Environmental Emergencies Dr Simon Smith Bendigo ED Conference September 3 rd 2014

To Be Discussed 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/ 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 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

100,000,000 volts Duration of milliseconds Types of strike – Direct – Side – step

Clinically Cardiac Cutaneous Vascular neurological

Differences from electric shock Reverse triage for disaster scenario Deep burns rare Cardiac arrest – usually asystole Anecdotally - ? Longer CPR

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 Environment Age Physical Medical medications

Clinical Effects 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 methodAdvantagesdisadvantages EvaporativeSimple, effective, non-invasiveShivering Difficult to maintain electrodes ImmersionNon-invasive, effectiveShivering, poorly tolerated Difficult to maintain Strategic ice packsNon-invasive, available Can combine with other technique Decreased efficacy Poorly tolerated Cold gastric lavageInvasive, intensive

Cooling Methods methodRate of cooling Ice packs to groin/axilla/neck0.1 (degree per minute) Evaporative cooling0.31 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

Defined as core temperature < 35 degrees temperatureclinicallycardiacneurological 32-35Maximum shiveringNormal blood pressureAmnesia, dysarthria ataxia 28-32Shivering extinguished poikilothermia Atrial fibrillation Susceptible to VF Stupor Pupils dilated at 29 <28Major 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 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 Afterdrop -?significance Limited handling Intubation Prolonged CPR

Submersion Injuries

Submersion Injury drowningDeath by suffocation after submersion in liquid Used if death within 24 hours Near drowningSurvival for > 24 hours post submersion Secondary drowningDeath >24 hours post submersion

Epidemiology 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 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 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