CCT Environmental Emergencies

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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

www.wsj.com

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



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 completely, 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


Question:Should we do the Heimlich Maneuver on drowning patients?


Heimlich ManeuverDelays much needed ventilations

Recommend against:American Red CrossUnited States Lifesaving AssocInternational Lifesaving FedEuropean Resus CouncilAmerican Academy PedAmerican Heart Assoc


Spinal ImmobilizationPrevalence of C-spine injury low with drowningUsually clear signs of traumaShould not delay resuscitation


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.

www.JaxEMS.com

THE ENDAndrew Schmidt, DO, MPHAssistant Professor, UF Jax Emergency Medicine

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CCT Environmental Emergencies