Transcript Environmental Emrgencies

Environmental Emergencies
Dr Simon Smith
Bendigo ED Conference
September 3rd 2014
To Be Discussed
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Electrocution Injuries
Lightning Strike
Hyperthermia
Hypothermia
Submersion Injuries
Other
– Altitude Medicine
– Diving Medicine
Electricity
• To understand the mechanism and injuries
sustained of electrical injuries, the underlying
basic physics should be understood
• GRRRRROOOOAAAN
Basic Physics
• Current (Amps)= Voltage(V)/Resistance(Ohms)
• I=V/R
• Resistance Influenced by
– moisture, type of tissue
• Example
– Moist skin , I=240V/1000 Ohms =240mA
– Dry thick skin, I=240V/100000 Ohms = 2.4mA
Current
• 1 mA
• 10 mA
• 50 mA
• 100 mA
• Mild sensation
• Muscular paralysis
• Shock, difficulties
breathing
• Respiratory paralysis
• Cardiac arrest
Factors Determining Injury
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Type of circuit – DC v AC
Duration
Resistance of tissues
Voltage
Amperage
Pathway of Current
Electric Shock
• Clinical effects
– Cardiac – VF common cause of arrest
– Burns – worse than they look
– Nervous system
– Renal – ARF secondary to myoglobin
– Vascular – thrombosis and haemorrhage
– Musculoskeletal – fractures, dislocations, other
Electric Shock Management
Investigations
ECG
Imaging (if indicated)
Bloods ( CK/CUE/FBE)
Lightning Strike
Lightning Strike
• 100,000,000 volts
• Duration of milliseconds
• Types of strike
– Direct
– Side
– step
Clinically
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Cardiac
Cutaneous
Vascular
neurological
Differences from electric shock
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Reverse triage for disaster scenario
Deep burns rare
Cardiac arrest – usually asystole
Anecdotally - ? Longer CPR
Hyperthermia
Hyperthermia
Hyperthermia
• Spectrum of heat related illness
– Heat stroke
– Heat exhaustion
– Heat cramps
Heat Stroke
• Definition
– Core body temp > 40 degrees
– CNS abnormalities – delerium , seizure, coma
• Types
– Classical
– exertional
Heat Stroke Risk Factors
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Environment
Age
Physical
Medical
medications
Clinical Effects
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Neurological
Cardiovascular
Rhabdomyalysis
Renal
Haematological
Investigations
• Bloods
– CUE/CK/LFT/FBE/ABG
• ECG
• Imaging
Management
• Rapid cooling
– If undertaken early, reduction in mortality
– Multiple methods
• Evaporative cooling
• Ice water immersion
• Other techniques
– Ice packs, lavage, body cooling units
• Support of organ function
• Exclude differential diagnosis
Cooling Methods
method
Advantages
disadvantages
Evaporative
Simple, effective, non-invasive
Shivering
Difficult to maintain electrodes
Immersion
Non-invasive, effective
Shivering, poorly tolerated
Difficult to maintain
Strategic ice packs
Non-invasive, available
Decreased efficacy
Can combine with other technique Poorly tolerated
Cold gastric lavage
Invasive, intensive
Cooling Methods
method
Rate of cooling
Ice packs to groin/axilla/neck
0.1 (degree per minute)
Evaporative cooling
0.31
Lavage (gastric / peritoneal)
0.56
Ongoing Management
• Avoid overshoot – hypothermia
• Manage complications
– Airway – intubation
– Circulation – fluid, inotropes
– Renal failure
– DIC
• Additional therapy
– Decrease shivering – diazepam, chlorpromazine
Hypothermia
Hypothermia
• Defined as core temperature < 35 degrees
temperature
clinically
cardiac
neurological
32-35
Maximum shivering
Normal blood pressure
Amnesia, dysarthria
ataxia
28-32
Shivering extinguished
poikilothermia
Atrial fibrillation
Susceptible to VF
Stupor
Pupils dilated at 29
<28
Major acid/base issue
Pulmonary oedema
Max risk of VF at 22
Asystole at 18 degrees
Cardiac output 45%
Loss of reflexes
Flat EEG
Hypothermia - causes
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Environmental
Drug induced
Sepsis
Iatrogenic
Dermal disease
Hypothalamic and CNS dysfunction
Hypothermia Management
• General measures
– Remove clothing
• Warming
– Passive external (mild hypothermia)
– Active external (moderate hypothermia)
• Core temperature afterdrop
– Active core re-warming (severe hypothermia)
• O2 / IV fluid / lavage
Hypothermia - Investigations
• Bloods
– CUE / glucose / CK / coags / ABG
• ECG
– Bradycardia
– Atrial fibrillation
– Heart block
– Osborne Wave
– VF
Osborn Wave
Hypothermia - Differences in ALS
• Warming core component
• Below 30 degrees
– Only one attempt at shock
– Only one dose of drug
• ? Delay to CPR
Hypothermia - Controversies
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Afterdrop -?significance
Limited handling
Intubation
Prolonged CPR
Submersion Injuries
Submersion Injury
drowning
Death by suffocation after submersion in liquid
Used if death within 24 hours
Near drowning
Survival for > 24 hours post submersion
Secondary drowning
Death >24 hours post submersion
Epidemiology
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Second most common cause of death in children
Most deaths – teenage boys, toddlers
Boys 5x more likely than girls
Alcohol major risk factor in adolescence
Pathophysiology
• Timeline
– Panic, struggling, breath holding, hyperventilation
– Aspiration (85%) or laryngospasm (15%)
– Hypoxia
– Loss of consciousness
– Pulmonary oedema
Important Points on History
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Estimated time of submersion
Temperature of water
How and when the victim was rescued
How soon after rescue respiration resumed
What kind of resuscitation was given
Consideration of trauma
Management
• Varies according to severity
• Varying classification systems
• Simple delineation on GCS
– GCS>13
• Ix as indicated (may be none), Sx treatment, O2
• Observe for 6 hours
– GCS<13
• Ix may include – CXR / ABG / imaging / etoh
• Resp support – O2,CPAP,intubation,PEEP,bronchodilator
Prognostic Factors
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Submersion >25 min
Resuscitation >25 min
VT or VF on ECG
Initial GCS<5 or pupils dilated
Severe acidosis
Altitude Medicine
Diving Medicine
Marine Evenomations
Snake Evenomations