which coincidentally teaches some environmental nuggets Are you sitting comfortably There once was a man called Jack Jack was an avid reader One day he was basking in the midday sun reading his Roald Dahl book when he ID: 714588
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Slide1
A Story of an Unfortunate Man
…which coincidentally teaches some environmental nuggetsSlide2
Are you sitting comfortably?
There once was a man called Jack. Jack was an avid reader. One day he was basking in the midday sun, reading his Roald Dahl book, when he
realised
he felt a bit hot…Slide3
Jack Had Hyperthermia.
Luckily a passing nurse found him and took him immediately to Auckland ED. Slide4
Stage 1
H
eat exhaustion
Volume and electrolyte loss as sweat, with inadequate replacement
Still have heat regulatory mechanisms and CNS not affectedSlide5
Stage 2
Heat stroke
Life threatening
M
ortality <10% if treated, approaches 80% if not
T >40 degrees
>42 degrees
uncoupling of oxidative phosphorylation cellular damage, failure of hypothalamic thermostat, inflammatory and
coagulopathic
stuff
Altered LOC (delirium, seizures, coma)
MOF
Not necessarily dehydratedSlide6
Classical heat stroke
Due to high environmental T
Young and
elderly
Hot and dry
Exertional
heat stroke
Due to physical activity
Athletes and military
To
acclimatise
must exercise 60-90mins/day; still takes up to 2/52 and max at 3/12
Hot and sweatyDehydration more commonSlide7
80%
hyperdynamic
(
ie
.
Incr
CO
),
20
%
hypodynamic
(
ie. Distributive / high output shock)
Ataxia occurs early Seizures, esp
during cooling
lactic
acidosis,
resp
alkalosis,
rhabdo
, DIC, electrolyte
disturbance
Organ failure
Prolonged
QTc
, ST changesSlide8
It’s not only the sun…
Jack could have:
Hypethyroidism
, sepsis, DT’s, epilepsy, dermatological problem, spinal injury…
Anticholinergic / serotonin syndrome, malignant hyperthermia, neuroleptic malignant syndromeSlide9
What should Auckland ED do?Slide10
What should Auckland ED do?
A+B: avoid
sux
C: IVF
resus
only if dehydrated
If
rhabdo
: aim UO
50-100ml/
hr
can
use mannitol / frusemide
to increase UOconsider urinary alkalinisation
Beware high output cardiac failure
pul
oedema
If need
pressors
avoid E+NE
Can cause
vasoconstriction and hence prevent heat dissipation
Treat coagulopathy
D: can use sedatives /
paralyse
to decrease shiveringSlide11
Jack was made cool…
Evaporative
Ice water immersion
Ice packs
Cooling blankets
Cooled IV fluids
Gastric lavage etc…Slide12
Jack recovered well…
Except for some residual ataxia (20% have a permanent residual neurological deficit)Slide13
Unfortunately…
The over-enthusiastic doctor was rather rigorous with the cooling…
He was found by a FED who came to offer him a sandwich. Slide14
The SSU nurse did a routine ECG…
Osborn wave
AF with slow ventricular response in 50% with mod hypothermia
Wide QRS
Long QT
No prognostic significanceSlide15Slide16
Jack had Hypothermia.
Mild: <35 degrees
Shivering; ataxia,
dyasthria
, apathy
Incr
HR / RR,
resp
alkalosis, peripheral vasoconstriction
Mod: <32 degrees
Failure of thermogenesis (no shivering,
decr
metabolism)
Initial cold-induced diuresis (don’t trust UO)
Decr
LOC / HR / RR,
resp
acidosis, arrhythmia, stupor
Severe: <28 degrees
Loss of reflexes and voluntary motion, pupil dilatation, rigidity (initially the nurse thought Jack was dead…)
Pul
oedema
, peripheral vasodilation,
rhabdo
, MOF,
haemoconcentration
and intravascular thrombosisSlide17
It’s not only enthusiastic doctors…
Drugs (
eg
. ETOH, sedatives), dermal disease, massive blood / fluid loss, elderly, neonates, hypothyroid / adrenal / glycaemia, neuropathies
…and cold weather / exposureSlide18
35
Mild hypothermia
Mod
hypothermia: shivering stops
AF
and other arrhythmias; 2/3 decr in HR and CO;
Osborn waves
common
Decr RR
/
LOC
Insulin resistance31 Shivering stops (24-35, very variable
)
30
O2
consumption and CO2 production decr by 50%
Incr
myocardial irritability, ectopics; threshold for spontaneous bad
arrhythmidefibrillation
and
antiarrhythmics become
ineffective
Double
intervals between drug doses
29
Pupils dilated
VF may
occur
28
HR
30-
40
Rigidity
BMR
decr by 55-65%; major
acidosis
26
Areflexia
25
Risk of asystole; CO 45% normal Cerebral blood flow 1/3 normal24 Loss of vascular tone and cerebrovascular autoregulation23 Absent corneal and oculocephalic reflex22 Max risk of VF20 HR 2019 EEG flat, appears dead18 AsystoleSlide19
What did Auckland ED do?
Filled out a risk proSlide20
Meanwhile Jack had a cardiac arrest…Slide21
What should Auckland ED do?Slide22
What should Auckland ED do?
Assess breathing and pulse for up to 1min to confirm
A+B: increased risk of gastric stasis
C:
T <30: most drugs /
defib
/ pacing ineffective
until…
T
30-35:
give but double intervals between doses
Can try single shock + initial drugs for VF/VT, but then wait until >30 degrees
Warm IVF resus
(42 degree 5% dextrose at 200ml/hr); will need large volumesOnly pace bradycardia
if persists after warmingSlide23
Pharmacology
Most drug activity temperature dependent
Toxic doses required for effect
Leading to problems when rewarmedMost arrhythmias revert with rewarmingVF treatment controversial
BretyliumSlide24
Jack was made warm…
Rapidly rewarm to 30-34 degrees then slow
Passive rewarming
If mild; give the dude a blanket
Active external
If moderate / not shivering / CV compromise
Bair hugger, heat back etc…
Active internal
If severe
Humidified O2, blood warmer, lavages,
haemodialysis
, ECMOSlide25
Rewarming research in general
Paucity of RCTs
esp
in humans
Volunteer studies predominate, usually in shivering mild
hypothermics
Methodological variations with same Rx
Questionable external validity
Limited clinical trials with small numbers
Many therapies ethically hard to studySlide26
Scoring Systems on Hospital Arrival
The simple approach
Asymptomatic
Symptomatic
Critical
Obviously dead
Modell & Conn 1984 – in ED within 1
hr
of rescue (
paeds
)
Category
Description
GCS
Neurologically Intact (%)
A
Awake – fully orientated
14-15
100
B
Blunted-
rousable
, purposeful to pain
8-13
100
C
Comatose- not
rousable
, abnormal response to pain
6-7
>90
C1
Flexor response to pain
5
>90
C2
Extensor response to pain
4
>90
C3
Flaccid
3
<20
C4
Arrested
3
<20Slide27
Luckily for Jack…
Rapid onset hypothermia and being young has better chance of survival
Here he is pictured with his discharge summary and the SMO On Call (Bernard?)Slide28
As Jack was leaving Auckland ED…
He went to the toilet, washed his hands as his mother had taught him, and was electrocuted by the hand
dryer
(don’t ask me how).
He was found by a patient with a sore toe. Slide29
Jack was frazzled.
How frazzled depends on:
Voltage: high risk if >600V
Household voltage is 240V; lightening is >100 million V
Current type
Household is AC; lightening is DC
Current size
mAmps
; >10mAmp
paralysis +
tetany
Resistance
Bone > fat > tendon > skin > muscle > BV’s > nerve
PathwayVertical = bad for brain; 20% mortalityHorizonal = bad for heart + lungs; 60% mortality; 3x incr risk of VF
If ground current, more severe injury if legs apart
Duration
AC = longer (0.3-2secs) due to
tetany
DC = shorter (
millisecs
) as thrown awaySlide30
AC vs
DC
AC
Deep tissue damage
More likely to need
fasciotomy
/ have
rhabdo
10% severe burns get ARF
Aim UO 1-2ml/kg/
hr
or use Parkland formula
Causes tetany
prolonged apnoea (even after ROSC)Causes VF (may cause
asystole
if high voltage)
DC
Superficial tissue damage (lightening can cause “flashover”)
Severe burns can be caused by high voltage arcs
BUT causes
asystole
Cardiac arrest in 75% direct lightening strike injuries
Lightening strike mortality rate 10-30% (2/3 in 1
st
hour due to
apnoea
/ arrhythmia); good prognosis unless significant 2Y injury
Blast injury (always look for TM rupture, hollow viscera)
Blunt trauma (high risk spinal #)Slide31
Lightening
Look for entry and exit wounds
Do not signify depth
Skin
Cutaneous findings in 90%
Lichtenburg figures (extravasation of blood in subcutaneous tissue)
Look for clothing injury
Keraunoparalysis
Delayed onset transient paralysis + sensory disturbance + peripheral vasoconstriction
Always examine the eyes
Corneal burns, intraocular
haemorrhage
, retinal detachment,
hyphema; late onset cataracts commonAll require opthalmology reviewDilated pupils don’t mean they’re dead
Always examine the ears
50% have TM rupture;
sensorineural
hearing lossSlide32
This is not JackSlide33
What did Auckland ED do?
Filled out a risk proSlide34
Yes, and what else?
Jack seemed alright.
What did Auckland ED do with him?Slide35
To monitor or not to monitor?
Do initial ECG
M
onitoring is NOT indicated if asymptomatic and initial ECG normal
Indications for ECG monitoring (at least 12hrs)
High voltage injury (>1000V)
Abnormal ECG
LOC / seizures
Previous cardiac disease
BurnsSlide36
To admit or not to admit?
Discharge if:
240V or less
Brief
No LOC /
tetany
/ burns
Normal exam and asymptomatic
Normal ECG
Do urine (for myoglobin) and ECG if:
Minor wound /
paraesthesia
Admit if:
>600VAbnormal ECG or examinationHorizontal transmissionSlide37
Jack was OK.
Jack had a normal ECG and examination. He felt great.
Jack was discharged home. Here he is, pictured with his discharge summary (Bernard had finished his shift).Slide38
Jack wandered home.
He took a ferry to
Waiheke
, where he lived with some twits. Guess what happened next… Slide39
No he wasn’t envenomated.
We’re not covering that
cos
we’re not bloody Australian.Slide40
Jack almost drowned.
He was found by a middle aged hippy.
He is
choppered into Auckland ED. The noisy R40 tells us his GCS is 6 and the RTA is 10 minutes. Slide41
From Auerbach: Wilderness Medicine, 5th ed. ( Submersion or near-drowning) Fig 68.4.Slide42
Cardiovascular Effects
Hypotension
Shock, acidosis,
hypovolemia (natriuresis
), autonomic instability
Arrhythmias
Asystole
(55%),
Ventricular tachycardia/fibrillation (29%)
Bradycardia
(16%)
Brugada
Long-QT syndromesSlide43
What should Auckland ED do?Slide44
Wait…
It is the helicopter after all.
Pictured below is the
resus team with Les Galler. Slide45
Drowning Resus
C:
C spine
immobilisation ifHistory
of diving, use of water slide, MVA, signs of injury,
ETOH
A+B:
aggressive respiratory
resus
Intubate if
R
equiring
FiO2 >40-60% to attain PO2 >70Use PSV starting at 10cm, PEEP 5-7.5cm; wean ASAP to prevent barotraumaC N saline IVF resus (but beware pul oedema)
Monitor electrolytesDo 1hr CPR if persistent apnoea and asystoleD Trt seizures; maintain normoG; rewarm if neededSlide46
Ventilation
Most text books will support a trial of NIV if blood pressure and GCS appropriate, however there are no literature to support its use
Start low and titrate up
volume support
Vt
low – 6mls/kg
PEEP 5-10 cm H
2
0 only if PaO
2
< 60 on FiO
2
<0.6Ventilate for 24 hours to allow regeneration of surfactantSlide47
A note on rewarming…
Consider induced hypothermia
If comatose
with spontaneous circulation
D
o
not actively warm to >32-
34
A
im T 32
-34 ASAP and maintain for
12-24hrs
Vanden et al. Part 12: cardiac arrest in special situations: drowning:2010 American Heart AssociationGuidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010;122:Suppl 3:S847-8Guenether U et al.Extended
theraeutic hypothermia for several days during extra-corporeal membrane-oxygenation after drowning and cardiac arrest: two cases of survival with no neurological sequelae. Resuscitation 2009;80:379-81WARNER et al.
Recommendations and consensus brain resuscitation in the drowning victim.
Bierens
JJLM, ed. Handbook on drowning: prevention, rescue and treatment. Berlin: Springer-
Verlag
, 2006:436-9Slide48
Asymptomatic patient
No comorbidities
If at 4 - 6 hours:
CXR, ABG normal
Normal vitals on air
Remain
ASx
= discharge with adviceSlide49
Symptomatic Patient
Consider foreign material in airway (approx. 50% of surf submersions)
Salbutamol /
Ipratoprium nebs for bronchospasm
NG placement on free drainage may improve
ventilatory
distress
High risk for vomiting and gastric content aspiration
Suction +++
Most will require fluid resuscitation secondary to diuresis
Beware hypothermia and traumaSlide50
Does it matter that it was salt water?
Nah, not really
Electrolyte abnormalities are theoretical
Abx if features of infection develop
B
road
spectrum if grossly contaminated
water
A
nti
-pseudomonal if in
spa
Chemical pneumonitis if swimming poolSand pneumonitis if salt waterFram neg, anaerobes, staph, fungi, algae, protozoa, aeromonas if freshwater)Slide51
Which of the following
factors is most relevant in history?
Fresh Water/Salt Water/Polluted water
How many mls/kg does the average submersion injury aspirate ?
How many mls/kg aspirate of salt water causes alteration of
blood volume?
electrolytes?
Orlowski
et al
instilled differing NaCl conc into dog ETT tubes Slide52
Nasty Water
Pollutants
Hydrocarbons (Low viscosity /High Volatility)
Heavy Metals
Particulates
Microorganisms
Gram Negative
Pseudomonas, Aeromonas, Burkholderia, Legionella
Gram Positive
Streptococci and Staphylococci (from mouth)
Fungi
Pseudoallallescheria boydii
Prophylactic treatment not indicated (maybe if raw sewage)Slide53
Other Ineffective Treatments
No head down positioning
No Heimlich maneuver
No diuretics
No prophylactic antibiotics
No steroidsSlide54
What’s the prognosis, doc?
<
5mins to
retrieval = good<10mins to CPR = good<
30mins to spontaneous
breathing = good
<
10% significant neuro deficit; 60-120mins = 50-80% chance of serious neuro
damage
ROSC
before
hospital = good
GCS on arrivalProlonged submersion (>25mins) = badAsystole = badSlide55
Jack was fine.
Here he is being discharged from DCCM. Slide56
Jack got a new job.
He became a fireman.Slide57
I can’t bring myself to say what happened next. Let’s just skip over that part of the story.
PS. I think I’m getting rather attached to Jack.
PPS. This is Jack’s last environmental injury
PPPS. Don’t worry, he survives. Slide58
Jack got burned.
Minor:
Partial thickness <15% (10% in <6yrs / >50yrs)
or
F
ull
thickness <2
%
Moderate
:
Partial thickness 15-25% (10-20% as above) or Full thickness 2-10%Major: Partial thickness >25%
(>20% as above) or Full thickness >10%
Burns
of special areas
(
hand, face, feet, ears, perineum,
crossing
major jts)
Inhalational
/ electrical burns
Circumferential
burns
Complicated
by # / trauma
Burns
in high risk ptSlide59
What’s the admission criteria to the Burn’s Unit?
P
artial
thickness >20% >10% if <10/>50yrs, >15% if
chemical
Full
thickness >5
%
Other
major burn criteria
Slide60
What about depth?
Superficial:
Epidermis only No blisters Red/pink
Painful
Normal CRT
Superficial
partial:
Epidermis
+ papillary dermis Small blisters Red, moist V painful Normal CRT
Superficial deep: Above + reticular dermis May blister Yellow, white, dry
Variable pain
No
blanching/
bleeding
Full:
Epidermis
+ dermis + subC tissue
No
blisters
Pearl
/charred, leathery
Insensate
No
CRT/bleedingSlide61
It’s not just the skin…
Consider blast injury
Consider inhalational injury
Steam can cause lung injury (12-24hrs)What are the hallmarks of airway injury?What are the indications for ETT?
Airway
oedema
can happen rapidly
Consider toxic gasesSlide62
Carbon Monoxide
CO has 240x affinity for
Hb
binds Hb shifts O2-Hb curve to L
Hb
holds on to O2 that is can bind cellular hypoxia
Cherry red skin
but cyanotic
SaO2
falsly
elevated
PaO2 probably OK
CO does not cause metabolic acidosisSlide63
Who should I treat and how?
Indications for HBO
impaired
LOC at any time / any neuro SxCOHb >15
%
persistent
Sx after 100% O2 for
4hrs (headache, weakness, visual disturbance, seizures, decr LOC)
angina
or ECG evidence of
myocardial toxicity
unexplained
metabolic acidosis>55yrsSlide64
What should I consider if there’s a metabolic acidosis?
CyanideSlide65
Cyanide Poisoning
Binds to Fe3
+
in cytochrome oxidase system Inhibits aerobic
metabolism
cellular hypoxia, severe lactic
acidosis
Lactate >10
SaO2 measure falsly high
PaO2 also high
No cyanosis
Cherry red macula, almond odour, headache, altered LOCTreatment is with antidotesNa thiosulphate, hydroxycobalamin (treatment of choice), di-cobalt EDTA (bad SE’s especially if not poisoned), amyl nitriteSlide66
Brooke-Parkland Formula
2
-4ml/kg/% (+ maintenance volume if child)
Titrate to UO 0.5-1ml/kg/hr
1
st
half in 8hrs N saline
2
nd
half in 16hrs N
salineAlways start IVF if >20% TBSASlide67
And don’t forget tetanusSlide68
Jack made a miraculous recovery
With extensive treatment he went from looking like this…Slide69
To this…
Wait…Jack
was now a woman????Slide70
…and they all lived happily ever after