Malignant Hyperthermia (MH) Excessive calcium efflux from sarcoplasmic reticulum in response to halogenated inhalational agents Results in uncoupling of oxidative phosphorylation with dramatically increased metabolic rate Incidence: 1:15,000 episodes of general anesthesia Affects 1:50,000 people Autosomal dominant inheritence

  34. Malignant Hyperthermia Signs FIRST: sudden rise in end-tidal CO2 Muscle rigidity Hyperthermia Depressed consciousness Autonomic instability Leads to: myonecrosis, rhabdomyolysis, acute renal failure

  35. Malignant Hyperthermia Management Discontinue anesthetic agent DANTROLENE- blocks Ca++ efflux from S.R. First: 1-2mg/kg IV bolus q15 min to max total 10mg/kg Then: 1mg/kg IV (or 2mg/kg PO) QID x 3 days Reduces mortality from 70% to 10% Victims should wear ID band and family should be tested

  36. Neuroleptic Malignant Syndrome Idiosyncratic drug reaction to usage or discontinuation of neuroleptic drugs that alter dopamine axis Symptoms: hyperthermia, lead-pipe rigidity, altered mental status, autonomic instability 20% mortality 0.2%-1.9% incidence (of those on neuroleptics) Most common: Haloperidol, Fluphenazine No relationship to duration or dosage Usually seen 24-72 hours after starting/ending drug

  37. NMS Treatment Discontinue offending new medication or resume dopaninergic therapy if recently stopped Volume resuscitation DANTROLENE: 2-3mg/kg/ IV q few hours to max total 10mg/kg/day BROMOCRIPTINE: 2.5-10mg PO TID Give with heparinization due to increased thromboembolism risk

  38. Serotonin Syndrome (SS) Caused by overstimulation of serotonin receptors in CNS Associated with SSRI, NMDA, amphetamine use Exam: abrupt onset of altered mental status Autonomic hyperactivity Mydriasis, diaphoresis Tachycardia, hypertension Hyperthermia Hyperkinesia, ↑DTR, rigidity, clonus (deep patellar, horizontal occular clonus)

  39. Serotonin Syndrome Treatment Discontinue medication Benzodiazepine (control agitation, hyperkinesia) Cyproheptadine (serotonin agonist) Only for severe SS Give 12mg PO/NG then 2mg PO q2h PRN symptoms Neuromuscular paralysis (Vecuronium) NO RESTRAINTS

  40. References Jurkovich GJ. Environmental Cold-Induced Injury. Surg Clin N Am 2007;87(4):247-267. Petrone P, Kuncir EJ, Asensio JA. Surgical management and stratagies in the treatment of hypothermia and cold injury. Emerg Med Clin N Am 2003;21:1165-1178. Hall JB, Schmidt GA, Wood LDH. Principles of Critical Care 3rd Ed. The McGraw-Hill Companies, 2005. Marino PL. The ICU Book, 3rd ed. New York: Lippincott Williams & Wilkins, 2007:697-712.

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