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Environmental EmergenciesAndrew Schmidt, DO, MPHAssistant Professor, UF Jax Emergency MedicineCRITICAL CARE TRANSPORTChapter 18
Heat transferHyperthermia
Radiation
Transfer of heat by electromagnetic waves from warmer object to colder
Air T < 35C60% Radiation30% Evaporation
Conduction
Heat transfer between surfaces in direct contact
Convection
Heat transfer by air of liquid moving across surface
Evaporation
Heat loss by vaporization of water
Air T > 35 CBody dependent on evaporation
As humidity increasesEvaporation decreases
Hyperthermia
40
Classic Heat Stroke
Elderly, very young, incapacitated, chronically ill
Commonly occurs during heat waves
Develops slowly
Exertional Heat Stroke
Generally younger/healthy
Engaging in strenuous activity
Develops rapidly
Differential Diagnosis
Hyperthermia
Endocrine
Pheochromocytoma
Thyroid Storm
Infectious
Brain abscessEncephalitisMalariaMeningitisSepsisTetanusTyphoid Fever
Neurologic
CVASeizures
Toxicological
Alcohol WithdrawlAnticholinergicAspirin OverdoseMalignant HyperthermiaSerotonin SyndromeNMS
Resuscitation GoalsABCs
Start Cooling
Prevent end organ damage
Cooling
Do not administer anti-pyreticsDantrolene not benefitial
Cool through active means
Cool until core T 101.5-102 F(38.6-38.8 C)
Conductive Cooling
Ice Water Immersion
Most efficient techniquePrimarily studied in exertional
Use restricted by resources, monitoring, patient condition
Conductive Cooling
Ice Pack Application
Axilla, Groin, Neck, Head
Cold, wet towels
Both techniques less efficient
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Evaporative + Convective Cooling
Mist and Fan Technique
Most useful for classic
Skin sprayed with tap waterCool, wet gauze on skin
Other Cooling Techniques
Cold IV FluidsUse as adjunct, ineffective alone
Cooling BlanketsIneffective, slow
HypothermiaHeat and Cold Emergencies
Causes of Hypothermia
Primary HypothermiaHeat production is overcome by stress of excessive cold
Causes of Hypothermia
Primary HypothermiaHeat production is overcome by stress of excessive cold
Secondary HypothermiaImpaired ThermoregulationEndocrine, neoplasm, malnutrition, toxins
Increased Heat LossSepsis, burns, cold infusions, trauma
Hypothermia
SEVEREMODERATEMILD283235Traditional Staging
Neuro
Depressed consciousness
Impaired judgment
Slurred speech
Shivering
Cardiac
InitialTachycardia/HTN
ProlongedBradycardiaDepressed cardiac output
ECG Changes
ECG Changes
Prolonged QRSOsborne J Wave
ECG Changes
http://www.thestudentcardiologist.co.uk/
Respiratory
Initialincreased respirations
ProlongedDecreased respiratory driveDecreased lung complianceRespiratory failure
Renal
Cold diuresis
Coagulation
Decreased clotting functionThrombocytopenia
Can also become hypercoaguable
Hypothermia
SEVEREMODERATEMILD
Dysarthria, AtaxiaPoor judgementShiveringTachy bradycardia
StuporShivering stopsA fib / arrhythmiasDecrease pulse / resp
Loss of reflex / vol motionDecreased V-fib thresholdSignificant brady / HypoTN
HT IVHT IIIHT IIHT I
Resuscitation GoalsABCs
Dont make things worse
Rewarm
ABCs
Check for signs of life for 60 seconds
Utilize UltrasoundCardiac monitorEtCO2http://www.cardiopulmonaryresuscitation.net/
ABCsRSI
Possibility of hyperkalemia due to hypoxia and rhabdomyolysis
Use caution with depolarizing neuromuscular blockers
http://www.clarkmedicalmedia.com/
Resuscitation Modifications
Little evidence
Primarily animal models
Concern for cold myocardial irresponsive to medications and defibrillation
No consensus
Hypothermia
30
Normal med intervals
Normal defib guidelines
3 5
Withhold vasoactive meds
Single defib at max JWithhold further until > 30
Meds at double intervals
Normal defib guidelines
CPR performed at normothermic rateThe above represents a combination of AHA and ERC guidelines. Poor evidence
Dont make things worse
Avoid CPR on patients with any signs of life, even profound bradycardia
Move/transport patients gently
Remove cold/wet clothingwww. http://medicalonline.pl/
Rewarm
Passive
Active, Non-invasive
Active, Invasive
Passive Rewarming
Remove clothesAllow shiveringDry skinWarm blankets
Rate: 0.5 C/hr
Active External Rewarming
Forced air deviceRadiant heat lampHot water bottlesWarm water immersion
Frostbite
FrostbiteCassification
FrostbiteFrostnip
SuperficialLocal discomfortNo tissue lostSymtpoms usually resolve within 30 minutes
Frostbite1st Degree
Numbness and erythemaWhite/yellow firm plaque
Frostbite2nd Degree
Superficial vesiculationClear/milky fluid surrounded by erythema
Frostbite3rd Degree
Deeper blistersPurple/blood-containing fluid
Indicates injury has extended through dermis into vascular plexis
Frostbite4th Degree
MummificationInjury completely through dermis
Clinical Presentation
Clinical PresentationDays to weeks after re-warmingSevere injury turns black and mummifies
3 Days12 Days 3 weeks
TreatmentPre-hospital treatment
TreatmentDO NOT
TreatmentRapid Field Rewarming
Treat systemic hypothermia before or during treatment of frostbite
TreatmentRapid Field Rewarming
TreatmentRapid Field Rewarming
Drowning ResuscitationAndrew Schmidt, DO, MPHAssistant Professor, UF Jax Emergency Medicine
Standard Definition for Drowning
Standard Definition for Drowning
The drowning processDrowning Resuscitation
HYPOXIA
Primary cause of all systemic injury and death associated with drowning
Change Your Thinking
Drowning is a brain disease
TreatmentDrowning Resuscitation
210>
O2O2O2
Do not try and attempt to remove the foam as it will keep coming. Continue rescue breaths/ventilation until an ALS provider arrives and is able to intubate the victim. If this prevents ventilation com- pletely, turn the victim on their side and remove the regurgitated material using directed suction if possible.
ERC 2015
Cardiac Cause
Tank is full, the engine is brokenCompressions/AED take priority
Respiratory Cause
The tank is empty, the engine worksVentilations take priority
Drowning: Update on a Global Disease
AEDs in the aquatic environment
Safe and effective to on wet patients as long as pads make good contact with skin
Safe for rescuers on wet surfaces
Effective in moving boats
Drowning: Update on a Global Disease
Question:Should we do the Heimlich Maneuver on drowning patients?
Drowning: Update on a Global Disease
Heimlich ManeuverDelays much needed ventilations
Recommend against:American Red CrossUnited States Lifesaving AssocInternational Lifesaving FedEuropean Resus CouncilAmerican Academy PedAmerican Heart Assoc
Drowning: Update on a Global Disease
Spinal ImmobilizationPrevalence of C-spine injury low with drowningUsually clear signs of traumaShould not delay resuscitation
Drowning: Update on a Global Disease
Airway
Prioritize establishing ventilation and optimizing oxygenation
Non-invasive
Maintaining patent airway, mentating wellNasal Cannula, Non-rebreather mask
Non-invasive Positive Pressure Vent
Maintaining patent airway, no emesisCPAP/BiPAP: if no rapid improvement, proceed to ETI
Endotracheal Intubation
Not protecting airway, large amount of foam or emesis
Mechanical Ventilation
No large drowning-specific trialsMost recommendations follow ARDSnet protocols (VT 6-8ml/kg, Augment PEEP)
Diving EmergenciesAndrew Schmidt, DO, MPHAssistant Professor, UF Jax Emergency Medicine
Injuries of AscentPulmonary Barotrauma
Expansion of gas trapped in lungs
May rupture into thoracic cavity or diffuse into capillaries
Worse with breath holds taken close to the surface
Injuries of AscentPulmonary Barotrauma
Pulmonary hemorrhage
Pneumothorax
Pneumomediastinum
Arterial Gas Embolism
Injuries of AscentArterial Gas EmbolismAir bubbles entering pulmonary venous circulation from ruptured alveoli
Pulmonary vein Left Ventricle Aorta Systemic
Bubbles become stuck in small capillariesBrain: ischemia and infarctionHeart: arrhythmias
Injuries of AscentArterial Gas Embolism
Presentation
Sudden and often life-threateningClassic: LOC during ascent or upon resurfacing
Any diver who loses consciousness or has signs of serious neuro injury within 10 minutes of surfacing must be considered to have AGE
Injuries of AscentArterial Gas Embolism
Treatment
ResuscitateHigh flow oxygenIV Fluids (avoid hypotension)
Hyperbaric oxygen therapyThe earlier, the betterEven if symptoms improveTransport at sea-level pressure
Indirect Effects of PressureNitrogen NarcosisIntoxication from increased partial pressure of nitrogen at increased depth
Typically occurs deeper than 20-30 meters below surface
SymptomsLightheadedLoss of fine motorPoor judgmentGiddinessEuphoria
Treatment: ascend to shallower depth
Indirect Effects of PressureOxygen ToxicityCNS poisoning due to increased partial pressure of oxygen at increased depth for prolonged period
SymptomsApprehensionNauseaMuscle twitchingSeizures
TreatmentAscend to shallower depthRemoval of supplemental oxygen, unless needed to resus
Decompression SicknessDecompression SicknessFormation of nitrogen bubbles within intravascular and extravascular spaces from reduction in ambient pressure
GasGas in solution
GasGas in solution
Gas in solution
Gas
1 ATA2 ATA1 ATA
Rapid
Decompression SicknessMusculoskeletal Decompression Sickness
Most common manifestation of DCSThe Bends
Pain in and around major jointsShoulders and elbows most commonCharacterized as dull acheWorse with movement
Decompression SicknessMusculoskeletal Decompression Sickness
DiagnosisInflate BP cuff around joint to 150-200 mmHgPain will decreaseHigh specificity, low sensitivity (does not rule out)
Limb bends not immediately life/limb threatening, but indicates bubbling in venous system and possible danger
Decompression SicknessCutaneous Decompression SicknessRelatively uncommon
Cutis Marmorata (mottling) can be sign of severe DCS
Decompression SicknessPulmonary Decompression Sickness
Relatively uncommonThe Chokes
Represents massive pulmonary venous air embolism
Burning substernal painWorse on inhalationCyanosisNonproductive cough
Decompression SicknessNeurologic Decompression Sickness
Spinal Lower thoracic and lumbar most commonLow back painHeaviness in legsParesthesias/paralysis
Decompression SicknessTreatment
Initiate resuscitation on scene
Prioritize oxygenationUse high-flow oxygenTight fitting mask
Improve tissue perfusionIV fluids
Decompression SicknessTreatmentLocate and contact closest operating hyperbaric chamber
+1-919-684-9111
Rapid transportAircraft which can maintain sea-level pressurizationIf helicopter, no greater than 800 ft altitude
Altitude SicknessAndrew Schmidt, DO, MPHAssistant Professor, UF Jax Emergency Medicine
Altitude Illness (1 of 4)Affects experienced mountain climbers pushing limits as well as people who travel from lower to higher elevations in everyday lifePeople with preexisting medical conditions, extremes of age, sedentary lifestyles, and people with unhealthy lifestyles at greatest risk
Altitude Illness (2 of 4)Symptoms can range from imperceptible sleep disturbances to life-threatening pulmonary edema, cerebral edema, and hypoxia.Altitude sickness is most commonly associated with mountain climbing and skiing at elevations of 3,0008,000 above sea level.
Altitude Illness (3 of 4)Lake Louise criteriaat least two criteria in each group must be present.Group ACrackles or wheezing in the lungsCentral cyanosisTachypnea (sleep disturbances)Tachycardia
Altitude Illness (4 of 4)Group BDyspnea at restCoughWeakness or decreased exercise performanceChest tightness or congestion
HAPE (1 of 2)High-altitude pulmonary edema (HAPE)People who change altitudes frequently are at highest risk.SymptomsCoughRespiratory distressChest tightnessFatigueFever
HAPE (2 of 2)ImplicationsPulmonary hypertension from alveolar hypoxiaCapillary or arterial thrombosesRapid descent is the preferred treatment.Give supplemental oxygen.Give nifedipine and salmeterol.Use portable hyperbaric bags.
HACEHigh-altitude cerebral edema (HACE)Life threateningSuspect in any person who experiences a significant change in altitude and has a mental status changeThought to be result of vasodilation from hypoxia
Flight ConsiderationsCCTP may be asked to perform a rescue or evacuation function.Locations may be difficult to reach, especially for ground transportation.CCTP should carefully consider safety issues such as training, experience of personnel, and capabilities and condition of equipment.
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THE ENDAndrew Schmidt, DO, MPHAssistant Professor, UF Jax Emergency Medicine