Environmental

Question 1

Burns

A 25 year old fireman has been brought to ED after being pulled unconscious from an apartment fire. He has significant thermal burns.

On arrival his vital signs are:
GCS 12 (E3 V4 M5)
HR 105 /min
BP 120/60 mmHg
RR 28 /min
O2 saturation 95% 15L O2 via non-rebreather mask

Answer 1

THREATENED AIRWAY IN THE BURNS PATIENT

1) Hypoxia despite high FiO2
2) Stridor, cough, wheeze, tachypnoea
3) Burns to face, singed nose hairs
4) Carbonaceous sputum or soot in mouth/nose
5) Dysphonia, horse voice
6) Oropharyngeal erythema, oedema and blistering
7) Reduced GCS and confusion

Early intubation for the following:

• exposed to a fire in a closed space
• full thickness facial burns
• circumferential neck burns
• progressive horse voice or air hunger
• acute respiratory distress
• altered mental state / coma
• supraglottic oedema

Question 2

Major Burns Management

*Associated trauma

*Carbon monoxide toxicity

*Cyanide toxicity

*Severe pain - need aggressive analgesia

*Full thickness burns need debridement in OT

*Compartment syndrome that needs escharotomy

*Hypothermia

*Massive fluid losses and electrolyte derrangements

*Infection - Staph aureus, Pseudomonas (prophylactic antibiotics are contraindicated in major burns)

Rhabdomyolysis

TRANSFER TO BURNS CENTRE:
Indications for transfer to burns unit

• Burns greater than 10% TBSA
• Burns greater than 5% TBSA in children
• Full Thickness burns greater than 5% TBSA
• Burns of Special Areas: (Face, Hands, Feet, Genitalia, Perineum, Major Joints and circumferential limb or chest burns
• Burns with inhalation injury
• Electrical burns
• Chemical burns
• Burns with pre-existing illness
• Burns associated with major trauma
• Burns at the extremes of age – young children and the elderly.
• Burn injury in pregnant women
• Non-accidental burns

Answer 2

MANAGEMENT:

cardiac monitoring and pulse oximetry

high flow oxygen 15L NRBM targeting SaO2 >95%

IV access
- can place femoral CVC, this area is often spared in burns

Analgesia:
ketamine 20mg IV
paracetamol 1g IV

AIRWAY MANAGEMENT:

Early intubation for the following:

• exposed to a fire in a closed space
• progressive horse voice
• air hunger
• acute respiratory distress with tachypnoea, stridor, wheeze
• altered mental state / coma
• supraglottic oedema with soot (can look with the flexible endoscope)
• full thickness facial burns
• circumferential neck burns

Consider awake fibre-optic intubation if equipment and medical expertise available

FLUID RESUSCITATION:

Modified Parkland formula

For >10% TBSA

Hartmans / plasmalyte

2-4 mL × weight (kg) × % BSA burned* over initial 24 h

• Half over the first 8 h from the time of burn
• Other half over the subsequent 16h

Titrate to UO and fluid status

ESCHAROTOMY:
- compartment syndrome
- circumferential chest burns with impaired ventilation
- cirumferential neck burns with neurological deficit

SURGICAL DEBRIDEMENT OF FULL THICKNESS BURNS:

Early debridement within 6hrs

ADT:

Prophylactic antibiotics are contraindicated in the major burns patient

CARBON MONOXIDE TOXICITY
- carboxyhaemoglobin on VBG >30% is significant
- High flow oxygen

CYANIDE TOXICITY
- clinical diagnosis
- altered mentation, hypotension, HAGMA, high lactate >8
- hydroxycobalmin 5g IV over 15min, can repeat
- add sodium thiosulphate 25% 50ml IV over 10min in severe toxicity

MONITORING:
- IDC for UO monitoring target 1ml/kg/hr
- Compartment syndrome assessment for escharotomy
- Hypothermia

TRANSFER to burns unit

Consider hyperbaric oxygen

Question 3

Burns

DEPTH OF BURN ASSESSMENT

TOTAL BODY SURFACE AREA ASSESSMENT

FLUID RESUSCITATION IN BURNS

Answer 3

DEPTH OF BURN ASSESSMENT:
- burns are dynamic and evolve over 48-72hrs

SUPERFICIAL:
- epidermis only (sunburn)
- red
- painful
- brisk capillary refill

SUPERFICIAL DERMIS BURN:
- burn extends to superficial dermis
- red, blisters
- painful
- capillary refill normal
- healing time 2-4weeks

DEEP DERMIS BURN:
- burn extends to deep dermis
- cherry red or pale
- reduced pain (as nerves are destroyed)
- sluggish capillary refill
- healing time 6 weeks and may required skin graft

FULL THICKNESS:
- involves all layers of the skin and subcutaneous tissue with involvement of underlying fascia, muscle and bone
- white and leathery
- not painful
- no capillary refill
- treatment is always surgical debridement

TOTAL BODY SURFACE AREA AFFECTED:

Lund and Browder chart.
- most accurate
- can be used in adults and paediatrics
- excludes superficial burns

FLUID RESUSCITATION IN BURNS

Isotonic crystalloid – Hartmann’s or plasmalyte

Large volumes of 0.9% saline may be associated with hyperchloremic metabolic acidosis

Estimating fluid requirements:

• Parkland Formula (most widely used):

Fluid requirement (ml) = 4 x body weight x percentage of burns. (Only deep dermis and full thickness)

One half of the calculated fluid is given over the first eight hours and the remaining over the
next 16 hours.

Question 4

Minor Burns

Answer 4

Minor Burns in children:
- Quierty non-accidental injury
- place under cold running water for 20min (can decrease depth of burn)
- Multimodal analgesia (paracetamol 15mg/kg, ibuprofen 10mg/kg, fentanyl 1.5mcg/kg IN), nerve blocks if ammenable

Clean wound with sterile water (betadine is cytotoxic)

de-roof blisters

Keep wounds moist - promotes reepithelialization

Use non-adherent dressing like jelonet or bactigras (has antimicrobial properties)
can be left for 2-3 days when they are scheduled for follow up

Question 5

Altitude Medicine

Question 6

Snake Bites

Question 7

Hyperthermia

Question 8

Hypothermia
Frost Bite

Question 9

Diving

Question 10

Elderly Hyperthermia and Collapse

EM Rapid bombs - ep 56

2023.2 Case based discussion

COMPLICATIONS OF HYPERTHERMIA

Neurological - confusion, delirium, coma, cerebral oedema, seizure, encephalopathy,

Rhabdomyolysis and renal failure

Metabolic - hypoglycemia

Electrolytes - hyponatremia

Cardiac - stress induced cardiomyopathy, MI, arrythmias

Respiratory - ARDS, pulmonary oedema

Haematological - DIC

Answer 10

DIFFERENTIAL DIAGNOSES FOR HYPERTHERMIA:

Environmental
- Heat stroke:
- Core temp >40
- Neurological disturbance - altered mental status, confusion, coma, seizure
- Anhydrosis

Toxicological
- malignant hyperthermia
- neuroleptic malignant syndrome,
- serotonin syndrome,
- anticholinergic toxidrome,
- salicylate toxicity,
- sympathomimetics - cocaine

Endocrinology
- thyroid storm

Infection
- Sepsis

HISTORY:
Heat exposure - no air conditioning
Lack of hydration

Medication review:
- Serotonin syndrome
- Neuroleptic malignant syndrome

Infective symptoms:

Thyroid disorders

MANAGEMENT:
core temperature - rectal or bladder probe (non-intubated patients), esophageal probe (intubated patient)

aim to drop core temp to 38 degrees within 1hr reduces mortality

Remove clothes

Place on specialised cooling mats

spray body with lukewarm water and fan - evaporative convection cooling

cool IV crystalloids - 4 degrees

ice packs to groin, axilla and neck

control shivering and agitation
- low dose diazepam 1-2mg IV in elderly

ice bath immersion - most effective, not conducive to the resuscitation environment, difficult to monitor patient

consideration of ECMO - though invasive, not readily available, labor intensive

consideration of pleural cavity, bladder and peritoneal lavage - though invasive and labor intensive

treat agitation - sedation or RSI and intubate - paralyse to prevent shivering and further heat production

IDC - maintain urine output 1-2ml/kg/hr (rhabdymyolysis)

Broad spectrum antibiotics

Question 11

GERIATRIC FALL

Answer 11

CAUSES FOR ELDERLY COLLAPSE:

Geriatric causes:
- polypharmacy
- cognitive impairment
- visual or hearing impairment
- parkinsons
- orthostatic hypotension
- deconditioning and muscle wasting
- loss of proprioception (diabetes)

Medical causes:

Medications!!!!
- beta blockers (AV block)
- dihydropyridine calcium channel blockers (orthostatic hypotension)
- diuretics (hypovolemia)
- benzodiazepines (ataxia)

Cardiac:
- AV block
- Prolonged QTc
- LV outflow obstruction (critical AS)

Haematological:
- Anaemia

Toxicological:
- alcohol
- opioids
- benzodiazepines

Hypovolemia:
- dehydration
- diuretics

Vascular:
- Stroke/TIA
- MI

Metabolic:
- hypoglycemia
- hyponatremia
- hyperkalemia

Question 12

Hypothermia

oesophageal temperature probe calibrated to read low temperatures

next best is rectal or bladder probe

remove wet clothing and wrap in warm blankets and bair hugger

apply warm humified oxygen

IV access + VBG

often hypovolemic due to cold diuresis
Give 0.9% NS warmed to 40deg 20ml/kg IV bolus - repeat fluid boluses should be guided by POCUS assessment of the IVC

gentle handling as can precipitate ventricular fibrillation (VF) in the irritable hypothermic myocardium

IV access is required
Move to early IO
If CVC required - do femoral CVC rather than IJ CVC to avoid guide wire induced VF

Core temperature afterdrop - when the peripheries are warmed, vasodilate and return cold acidotic blood to the core

The efficacy of epinephrine is decreased at low body temperatures, especially below 30°C. Epinephrine and anti-arrhythmic medications may accumulate in the periphery after repeated doses in the hypothermic patient, and cause an effective overdose when they flood the central circulation upon rewarming.

Hypothermic pediatric patients can have excellent neurologically intact recovery following prolonged cardiac arrest.

Answer 12

SEVERITY:
Mild 32-35
Moderate 28-32
Severe <28

ECG FINDINGS IN HYPOTHERMIA

• bradycardia
• prolonged PR, QRS and QT
• AF with slow ventricular response
• Osborn waves
• heart blocks
• asystole

MANAGEMENT:

Endogenous Rewarming:

• 0.5-2 degrees per hour
• remove wet clothing, warm environment, warm clothing, prevent heat loss with insulation

Passive Rewarming:

• 0.5-2 degrees per hour
• as above plus blankets

Active External Rewarming:

• 1-2 degrees per hour
• as above plus bair hugger, warm blankets, radiant heat

Active Internal Rewarming:

• fluid warmers for IV fluids (1-1.5 degrees/hr)
• peritoneal lavage (2-4degrees/hr)
• gastric and bladder lavage
• thoracic lavage (3-6 degrees/hr)
• ECMO (7-10 degrees/hr)
• hot bath immersion (4-10 degrees/hr)

NON SALVAGEABLE PATIENT

• K+ >12
• pH < 6.5
• core temp <6 degrees
• core temp <15 degrees and no circulation for >2hrs
• large intra-cardiac thrombus on USS

HYPOTHERMIC CARDIAC ARREST:

• difficult to palpate for pulse - use USS to check for pulse
• no adrenaline until core temp >30
• double the time between dosing of adrenaline until core temp >35
• only give drugs IV
• can defibrillate up to 3 times
• can stop resuscitation if still no ROSC once patient rewarmed to 32

COMPLICATIONS WITH REWARMING SEVERE HYPOTHERMIA:

• pulmonary oedema
• vasodilation leading to shock
• rhabdomyolysis leading to renal failure
• rewarming metabolic acidosis (lactic acidosis)
• intravascular thrombus